RADIOLOGY- end of year exam

ALARA

"As low as reasonably achievable" concept that any radiation dose that can be lowered without major difficulty, great expense, or inconvenience should be reduced or eliminated. Adopted as a culture and attitude by professionals who work with ionizing radiation to minimize radiation exposure and risks.

Describe the occlusal film technique:

#4 for adults #2 for children -The all white side of the film faces the arch being radiographed -The film is usually placed with the long axis side-to-side, but this is not critical -Position the film as far back into the mouth as possible, allowing 1/4 inch with identification dot to protrude out of mouth. The patient gently bites on it to keep it in place -The exposure times are the same as for a BWX film of comparable film speed -X-ray beam is centered on the area of interest, because of the curved beam, the corners of the film that stick out of the mouth are often not exposed. This conecut is acceptable with no loss of information.

What is the particle concept and wave concept of electromagnetic ionizing radiation?

*Particle concept: bundle of energy or PHOTONS travel as a wave at the speed of light moving through space in a straight line *Wave concept: wave with properties that are WAVELENGTH (distance between crests, measured in angstrom or metric units) and FREQUENCY (number of waves that pass in a certain amt. of time). High frequency=short wavelength=higher energy. Low frequency=long wavelength=less energy and VELOCITY (speed of the wave).

What are some PT w/disabilities you could have and what could you do for them?

*apprehensive- confident, organized, encouraging *vision- clear verbal explanations, avoid "talking behind their back" b/c they can still hear *hearing- interpreter, gestures, written, lip reading *mobility- wheelchair, caretaker *developmental- sedation, caretaker *elderly- xerostomia, stroke, alzheimer's *Radiation therapy- may not be able to take *Pregnancy- technically you can (not for elective) but at UCDH policy is no

Recognize errors caused by incorrect radiographic image receptor handling, apply appropriate corrective action:

-Black image: film exposed to white light, unwrap film only under safelight conditions -Pressure marks, scratches and artifacts: bending or pressure cracked emulsion, forcefully placed receptor into receptor positioner, handle w/ damp fingers or latex gloves w/ powder smudges, static electricity from film pulled out of packet quickly creates while light spark (open in dry environment)

Discuss steps of equipment preparation for PA's and what order you take them in

-Complete infection control -Choose correct size (2) and # of films (14 if PA's only) -Obtain and assemble beam alignment devices -Set exposure factors on x-ray unit ...Take in this order: anteriors, right maxillary and left mandibular premolars then molars, left maxillary and right mandibular premolars and molars

Identify the intraoral film speeds currently available for dental radiographs

-D: less expensive and clearer image so a lot of people don't want to switch, but it has smaller crystals and is a slower film requires more exposure to radiation -E: don't really see it sold much anymore -F: larger crystal, faster film, requires less radiation ...to compensate for grannies of a faster film, kodak developed the t-grain of silver halide, that are flat and oriented with that side to the tube head, rather than round crystals

Explain the difference between deterministic and stochastic effects

-Deterministic: when the severity of tissue change is dependent on the dose, the effect is called deterministic like a sunburn (noschotastic). Schotastic: when biological response is based on probability of occurrence rather than severity of change, when dose of radiation is increased, the "probability" of the scholastic effect (cancer) occurring increases, but not its severity. Genetic mutations is another example.

Differentiate between the direct and indirect theories of biological damage

-Direct theory: cell chemicals break apart by x-ray ionization and it damages large molecules (one third of effects), most of the time it passes through cell with no damage and it can repair minor damage -Indirect theory: radiolysis of water, ionizes water within cell, dissociates into hydrogen and free radicals (when the electron leaves the water molecule and the molecule is out of balance that electron is referred to as a free radical, when they go to find balance again they don't always find balance again, most the time the water molecule goes back to original state when they don't you can end up with toxins like hydrogen peroxide. (two thirds of x-ray effects). Indirect because it wasn't the break of the water molecule that hurt us but the toxin. High likelihood of occurring since we are 80% water. ...Only in extreme massive radiation will entire body tissues be destroyed.

Why is interpretation of radiographic findings enhanced when a patient is present?

-Facilitates a comparison of radiographic findings with a clinical examination. Attempting to determine what a particular finding is from a radiograph alone may be difficult. For example, a clinical examination may reveal the presence of a composite resin restoration, which can mimic decay radiographically.

What are the different types of PT's with a gag reflex? What can you do to help?

-Gagging: the strong involuntary effort to vomit -Psychogenic stimuli: originating in the mind (don't ask, empathize, positive power of suggestion, distraction breathing) -Tactile stimuli: originating from touch (start w/anterior exposures/maxillary molar most likely to elicit response, use one decisive motion/don't slide receptor onto spot on palate, bisecting if its really bad, demonstrate receptor placement by touching your finger in the place first and telling them where it will be positioned) -Gag reflex: retching due to stimulation of the sensitive tissues: soft palate or lateral posterior 1/3 of the tongue ...every effort should be made to limit the amt. of time that the receptor remains in the mouth, when preparations are made before placement time is saved and there is less likelihood of stimulating the gag reflex

What is the occlusal film used for?

-Identify buccolingual location of impacted teeth or other abnormalities (A long list...) -Identify the extent of lesions in a buccolingual direction -Substitute for PA's in children -Image PT's with TRISMUS that have limited mouth opening

List the sequence of events that may follow exposure to radiation

-Latent period: before detectable effects, could be long or short -Period of Injury: certain effects can be observed, stoppage of mitosis is common as well as breaking or clumping chromosomes and formation of giant cells associated with cancer, could include cell death -Recovery period: can take place and more apparent with short term effects, not always recovery-able

What are airspaces seen on radiographs (especially panoramic)?

-Maxillofacial region contains many cavities and sinuses collectively called air spaces. When radiolucent air spaces are pronounced, interpretation of normal radiographic landmarks becomes increasingly difficult. Correct PT positioning within the focal trough of the panoramic machine will help to minimizes the appearance of these air spaces. 1. palatoglossal air space 2. nasopharyngeal air space 3. glossopharyngeal air space

List three conditions that influence the radio sensitivity of a cell.

-Mitotic activity: more susceptible -Metabolism high: more sensitive -Differentiation: immature and less specialized cells (like stem cells) more susceptible

What are local contributing factors to PD that can be seen on a radiograph?

-Overhanging margins of restorations. -Calculus (slightly radipaque and must be significantly calcified to be recorded on radiographs) -Occlusal trauma: has been sown to hinder the body response to the disease, effects on radiograph are: WIDENED PDL (called triangulation)

Describe how to place the receptor in PA's

-Patient must bite down on the bite block as far away from the teeth as possible, utilizing the full extent of the bite block. (exception to this rule is for mandibular pre-molar and molar regions). -Patient must bite down on the bite block firmly enough to hold the image receptor in place. A cotton roll may be placed on the opposite side of the bite block for stabilization and comfort. -Slide the indicator ring all to way down the extension arm getting as close to the patients skin as possible without touching. -The PID must be aligned to the indicator ring as close as possible (further away you'll get blurring) without touching to achieve correct horizontal and vertical angulations and correct point of entry. Exception is maxillary canine, aim for distal contact.

List and describe the 5 sizes of intraoral film:

-Periapical and bitewing film: 2: standard, used for anterior and posterior teeth in adults, Adult PA & BW and child occlusal (w/big enough mouths) 1: used for children and anterior teeth in adults (ideal for narrow areas of oral cavity, only images 1-2 teeth), Adult ant. PA 0: used for small children often called pedo film, Child PA &BW 3: Made it longer for an extra-long BW to try and get more teeth in at one time but the MAIN problem is that the teeth are in different angles from the front to the back and you can't get the angulation right -Occlusal film 4: Used to examine large areas of the maxilla or mandible in adults, almost 4x the size of standard #2 film

What is a post and core build up radiographically?

-Prefabricated and custom-made posts appear radiopaque. Posit is inserted into an endodontically treated tooth and cemented into a pulp chamber; presence of endodontic filler will be observed.

Identify causes of film fog and apply appropriate actions for preventing film fog:

-Radiation fog: not protecting image receptor from stray radiation before or after exposure, store in safe place -White light fog: white light leaking into darkroom, check room for leaks -Safelight fog: safelight will fog film if the bulb wattage is stronger than recommended or is too close over work space, perform quality checks on it -Misc. light fog: from watches, indicator lights on equipment stored in darkroom, cell phone, etc. -Storage fog: from damp/warm conditions and vicinity of fume-producing chemicals -Chemical fog: developing films too long @ too high temp or in contaminated solutions -Aged film fog: emulsion has shelf life, consult date on boxes -Digital radiographic noise: exposure settings that are extremely low, digital sensors esp. sensitive to scatter radiation, so switch to a rectangular rather than round collimation to reduce scatter radiation

List some radiosensitive and radioresistant cells

-Radiosensitive: lymphocytes, blood forming cells (bone marrow), reproductive cells -Radioresistant: bone, muscle, nerves

discuss history of radiation injury

-Remember dr. kells who eventually lost life from putting finger in PT mouth -1st report was months after the discovery of x-rays -1902- first report of skin cancer due to x-rays -Nuclear accidents and bombings increase public fear of radiation -Data used is derived from high doses and high dose rates

What are some unique problems people might have for PA's, their problems and solutions:

-Shallow palate: tilts the film away from the tooth and out of parallel, use cotton rolls below the bite block and above if necessary, increase the angle 5-15 degrees -Maxillary tori: its in the way of the film, place film on the far side of the torus -Mandibular tori: gets in the way of the film and very sensitive, place the film under the tongue, between the tori wrapped in a 2x2 gauze or on the tongue

Explain the difference between short and long-term effects of irradiation

-Short: seen after minutes, days or months when a large dose is delivered in a short time, if large enough ARS (acute radiation syndrome) can happen, includes erythema, nausea, vomiting, diarrhea, etc. (not concent./amt. in dentistry) -Long term: latent period is years, previous acute exposure or chronic low levels of exposure, no unique disease but increase in statistics of other diseases like cancer, embryological effects and genetic mutations

Differentiate between a threshold dose response curve and a non-threshold dose response curve

-Threshold dose response curve: indicates that below the threshold amount of radiation no response is expected. Non-linear: the response is not proportionate to the dose. An increase in dose may result in a larger or smaller increase in the response depending on the location on the dose-response curve. -Non-threshold dose response curve: indicates that any amt. of radiation has a response. We can't be sure if threshold does exist so we adhere to non-threshold in dentistry and ALARA concept where ALARA stands for "As low as reasonably possible. Linear- the response is directly related to the dose. As the dose increases, the response increases proportionately.

Discuss mA:

-amount of electric current/determines # of x-rays generated, typically preset by manufacturer -Impacts density (up or down) -increased mA=increased heat=increased electrons=increased x-rays

Discuss kVp, it is the only factor that directly impacts what?

-controls radiation quality/increases the strength of the beam (x-rays strike heavier, moree concentrated, also, more will get through filter because they are stronger) -ONLY FACTOR THAT DIRECTLY IMPACTS CONTRAST (inverse relationship) -know that increasing kVp means a decrease in TIME is needed

List advantages of mounting film-based radiographs:

-easier to view -able to compare -block out extra light -decrease confusing L/R -avoid damage to emulsion -ability to label -storage/filing -PT education -Transfer info to chart

Identify the three major components of a dental x-ray machine:

-extension arm: suspends tubehead, houses wires, enables tube head to be positioned, folding extension arm that suspend tube head, yoke allows full revolving of tube head, must be returned to position to avoid drifting -tubehead: contains x-ray tube where x-rays are produced, spins all the way around and tips back and up, grounds high-voltage components, prevents overheating (only 1% of x-rays become energy but 99% become heat), lined with lead to absorb non-useful x-rays that do not contribute to the primary beam that exits the PID, also has oil, air or gas to absorb heat -control panel (master switch, exposure buttons: time, kVp, mA, expose...only one Kodak in the school, most are belrays

What are things you can do in extreme cases of gag reflex?

