radiology final
The sagittal or median plane
A lateral cephalometric takes a picture of what plane?
A visual interrogation
After taking a lateral ceph, what should you do to ensure that all anatomic structures are assessed?
Cephalostat
All cephalometric radiographs, including the lateral view, are made with a ________________________
20 by 25 cm can also be written as 8 by 10 inch
Cephalometric and skull views require at least a _______ by _______cm image receptor
Evaluate the base of the skull and calvaria. Identify the mastoid air cells, clivus, clinoid processes, sella turcica, sphenoid sinuses, and roof of the orbit. In the calvaria, assess vessel grooves, sutures, and diploid space. Look for intracranial calcifications.
Describe step 1 of lateral ceph interrogation
Evaluate the upper and middle face. Identify the orbits, sinuses (frontal, ethmoid, and maxillary), pterygoimaxillary fissures, ptrygoid plates, zygomatic processes of the maxilla, anterior nasal spine, and hard palate (floor of the nose). Evaluate the soft tissues of the upper and middle face, nasal cavity (turbinates), soft palate, and dorsum of the tongue
Describe step 2 of lateral ceph interrogation
Evaluate the lower face. Follow the outline of the mandible: from the condylar and coronoid processes; to the rami, angles, and bodies; finally to the anterior mandible. Evaluate the soft tissue of the lower face.
Describe step 3 of lateral ceph interrogation
Evaluate the cervical spin, airway, and area of the neck. Identify each individual vertebra, confirm that the skull-C1 and C1-C2 articulation are normal, and assess the general alignment of the vertebrae. Assess soft tissues of the neck, hyoid bone, and airway
Describe step 4 of lateral ceph interrogation
Evaluate the alveolar bone and teeth
Describe step 5 of lateral ceph interrogation
Canthomeatal line parallel to receptor
Describe the patient placement for a SMV.
Receptor is parallel to mid sagittal plan
Describe the patient placement for a lateral ceph.
Canthomeatal line 37 degrees with receptor
Describe the patient placement for a waters radiographic projection?
Parallel
In a lateral ceph, the image receptor is placed __________ to the patient's mid sagittal plane
X-ray source and the image receptor (film or digital sensor)
In extraoral radiographic images, the _____________ and the ______________ are outside of the patient's mouth
It is generally accepted that, ideally, the implant should be placed at least 1.5 mm from the adjacent teeth, 3 mm from an adjacent implant, and 2 mm from vital anatomic structures, such as the inferior alveolar canal.
It is generally accepted that, ideally, the implant should be placed at least _____ mm from the adjacent teeth, _____ mm from an adjacent implant, and _____ mm from vital anatomic structures, such as the inferior alveolar canal.
its higher cost, larger radiation dose, and limited accessibility to dentists have restricted its widespread adoption for the purposes of dental implant planning.
MDCT scans have been used to evaluate several maxillofacial conditions. why is it not used for placement of dental implants?
...
On a periapical radiograph, the radiolucency of the normal incisive foramen may be projected over the apex of one central incisor to mimic a periapical radiolucency. The presence of an intact lamina dura around the central incisor in question and a lack of clinical symptoms will indicate absence of periapical disease i didn't know how to turn this into a question but i feel like it could be important..?
Coronal or frontal plane
The Waters, posteroanterior (PA), cephalometric, and reverse Towne projections that a picture of what plane?
10 degree
The canthomeatal line forms approximately a ________ degree angle with the Frankfurt plane
The transverse or horizontal plane
The submentovertex (SMV) projection takes a picture of what plane?
There is a broad range in the dimensions of the sella turcica, with the anteroposterior dimension ranging from 5 to 16 mm and the depth ranging from 4 to 12 mm
There is a broad range in the dimensions of the sella turcica, with the anteroposterior dimension ranging from __ to ___ mm and the depth ranging from __ to __ mm
Lateral ceph
This diagram of the patient placement represents which extraoral projection? Answer options: lateral ceph, SMV, waters
SMV
This diagram of the patient placement represents which extraoral projection? Answer options: lateral ceph, SMV, waters
Waters
This diagram of the patient placement represents which extraoral projection? Answer options: lateral ceph, SMV, waters
Lateral ceph
This resultant image represents which type of extraoral radiograph? Answer choices: lateral ceph, SMV, and waters
SMV
This resultant image represents which type of extraoral radiograph? Answer choices: lateral ceph, SMV, and waters
Waters
This resultant image represents which type of extraoral radiograph? Answer choices: lateral ceph, SMV, and waters This picture is so scary!!
Lateral ceph
This skull view represents which extraoral projection? Answer choices: lateral ceph, SMV, and waters
SMV
This skull view represents which extraoral projection? Answer choices: lateral ceph, SMV, and waters
Waters
This skull view represents which extraoral projection? Answer choices: lateral ceph, SMV, and waters
Take 2 radiographs at right angles to one another
To spatially localize pathology, what do you need to do?
True
True or False: in lateral cephs, SMVs, and water projections should all have their central beams perpendicular to the receptor
Helps to maintain a constant relationship between the skull, the receptor, and the x-ray beam
What is a caphalostat?
The line that connects the superior border of the external auditory canal with the infraorbital rim
What is the Frankfurt plane?
The identification of anatomy
What is the first step in interpreting radiographic images?
Selecting the appropriate projection(s)
What is the first step in obtaining and a radiograph?
The canthomeatal line. It joins the central point of the external auditory canal to the outer canthus of the eye
What is the main anatomic x-ray used in patient positioning during extraoral radiography?
10 to 15 cm and should be maintained constant for sequential radiographs of the same patient
What is the object-to-receptor distance in a cephalometric radiograph?