-smaller film supplementation -give PT cup of water to drink -place small amt. of ordinary table salt on tip of tongue -use topical anesthetic spray/make sure they don't inhale it though -LAST RESORT: use extra oral images like pano or lateral jaw images to obtain the information

Compare the three intraoral radiographic examinations:

1. Bitewing examination: examines the crowns of with both maxillary and mandibular at the point they touch (medial, distal), used for detecting carries and crystal bone of people with periodontal disease (because of the almost parallel relationship of the image receptor to the teeth, the bitewing technique could be considered to be a modification of the paralleling technique used for PA's), the bitewing technique for horizontal and vertical is described in ch. 15 2. Periapical examination: peri=around, apex=terminal end of tooth, examines entire tooth (crown and root) and the supporting bone structures, a full mouth series FMX would include 8 BWX and 14 PA's., PA show all the tooth bearing areas of both jaws dentulous and edentulous (with or without teeth), two techniques are paralleling (better of the two and we will take 3 sets of these) and bisecting (only take 1 set) 3. Entire maxillary or mandibular arch, or a portion thereof, on a single radiograph, most often taken w/size 4, sometimes taken in orthodontics to see if palate needs to be expanded or contracted, PT occludes "bites on image receptor", could be considered modification of bisecting technique

What are the three fundamentals of paralleling?

1. Film (receptor) is placed intramurally parallel to the long axis of the tooth (one of main differences from bisecting technique) 2. The central ray of the beam is directed perpendicular to the film and the long axis of the tooth (at a right angle) 3. The XCP is used to keep the film parallel to the tooth

What are five rules of PA's

1. Film must cover teeth to be examined 2. Film must be parallel to long axis of the tooth and set toward the middle of the mouth 3. The central ray must be perpendicular to the film and the long axis of the tooth 4. The central ray must pass through the contacts of the teeth (avoid horizontal overlap) 5. The beam must be centered on the film to avoid cone cuts

What are the two types of x-rays produced? (this is different from electromagnetic and particulate radiation, or ionizing and non ionizing radiation). This is what is happening IN THE X-ray tube

1. General radiation aka bremsstrahlung aka braking: 70% of x-radiation produced, high-speed electrons stop or slow by tungsten atoms at target, closer they strike to nucleus, slower they will become (can strike many times). The first thing that can happen is the electron can hit at nucleus, loose all its energy and produce an x-ray that has equal energy to what it had. The second thing that can happen is that the electron enters but is slowed and bent off course by nucleus, this just has kinetic energy that it looses which is converted into an x-ray. (and electron continues on to interact). 2. characteristic radiation: when high speed electron dislodges a K-shell electron causing ionization, the rearranging of electrons to fill the vacancy makes x-ray photon (only occurs at 70kVp and above)

List 4 tips to placing the XCP

1. Hold onto the arm of the XCP, not the biteblock 2. Hold the bite block on the target tooth then ask the pt. to slowly close (anterior-contact between central, canines and posterior-2nd premolars and 2nd molars) 3. On posterior films be certain the XCP arm is all the way inside the cheek 4. Cotton rolls (anterior on the film side to see incisal and posterior on the opposite side of the film for stability

Identify and explain the functions of the five controls on the control panel:

1. Line switch: on/off switch, when indicator light turns on, it indicates the machine is operational 2. Miliampere selector- mA usually preset, determines the available number of free electrons at the cathode filament and thereby controlling he amount of x-rays produced 3. Kilovoltage selector- kVp, usually preset, determines the speed of the electrons therefore controlling the penetrating ability of the x-rays (stays on 70) 4. Timer- regulates the duration of the interval the current passes through the x-ray tube. Timed in fractions of seconds or impulses (60 impulses=1 second so 1/10 of a second would deliver 6 impulses and so forth), at the school we have to tell it what type of x-ray we are taking and it will set the correct time 5. Exposure button- Activates the x-ray production. A 'dead man' switch, when you stop pressing it stops exposing. However, you must hold it for the entire time set to get a good image. Only touch with one digit ...mA and kVp are preset at the school

What are the 4 possible interactions of radiation with the patient?

1. No interaction: 9% produces densities/makes radiograph 2. photoelectric effect (or photoelectric absorption): 30%, primary x-ray strikes inner shell election, knocks it out (IONIZATION) loses all it's energy and disappears (no scatter radiation) 3. Compton scatter (aka incoherent): 60% primary ray strikes outer shell electron, knocking it out (IONIZATION), the primary x-ray loses some of its energy and continues in a different direction as a scattered x-ray. 4. coherent scatter (unmodified or Thompson): 8%, LOW energy x-ray interacts with outer-shell electron which makes it vibrate briefly, scattered x-ray of SAME energy of primary one is emited going in different direction (no ionization)

What are 4 basic locations of caries?

1. Proximal 2. Occlusal 3. Buccal/Lingual 4. Root (cemental)

What is the procedure for film duplicating?

1. Remove original radiographs from mount and place on glass of duplicator with convex pimple, so contact is tight between it and duplicating film. 2. Under safelight conditions, remove sheet of duplicating film from sleeve. 3. Place film emulsion-side down (notches upper right), on top of original radiographs. 4. Close duplicator cover, set desired exposure time, and depress exposure button. (to make a darker duplicate image decrease exposure time, decreasing and increasing duplication exposure time has the opposite effect on the density of the image than increasing and decreasing x-ray exposure time has on a radiographic film). 5. Process duplicating film in the same time-temperature manner as a radiographic film.

It is our ethical responsibility to take diagnostic radiographs. What are the three characteristics of diagnostic radiographs?

1. Same shape and size as actual anatomy 2. Complete structures and surrounding areas 3. No errors. Correct density, contrast and definition

What are the two occlusal radiographic examinations?

1. Topographical- similar to a PA with bisecting technique, shows a larger area than a PA ...max anterior topographic: maxillary arch is parallel to floor and midsagital plane perpendicular, VA at 65 degrees, most COMMON FILM taken in maxillary arch ...maxillary posterior topographic: center film on the side of interest, long axis front to back, same PT positioning, VA 45 degrees. If PT has hard time opening mouth this can be used to provide reasonable image of the teeth, greatly distorted, but may provide necessary information. ...mand anterior: -55 degrees ....mand posterior: center film on the side of interest, long axis front to back, -45 degrees 2.Cross-sectional: used almost exclusively on mandibular, shows impacted or malposed teeth and calcifications of soft tissues ...mandibular cross-sectional: with head tipped back as much as possible (recline chair), the x-ray beam is at a 90 degree angle to the film (VA of 0 degrees). Bony expansions of the mandible as well as abnormalities or pathology in the floor of the mouth can be imaged with this film.

Identify the factors that determine whether radiation injuries are likely

1. Total dose- the higher the dose, the more severe the effect 2. Dose rate- a high dose given over a short period of time (or all at once) will produce more damage than the same dose received over a longer period of time 3. Amount of tissue irradiated- the more cells that are exposed to radiation, the greater the effects will be 4. Variation in species- Plants, etc. vs. mammals. 5. Individual sensitivity- genetic make-up varies (some people more genetically susceptible) 6. Cell sensitivity- new cells and rapidly dividing cells more sensitive (why we use less radiation on children) 7. Age- Because the cells are dividing more frequently in a growing child, young people are affected more by radiation than are older people

List panoramic equipment

1. Tubehead 2. Collimator (narrow slit- reduces size of the beam and shapes it, in a pano it is slit rather than square or circle like bwxs) 3. Head positioner: chin rest and notched bite block (impt. to get anterior/posterior limits of the trough), forehead rest, lateral head supports 4. Screen film 5. Casette: with intensifying screens

List the five rules for shadow casting:

1. Use the smallest possible focal spot (area on the machine the creates the x-rays) 2. The object (tooth) should be as far as practical from the target (source of radiation)...why an 18 inch PID is better than a 16 inch PID 3. The object (tooth) and the image receptor (film, phosphor plate, or digital sensor) should be as close to each other as possible....when we are doing paralleling as close as possible while still keeping it parallel can be tricky 4. The object (tooth) and the image receptor (film, phosphor plate, or digital sensor) should be parallel to each other. Bisecting periodicals don't follow rule number 4. 5. The radiation (central ray) must strike both the object (tooth) and the image receptor (film, phosphor plate, or digital sensor) at right angles (perpendicularly)...if it hits image receptor at right angle and film is parallel it will also hit teeth at right angle

Describe the 4 components of an intraoral film packet

1. X-ray film- one or two (if they need to take a copy to another doctor) films with an identification dot (helps you know if it was a right or left film) 2. Black wrapper- additional protection from light 3. Lead foil- absorbs scattered radiation that strikes the film emulsion from the back side of the film (side away from the tube), has pattern seen on developed image if film was accidentally placed backwards 4. Outer package wrapping- paper or plastic, resists moisture. Front side faces tube, back side has a tab (or things like manufacture name, film speed, etc.) and faces the tongue

Discuss the steps in x-ray exposure:

1. X-ray machine is plugged into the electrical outlet (usually 110 V). 2. When turned on, current flows into x-ray tube head, activating low-voltage circuit, which heats the filament. 3. Length of exposure selected by timer. 4. When exposure button depressed high voltage circuit is activated to pull electrons from the filament to the target, producing x-rays. 5. The x-rays pass through the filter and collimator before exiting through the PID

List the six steps of the radiograph mounting procedure immediately after processing:

1. label mount w/necessary info: PT full name, date, DDS, radiographers name 2. w/clean hands find the embossed dot, place the film down with the dot UP 3. Sort into anterior, posterior, bite-wings 4. Place in anatomic order (molars on outside, premolars on inside, roots up=for maxilla, roots down=for mandible) 5. Bite-wings, anterior PA's Posterior PA's 6. Check your work ...see pics on Ch. 20 ppt. for mounting BWX and FMX

What are the 7 concerns considered for the best sharpness?

1. small focal spot (too small will burn up) 2. target to film distance (longer PID better, less divergent) 3. object to film distance (film as close to tooth as possible, don't sacrifice parallel to the tooth) 4. motion (PT still) 5. screen thickness (thinner intensifying screens are faster) 6. screen-film contact (keep them close) 7. crystal/pixel size- small enough to be sharp, but large enough to be fast

What are the five rules of shadow casting?

1. small focal spot: reduce penumbra 2. long target to object distance: reduce penumbra 3. short object to image receptor distance: reduce penumbra 4. parallel relationship between object and image receptor: prevents distortion 5. Perpendicular relationship of central ray to object and receptor: prevents distortion

With bisecting technique you should put the front edge of the beam...

1/4'' anterior to the edge of the film

What is a molecule?

2 or more atoms joined by chemical bonds

What percent decalcification has to be there for a carie to be seen on RAD?

40-50% decalcification, a carious lesion is CLINICALLY DEEPER than a RAD shows

What are periodical accesses?

A POORLY DEFINED radiolucency due to a bacterial infection (acute-painful, chronic-asymptomatic). Lamina dura is not seen between the apex and lesion.

What is hypodontia? What teeth are most likely to have this?

A congenitally missing tooth. Or retained deciduous tooth (can be because of a developmental absence of succedaneous teeth). Most often... 1. 3rd molars 2. 2nd premolars 3. maxillary lateral incisors

What is pulpal sclerosis?

A diffuse calcification of the pulp chamber and pulp canals of teeth. Results in a pulp cavity of reduced size (can see canal but not pulp chamber on radiograph). It is associated with aging. It is of little clinical significance unless endodontic therapy is indicated.

What is film duplication and how does it work?

A duplicate radiograph, an identical copy of original is produced with a duplicator and duplicating film (whose emulsion is specially formulated to work with a film duplicator that emits UV light). Duplicating film is available in a variety of sizes. It does come in intra-oral film size but we use pano size. With duplicating film the emulsion is only on one side, put notches on upper right side to get it right. It still has to develop, doesn't matter which side is up for that.

Backscatter ring shield

A leaded acrylic circular ring surrounding the PID of a handheld dental x-ray machine that serves to protect an operator from backscatter radiation when used appropriately

Intensifying screens

A pair of plastic sheets coated with calcium tungsten or rare-earth fluorescent salt crystals positioned inside a cassette, used to expose film-based extra oral radiographs. When exposed to radiation, calcium tungstate and rare-earth screens produce blue and green light, respectively.

Radiation worker

A person who works with or near ionizing radiation or equipment that produces ionizing radiation

retake radiograph

A second radiograph that must be taken after the first image is deemed undiagnostic

What is supraeruption?

A tooth that has erupted out of the socket

What is dens en dente and where does it happen most often?

A tooth within a tooth. Teardrop shape within the pulp, most often in maxillary lateral incisors.

If indicated, bitewings can be taken in the anterior region. If so, how many films would be used and where?

A total of three anterior films would be used: one centered on the midline to show the incisors and one on each side to image the canine regions.

Advocate the use of the lead/lead equivalent thyroid collar and apron.

ADA recommends that a lead apron and thyroid collar be used on all patients. The actual exposure from scatter radiation to other parts of the body is minimal but considering the ease of placing the apron and collar, there is no reason not to use them. PT will appreciate your efforts in keeping their exposure to a minimum. PT's expect it now and trust you when you use it. No thyroid collar is used for PANOS, keep apron hanging or lying flat, NO folding.

Added filtration

Added to the inherent filtration built into a dental x-ray machine, in the form of thin disks of aluminum, inserted between the x-ray tube and the lead collimator when inherent filtration is not sufficient to meet radiation safety requirements.

What are the advantages and limitations of bisecting technique?

Advantages: image receptor placement easier with some PT (kids, etc.), short PID can be easy to manuver and stabilize (8 inch minimizes distortion) Disadvantages: some elongation and foreshortening will occur EVEN when technique is performed correctly, often superimposes adjacent structures (b/c you have to increase vertical angle the zygomatic process can be superimposed over the molar roots in maxillary region), takes skill to estimate location of imaginary bisector, PT rad dose may be increased w/shorter PID

What is the CDC's role (center for disease control) in infection control?

Advisory role-Standard precautions. Expanding potential for transmission of not only blood-borne pathogens, but to include all body fluids (except sweat), of all patients, whether known to be infected or not.

What is the difference between AC and DC currents?

Alternating current alternates between positive and negative and the X-ray machine only works when it's positive. DIrect current flows in only one direction. X-ray machine will produce a more consistent wavelength.

What finger should you use when using the PT finger for retention?

Always hand opposite of the side being irradiated. Thumb- maxillary incisor. Thumb or index finger- maxillary canines. Index finger- maxillary and mandibular posterior.

What is a dilaceration?

An abnormal angulation or bend in the ROOT OR CROWN of the tooth due to a lesion, ortho or maybe another tooth.

What is an abutment vs. a Pontic?

An abutment is the crown that is attached to teeth or implants and the poetics are the floating teeth in between

What is a macrodont?

An enlarged tooth

Ala-tragus line

An imaginary plane or line from the ala of the nose to the triages of the ear. Important in deciding the correct head position for determining angles and points of entry for panoramic radiographic techniques.

Frankfort plane

An imaginary plane or line from the orbital ridge (under the eye) to the acoustic meatus of the ear; an important landmark used to determine correct positioning for a panoramic radiograph.

External aiming device

An indicator ring or rectangle attached to an extension arm used to assist in locating correct angles and points of entry needed to expose intramural radiographs, eliminating the need for precise patient head positioning

What is an electrical circuit? What are the two circuits in an x-ray machine?

An unbroken loop of conductive material that allows electrons to flow continuously. Filament circuit (3-8 V): heats tungsten filament in focusing cup (cathode) to produce electrons High-voltage circuit (50-100 kV): accelerates electrons to the target (anode) and produces x-rays

Crown fractures most often involve which teeth?

Anterior teeth! May involve enamel, dentin, and/or pulp. A dental image permits evaluation of the proximity of the damage to the pulp chamber and for evaluation of the root for any additional fractures.

Describe the who, what, when and where of film viewing, as well as the step by step viewing procedure:

Anyone w/knowledge can interpret but only DDS can make diagnosis, what equipment used is a view box and magnification, view immediately after mounting typically chair side. 1. Check for diagnostic parameters, orient 2. Dim lights, magnification 3. Clockwise, beginning max right to mandibular right then BXW R to L (example on ppt) 4. Check for pathology: presence or absence of teeth, tooth morphology/eruption patterns, suspected pathology, dental materials, caries, periodontal conditions/risks

contact point

Area on a tooth surface that touches an adjacent tooth; the medial surface of one tooth makes contact with the distal surface of the tooth adjacent to it in the dental arch

The film may be angled in the mouth to facilitate anterior placement when using the tabs, how will teeth not be overlapped?

As long as the horizontal angulation is aligned properly, the teeth will not be overlapped.

Discuss the inverse square law:

As the beam goes further it spreads out and becomes less intense. The inverse square law measures the intensity. The distance D2 is 2xs the distance of D1. The X-ray beam covers one square at d1 and 4 squares at D2. The intensity is 1/4 as much as the beam is spread out over 4xs as many squares.

What are some things to remember when setting up an XCP?

Attache bite block to two prongs on the arm, slide the ring into the arm being certain the bite block can be seen directly through the ring. Slide the film into the slot with the dot in the slot. When you lay it out it should look like a staircase. In pt, preparation you use all the same steps except it is not as important to position the head w/maxillary arch parallel to floor and midline perpendicular because the ring is aiming for you. Corner of the silver metal stick needs to point to the noise for it to be in proper orientation.

If someone has recession it is guaranteed they have what?

BONE LOSS

Who determines when and what radiographs are prescribed?

Based on patients needs, ultimately determined by the DDS. Also some guidelines from the ADA.

Binding energy and electrostatic force

Binding energy is determined by the distance between the nucleus and orbiting electron. Basically represents amt. of energy required to overcome the electrostatic force to remove an electron from its orbit. Higher the atomic number (more protons) higher electrostatic force. K strongest/closest to nucleus.

In regards to bone loss, why do hygienists and periodntists prefer the paralleling technique?

Bisecting distorts the crest of the bone

Identify the two intraoral techniques:

Bisecting: or "Short cone" originated from geometric principles known as rule of isometry, theorem states that two triangles having equal angles and a common side are equal triangles, only method used for years but a less complicated was discovered Paralleling: technique of choice because it is more likely to satisfy more of the shadow casing requirements, formerly called right-angled or long cone technique ...more discussed in Ch. 13 and 14

Discuss the number of films for bitewings, PA's and a FMX

Bitewing survey may consist of two to eight radiographs, a full mouth series has a minimum of 4 bitewings and 14 periapical radiographs to make up a full mouth survey in most adult patients: total of 18 films.

Recognize errors caused by incorrect radiographic processing and apply appropriate corrective action:

Blank/clear image: film placed in fixer before in developer, or remained in warm water rinse too long/emulsion disolved Green films: film stick together in developer and solution prevented from reaching green emulsion, separate double film packets and use alternate intake slots -Brown image: insufficient or improper washing, rinse films in circulating water for at least 20 minutes

What is the color code for RinnXCP film holders?

Blue- anteriors Yellow- posteriors Sometimes all white The colors can vary based on brand (state is another brand), but this is the standard. A lot of the problems we get in BWX are taken care of with these placers, as long as you first place the film properly in the center of the mouth. The most important factor is to get the whole apex (root).

What are other names for the tube-shift method of object location? And how does it work?

Buccal-object rule, clarks projection-1909, and SLOB (same lingual, opposite buccal). Most versatile. Takes 2 radiographs (with additional one FP needs to be same but don't care if there are HA errors, just move in direction you need). If image moves mesially when the tube head is moved mesially then the object is located on the lingual. If image moves distally when tube head moves mesially, the object is located on the buccal. The closer the object to be localized is to the reference object (the object you choose to see which direction it moves), the less amount of movement of the image of the object will be in relation to the reference object.

With bisecting (and PAs) it is sometimes difficult to get the film far enough back to cover the third molar region due to gagging or anatomy, and all of the third molar will not be seen on the film. What can be done about this?

By rotating the tube had so that the beam is directed more anteriorly, the third molar is projected on to the film, giving us the needed information (so you basically point the beam at the head from behind the ear). Note, however, the increase in overlap that results.

What are the 4 grades of caries from haugejorden and slack?

C-1 Incipient or Enamel: usually put a "watch" but don't treat, penetrates less than half way through enamel (why more than 1/2 is a 0 when grading BWX) C-2 Moderate: penetrates over halfway through enamel but does not reach DEJ C-3 Advanced: penetrates through the DEJ but less than half way through the dentin C-4 Severe: penetrates over halfway through the dentin

Identify the error codes for grading

CC: cone cut, tubehead HA: horizontal angle, PID VA: vertical angle, PID FP: film placement, film XE: x-ray unit setting PE: processing error O: Other ...use an arrow next to the code to indicate the direction needed for correction

What is the best exam for detection of root caries? What must you have to have rut caries?

CLINICAL exam is best. You must have RECESSION to have root caries. Other things that could contribute include prominent recession/periodontitis and xerostomia due to medications.

What are pulp stones?

Calcifications in the pulp chamber or pulp canals. Round, ovoid, or cylindrical radiopacities. May vary in shape, size and number. Do not cause symptoms and do not require treatment.

What are some other (than calculus) predisposing factors of PD?

Caries, open contacts, restoration overhangs, poor contour of restorations, deficient margins of restorations, impacted teeth.

What can be confused as root caries on x-rays?

Cervical burnout, an area that will look darker, but it is just a concavity or something normal. For example a distal concavity on a posterior tooth that looks radiolucent on the BWX, but it disappears on a PA of the same tooth. With anterior cervical burnout there could be a radiolucency because of the gap between enamel and alveolar bone covering the tooth (the less dense and uncovered cementum will be less opaque).

What is dentinogenesis imperfect?

Characteristically shows bulbous crowns, constriction of tooth at the cementoenamel junction, short roots, and a reduced size of the pulp chamber and root canals.

State what size and how many films and what orientation are reccomended for bitewings for children w/primary dentition, children w/mixed dentition, adults and per involved patients. Which size is not reccommened and why.

Children with primary: size 0, 2 films horizontal (Gets every tooth they have) Children with mixed: size 2, 2 films horizontal Adult posterior: size 2, 4 films horizontal (or 4 vertical if over 30) Perio involved: size 2, 4 vertical Size 3 is NOT REC. because teeth are different angles molars to pre-molars so you will get overlap and they are shorter top to bottom so you won't get as much bone showing.

What is a dentigerous cyst?

Classified as a odontogenic cyst. Forms around the crown of an interrupted tooth. Less common than periodical cyst.

What is a periapical cyst?

Classified as an odontogenic cyst. A well-defined radiolucency. Most common (50-70%) of all odontogenic cysts. Asymptomatic

Extraoral film

Classified as screen film (requires a screen in a cassette with phosphors for exposure and rather than direct exposure to radiation, the film is sensitive to fluorescent light from intensifying screens), larger in size and used from outside of the mouth, the image produced results from exposure to florescent light given off by a screen instead of directly from x-rays. Panoramics are an example. See picture on slide 13.

Discuss collimation and the federally mandated diameter requirement.