PA cephalometric projection. It is mainly used for the evaluation of facial asymmetries and assessment of orthographic surgery outcomes involving the patient's midline or mandibular-maxillary relationship
What is the second most common skull radiograph used in dentistry and what is it used for?
5 ft (60 inches) — she repeated this like 3 times during class; the large distance helps to minimize magnification
What is the source-to-object distance in a cephalometric projection?
You can use film or digital receptors
What type of receptors are used for cephalometric projections?
15%
a bifid inferior alveolar canal occurs in about _______% of patients
Cervical burnout is caused by the normal configuration of the teeth, which results in decreased x-ray absorption in the areas in question. Close inspection reveals intact edges of the proximal surfaces. The perception of these radiolucent areas results from contrast with the adjacent, relatively opaque enamel and alveolar bone. Such radiolucencies should be anticipated in almost all teeth and should not be confused with root surface caries, which frequently have a similar appearance
a major radiographic phenomenon is cervical burnout. describe this.
its depiction of the hard tissue structures is inadequate for implant planning
an MRI produces a cross-sectional image of the jaws without ionizing radiation. why are MRIs not used for implant placement and treatment planning?
uniform radiolucent
an implant that fails to osseointegrate will reveal a _________________ _________________ junction between the implant fixture and the surrounding bone
The classification system proposed by Misch et al. is most widely used and describes four categories of bone (D1 to D4) based on the thickness of cortical bone and the density and distribution of trabecular bone
bone quality is an important factor for implant success. current radiologic assessment of bone quality is largely a subjective assessment of of the trabecular architecture. what is the most widely used classification system?
monthly task The dental office should maintain a radiographic exposure chart next to the radiographic unit, preferably adjacent to the x-ray unit control panel where these parameters are selected. The chart should indicate the proper peak kilovoltage (kVp), milliamperes (mA), and exposure times(s) for making radiographs of each region of the oral cavity. These tables help to ensure that all operators use the appropriate exposure factors.
checking exposure charts is a quality improvement procedure. what does this task entail? is this a daily, weekly, monthly, or yearly task?
monthly task check the aprons and collars for signs of cracks. a fluoroscopic examination by a qualified individual can confirm and cracks. cracks can be caused by the folding of the shields when not in use.
checking the protective aprons and collars is a quality improvement procedure. is this a daily, weekly, monthly, or yearly task? what all does this task involve?
objects that lie posterior to the center of rotation and that are intercepted twice by the x-ray beam for double images. this region includes the hyoid bone, epiglottis, and cervical spine, all of which cast images on both the right and left side of the image
describe double images produced by panoramic machines?
some objects are located between the x-ray source and the center of rotation. these objects cast ghost images. on the panoramic image, ghost images appear on the opposite side of its true anatomic location and at a higher level because of the upward inclination of the x-ray beam. the mandibular ramus lies between the x-ray source and the center of rotation and its ghost image is superimposed over the left side of the image. similarly, the ghost image of the left ramus is superimposed over the right side of the image. the hyoid bone and cervical spine also form ghost images when the anterior regions of the jaws are imaged. in addition, metallic accessories, such as earring can form ghost images.
describe ghost images produced by panoramic machines
As described earlier for the lateral and PA cephalometric projections, a systematic approach that ensures interrogation of the complete image and evaluation of all anatomic structures is paramount in the interpretation of the reverse Towne projection
describe how a reverse town radiograph should be interpreted
objects that lie between the center of rotation and the receptor form a real image. within this zone, objects that lie within the focal trough cast relatively sharp images, whereas images of objects located outside of the focal trough are blurred
describe real images produced by panoramic machines
. Its radiographic appearance is caused by the fact that the x-ray beam passes tangentially through many times the thickness of the thin bony wall, which results in its observed attenuation (the eggshell effect)
describe the eggshell effect seen in the lamina dura
the image receptor is positioned parallel to the patient's transverse plane and perpendicular to the midsagittal and coronal planes. to achieve this position, the patient's neck is extended as far back as possible, with the canthomeatal line parallel to the image receptor
describe the image receptor and patient placement for a submentovortex projection display
the image receptor is placed in front of the patient and perpendicular to the midsagittal plane. the patient's head is tilted upwards so that the canthomeatal line forms a 37 degree angle with the image receptor
describe the image receptor and patient placement for a waters projection
The image receptor is placed in front of the patient, perpendicular to the midsagittal plane and parallel to the coronal plane. The patient's head is tilted downward so that the canthomeatal line forms a 30-degree angle with the image receptor. To improve the visualization of the condyles, the patient's mouth is opened so that the condylar heads are located inferior to the articular eminence. When requesting this image to evaluate the condyles, it is necessary to specify "open-mouth reverse Towne"; otherwise a standard Towne view of the occiput may result.
describe the image receptor and patient placement in a reverse town projection
The reverse Towne projection was frequently used to evaluate patients with suspected fractures of the condyle and condylar neck. Today these diagnostic objectives are best achieved by computed tomography.
describe the indications of the reverse towne projection
As described earlier for the lateral and PA cephalometric projections, a systematic approach that ensures interrogation of the complete image and evaluation of all anatomic structures is paramount in the interpretation of the Waters projection.
describe the interpretation of a waters image
the central beam is perpendicular to the image receptor, directed from below the mandible toward the vertex of the skull and centered about 2 cm anterior to a line connecting the right and left condyles
describe the position of the central x-ray beam for a submentovortex projection
the central beam is perpendicular to the image receptor, directed from posterior to anterior, parallel to the patient's midsagittal plane, and centered at the level of the bridge of the nose
describe the position of the central x-ray beam in a PA cephalometric radiograph.