Collimators can be round or rectangular (about the size of #2 film) and reduce the production of scatter radiation by controlling the size of the x-ray beam. The shape of the opening determines the shape of the x-ray beam. The size of the opening determines the size of the beam at the end of the PID. Federally, round must be no larger than 2.75 inches in diameter. Rectangular are 1.5 by 2 inches (slightly bigger than #2 film)...less surface area, less beams hitting and probably safer than round.

Discuss equipment preparation and organized order of taking bitewings:

Complete infection control and then choose correct size and number of films. Set exposure factors. You set them up as if you were looking at the patient and go from the patients right to left in picking the films up. We expose Pt right molar then right pre-molar then left pre-molar then left molar. If the patient is gaggy you can do right premolar, left premolar, right molar, then left molar.

What is an odtontomta mixed lucent-opaque (complex vs. compound kind).

Complex: radiolucent lesion with an opaque irregular mass of dental tissues Compound: radiolucent lesion with opaque structures that appear to be small teeth "denticles"

What does the concept of universal precautions as set forth by OSHA state?

Concept of universal precautions states that human blood and all other body fluids, including saliva, are potentially infectious. In healthcare we either need to assume everyone is lying or doesn't know they are infected yet.

Explain how PID shape and length contribute to reducing patient radiation exposure

Conical-no longer used b/c they scattered radiation. PIDs usually come in 8", 12" and 16" lengths. They are open ended and lead lined. The longer PID is preferred due to having the least divergence of the x-ray beam/less scattered radiation. They come in rectangle or square, but a lot of times a square collimator is put in a round PID.

Increase source-object distance...

DECREASE MAGNIFICATION (When the target/source is closer to the object the rays spread out as they pass causing increased magnification)

Decrease object-film distance...

DECREASE magnification

How are buccal/lingual caries diagnosed?

Diagnosed from clinical exam (would check in mouth to see which side rather than slob rule). Well defined circular area that is slightly radiolucent but DEPTH CAN'T be determined on radiograph.

Describe the difference between disinfection and sterilization.

Disinfection: use of chemical or physical procedure to reduce, destroy, or inactivate pathogens, but not all (cannot destroy particularly resistant bacterial spores), too toxic to use on living tissue. Steriliztion: total destruction of ALL pathogens and spores, usually accomplished by steam autoclave or dry heat processes (EPA-registered high-level disinfectants also sterilize?), all critical and semi-critical equipment and instruments should be sterilized

Discuss placing anterior PA's

Do them FIRST because they are more comfortable and cause less gagging, place the film in the XCP vertically, begin on the maxilla and go right to left then continue on the mandible. For maxillary you can use use 4 size 1 films (r. canine, 2 central and l. canine) or 3 size 2 films (r. canine, 1 central, l. canine). For mandibular you can use 3 size one or 2 films (r. canine, 1 central, and l. canine).

What should be the technique of choice when exposing periodical radiographs? What is another name for this technique?

Due to its ability to produce superior diagnostic quality radiographs, the paralleling technique should be the technique of choice when exposing periapical radiographs. Long cone paralleling is another name.

Utilize effective dose equivalent to make radiation exposure comparisons

Effective dose equivalent can be used to compare dental radiation exposures with days of natural background ionizing radiation exposure (8 microseverts per day). Full mouth series is 23.4 microseiverts and thus 2.9 days of naturally occurring background ionizing radiation exposure.

What is the voltage unit?

Electrical force that determines the speed electrons move from a negative pole to a positive one. kV is 1000V. kVp is usually set at 50-100 kVp and controls current passing from cathode to anode.

How do image receptor holding devices help reduce PT radiation?

Eliminates need for PT to hold film in with their finger, reducing unnecessary exposure and stabilizes the film position in the mouth and reduces the change for movement or error on the radiographers part, which will reduce retakes and exposure there.

What is background radiation?

Environmental radiation we are exposed to daily, composed of external and internal sources. Cosmic rays and food. US 150-300 rads or .0015-0.003 Gy per year. The actual dose depends on the degree of exposure to the ionizing radiation sources.

List the basic steps for taking a panoramic film

Equipment setup, patient setup, exposure, developing. -Mount loaded cassette on the cassette holder -Adjust kVp up or down dependent on PT size -adjust hight of chinrest -depress the indicator switch (the fewer times you time out the lights and have to push the indicator button, the better you are doing with your speed and efficiency) -Frankfort plane: Adjust the beam up or down, toggles left and right -Median plane: pt. adjust head left or right while looking in mirror -Focal trough: adjust chin rest forward or backward, roll light up to be on canine -Press reset, then press ready

What is bone loss estimated as/how do you determine bone loss on a RAD?

Estimated as the difference between the physiologic level of bone and the higher of the remaining bone. To determine bone loss on a radiograph, use a probe to measure from the CEJ to the bone. If it is more than 2mm from the CEJ to the bone, there is bone loss.

What is a supernumerary root and what teeth does it occur most often on?

Extra root Most often: 1. Third molars 2. Mandibular premolars 3. Canines

What are supernumerary teeth? Where are there possible locations?

Extra teeth named for location and shape. -Distomolars -Paramolars -Mesiodens (between 2 front teeth)

Screen film

Extraoral dental radiographic film used in conjunction with a cassette and a pair of intensifying screens. Produces and image as a result of exposure to both radiation and green, blue, and violet light that is emitted when radiation strikes intensifying screen phosphors

What are important things to remember about film storage and protection?

Film is negatively affected by heat, cold, humidity and radiation. Keep it in a cool dry place, film also has an expiration date. Also effected by chemical fumes, physical pressure and bending.

What are receptors?

Film, sensors or phosphor plates. Different things that can be exposed to x-rays to obtain the image.

What is fusion and what is the tooth count like when this happens?

Fusion is when two teeth are fused together and you're usually short a tooth when counting.

selection criteria

Guidelines developed by an expert panel of health care professionals to assist in deciding when, what type, and how many radiographs should be prescribed for specific conditions

What does the snap a ray do?

Has alligator jaws to hold the film tightly and makes it more comfy for the PT, but with no support behind the film, the film can flex as the PT closes.

What settings are preferred for caries detection on rads?

High contrast/short scale. Correct HA is a must!

What is the difference between high contrast and low contrast? Short scale vs. long scale?

High contrast/short scale: fewer shades of grey, stark difference between black and white. Better for caries. Low contrast/long scale: many shades of grey. Better for perio.

What type of radiation are x-rays classified as? What are some of it's characteristics?

High energy electromagnetic ionizing radiation. -invisible -straight line, scatter -no mass or charge -causes ionization -fast-speed of light -can penetrate all forms of matter (penetrate, pass through, absorbed) -can produce an image on film -can cause biologic changes in living cells

What type of bone loss is parallel and not parallel to the CEJ?

Horizontal AKA SUPRABONY- parallel Vertical- not parallel ...it is possible for one wall to be horizontal and another vertical

What is abrasion?

Horizontal defect at CEJ from mechanical cause (i.e., improper tooth brushing [a lot more defined/triangular than decay], abrasive toothpaste, pipe smoking, toothpick, opening bobby pins).

What are the radiographic signs of the 4 ADA case types?

I Healthy: alveolar crest 1-2 mm below CEJ and lamina dura (dense cortical bone seen as a radiopaque outline around the tooth) II Mild Periodontitis: crest is 2-3mm apical to CEJ, indicating up to a 15% bone loss, loss of crystal bone density is FIRST RAD INDICATION of PD. Anterior crests will look blunted and posterior will have a fuzzy lamina dura and cupping. III Moderate periodontitis: crest 3-5 mm apical to CEJ of teeth indicating up to a 16-30% bone loss. Anterior- patterns become visible. Posterior- radiolucencies may appear in the furcations of multicoated teeth. IV Severe periodontitis: alveolar crest located greater than 5 mm apical to the CEJ of the teeth indicating up to a 30% or greater bone loss. Anterior and posterior: teeth may show evidence of changes in position.

What is the canine horizontal angulation to consider when bisecting (and PA's)? What is another thing to consider with maxillary canines?

IF you direct the beam perpendicular to the canine, there will normally be overlap between the canine and first premolar. In order to open this contact, the horizontal angulation must be rotated posteriorly to the distal contact. Align the beam parallel with the medial surface of the first premolar . In Pt w/narrow maxillary arch widths its hard to align the film ideally b/c the top edge of the film contacts the palate on the opposite side and doesn't allow enough film to register the apex of the canine. By rotating the film into a diagonal placement, this won't be a problem.

Match the bitewing examination with two ideal uses, what are they named for, and how many are in a series.

Ideal to detect interproximal caries and check the condition of the alveolar bone. They are named for the tab "wing" that pt bites on. A series is 2-8 images or with PA's/Pano.

What is the FDA's role in infection control?

Identifies protective barriers for digital radiographic image receptors.

For anterior bisecting PA, where is the film placed? What about a posterior PA?

Identifying dot is placed at the incisor edge of the teeth. The film should extend 1/4'' beyond the incisal edges of the teeth. For posterior the holder is applied to the back of the film; approximately the gingival margin, providing support for the film and avoiding film bending. The film should extend 1/4'' beyond the incisal edges. The dot still goes to the incisal.

What can film softening cause?

If "softening" the corners or edges, the emulsion of the film will be affected, resulting in black lines.

While 1/4'' of film should extend beyond the incisal edge or occlusal surface during bisecting PA's...

If too much film extends beyond, the roots of the teeth will usually not appear on the film.

What is the imaginary line which bisects the angle formed by the long axis of the tooth and the long axis of the film?

Imaginary bisector, between 2 isometric triangles. The X-ray beam is directed perpendicular to this bisector.

What is one of the most common errors seen in PAs?

Improper film placement. 8-11 mm beyond the height of contour of the second molar is best.

What are the 6 extra-oral two dimensional radiographs? And why do we use them?

In general to examine large areas of the arches and/or skull. Study growth and development of bone and teeth. Detect fractures and evaluate trauma. Detect pathological lesions and diseases. Detect and evaluate impacted teeth. Evaluate temporomandibular disorder. Used by orthodontists, prosthodontists, oral surgeons, etc. 1. Lateral cephalometric projection: growth, trauma disease 2. Posteroanterior projection: growth, trauma, disease 3. Waters projection: maxillary sinus 4. Submentovertex projection: position of condyles, base of skull fractures of zygomatic arch 5. Reverse Towne projection: fractures of condylar neck and ramus area 6. Transcranial projection: superior surface of the condyle and articular eminence

When using the SLOB rule, the direction of the beam must be opposite to the way the tube head is moved (but you go off which way the tube head was moved to whether it is the same or opposite of THAT).

In horizontal tube shift for example, if the tube head is moved mesially, the beam must be directed more distally and vice versa. Like when you move from the incisor image to canine image to premolar and molar the tube head moves distally and the beam is directed more mesially. In vertical tube shift if there is downward movement of the tube head it requires that the beam be directed upward and vice versa. Moving from maxillary PA to the bWx to the mandibular PA the tube head moves down and beam is redirected upward (opposite direction; decreased vertical angulation).

Where are jaw fractures most often observed?

In the mandible. Panoramic is good for seeing this and it will appear as a radiolucent line. Maxillary factors are difficult to detect on dental images.

What is the formula/why do we set the vertical angulation to +10 for bwx.

In the mouth the upper portion of the film is angled approximately +20 and the lower portion is at at 0 degree angle (mandible), the average between these two angles is +10, thus the vertical angulation selected when using bitewing tabs.

What will happen if PT is posterior to focal trough (bite posterior to groove)

Increase in width of front teeth and blurred, more magnification

retake policy

Increasing a PT's rad exposure, retake radiographs require additional consent and may reduce pt confidence in the operator and the practice, a retake policy statement could look like this: "No radiograph should be retaken until a thorough investigation determines the exact cause of the error and the appropriate corrective action is identified and can be implemented."