The central beam is perpendicular to the image receptor and parallel to the patient's midsagittal plane; it is centered at the level of the condyles.
describe the position of the central x-ray beam in a reverse town projection
the midsagittal plane should divide the skull image into 2 symmetric halves. the petrous ridge of the temporal bone should be projected below the floor of the maxillary sinus.
describe the resultant image for a waters projection?
the midsagittal plane should divide the resultant image into two symmetric halves. the buccal and lingual cortical plates of the mandible should be projected as uniform opaque lines.
describe the resultant image for an SMV projection
the midsagittal plane should divide the skull into two symmetric halves. the superior border of the petrous ridge should lie in the lower third of the orbit
describe the resultant image of a PA cephalometric radiograph
The midsagittal plane (represented by an imaginary line extending from the middle of the foramen magnum and the posterior arch of the atlas through the middle of the bridge of the nose and the nasal septum) should divide the skull image in two symmetric halves. The petrous ridge of the temporal bone should be superimposed at the inferior part of the occipital bone, and the condylar heads should be projected inferior to the articular eminence.
describe the resultant image of a reverse town projection.
more frequent in black patients, male patients, older patients, patients with high blood pressure, diabetes mellitus, or advanced periodontal disease
describe the situations in which nutrient canals are more common?
The trabeculae in the anterior maxilla are typically thin and numerous, forming a fine, granular, dense pattern, and the marrow spaces are consequently small and relatively numerous. In the posterior maxilla, the trabecular pattern is usually quite similar to the pattern in the anterior maxilla, although the marrow spaces may be slightly larger.
describe the trabeculae pattern in the anterior maxilla versus the trabeculae pattern in the posterior maxilla
this occurs in a panoramic x-ray. three potential locations of of the mandibular canal are shown. the location lie in the same horizontal plane but differ in their buccolingual position. the x-ray beam (dotted lines) is angulated relative to the horizontal plane. apparent locations of the mandibular canals in the resultant image. when lingually positioned (orange), the canal is projected more superiorly than when the canal is located buccally (green).
describe what is going on in this figure
n. Cementum is not usually apparent radiographically because the contrast between it and dentin is so low and the cementum layer is so thin.
does cementum usually appear on radiographs?
enamel = 96% more radiopaque dentin = 75% (similar radiopacity of bone) cementum = 50-60% (does not end up on x-rays)
enamel is _____________% mineral, dentin is ____________ % mineral, and cementum is ____________% mineral
osteometal complex, frontal recess, and sphenoethmoidal recess
evaluation of the paranasal sinuses should include a critical examination of which of the following structures?
yes
for diagnostic tasks, are the radiographic anatomy of teeth displayed on intraoral radiographs adequate to detect and evaluate dental hard tissue abnormalities?
;)
here is the schedule for radiographic quality assurance procedures
since it is composed primarily of collagen, it appears as a radiolucent space between the tooth and the laminar dura/
how does the PDL appear on a radiograph?
it is frequently retruded
how does the condyle frequently appear in individuals with TMJ dysfunction?
he lingual foramen is typically visualized as a single round radiolucent canal with a well-defined opaque border lying in the midline below the level of the apices of the incisors.
how does the lingual foramen appear on periapical radiographs?
radiographs of the region of the mandibular symphysis in infants demonstrate a radiolucent line through the midline of the haw between the images forming deciduous central incisors. this suture usually fuses by the end of the first year of life. if this structure is found in older individuals, it is abnormal and may suggest a fracture or cleft
how does the mandibular symphysis of infants appear on a radiograph?
An oblique line demarcating a region that appears to be covered by a veil of slight radiopacity frequently traverses periapical radiographs of the premolar region
how does the nasiolabial fold appear on the radiograph?
It is only slightly thicker and with the same radiodensity as the trabeculae of cancellous bone in the area.
how does the radiodensity of the lamina dura relate to the radiodensity of the trabeculae of cancellous bone
mineral mass per unit volume
how is bone density formally defined?
The anatomic location is essential in presurgical treatment planning because damage to the neurovascular bundle in the course of implant bed preparation, for example, may lead to excessive bleeding.
how is the lingual foramen an important structure for presurgical treatment?
every week
how often should you clean the processing equipment or the viewboxes?
a dental office should identify one individual to assume the primary responsibility to implement the quality assurance program and to coordinate corrective action when indicated
how should a dental office effectively manage a quality assurance program?
a systematic approach that ensures interrogation of the complete image and evaluation of all anatomic structures is paramount in the interpretation of the SMV projection
how should an SMV projection be interpreted?
perpendicular
how should the central beam be oriented in regards to the midsagittal plane?
parallel
how should the image receptor be positioned in regards to the patient's midsagittal plane?
As a result of the presence of air, the mastoid air cells appear as radiolucent air spaces, and opacification of these air cells often indicates disease.
how should the mastoid air cells of the mastoid process appear on a radiograph? how will they appear in the presence of disease?
To check for light leaks in a darkroom, all lights are turned off; the individual allows his or her vision to accommodate to the dark and checks for light leaks, especially around doors and vents. Light leaks should be marked with chalk or masking tape to facilitate correction. Weather stripping is useful for sealing light leaks under doors. evaluating the darkroom should be done monthly
how should you check for light leaks in your darkroom (room used for processing x-rays_?
it should be viewed as a skull projection first. before any cephalometric analysis. a systematic review of all structures should be followed.
how should you interpret a PA cephalometric projection?
the anteroposterior head position is achieved typically by having patients place the incisal edges of their maxillary and mandibular incisors into a notched positioning device (bite stick). patient's midsagittal plane must be centered within the focal through without any lateral shift in the mandible when making this protrusive movement.
how should you position a patient when taking a pan?
the occlusal plane on the radiograph appears flat or inverted, and the resultant image of the mandible is distorted. the radiopaque shadow of the hard palate is sumperimposed on the roots of the maxillary teeth
if a patient's chin is tipped to high while taking a pan, what will the resulting image look like?
the occlusal plane shows an exaggerated smile line, the teeth become severely overlapped, the symphyseal region of the mandible may be cut off the film, and both mandibular condyles may be projected off the superior edge of film
if a patient's chin is tipped too low while taking a pan, what will the resulting image look like?
In the anterior maxilla, the absolute vertical limitation is the floor of the nasal fossa. However, the vertical dimension of available bone is often limited by residual ridge atrophy, which can lead to the development of a prominent buccal concavity
if you are planning on placing a dental implant in the anterior maxilla, what is the absolute vertical limitation that you need to consider before placing it?
The American Association of Physicists in Medicine (AAPM) report number 175
if you wanted to find a report that showed each procedure involved in acceptance testing in detail, what report would you need to be looking for?
18
in adults, the articular surfaces of the condyle, glenoid fossa, and articular eminence have a corticated border. pathologic conditions often cause a thinning or loss of this normal cortication. however this corticated border is not seen until _______ years of age
every week to 2 weeks
in most offices, how often should processing solutions be changed?
the floor of the maxillary sinus
in the posterior maxilla, what is the vertical boundary to implant placement?
it is a yearly task
inspecting and calibrating the x-ray unit is a quality improvement procedure. is this daily, weekly, monthly, or yearly task?
no, the main disadvantage of panoramic radiography is the lack of fine anatomic detail available on intraoral periapical radiographs thus it is not useful for detecting these issues
is a panoramic image useful for detecting small carious lesions, fine structure of the marginal periodontium, or early periapical disease?
jaw bone density in the anterior mandible is higher, whereas it is lowest in the posterior maxilla.
jaw bone density in the anterior mandible is __________ compared to the posterior maxilla where it is the __________
daily task retake log = all errors for images that must be reexposed are recorded. This process quickly reveals the source of recurring problems and facilitates quick resolution
keeping a retake log is a quality improvement procedure. what is the purpose of this task? is this a daily, weekly, monthly, or yearly task?
96% to 100%
midline lingual foramina are present in _______% to _______% of individuals
5 to 40%
nutrient canals are visible in about _______% to _______% of patients
large
often a _______ incisive foramen may mimic disease
between the roots in and in the region of the middle and apical thirds of the central incisors
on intraoral and panoramic radiographs, where is the incisive foramen usually projected?
an inverted Y
on periapical radiographs of the canine, the floors of the maxillary sinus and nasal cavity are superimposed and seen crossing one another. what does this look like on the radiograph?
gutta percha is radiopaque, but it is lower in radiodensity than amalgam composite restorations are typically partially radiopaque, as are porcelain restorations orthodontic appliances are relatively radiopaque , although less than stainless steel crowns
out of these restorative materials, which ones are not completely radiopaque? silver amalgam gold stainless steel pins calcium hydroxide base gutta percha silver points composite restorations orthodontic appliances
concha bullosa and it is a common variant with a reported frequency of 14% to 53%
pneumatization of the nasal concha is termed _______________ ___________
weekly task The retake record should be reviewed weekly to identify any recurring problems with film processing conditions or operator technique. This information can be used to initiate corrective actions, including staff education
reviewing the retake log is a quality improvement procedure. what does this task entail? is this a daily, weekly, monthly, or yearly task?
The shape of the tooth may create the appearance of a double PDL space. When the x-ray beam is directed so that two convexities of a root surface appear on a film, a double PDL space is seen. A common example of this double PDL space is seen on the buccal and lingual eminences on the mesial surface of mandibular first and second molar roots
sometimes you can have the appearance of a double PDL space on the radiograph. how is that possible? where is a double PDL space commonly seen?
It is usually thinner in the middle of the root and slightly wider near the alveolar crest and root apex
the PDL is usually ______________________ in the middle of the root, and slightly ________________ near the alveolar crest and root apex
alveolar and palatine processes
the ___________________ and ________________________ processes articulate to form the intermaxillar suture between the central incisor
Recommendation 1. Panoramic radiography should be used as the imaging modality of choice in the initial evaluation of the dental implant patient. Recommendation 2. Use intraoral periapical radiography to supplement the preliminary information from panoramic radiography. Recommendation 3. Do not use cross-sectional imaging, including cone beam computed tomography (CBCT), as an initial diagnostic imaging examination. Recommendation 4. The radiographic examination of any potential implant site should include cross-sectional imaging orthogonal to the site of interest. Recommendation 5. CBCT should be considered as the imaging modality of choice for preoperative cross-sectional imaging of potential implant sites. Recommendation 6. CBCT should be considered when clinical conditions indicate a need for augmentation procedures or site development before placement of dental implants: (1) sinus augmentation, (2) block or particulate bone grafting, (3) ramus or symphysis grafting, (4) assessment of impacted teeth in the field of interest, and (5) evaluation of prior traumatic injury. Recommendation 7. CBCT imaging should be considered if bone reconstruction and augmentation procedures (e.g., ridge preservation or bone grafting) have been performed to treat bone volume deficiencies before implant placement. Recommendation 8. In the absence of clinical signs or symptoms, use intraoral periapical radiography for the postoperative assessment of implants. Panoramic radiographs may be indicated for cases requiring more extensive implant therapy. Recommendation 9. Use cross-sectional imaging (particularly CBCT) immediately postoperatively only if the patient presents with implant mobility or altered sensation, especially if the fixture is in the posterior mandible. Recommendation 10. Do not use CBCT imaging for periodic review of clinically asymptomatic implants. Recommendation 11. Cross-sectional imaging, optimally CBCT, should be considered if implant retrieval is anticipated.
the american academy of oral and maxillofacial radiology has 11 recommendations for imaging the the dental implant patient. what are they? this is incredibly long but it was highlighted in the book so i think it would be good to read over
trauma, orbits, and sinonasal disease
the american college of radiology appropriateness criteria considers that a waters projection is not usually appropriate for the evaluation of ____________, __________, and ________________
it is best evaluated on axial and coronal sections on a CBCT scan
the anatomy of the base of the skull is best evaluated on what type of radiograph?