Compare inherent, added and total filtration:

Inherent is bult in with the glass of x-ray tube, insulating oil, and tube head seal, however those things alone don't meet state and federal standards. Thus added filtration in the form of aluminum disks or samarium is placed between the tube head seal and the PID. Total filtration is what we need to meet by law and is inherent+added. For less than or equal to 70 kVp 1.5 mm aluminum filtration is needed, but with greater than 70 kVp 2.5 mm aluminum filtration is needed. (stronger beam=more filtration needed).

How is handling and darkroom protocol impt. in reducing PT exposure

It helps avoid the need for retakes. Handle film by the edges taking care not to get fingerprints or other artifacts or bends in the film. Don't put the film in the processor until it is up to temperature (when light has stopped blinking) and don't allow any light in the dark room. Process films for the correct amount of time.

What is microdontia and where is it often seen?

It is a small tooth and is often the third molars

What is pulpal obliteration?

It is caused by secondary dentin. There isn't even a pulp canal, like a "biological" root canal.

Discuss what will cause a ghost image error and what ghost images look like

Jewelry, dense bone, glasses, implants, hearing aids, etc. It will produce a real image on the side where the object is located and a "ghost image" on the opposite side that is the same shape, same orientation, but larger and projected higher and very blurred.

Describe the difference between the labial and lingual methods of mounting, which is preferred?

Labial: -preferred method by ADA -raised side of the identification dot is convex -as if you are looking at the patient "shaking hands" with them Lingual: -alternative (obsolete) method -raised side of identification dot is concave -as if you are sitting on the patients tongue or standing behind the patient

Rare-earth phosphors

Lanathanum (La) and gadolinium (Gd) salt crystals used in intensifying screens that fluoresce and emit energy in the form of green light when x-rays are absorbed

How do stainless steel crowns look?

MEtal is less dense and will allow the passage of more x-rays, giving the material a "See-through" appearance

The radiopaque shape of a metal shell in a PFM crown will appear

MORE rounded than a full metal crown

Describe types of film mounts, what a film mount does, and what type is preferred:

Made of cardboard, plastic, or vinyl. They are opaque or clear, opaque is preferred since it helps block out extra light making subtle changes easier to detect. Film mounts hold film to be viewed in an ant atomic order.

Where can recurrent caries occur and what contributes to them?

Margins of existing restorations! -unusual susceptibility to caries, poor oral hygiene, left caries during prep, defective restoration, combination of these things

What are liners, bases and cements?

Materials such as calcium hydroxide and zinc oxide-eugenol are utilized as intermediate restorations, cavity liners, bases, and cements. May not be recorded on the radiograph, but if they do will appear slightly more radiopaque than the surrounding dentin.

What is the head position for bisecting technique?

Maxillary arch is parallel to the floor and midsagittal plane is perpendicular to the floor.

Ghost image

Mirror or second image of an anatomical structure or other object that is penetrated twice by the ed-ray beam observed on a panoramic radiograph.

Discuss radiation monitoring.

Monitor the area to see if there is leakage, it is making it through walls, or if certain areas are dangerously exposed in the workplace. Personnel are monitored, at UCDH you HAVE to wear one if you are pregnant. Wear a radiation monitoring badge at the waist. Required in some states. Just need to know direct ion storage dosimeter: uses miniature ion chamber to absorb radiation; exposure is determined through digital processing. Instant real-time unlimited readouts. Requires onsite reader or connection to the internet.

What is a glass ionomer?

More radiopaque than composite resin due to an addition of a metal alloy. When used as a dental liner or cement, seen as a distinct radiopacity under another restoration.

List guidelines adopted by the ADA for prescribing dental radiographs. Table 6-1

NEW PT (being evaluated for dental disease and dental development): posterior bitewings with a panoramic exam or posterior bitewings with selected PA's, FMX preferred when PT has clinical evidence of generalized dental disease or hist. or extensive dental treatment RECALL PT (with clinical caries or at increased risk for caries): posterior bitewing exam at 6- to 18-month intervals RECALl PT (with no clinical caries and not at risk for carries): posterior bitewing exam 18-36 month intervals for adolescents and 24-36 month intervals for adults RECALL PT (with periodontal disease): use clinical judgement on what to take and how many, imaging may consist of selected BW and/or PA of areas where disease can be identified clinically -PT (for monitoring of growth and development): clinical judgment as to need, maybe take images to monitor dentofacial growth or development in children or PANO or PA for third molar in adolescents PT (with other things like implants, pathology, caries remineralization, etc.): use judgment

What will happen if the arches are tilted too far to one or the other side of the focal trough, head turned laterally.

Narrowing of teeth closer to image receptor (closer to receptor so less magnification) and a magnification or widening of teeth on the side closer to the x-ray tube (further from the image receptor, less magnification).

What are some nonodontogenic cysts?

Nasopalatine cyst: at the incisive canal Globulomaxillary cyst: between maxillary lateral incisor and canine

Ions are electrically unbalanced atoms. What is ionization? What about an ion pair?

Negative ions have an extra electron and positive have one missing. Ionization= the process of converting an atom into an ion, this requires enough force to overcome the binding energy. The ion pair is the result of an electron being removed from an atom (consists of the atom that is now an ion and the electron that was ejected). The pair reacts w/other ions until neutral atoms are formed.

What is radiographic DENSITY used to describe?

OVERALL blackness or darkness of a radiograph. Black areas have maximum density. If it is more dark overall it means more silver halide crystals have been struck. Light areas have little density. THIS IS DIFFERENT FROM THICKNESS (because thick things, which are more dense get white, not dark). If an image is overall too dark it was exposed to more radiation, or longer radiation OR white light.

Discuss amalgam fragments radiographically?

Often found in edentulous area of mandible. Fragments of amalgam appear radiopaque, an amalgam tattoo may result on gingiva.

State indications for use of handled x-ray devices:

Only used when: -conventional wall-mounted x-ray machine is not available -when it isn't practical to move a pt to a conventional x-ray machine Should be manufactured with: -Increased inherent tube head shielding -Additonal shielding around PID -leaded acrylic external backscatter ring

List the pros and cons of long cone paralleling:

PROS: -Accuracy- represents the actual tooth (minimal distortion and superimposition) -Simplicity- easy to learn and use with XCPs and may save time -ALARA- with long cone -Long axis of tooth and recording plane of image receptor can be visually located making it easier to direct x-rays appropriately CONS: -Receptor placement can be tricky, especially with unique individuals (parallel placement of image receptor may be diff. on its with small mouths, kids, low palatal vaults or presence of tori, people with sensitive mucosa or a gag reflex) -Sometimes a long PID can be hard to maneuver and stabilize (but 16" is reccomended for PA paralleling) -Discofort because XPS's can "pinch"

List the pros and cons of panoramic x-rays:

PROS: -lots of information -little time compared to FMX -less radiation -pt co-op easier -more comfortable -easier infection control -easy for pt discussion CONS: -minimal detail/sharpness,overlapping (thus bad for caries and boneless) -Distortion and magnification -Structures can be superimposed -Overuse (use them because they are easy even if they aren't the best option) -Technical requirements (but fit in trough) -Patient anatomy differences (if out just a few mm pano will distort image, and you can't change their anatomy)

What panoramic errors can happen with positioning of lips and tongue in the palatoglossal air space?

PT must swallow and hold the tongue against the palate. If not, the palatoglossal air space will produce a radiolucent band that may cover periodical radiolucencies.

Describe the panoramic image receptors

Panoramic extraoral film requires the use of intensifying screens that transfer x-ray energy into visible light, they "intensify" the effect of x-rays on the image receptor. Smooth cardboard or plastic sheet coated w/ phosphors (minute fluorescent crystals) work in pairs and are on each side of the film that is placed in the cassette.

Explain the roles technique and exposure choices play in preventing unnecessary radiation exposure.

Paralleling should be the technique of choice for periapicals, but we should be aware of the individual patient and if bisecting technique may be quicker and less likely for retakes (if they have a very narrow mouth). Exposure factors: kVp between 60-70 gets a good enough image but not above 90 which exposes unnecessary radiation, mA our machines are pre-set, time settings only go up with people with very heavy bone structure

Explain the roles of communication, working knowledge of quality radiographs and education play in preventing unnecessary radiation exposure.

Patient must understand what they are to do and why to increase compliance. Continuing education hours will help keep radiographers up to date on technology and techniques that will reduce exposure.

What is PPE and its purpose?

Personal protective equipment includes: clothing, masks, eyewear, and gloves and it prevents transmission of infective microbes between oral health care practitioners and patients.

What is the difference between physiology and pathologic (also external vs. internal) resorption?

Physiologic: NORMAL, with roots of primary teeth Pathologic: abnormal alteration of the tooth, can be... -external: periphery of the root surface. Uknown etiology, may be cysts, tumors, infection, occlusion, impacted teeth, reimplanted teeth and ortho -Internal: within the tooth structure, unknown etiology, but can be intimated by trauma, pulp capping, pulpotomy (root canal prep)

What should we do for edentulous areas when taking bitewings?

Place a cotton roll where a tooth is missing. This offers support for the tab. Ensure it is not on the occlusal surface of adjacent teeth before exposing. Without a cotton roll-the tab and film dropped down into the edentulous area, resulting in a tipped film. With the cotton-roll the tab and long axis of the film parallel with the occlusal plane.

What happens with a lead apron shadow?

Place the lead apron low on the pt's back so it is cleared by the x-ray and this issue doesn't happen. If lead apron is in the way a radiopaque shadow on the film overlying a portion of the mandible is seen with NO evidence of teeth or bone seen in this area.

Cone

Pointed cone was replaced by open cylinders to decrease the size of the x-ray beam, older term used to describe the positioning indicating device PID

handheld x-ray device

Portable, battery-operated dental x-ray unit that a radiographer holds in place during exposure

describe the chain of infection

Portal of entry Suceptible host Pathogen Reservoir Portal of Exit Transmission ...and back to portal of entry and around again and again

What does a pre-molar bitewing need to cover? What does a molar bitewing need to cover?

Pre-molar: covers pre-molars, including distal 1/3 of the canines. First molars and a portion of second molars will also be seen. Molar: covers molars including the distal 1/3 of the second premolars (wisdom teeth not required at UCDH, but you may take a supplemental)

Where do you center film for a horizontal premolar bitewing? Where do you center film for a horizontal molar bitewing?

Premolar: center film on the 2nd mandibular pre-molar, all premolars must be fully viewed in the radiograph, the front edge of the film should at least be at the middle of the mandibular canine Molar: center film on the 2nd mandibular molar, 1st and 2nd molars must be viewed fully in the radiograph

Discuss positioning posterior PA's

Premolars first for less gagging, and unlike anterior PA's you place the film in the XCP horizontally. Orientation of the XCP matches for the maxillary right and mandibular left, so do the max r premolars then molars first and then the mandibular l premolars then molars. It also matches for the maxillary left and mandibular right. So second do maxillary left premolars then molars and then the mandibular right premolars then molars.

Describe protocol for infection control in radiography.