30 to 60 degrees
the angle of the posterior slope of the articular eminence (TMJ) can vary considerably and is typically _____ to _____ degrees to the Frankfurt plan
periapical radiographs of the maxillary central incisors
the anterior nasal spine is frequently demonstrated on what type of radiograph?
1.5 to 2 cm
the anterior nasal spine is located ____ to _____ centimeters above the nasal spine
10
the canthomeatal line forms approximately ________ degree angle with the Frankfurt plane, the line that connects the superior border of the external auditory canal with the infraorbital rim.
describe the position of the central x-ray beam in a waters projection
the central beam is perpendicular to the image receptor and centered in the area of the maxillary sinuses
75%; it is similar to that of bone
the dentin is about ________% mineralized
agger nasi air cells = cause lacrimal bone haller cells = cause pneumatization of the orbital floor
the ethmoid sinuses are divided into the anterior and posterior ethmoidal air cells. Extramural air cells (air cells outside of the ethmoid bone). extramural air cells include what 2 types of cells?
implants
the evaluations of the locations of the incisive foramen and canals is important for what dental procedure?
it is located in the sphenoid body and it transmits the mandibular division of the trigeminal nerve to the infratemporal fossa
the foramen rotundum transmits what cranial nerve?
it transmits the maxillary division of the trigeminal nerve to the pterygopalatine fossa
the foramen rotundum transmits what cranial nerve?
The ideal position of the putative implant is first identified based on the functional and esthetic needs of the patient as well as the state of the remaining dentition.
the ideal position of the putative implant is first identified based on ...?
closest; those that are progressively farther from the center become progressively less clear
the images positioned in the _____________ of the focal through are the clearest
7
the incidence of an accessory mental foramen is _____%
alveolar, palatine, zygomatic, and frontal
the maxilla comprises a pyramidal-shaped body and four processes. what are the 4 processes?
Its three sides are (1) the superior wall forming the floor of the orbit, (2) the anterior wall extending above the premolars, and (3) the posterior wall bulging above the molar teeth and maxillary tuberosity
the maxillary sinus is considered to be a 3 sided pyramid. what are the 3 sides
15 to 18 years
the maxillary sinuses shows considerable variation in size; they change during adult life in response to environmental factors. when do the maxillary sinuses reach mature size?
... :)
the misch classification of bone density i would just glance at the chart
excessive negative angulation
the mylohyoid ridge is more evident on periapical radiographs when the beam is positioned with ....?
cysts The presence of a cyst is presumed if the width of the foramen exceeds 1 cm or if enlargement can be demonstrated on successive radiographs.
the nasopalatine canal is a potential site for what pathology?
the angulation of the x-ray beam relative to the tooth root. when the x-ray beam is directed through a relatively long expanse of the structure, the lamina dura appears radiopaque and well defined. when the beam is directed more obliquely, the lamina dura appears more diffuse and may not be discernible.
the radiographic appearance of the lamina dura is determined by what?
III, IV, V, and VI occulomotor, trochear, trigeminal, and abducens
the superior orbital fissure transmits what cranial nerves?
1. the differing angles at which the x-ray beam is directed for the maxillary central incisors 2. some variability in its anatomic size
there is a wide variation in the appearance of the incisive foramen on periapical radiographs. this is primarily the result of what two 2 things?
axial
this is a CBCT image, what plane is it showing?
you should examine other regions in the jaws, preferably on the contralateral side. compare with previous radiographs of the region in question to determine whether the current appearance represents a change from a prior condition If prior films are unavailable, it is frequently useful to repeat the radiographic examination at a reduced exposure because this may demonstrate the presence of a sparse trabecular pattern that was overexposed and "burned out" in the initial projection In an asymptomatic patient, it may be appropriate to expose another radiograph at a later time to monitor for interval changes.
trabecular sparseness can either be attributed to anatomic variation or disease. when looking at the trabeculae pattern on a radiograph, what should you look at to determine if the pattern is an anatomic variation or disease?
false even though they can be used to predict implant stability, they are not a reliable source for bone density
true or false hounsfield units can be used to predict bone density
true
true or false: periapical images do not provide information on the buccolingual dimension
false it is often calcified with reported frequencies of up to 30%
true or false: the stylohyoid ligament is almost never calcified
false the width of the inferior alveolar canal shows some interpatient variability but is usually constant anterior to the third molar region
true or false: the width of the inferior alveolar canal shows some interpatient variability but is usually constant anterior to the second molar region
The receptor travels upward through the beam at the same speed as objects A through C rotate through the beam. A lead collimator in the shape of a slit located at the x-ray source limits the x-rays to a narrow vertical beam. Another collimator between the objects and the image receptor reduces scattered radiation from the objects to the image receptor. Consider first radiopaque objects A through C. As the disk rotates, their radiographic images are recorded sharply on the receptor that also moves through the beam at the same direction and speed. The spatial relationship of the shadows of these objects correctly represents the relationship of the actual objects. Because the source-receptor distance is constant and the object-receptor distance is the same for each object, all objects are magnified equally. Now consider objects D through F. They are located on the opposite side of the disk, between the x-ray source and the center of rotation of the disk. These objects move in the opposite direction of the receptor, so their shadows are reversed on the receptor. Because these objects are much closer to the x-ray source, their images are greatly magnified
use this image to describe how a panoramic machine works? also it is a super long answer. i'm sorry.
ethmoid, sphenoid, occipital, frontal (paired), and temporal (paired)
what 5 bones form the skull base?
involvement of the pterygoid plates is an essential feature of Le Fort fractures
what anatomical feature must be carefully evaluated when assessing a patient with facial trauma?
1. lower resolution images that do not provide the fine details provided by intraoral radiographs 2. magnification across image is unequal, making linear measurements unreliable 3. image is superimposition of real, double, and ghost images and requires careful visualization to decipher anatomic and pathological details 4. requires accurate patient positioning to avoid positioning errors and artifacts 5. difficult to image both jaws when patient has severe maxillomandibular discrepancy
what are 5 disadvantages of panoramic images?
1. superior orbital fissure 2. foramen rotundum 3. foramen ovale 4. foramen spinosum
what are 5 key communications that occur between the middle cranial fossa and the extracranial space
1. broad coverage of facial bones and teeth 2. low radiation dose 3. ease of panoramic radiograph technique 4. can be used in patients with trismus or in patients who cannot tolerate intraoral radiopgraphy 5. quick and convenient radiographic technique 6. useful visual aid in patient education and case presentation
what are 6 advantages of panoramic imaging compared with a full mouth examination?
1. overall evaluation of dentition 2. examine for intraosseous pathology such as cysts, tumors or infections 3. gross evaluation of temporomandibular joints 4. evaluation of position of impacted teeth 5. evaluation of eruption of permanent dentition 6. dentomaxillofacial trauma 7. development of disturbances of maxillofacial skeleton
what are 7 indications of panoramic imaging? (the book uses the word indications, but i honestly don't know what they mean by this)
two commonly used analyses that employ the skeletal, dental, and soft tissue landmarks
what are Steiner and Ricketts analyses?
panoramic images are most useful for diagnostic challenges requiring broad coverage of the jaws Common clinical applications include evaluation of trauma including jaw fractures, location of third molars, extensive dental or osseous disease, known or suspected large lesions, tooth development and eruption (especially in the mixed dentition), impacted or unerupted teeth and root remnants (in edentulous patients), temporomandibular joint (TMJ) pain, and developmental anomalies.
what are panoramic images most useful for clinically? what are some common clinical applications of panoramic images?
inadequate anesthesia or surgical complications, for example, from implant placement
what are patients with bifid canals are at a greater risk for?
replenish processing solutions, check temperature of processing solutions, and compare film radiographs with reference films
what are some daily quality assurance tasks for film-based radiography?
along with all other forms of ionizing radiation based imaging, you want to limit radiation exposure as much as possible. the use of CBCT should follow responsible judicious image acquisition protocols and the anatomic field of view should be limited to the region of interest. To produce a diagnostically acceptable study using the least amount of ionizing radiation, the exposure parameters should be tailored to the patient's age, size, and anatomy, and efforts should be made during image acquisition to minimize motion
what are some important things to consider if you are using CBCT for implant placement?
major limitations of panoramic imaging are image distortion and superimposition of ghost images. The degree of distortion is unpredictable—it depends on patient positioning and approximation of the patient's jaws within the standardized curvature of the focal trough.
what are some of the downsides of panoramic imaging?
The major advantages of intraoral radiography are its relatively low cost and near-negligible radiation risk; widespread availability in dental offices; excellent spatial resolution; and, in the case of solid-state-based digital systems, the possibility of instantaneous image generation However, intraoral imaging is limited by its relatively narrow anatomic coverage and the inability to provide accurate three-dimensional analyses. Superimposition of contiguous structures makes it impractical to analyze the thickness of the buccal and lingual cortical plates and may obscure accurate visualization of crucial anatomic structures such as the inferior alveolar canal. Moreover, periapical imaging is subject to geometric distortion and magnification arising from elongation or foreshortening, which limits its use for linear measurements—a crucial objective of preoperative imaging for implant planning
what are some of the major advantages of intraoral radiography? disadvantages?
nasopharynx, oropharynx, and hypopharynx
what are the 3 zones of the pharynx?
they are bony protuberances. they attach the genioglossus muscles (at the superior tubercles) and the geniohyoid muscles (at the inferior tubercles)
what are the genial tubercles?
the frontal sinuses; they start at approximately 6 to 7 years of age
what are the last paranasal sinuses to develop?
The most reliable indicators of implant success are clinical stability and radiographic evidence of bone adjacent to the implant body.
what are the most reliable indicators of implant success?
The kVp of the beam should be measured to ensure accuracy and reproducibility. Measurement of kVp requires specialized equipment. Measurements should be made across the full spectrum of kVp values used for that unit, with an acceptable variation of 10% or less.
what are the parameters for testing beam energy during acceptance testing?
The HVL of the beam should be measured to ensure that the beam meets regulatory requirements. This is done using a dosimeter and aluminum sheets of specific thickness. requirements are listed by the FDA
what are the parameters for testing beam half-value later (HVL) during acceptance testing?
The field diameter for dental intraoral x-ray machines should be no greater than 2.75 inches (7 cm). The tip of the position-indicating device (PID), or aiming cylinder, should be closely aligned with the x-ray beam.
what are the parameters for testing collimation and beam alignment during acceptance testing?
Measure the size of the focal spot because it may become enlarged with excessive heat buildup within an x-ray machine. An enlarged focal spot contributes to geometric fuzziness in the resultant image. A specialized piece of equipment is required for this test.
what are the parameters for testing focal spot size during acceptance testing?
a high-sensitivity radiation detector should be used to detect leakage radiation from the tube house. no leakage radiation should be detected.
what are the parameters for testing leakage radiation during acceptance testing?
mA: The linearity of the mA control should be verified if two or more mA settings are available on the machine. Typically, an exposure using the usual adult bite-wing setting is made. The mA are then reduced to the next lower value, and the exposure time is increased to yield the same mAs (product of the mA and exposure time in seconds). Example: A machine has 10-mA and 15-mA settings, and 15 mA and 0.4 seconds are used for adult bite-wings First test exposure setting: 15 mA and 0.4 seconds (= 6 mAs) Second test exposure setting: 10 mA and 0.6 seconds (= 6 mAs) A discrepancy implies nonlinearity in the mA control or a fault in the timer. This variation should not exceed 10%.
what are the parameters for testing the mA during the acceptance testing?