Prior to and following procedures clean (disinfectant not effective on surface that hasn't been pre cleaned) AND disinfect equipment and or place barriers. -Prior to: clean, disinfect, and/or cover with a protective barrier all treatment area surfaces likely to come in contact with potential contaminants. For film, to avoid contamination dispense intramural film packets just prior to use in a disposable container. Film packets cannot be sterilized and liquid saturation with disinfectant is not recommended. -During: prepare treatment area and ready the supplies prior to seating the PT, provide PT with antimicrobial mouth rinse, have them remove items that may interfere, drape with lead apron and thyroid collar. During exposures: take care to touch only covered surfaces and touch as few surfaces as possible (push button w/one hand and don't wrap hand around wall), immediately wipe image receptor w/gauze or a paper towel to remove excess saliva. Transfer image receptor holder from a barrier protected surface to the oral cavity and then back to same covered surface. Don't place contaminated instruments on an uncovered surface. -After exposure examination: do not immediately remove the lead aprons and collar while wearing gloves. Perform hand hygiene first! Locate folded black paper tab and grasp it and slowly pull it out allowing the film to drop out, be careful not to touch the film while doing this. Then devolve and sanitize to put films through the machine.

lead/lead equivalent apron

Protective barrier made of lead or lead equivialent materials used to shield a pt from scatter radiation during radiographic exposure

Recognize errors caused by incorrect radiographic techniques and apply appropriate corrective action for errors:

RECEPTOR: -Anterior structures not recorded: move film not as far back in oral cavity -Posterior structures not recorded: receptor placed too far back or PT has a small oral cavity and you need to talk with them about acceptance and work w/ gag reflex -Not recording apical structures: receptor not placed high enough or low enough, ensure PT biting down all the way on tap, tip receptor and positioned toward midline where palatal fault is highest, when placing for mandibular gently massage sublingual area to relax, increase vertical angulation slightly (no more than 15 degrees to get more apex) -Not recording coronal structures: image receptor placed too high or too low, cause often result of excessive vertical angulation, decrease vertical angulation, if correctly directing the central rays of the beam does not record enough coronal structures decrease the vertical angulation slightly, a decrease of no more than 15 degrees will help -Slanting or tilted instead of straight occlusal plane: edge of image receptor not parallel w/occlusal plane, or image receptor positioned biteblock or tab not placed flush against occlusal surfaces, straighten image receptor -Reversed film error (herringbone error): image receptor lim packet positioned so back side faced teeth and radiation source, determine front side of packet prior to placing -Incorrect position of film identification dot: dot positioned toward apical area where it can interfere w/ diagnosis, pay attention and position the dot toward the incised or occlusiual region where it is less likely to interfere w/ interpretation "dot in the slot" PID: -elongation/foreshortening of image (only w/bisecting technique) -overlapped proximal contacts: incorrect rotation of tube head in horizontal plane so beams aren't directed perpendicular through the interproximal spaces (mesiodistal or distomesial overlap), also not positioning image receptor parallel to teeth will prevent rays being directed perpendicular through contacts -Conecut error: central rays not directed toward center of image receptor, beam diameter couldn't completely encircle entire surface area of receptor or incorrectly assembled image receptor positioner or not rotating a rectangular PID so short and long dimensions match, double check to correct all of these EXPOSURE FACTORS: -Light/dark images: reversed film error (look for embossed pattern), exposure factor selection error (insufficient time underexposure and light image, too much time overexposure and dark image), sometimes due to equipment malfunction, place exposure chart near control panel, hold button down until beep is completely done -clear or blank images: failure to turn on power or push button down, no exposure to rays, equip. malfunction, exposed back side of digital or PSP plate receptor -Double image: exposed same film twice, have a systematic way you expose MISC.: -Poor definition: movement of PT or receptor, stabilize tube head, PT and receptor -Artifacts: presence of foreign objects, perform a cursory examination of oral cavity to check for removable appliances, and remove classes, earrings, etc.

What type of caries might you see in a cancer patient?

Radiation caries

What is radiation (dentistry uses) vs. radioactivity? What is ionizing radiation and it's two groups?

Radiation- the emission and movement of energy through space or a substance in the form of waves or particles Radioactivity- the process which certain unstable atoms or elements undergo spontaneous decay while trying to reach a more balanced nuclear state -Ionizing radiation: type of radiation that makes ions by removing or adding an electron to an atom 1. electromagnetic radiation (x and gamma rays): has magnetic and electric fields that are at right angles to each other, moves through space as a particle and in a wave (arranged according to energy/spectrum)...has particulate and wave CONCEPTS 2. particulate radiation (alpha and beta particles)

What is a periapical granuloma?

Radiolucent b/c of chronically inflamed tissue. It appears as a widened PDL space at the apex of a maxillary lateral incisor. Similar to triangulation except triangulation typically doesn't wrap all the way around the tooth like with a periapical granuloma.

What is condensing osteitis and where does it usually occur?

Radiopaque proliferation of periodical bone. Well-defined at apex and associated with a non-vital tooth. Usually it is the mandibular 1st molar.

What is hypercementosis?

Radiopaque, excessive cementum at the tooth making root appear bulbous, but PDL still appears normal.

What is osteosclerosis or sclerotic bone?

Radiopaque, well defined and seen below the apices of vital, non carious teeth. Unknown cause and not attached to the tooth, varies in shape and size. Margins may be smooth or irregular and diffuse. Asymptomatic.

What are the 4 landmarks of the mandibular anterior? (radiopaque, Lucent)

Radiopaque: 1. Genial tubercle: tongue muscles attache here, bony crest at midline of mandible, "doughnut" 2. Mental ridge: lateral surface of mandible, dense bony ridge from pre-molars to symphysis (midline) Radiolucent: 1. Lingual foramen: radiolucent circle in center of genial tubercles 2. Mental fossa: depression just above the mental ridge on facial of mandible, thinner area

What are the 8 radiographic landmarks? (radiopaque and radiolucent)

Radiopaque: 1. Nasal septum: a vertical cartilage wall, divides the nasal fossa into L and R 2. Anterior nasal spine: a V-shaped projection at the midline of the floor of the nasal fossa, triangular shaped radiopacity (or diamond) 3. Inverted Y: the intersection of the lateral wall of the nasal fossa and the anterior-medial wall of the maxillary sinus 4. Soft tissue of the nose: magnified end of the nose (can't always see, depends on PT position) Radiolucent: 5. Median palatine suture: junction of two maxilla palatine processes, extends from 8-9 to the posterior of the hard palate 6. Incisive foramen (aka anterior palatine foramen): round/pear shaped, visible between central incisors apices (palatal) 7. Nasal fossa (AKA nasal cavity): divided by nasal septum, occasionally nasal conchae will impact the opacity 8. Lateral fossa: between maxillary lateral incisor and canine, decreased thickness in the bone

What are the 7 landmarks of the mandibular posterior? (radiopaque, Lucent)

Radiopaque: 1. external oblique ridge: a continuation of the anterior border of the rams, passes down and forward on the buccal side of the mandible (top line) 2. Mylohyoid ridge: crest of bone on lingual surface for muscle attachment (bottom line) 3. Inferior border of the mandible: only if receptor is placed deep in the floor of the mouth 4. Torus mandibularis: a bony benign tumor in varied sizes (looks like a radiopaque circle on mandibular roots) Radiolucent: 1. Mental foramen: located near the apices of the premolars, mimics pathology 2. Submandibular fossa: decreased bone density at the mandibular molar apices 3. Mandibular canal: contains inferior alveolar nerve and vessels, outlined by 2 THIN radiopaque lines

What are the 10 landmarks of the maxillary posterior? (radiopaque and Lucent)

Radiopaque: 1. Sinus wall: floor of it flows around the roots of maxillary molars and premolars 2. (Sinus) Septum: separates maxillary sinus into components (around premolars) 3. Zygomatic process: U shaped band at roots of 1st and 2nd molars (most anterior) 4. Zygoma: wide radiopacity at corner of radiograph (middle) 5. Zygomatic arch: continuation distally of zygoma (most posterior) 6. Maxillary tuberosity: posterior end of maxillary arch distal to the molars (lower than the zygomatic process) 7. Pterygoid plate (of the sphenoid bone): distal to the tuberosity, may be superimposed over the maxilla 8. Hamulus (aka hamular process): an extension of the medial pterygoid plate, may be superimposed over the maxilla 9. Coronoid process (of the mandible): seen in a maxillary image if the mouth is open wide, moving the coronoid down and forward Radiolucent: 10. Maxillary sinus: large air chamber seen in most maxillary PA images

What will happen if PT is anterior to focal trough (bite anterior to bite groove)

Reduction in width and blurring of front teeth, less magnification

What are possible uses of duplicate radiographs?

Referral to specialist accompany a biopsy PT moves or chooses another dentist Consultation with other professionals Third-party payment approval Adding to evidence-based practice through publication, professional study group discussion Legal cases

What is OSHA's role in infection control? (occupational safety and health administration)

Regulatory role. Standards set by them become basis of laws that govern the conduct and practice of oral health care.

T/F some restorations can be differentiated by relative degree of radiopacity, others are better identified by size and contour or by location on a tooth

Restorative materials may appear radiopaque or radiolucent and some are differentiated by relative degree of radiopacity. For example, metal crowns will most often appear to have smooth margins, whereas the margins of amalgam restorations are irregular.

Collimation

Restricton of the useful beam to an appropriate size. Beam diameter used to expose intramural dental radiographs is collimated not to exceed 2.75 inches (7cm) at the skin surface. Collimator= a diaphragm, usually lead, designed to restrict dimensions of the useful beam

What will happen if the frankfort plane (tragus to orbit of eye parallel) is tipped upward, head tipped up?

Reverse smile, squared off mandible, and hard palate superimposed over roots of maxillary teeth.

Parts of the X-ray machine

See paper in radiology folder

latent image

Silver halide crystals contain various levels of stored energy, depending on the density of the objects in the area exposed (enamel is denser and will absorb/stop more rays and thus appears whiter), the stored energy forms a pattern known as the latent image which can't be seen until chemical processing to produce a visible image. This happens because when radiation reaches the crystals they are ionized into silver and bromide and iodide ions that store the energy as a latent image

Discuss how to get film parallel to the tooth in PA's and what shadow-casting rule you may have to break. What do we do to help fight the effects of breaking that shadow-casting rule?

Since the palate curves, the film must be moved toward the middle of the mouth. Moving the film away from the tooth keeps it parallel. This will cause some image magnification and loss of definition because it breaks shadow casting rule of object to receptor distance (Aka tooth to film distance) being as short as possible. However, we use a long cone to decrease magnification and increase target to receptor distance (another shadow-casting rule). The long cone also protects PT from radiation and increases definition.

What is gemination and what happens to the tooth count?

Single tooth germ divides and forms 2 joined teeth. Sometimes extra tooth or just extra pulp.

Identify critical tissues for dental radiography

Skin of face and neck, blood forming tissues in the mandible, thyroid

What are enamel pearls?

Small outgrowths of enamel and dentin in the furcation areas of teeth

How is a full metal gold crown distinguished from amalgam?

Smooth margins

Why is it important to make sure the film clears the palatal gingiva in bitewings?

So as the patient closes, it keeps the film from being pushed down into the mandible. If it is too far in for them to occlude on the tab you can extend it with more sticky tabs. If they have tori in the mandible you will have to go past even that for them to occlude.

Embrasure

Space between the sloping proximal surfaces of the teeth. The space may diverge facially, lingually, occlusal or apically; important to alignment of an intramural image receptor to achieve correct horizontal angulation.

Who sets exposure guidelines/performance standards?

State and federal, all have to follow federal but some states are even stricter than that.

What is the difference between the step-up and step-down transformers?

Step down decreases voltage from the wall 110-220 V to approx 5 V and is in the cathode. The step up transformer increases voltage from the wall 110-220 V to 50-100 kVp

What is an element?

Substances made up of only one type of atom

Dental radiographs, when used to ____________________ a clinical examination, play a key role in the diagnosis, prognosis, management, and evaluation of __________________.

Supplement, periodontal disease. RADS can confirm bone loss and may assist with identifying local periodontal disease-contributing factors not detected clinically. To be of maximum benefit, radiographic images must be correctly exposed and meticulously processed.

Acute radiation syndrome (ARS)

Symptoms of short-term radiation effects after a massive dose of ionizing radiation

T/F In the bisecting PA the buccal roots appear much shorter than the palatal root. In the paralleling PA, the lengths are projected in their proper relationship.

TRUE

T/F: Careful attention to the steps of the bisecting technique can produce acceptable results when needed.

TRUE, but bisecting technique is not often recommended because images produced contain inherent dimensional distortion

What should distances be for the bisecting technique?

Target to film: shorter is better 8 inch PID compensates for film not being parallel to the tooth Object to film: receptor is close to the tooth so it cannot be parallel as well (mandibular posterior can still be parallel, but other areas need the bisecting technique)

Negative shadows

Term given to the radiolucencies produced on a panoramic radiograph as a result of more radiation reaching the image receptor in the areas of air spaces. Negative shadows are shadows of "nothing".

Extension arm

That part of an image receptor positioner the attaches a bite block to an indicator ring.

film speed and what it is determined by

The amount of radiation required to produce a radiograph of acceptable density, the faster the film speed, the less radiation is required to expose the film. Film speed determined by: -size of silver halide crystals (most important factor): larger the crystals, the faster the film speed and less radiation required, however image sharpness is more distinct when the crystals are small

Define maximum permissible dose (MPD) and state the maximum permissible dose (MPD) for radiation workers and for the general public.

The amount of radiation the body can endure with the expectation of no injury (per year). Dose limits are recommended by the nuclear regulating committee and may vary from the state guidelines. Occupationally exposed persons is 5.0 rem/year (50 mSv). Occupationally exposed pregnant women is the same as a non-occupationally exposed person, which is 0.5 rem/year (5mSv).

Tomography

The basic principle of panoramic imaging, where structures located within a selected plane of tissue will be recorded with relative clarity, which structures outside the selected plane will appear less visible. With a pano this selected plane is the focal trough.

What is avulsion?

The complete displacement of a tooth from alveolar bone. The PA will show a socket without a tooth.

maximum permissable dose (MPD)

The dose equivalent of ionizing radiation that, in light of present knowledge, is not expected to cause detectable body damage to average persons at any point during their lifetime

Which way should the identification dot be facing when film is placed inside the mouth?

The dot should be facing outward, not into the oral cavity. It is pointing to the viewer who is standing outside the mouth looking at the teeth.

What considerations do we make when taking bw on individuals with lingual tori.

The film must be placed lingual to the torus. The nursing tabs, it is often helpful to attache another tab to the one attached to the film, this lengthens the portion you hold on to, making it easier to position the film more toward the tongue and lingual to the torus.

Were do root fractures most often occur?

The maxillary central region. Vertical or horizontal, single or multiple. If the x-ray beam is parallel to the fracture, it will appear as a radiolucent line, but if the x-ray beam isn't parallel the fracture may not be apparent at all.

What is the amperes unit?

The number of electrons,unit of quality electric current. A mA is 1/1000 of an ampere, usually set at 4-15mA.

Personnel monitoring

The occasional or routine measuring of the amt. of radiation to which a radiation worker may be exposed during a given period of time

What is a taurodont?

The peculiar feature is the elongated pulp chamber and the more apically positioned furcation (hammer pants tooth).

What is ankylosis?

The tooth is fused to the alveolar bone and the crown is below the occlusal plane. Usually happens with primary teeth and often happens along with hypodontia.

What is the difference between primary radiation and secondary radiation? Scatter radiation?

The useful beam that is produced at the anode target (aka PRIMARY BEAM). Secondary radiation is made when this beam interacts with matter....scatter radiation is a form of secondary radiation from an x-ray that is deflected from its path by the interaction with matter.

What will happen if the patient slumps rather than stands straight up?

The vertebra will be superimposed over the oral structures. It will be a shadow, although faint, you will usually be able to see outlines of the teeth and bone in that area. (unlike lead apron issue)

Discuss how to obtain proper horizontal angulation and what problems may occur with improper horizontal angulation:

The x-rays will pass straight through the contact areas between the teeth if you picture a line on the PID opening being parallel wit ha line connecting to the buccal surfaces of the teeth (if your image receptor is parallel to those teeth it will also be parallel to the PID opening). If the horizontal angulation is off you will get overlap.

Aluminum equivalent

Thickness of a material affording the same degree of attenuation of the primary x-ray beam as aluminum, under specified conditions.

Half Value Layer (HVL)

Thickness of a specified material that, when introduced into the path of a given beam of radiation, reduces the exposure by half. The mm of aluminum it takes to reduce the intensity of the beam by 1/2.

Explain radiation protection measures that can be taken for the operator

Time- get in and get out. We don't stand in the room because we would be exposed multiple times a day, everyday. We must avoid the primary beam and not stand in its path. No holding films! At UCDH we can't treat them but in practice they or a parent can hold it. Stand behind a protective barrier (drywall is adequate protection). But if barriers aren't available, the operator should follow the position and distance rule:Stand at least six feet way from the patient and a 90-135 degree angle from where beam is pointing, as the tube head is moved, this safe position will change relative to the PT's head. Also be aware if there are other people sitting beyond your patient not covered w/protective barrier or drywall.

Why do we use object localization techniques? What are the three basic methods of object localization?

To determine 3-D information based on a 2-D image. PA films can find an object and identify the msiodistal position but can not identify the buccolingual position. 1. Definitive evaluation method: based on shadow casting, not consistently reliable 2. Right-angle method (occlusal projection): primarily identifies buccolingual location, but also may check mesiodistal location. Once you have identified something on the PA film you can take an occlusal film with the beam at a right angle (perpendicular) to the direction of the beam for the PA. 3. Tube-shift method: utilizes two films with different horizontal or vertical angulations. Buccolingual location is identified by the object appearing to move in either the same or opposite direction of the tube head.

T/F composite resin restorations may appear radiolucent

True, it can vary from Lucent to opaque (older restorations may appear radiolucent)

What are units of radiation measurement used to define and what are the two systems to measure them?

Two systems used to measure are systems Internationale (SI, newer) and Traditional or standard (older). 1. exposure: Columbus per kilogram (C/kg) SI and roetgen (R) traditional. Measurment of ionization in air produced by radiation quantity before the radiation enters the body. 2. absorbed dose: Gray (Gy) SI and rad traditional. Measures energy deposited in matter (skin, etc.). 1 Gy= 100 rads, 1 rad=0.01 Gy 3. dose equivalent: Sievert (SV) SI and rentgen equivalent man (rem) traditional. Compares biologic effects of different types of ionizing radiation (electromagnetic and particulate). Each type of radiation has a quality factor (QF). QF of x-rays=1. 1 rem= 0.01 Sv and 1 Sv=100 rems 4. effective dose equivalent: compares risk of radiation exposures that produce a biological response, effects will vary based on area being tested, compensates for the differences in tissue, etc.

What are the limits of RADs when detecting PD?

Two-dimensional image of three dimensional object. Changes in soft tissue not imaged. Cannot distinguish treated vs. untreated disease (Stable periodontium). Actual destruction is more advanced clinically.

What is the umbra vs. penumbra?

Umbra: the image of a tooth COMPLETE shaddow Penumbra: the area around the umbra or PARTIAL shadow (zone of unsharpness along the edge of the image; larger it is/less sharp image will be)

What is distortion? Why does it happen? What are the two shadow casting rules we use to prevent distortion?

Unequal magnification of different parts of the image due to incorrect film placement and beam angulation. 4. place film parallel to object 5. aim beams perpendicular to film and object

What are vertical bwx used for, how old are pt's we take them on at UCDH, what is the difference in technique from horizontal box?

Used for pt w/alveolar bone loss. At UCDH we take them on any pt 30+ years old. The only difference in technique is the film placement (with molars, not pre-molars: center film at the contact between the 1st and 2nd mandibular molars, not on the 2nd mandibular molar). Horizontal and vertical angulation placement of the PID are the same.

Explain fast film reducing PT radiation exposure

Using faster film requires less radiation. F-speed film instead of D-speed film reduces PT exposure by 60%. Digital may reduce it even further.

What will happen if the frankfort plane (tragus to orbit of eye parallel) is tipped downward, head tipped down?

V-shaped mandible, and shortening of mandibular incisors, grinch shaped smile.

What will happen if the vertical angulation is too steep or too shallow?

VA too steep= like sun being high above something (the image will be foreshortened) VA too shallow= elongated

Describe the rotational center during a panoramic radiograph.

We are on an axis as a rotational point, but b/c the head isn't circular the axis moves as the radiograph is being taken.

stochastic effect

When a biological response is based on the probability of occurrence rather than the severity of the change

Discuss digital orientation (in relation to film mounting)

When image is entered in the software it may not have the correct orientation! Direct digital (cord)- chose a template (mount) prior to exposure. Choose the location and expose. The software will place the image in the correct position. Repositioning as needed with drag and drop. Indirect digital: orientation is a combination of traditional film and digital

How is severity of PD best identified?

When measured by clinical attachement loss (CAL). CEJ to base of the pocket. Furcation involvement can also help determine severity.

When are some times when bisecting principle is applied?

When the image receptor is not, or cannot, be placed parallel to the long axes of the teeth. Children, adults with shallow palatal vaults or large torus, when edentulous regions exist.

What is the Mach Band Effect?

When two proximal surfaces overlap, the result is a dense radiopacity outlined by radiolucent lines. These radiolucent lines represent an optical illusion called the mach band effect.

What is concrescence?

When two teeth are joined by cementum

Describe ionization

When x-rays struck matter they can remove electrons from an atom (this knocking off of electrons is ionization), an electrical imbalance is the result, as the body tries to regain balance in the atom it may cause unwanted changes leading to cell damage or destruction

What is radiographic sharpness?

When you can see the smallest detail clearly. Much easier to read, PT movement is typically the reason or the tube head wiggled.

Duplicating film (and explain how duplicating film is different than radiographic film):

When you didn't know you needed another copy and you didn't use a film packet with more than one film in it a duplicating machine with special duplicating film can be used. Good for referrals and submission of insurance claims. Duplicating film is exposed by inferred and UV light rather than by x-rays and only one side has an emulsion. You can tell which side has the emulsion by this: if the notches are on the upper right corner the emulsion is up, or the non-emulsion side will appear shinier and darker than the emulsion side. To make copy: emulsion side of film is placed against the original radiograph with the non-emulsion side up then put it in the machine. Gets darker with less light exposure and lighter with more light exposure. So the longer it is exposed, the lighter the film will be.

What is thermionic emission?

When you turn on the machine electricity flows through filament and it gets hot. The hot filament releases electrons that surround the filament in a cloud. The hotter it gets, the more are released.

When and what radiographs are needed for pediatric patients?

When= after all primary teeth are erupted Primary= #0 or #1 Mixed= #2 2 films total till 2nd molar eruption, then traditional 4 films ...if occlusal needed do with BWX one on each arch, with mixed dentition around age 6 and FMX w/12 images can be considered, panos are good for evaluation of eruption patterns ....use same technique as with adult

What is the focal trough and the three dimensions of it?

Where the arches are positioned for the clearest image. It is a 3-D area and objects outside of the trough are not clear. -Anterior-posterior (front-back) -Lateral (left-right) -Superior-inferior (up-down)

State when x-rays were discovered and by whom

Wilhelm Conrad Roentgen, Nov. 8, 1895. He noticed that crookes tubes and cathode rays made florescent screens near his work glow. "x"-ray name was for the unknown properties of the x-ray. Images could be preserved on photographic plates. 1st ever was his wife's hand.

When are bitewings unnecessary and why is it considered an ethical infection to take them?

With no second or third molars on a certain side, the premolar bitewing is all that is needed on that side, because you can capture all the premolars and the first molar in that one film. With a full denture, no bitewing film is needed. It's an ethical infraction because you didn't keep ALARA.

Radiopaque and radiolucent are relative terms?

Yes, you just compare what is more one than the other. Lucent has no resistance for the beam and opaque resists/absorbs the beam.

What are things to keep in mind when bisecting?

You don't have an external guide, but with practice it can be a beneficial adjunct. All teeth incline slightly toward to the middle of the head; they are not straight up and down.