Electrical pulse counters count the number of pulses generated by an x-ray machine during a preset time interval. The timer should be accurate and reproducible. Deviation should not exceed 10% for timer settings greater than 10 ms.
what are the parameters for testing the timer during acceptance testing?
The tube head should be stable when placed around the patient's head, and it should not drift during the exposure. When the tube head is unstable, service is necessary to adjust the suspension mechanism. The drift should be 0.5 cm or less.
what are the parameters for testing tube head stability during acceptance testing?
a radiation dosimeter should be used to evaluate the reproducibility of radiation output. Make at least three measurements and calculate the coefficient of variation (COV = standard deviation divided by mean). The COV should not exceed 5%.
what are the parameters for testing x-ray output during acceptance testing?
the incisive canals or foramina of stensen
what are the to lateral canals that are located in the incisive foramen?
the frontal bones (laterally), the cribriform plate and crista galli of the ethmoid bone (medially), and the lesser wing of the sphenoid bone (posteriorly) this structure is visualized on coronal and sagittal sections
what bones form the anterior cranial base?
patient images: make sure it is a patients radiograph that has been properly exposed and processed with the exact time temperature technique radiographs of a standard test object: This is the most accurate and rigorous method of testing film processing solutions but requires additional equipment and more time to perform. An aluminum step wedge serves as a test object that provides a consistent range of gray shades. A step wedge can be fabricated using few overlapping sheets of lead foils, staggered to create "steps" with multiple thicknesses of lead. The step wedge is placed on the film and exposed to make the reference image.
what could you use as a reference film?
a bony lesion
what do inexperienced clinicians often confuse the submandibular gland fossa with
they are thick horizontal bony projections that form the anterior 3/4th of the hard palate and the floor of the nasal cavity
what do the palatine processes form?
SMV display the base of the skull, the zygomatic arches, and the sphenoid sinuses. these radiographs can demonstrate osseous changes from skull base tumors, fractures of the zygomatic arches, and the integrity and aeration of the sphenoid sinuses
what does a submentovertex (base) projection display?
The Waters projection, also referred to as the occipitomental projection, displays the paranasal sinuses, predominantly the maxillary sinus and to a lesser extent the frontal sinus and ethmoid air cells. It also demonstrates the midfacial bones and orbits. A Waters projection was used to evaluate maxillary sinusitis and midfacial fractures
what does a waters projection display?
because it is the most dense naturally occurring substance in the body. because it is about 96% mineral, it causes the greatest attenuation of the x-ray photons.
what does the enamel "cap" on teeth appears more radiopaque than other tissues?
it may be mistaken for periapical disease involving the incisors
what does the mental fossa commonly be mistaken for?
a vital pulp
what does the presence on an intact lamina dura around the apex of a tooth strongly suggest?
The superior foramen contains a neurovascular bundle from the lingual arteries and nerve the inferior foramen is supplied from the sublingual or submental arteries and from the mylohyoid nerve.
what does the superior lingual foramen contain? what does the inferior lingual foramen contain?
the successful transfer of the virtual plan to the surgical suite
what does the ultimate success of an implant procedure depend on?
the body and greater wings of the sphenoid bone and the petrous and squamous portions of the temporal bones
what forms the middle cranial base of the skull?
it results in a radiograph showing right and left sides that are unequally magnified in the horizontal dimension. Poor midline positioning is a common error, causing horizontal distortion in the posterior regions; excessive tooth overlap in the premolar regions; and occasionally, nondiagnostic, clinically unacceptable images.
what happens if you do not align a patient's midsagittal plane when taking a pan?
reduced mesiodistal dimensions ("thin teeth")
what happens if you position a patient too far anterior when taking a pan?
it results in a magnified mesiodistal dimensions ("fat teeth")
what happens if you position a patient too far posterior when taking a pan?
hypoplasia
what is a common normal variant that is seen in the frontal sinuses?
the inferior alveolar canal
what is a limitation to implant placement in the posterior mandible?
a series of procedures designed to ensure optimal and consistent operation of each component of the imaging chain
what is a quality assurance program in radiology?
A simple method for evaluating the degree of horizontal distortion of the image is to compare the apparent mesiodistal width of the mandibular first molars bilaterally
what is a simple method for determining the degree of horizontal distortion in a panoramic image?
acceptance testing refers to a formal group of tests that inspect the x-ray unit and confirm that the x-ray unit functions according to vendor-specific and industry standards.
what is acceptance testing?
the anterior loop, where the inferior alveolar canal extends anterior to the mental foramen before it loops posteriorly to exit through the mental foramen
what is an important anatomic variation to detect when placing implants in the premolar region?
the velopharynx i put this on her mainly because im nervous she will give us the uvula as an anatomical landmark and this will be listed as an answer choice instead of uvula
what is another name for the uvula?
the position of the object within the focal trough
what is horizontal magnification in a panoramic image determined by?
The image distortion is influenced by several factors, including x-ray beam angulation, x-ray source-to-object distance, path of rotational center, and position of the object within the focal trough
what is image distortion in panoramic images influenced by?
the gingival margin of the alveolar process that extends between the teeth is apparent on radiographs as a radiopaque line
what is the alveolar crest?
a root fragment
what is the coronoid process commonly mistaken for?