What do you need to know to list a tooth as impacted on your radiographic evaluation?

You need to know their age, because by 21 years all teeth should be done. If not, their teeth may just be unerrupted.

What would you do for an edentulous PT?

You would still take PA's/pano/occlusal or whatever to look at the bone, but will only take the BWX where there ARE still teeth. -PANO is MOST COMMON way of evaluating the edentulous jaw, PA if pano machine isn't available or you need to follow-up w/area found on pano (or occlusal film) -Edentulous PT might need RADS to: detect presence of root tips, impacted teeth, lesions, objects embedded in bone, establish position of normal anatomic landmarks relative to the crest of the alveolar ridge, check quantity and quality of bone that is present

What are the two types of crowns that look almost exactly the same?

Zirconium (milled from a solid piece of crystal, very strong with good aesthetics) and full metal

paralleling technique

a long cone PID that made the paralleling technique more practical, intraoral radiographic technique that positions an image receptor parallel to the long axes of the teeth and directs the central rays of the x-ray beam perpendicular to both the long axes of the teeth and the image receptor

Direct ion storage (DIS) dosimeter

a personal radiation monitoring device that uses a miniature ion chamber to absorb radiation. exposure is monitored through digital processing

Indicator ring

a ring or rectangle attached to an extension arm of an image receptor positioner used to assist in locating correct angles and points of entry, eliminating the need for precise pt head positioning

What is luxation?

abnormal displacement of teeth. Intrusion is into bone and extrusion is out of the bone.

deterministic effect

also called noschotastic effect, observable adverse biological effects caused by radiation exposure, the severity of change in tissues depends on the radiation dose

lethal dose LD

amount of radiation that is sufficient to cause death of an organism

thyroid collar

an attached or detachable supplemental protective barrier made of lead or lead equivalent materials used to child the thyroid gland from scatter radiation during radiographic exposures

Bitetab

an extension attached at the center of an image receptor that a patient occludes on to stabilize the image receptor during a bitewing exposure

film loop

an image receptor loop holder with a bite tab extension that wraps around an image receptor providing a surface for a patient to occlude on to stabilize the image receptor during a bitewing exposure

Long axis of the tooth

an imaginary line that divides the tooth longitudinally into two equal halves from cusp to root tip

Position indicating device PID

an open ended cyndrilical or rectangular device attached to a dental x-ray machine tube head at the aperture used to direct the useful beam of radiation, available in different lengths

opportunistic screening

anomalies and lesions detected incidentally by a radiographic examination that was prescribed to assess another condition

emulsion

attached to film base on each side by a thin layer of adhesive, composed of gelatin in which crystals of silver halide salts are suspended

Panoramic radiography

became popular in 60's, exposes entire dentition in one picture with surrounding structures, an extra oral radiographic technique used to image the entire dentition and surrounding structures based on the principle of tomography; used to record images of structures within a selected plane of tissue while blurring structures outside the selected plane

vertical bitewing radiograph

bitewing radiograph placed in the oral cavity with the long dimension of the image receptor positioned vertically, records more information in the vertical dimension, especially useful when the area of interest is the periodontium

mitosis

cell division

Silver halide crystals

compounds of a halogen 90-99 percent silver bromide and 1-10 percent silver iodide, they retain the latent image when exposed to x-rays, together gel and crystals are called emulsion

Cone beam computed tomography

delivers less radiation doses (4-15 times that required for a panoramic radiograph) for dental application is purported to become the gold standard of diagnosis for certain dental applications in the future, produces 2 and 3D images, technology based on medical computed tomography (CT) that has been designed specifically for three-dimensional imaging of the oral and maxillofacial regions

Head positioner guides

devices on panoramic and other extra oral dental imaging systems used to stabilize the head in the correct position during exposure

How are the 4 grades of caries diagnosed when the caries are occlusal?

diagnosed from clinical exam Incipient and moderate: not seen on radiograph Advanced: a thin radiolucent line Severe: large cup shaped radiolucency

Superimposition of tooth surfaces can make it...

difficult to definitively identify the type, size, number, and location of restorations. The appearance of a base material may be observed apical to a metallic or composite restoration, or the presence of metallic retention pins may be detected apical to a crown.

sensor

digital imaging systems replace film as the image receptor with a sensor, an image receptor based on charge-coupled device (CCD) or complementary metal oxide semiconductor active pixel sensor (CMOS-APS) technology, containing an electron chip, made up of a grid of x-ray or light-sensitive cells (pixels) that convert x-rays into an electronic signal that is sent to a computer that will produce a radiographic image

occult disease

disease that may exist without signs or symptoms, the present of which is not apparent clinically but detected via a diagnostic test, such as a radiograph

x-ray film

early packets consisted of glass photographic plates wrapped in black paper and rubber, it wasn't until 1919 that the first machine-wrapped dental x-ray film became available, photographic film especially adapted in size, emulsion, speed, and packaging for producing examinations of the oral and maxillofacial regions

somatic effect

effects the individual that was exposed to the radiation, not the offspring

gelatin

evenly suspends millions of microscopic silver halide crystals over the base, it swells and shrinks during processing, swells when placed in liquid exposing silver crystals to chemicals, superheat layer of gel shrinks as it dries and exposes a smooth surface that becomes the radiograph

Define extraoral examinations:

examines a large area of the skull or jaws, like a panoramic, see ch. 17

What are exotoses/tori?

excess bone growth, variation of normal but not disease process

In bisecting what does excessive and inadequate vertical angulation cause?

excessive: foreshortened image (PID is more parallel with the film than bisector), angle x-ray beam forms with bisector is GREATER than 90 degrees inadequate: elongated image (PID is more parallel with long axis of the tooth), angle x-ray beam forms with the bisecting line is less than 90 degrees

What are rampant caries?

extensive and rapidly progressing caries

inherent filtration

filtration built into a dental x-ray machine by the manufacturer, includes the glass wall of the x-ray tube, the insulating materials of the tube head, and the materials that seal the port

What is generalized vs. localized bone loss?

greater than 30% generalized and less localized

What are the film placements for different teeth when bisecting?

incisors: midline canines: on canine premolar: second premolar molar: second molar

radiolysis of water

ionization can dissociate water within a cell into hydrogen and hydroxyl radicals that have the potential to recombine into new chemicals such as hydrogen peroxide, these new chemicals act as toxins, causing cellular dysfunction. Considered an indirect effect of radiation exposure

x-ray

ionizing radiation of minute bundles of pure electromagnetic energy with the ability to penetrate materials and tissues and record shadow images on photographic film, phosphor plates and digital sensors/invisible ray that was so named because x means unknown variable

What are the six things that can effect radiographic contrast?

kVp- inverse realtionsip subject- different tissues scatter radiation- more=lower contrast film/sensor type- inherent/pixel size we can't change exposure- under or over gives poor contrast processing- time and temperature

radiography

making of radiographs by exposing an image receptor, either film or digital sensor to ionizing radiation

With radiographic factors if you change one you....

must change another to maintain correct density. mA, exposure time, kVp

What is attrition?

occlusal wear on teeth

bisecting technique

only one used for many years until they went with paralleling technique, a dental radiograph technique in which the central rays of the x-ray beam are directed perpendicular to an imaginary bisector of the angle formed by the recording plane of the image receptor and the long axes of the teeth

intraoral film

placed inside mouth and used to examine teeth and supporting structures

Film base

plastic, supports emulsion, tinted blue to help provide contrast

What should retention pins not be confused with?

post and core restoration (retention pins are metal pins used to support a restoration).

Electrons are equal to the number of?

protons, most atoms have a neutral charge because these two are balanced

genetic effect

radiation effect that is passed on to future generations

What is the order of the electromagnetic spectrum?

radio (longest), micro, infrared, visible, UV, x-ray, gamma ray

oral radiography

radiographic examinations of the oral and maxillofacial regions/use of x-rays to produce oral radiographs

How does gutta percha appear on a radiograph?

radiopaque

Characteristics of quality radiographic images

receptor placed correctly to record area of interest, qual portion of maxilla and mandible recorded (bitewing), entire tooth plus 2mm beyond incised occlusal edge and apex recorded (PA), occlusal incised plane of teeth parallel to edge of image receptor, occlusal plane straight or slightly curved upward toward posterior (BW), dot positioned toward incisal/occlusal edge (PA), most posterior contact point between adjacent teeth recorded (BW), in full mouth survey, each tooth should be recorded at least once, preferably twice

overlap

refers to a distortion of the tooth image in which the structures of one tooth are superimposed over the structures of the adjacent tooth. Caused by incorrect horizontal angulation of the central beam and/or incorrect positioning of the image receptor in relation to the teeth of interest. See distomesial and mesiodistal overlap.

radioresistant

refers to a substance or tissue not easily injured by ionizing radiation

radiosensitive

refers to substance or tissue that is relatively susceptible to injury by ionizing radiation

What is the EPA's role in infection control?

regulates and classifies chemical disinfectants (like our wipes)

filtration

selectively absorbing or screening out low energy x-rays from the primary beam, usually aluminum, results in a higher-energy and more penetrating useful beam. Unuseful has long-wavelengths without lots of energy and so it doesn't do well in creating an x-ray, it just adds unnecessary radiation, so we filter it out.

Discuss the use of barriers for radiology:

some surfaces may be difficult to clean and prevent effective disinfection and also disinfectants have the potential to affect electrical connections, plastic wrap or barriers are commonly used to cover surfaces most likely to be contaminated, disinfectants have residual activity -Use slap wrap on buttons (disinfectant degrades them) -Barrier tray, buttons, on/off switch included -we don't place barriers with gloves!

What are other names for the tungsten target? Image receptor?

source, focal spot, target film, sensor, phosphor plate (combo of film and digital)

List misc. PANO technique errors

static electricity, failure to remove dentures, failure to remove glasses, pt movement, over-exposure (dark) or under-exposure (light)

roentegenograph

term given to the image wilhelm conrad roentgen produced on photosensitive film in 1895, eventually replaced by the term radiograph

roetgen ray

term given to x-rays by scientists following its discovery by wilhelm conrad roentgen in 1895 after his findings were reported and published, the term was eventually replaced with the term x-ray

panoramic radiograph, and uses/purposes of it

term meaning "wide view" used to describe an extra oral dental radiographic image that records the entire dentition and supporting structures of the maxilla and mandible. Used to supplement BW and PA's. Purposes: -Impacted teeth (wisdom teeth) -Evaluate trauma -Detect disease or lesions (cancer) -Evaluate eruption patterns, growth, development (kids around 8 for erupt. patterns) NOT FOR: caries and bone loss, seen here only if significant but not best for these two, you wouldn't use this for the sole purpose of exposing them

Radiograph

term used today by health professionals, given to a film-based or digital image produced by exposure to x-rays for the purpose assessing, diagnosing, and evaluating a condition or treatment intervention

Central ray

the central portion of the primary beam of radiation

total filtration

the combination of inherent and added filtration. Many state radiation safety regulations require a total filtration of 2.5 mm of aluminum equivalent for dental x-ray machines operating above 70kVp

Discuss time:

the easiest and sometimes only factor we can change, impacts the density up or down -more like more raindrops hitting you because your out in rain longer, not bigger or more raindrops coming down

Discuss selecting size of receptor in the radiographic examination:

the general rule is to use the largest image receptor that can readily be positioned to minimize the number of exposures

oral radiology

the study of x-rays and the techniques used to produce radiographic images

cumulative effect

the theory that radiation-exposed tissues accrue damage and may function at a diminished capacity with each repeated sequence. How much exposure and how often? ...somatic cells recover approx. 75% in 24 hours, genetic cells do not repair themselves

latent period

time between exposure to radiation and the first clinically observable symptoms

Proximal surface

where adjacent teeth contact each other in the arch the medial and distal surfaces are proximal surfaces