The focal trough or image layer is a wide, three-dimensional curved zone, where the structures positioned within this zone are reasonably well defined on the panoramic image. The anatomic structures seen on a panoramic image are primarily those positioned within the focal trough during imaging
what is the focal through?
to avoid cross contamination among patients and between patients and the dental staff in the course of imaging
what is the goal of an infection control program in radiology
the lining of the bony crypt that surrounds each tooth during development
what is the lamina dura an extension of?
it is a gentle depression in the maxilla near the apex of the lateral incisor. it may appear diffusely radiolucent on periapical projections of this region or superimposed over the root of the lateral incisor. An intact lamina dura around the root of the lateral incisor coupled with absence of clinical symptoms will indicate absence of periapical disease.
what is the lateral fossa (also called the incisive fossa)?
The magnitude of the horizontal distortion depends on the distance of the object from the center of the focal trough and thus is strongly influenced by patient positioning.
what is the magnitude of horizontal distortion dependent on? (panoramic imaging)
poor processing in the darkroom, in particular, the use of depleted solutions
what is the most common cause of poor film radiographs?
A reference film provides a visual standard for optimal film processing. Comparison of daily images with the reference film may reveal problems before they interfere with the diagnostic quality of the images
what is the purpose of comparing film radiographs with a reference film at the beginning of every work day?
the path and velocity of the receptor and x-ray tube head, alignment of the x-ray beam, and collimator width
what is the shape and width of the focal through determined by?
a narrow buccolingual bone width secondary to residual ridge atrophy
what is the usual limitation to implant placement in the anterior mandible?
the alveolar crests they are seen as cortical borders of the alveolar bone. The alveolar crest is continuous with the lamina dura.
what is this structure showing?
the distance between the x-ray source and the object, similar to conventional radiography
what is vertical magnification in a panoramic image determined by?
Allowing patients to slump their heads and necks forward causes a large opaque artifact in the midline created by the superimposition of the cervical vertebrae. This shadow obscures the entire symphyseal region of the mandible and may require that the radiograph be retaken this ghost image could have been eliminated by having the patient sit straight and align or stretch the neck
what is wrong with this pan and how would you fix it?
Panoramic radiograph showing improper tongue positioning, where the dorsum of the tongue was not positioned flat against the hard palate, resulting in the airspace below the hard palate hindering visualization of the apices of the maxillary teeth. it is very easy to fix; just have the patient press the dorsum of the tongue to the roof of the mouth
what is wrong with this pan? how can it be fixed?
The level of this bony crest is considered normal when it is 0.5 to 2 mm apical to the cementoenamel junction of the adjacent teeth.
what level of the alveolar crest is considered normal?
sagittal plane
what plane is seen in the this CBCT?
coronal
what plane is shown this CBCT?
the hard palate
what structure forms the floor of the nasal cavity?
the cribriform plate of the ethmoid bone and the ethmoidal air cells form the roof of the nasal cavity
what structures form the roof of the nasal cavity?
both PSP and solid state detectors (CCD or complementary metal oxide semiconductor [CMOS] device)
what two image receptors are used for panoramic images?
hounsfield units or HU
what unit of measurement is used to predict implant stability?
it is most prominent when the beam is directed parallel with the surface of the mental tubercle (as in using the bisecting-angle technique)
when is the image of the mental ridge most prominent?
intraoral radiography remains a valuable tool in the initial assessment of a single edentulous space or short edentulous span and should be considered as the first line imaging modality in both intra- and postoperative phases of implant treatment. panoramic imaging is of value for the initial examination of a dental implant patient, particularly when multiple implant sites are considered at once, or when intraoral images cannot be made due to difficult patient anatomy or poor patient cooperation. Guidelines from the American Academy of Oral and Maxillofacial Radiology recommend panoramic and intraoral radiography for the initial assessment of the dental implant placement
when placing implants, intraoral radiographs and periapical images have some limitations. Are these types of radiographs utilized during implant placement? why or why not?
they are located on lingual surface of the mandible slightly above the inferior border and in the midline
where are the genial tubercles (also called the mental spine) located?
On the lingual surface of the mandibular body, immediately below the mylohyoid ridge in the molar area, there is frequently a depression in the bone. This concavity accommodates the submandibular gland and often appears as a radiolucent area with the sparse trabecular pattern characteristic of the region
where does a submandibular gland fossa show up on a radiograph?
the nasopalatine canal originates in the anterior floor of the nasal cavity and exits on the anterior maxilla as the incisive foramen. it is located in the midline on the anterior aspect of the palatine process immediately parallel to the maxillary central incisors
where does the nasopalatine canal originate and exit? where is it located?
in front of the patient, perpendicular to the midsagittal plane and parallel to the coronal plane
where is the image receptor placed in a PA cephalometric x-ray?
the patient is placed so that the canthomeatal line forms a 10 degree angle with the horizontal plane and the frankfurt plane and is perpendicular to the image receptor
where is the patient placed for a PA cephalometric radiograph?
cortical bone has a higher mineral content than adjacent cancellous bone so therefore it is more radiopaque
which has a higher mineral content: cortical bone or cancellous bone?
structures further away
which structures would have more discrepancy on a radiograph, structures close to the midsagittal plane or structures further away to the midsagittal plane?
it is the most dense naturally occurring substance in the body. since it is 96% mineral, it causes the greatest attenuation of x-ray photons
why does the enamel cap appear more radiopaque than other tissues?
the location of the focal trough can change with extensive machine use, so recalibration may be necessary if consistently suboptimal images are being produced
why is it important to recalibrate your panoramic machine regularly?
the nasopalatine canal side note that is unimportant but CN V3 runs through this canal; this canal is an important consideration when placing implants for maxillary central incisors!!!
you are general dentist who is working with an oral surgeon to place an implant for #8 in your patient. while coming up with a treatment plan, the oral surgeon says that they cannot place the implant in a certain location, because there is a canal located there. what canal is the surgeon most likely referring to?
