Chapter 17,20,21

Fossa

a broad, shallow depressed area scooped out

sinus

a hollow space, cavity or recess in bone

The pediatric projection is recommended for use in children ______ years old or younger.

5

Radiographers appearance of cementum

50% mineral content It appear very thin layer In the root surface It is usually apparent radiophi

Which size 1 receptor, a total of Anterior placcements are used in the paralleling technique

7 total 4 for maxillary and 3 for Mandibular

septum

A bony wall or partition that divides two spaces or cavities radiopaque

canal

A tubular passage or tunnel in a bone (auditory canal of the skull) contains nerve band blood vessel

Which occlusal projection is used to locate foreign bodies or salivary stones in the region of the floor of the mouth?

Cross-sectional occlusal projection

When overlapped contacts appear on an image, the cause is:

Incorrect horizontal film angulation

When the patient has a shallow plate requiring a modification in technique

Place cotton roll

When the distal surfaces of the canines are not visible on a premolar bite-wing image, the solution is to:

Position the anterior edge of the receptor at the midline of the mandibular canine.​

In children, size ____ receptor is used in the occlusal examination.

2

In adults, size _____ receptor is used in the occlusal examination.

4

What is the purpose of the localization technique?

A localization technique is a method used to locate the position of a tooth or object in the jaws. The dental radiograph is a two-dimensional picture of a three-dimensional object. Localization techniques can be used to obtain this three-dimensional information. Localization techniques may be used to located foreign bodies, impacted teeth, unerupted teeth, retained roots, root positions, salivary stones, jaw fractures, broken needles and instruments, and filling materials.

You are teaching the new dental radiographer in your dental office how to take occlusal images. What important items must you remember to tell her? Guidelines: After completion of infection control procedures

After completion of infection control procedures and preparation of the treatment area and supplies, the patient should be seated. After seating the patient and before exposing any images, the dental radiographer must prepare the patient for exposure. Position the patient upright in the chair. The level of the chair must be adjusted to a comfortable working height for the dental radiographer. Adjust the headrest to support and position the patient's head. For maxillary occlusal exposures, the patient's head must be positioned so that the upper arch is parallel with the floor and the midsaggital (midline) plane is perpendicular to the floor. For some mandibular occlusal exposures, the patient's head must be reclined and positioned so that the occlusal plane is perpendicular to the floor. For others, it is positioned parallel with the floor. Place the lead apron with thyroid collar on the patient and secure it. Remove all objects from the mouth that may interfere with exposure. Eyeglasses must also be removed. Set the exposure factors on the x-ray unit according to the recommendations of the receptor manufacturer. Either a short or a long PID device may be used with the occlusal technique.

When exposing paralleling technique, which area should you begin with?

Anterior

How would you provide instructions to the new assistant when taking an image for the maxillary second molar using the buccal object rule and when determining the position of a radiopaque object using the right-angle technique?

Before exposing localization images, infection control procedures must be carried out. In addition, patient and equipment preparations must be completed. The buccal object rule can be used to determine the position of a root canal filled gutta percha in a maxillary second premolar. Position the maxillary arch parallel to the floor. Expose one molar periapical receptor using proper technique and angulation. Shift the PID in a mesial direction and expose a premolar periapical receptor. In the second exposure, when the PID was moved in a mesial direction, the gutta percha moved in the opposite direction. Therefore the gutta percha is in the root canal that lies to the buccal. The right-angle technique can be used to determine the position of a radiopaque object. Position the maxillary arch parallel with the floor. Expose one periapical receptor using proper technique and angulation. Expose an occlusal receptor and direct the central ray perpendicular to the receptor. In the occlusal exposure, the radiopaque object is located buccal to the mandible.

A thin radiolucent line appears on the image with:

Film bending

am alignment devices can be bagged and sterilized for continuous use. CRITICAL THINKING QUESTION After exposing and processing radiographs, the dental radiographer notices that all four of the bite-wing radiographs have overlapped contact areas and cone-cuts. Why did these errors happen and what can the dental radiographer do to correct them?

Guidelines: Bite-wing radiographs are used to detect interproximal decay, so it is very important that the central ray of the x-ray beam is directed through the contact areas of the teeth. To achieve the correct horizontal angulation, the operator can place his or her finger along the arch and align the open end of the position-indicating device (PID) to the finger. To correct cone-cuts, the operator must position the PID so that the central ray is centered on the receptor to ensure that all areas of the receptor are exposed.

An existing patient comes to the office for a dental examination. He states that he is having sensitivity when biting down in the upper left quadrant. After an intraoral examination, the dentist prescribes a radiograph of tooth numbers 12-14. Upon placement of the XCP and receptor in the patient's mouth, the patient is unable to close or bite down on the bite-block. The dental radiographer examines the patient's mouth and discovers the patient has a very shallow palate due to a bony growth. What should the dental radiographer do in order to capture a diagnostic radiograph?

Guidelines: The patient appears to have a very shallow palate, which is not a good indicator for use of the paralleling technique. Modifications in the paralleling technique may be used to accommodate various conditions in anatomic conditions. In a patient with a shallow palate, tilting of the bite-block should occur, which will result in a lack of parallelism between the receptor and the long axis of the tooth. Of the lack of parallelism between the receptor and the long axis of the tooth does not exceed 20 degrees, the resultant radiograph is generally acceptable. When the lack of parallelism is greater than 20 degrees, a modification in technique is necessary.

It is recommend that each receptor be placed in the bite-block with the dot

In the slot

​1.​The occlusal technique is used to examine:

Large areas of the upper and lower jaw

Which of the following is a maxillary occulsal projection, but not a mandibular occlusal projection?

Lateral occlusal projection

Parallel is defined as

Moving or lying in the same plane, always separated by the same distance and not intersecting​c.​moving or lying in the same plane, always separated by the same distance and not intersecting

Foramem

Opening hole that permit the passage of nerve and blood vessels

The "S" in the mnemonic SLOB stands for:

Same

tuberucle

Small bump or noodles

Which of the following is a disposable beam alignment device designed for one-time use only?

Stabe bite-block

Reusable beam alignment device must be after each use

Sterilize

​A cone-cut occurs when:

The PID was not properly aligned with the periapical beam alignment device.

Why is it important for the dental radiographer to be able to recognize exposure and technique errors?

The dental radiographer must be able to recognize exposure and technique errors, identify their causes, and know what steps are necessary to correct such problems.

Why is it important for the dental radiographer to have a working knowledge of the exposure and technique errors that result in nondiagnostic images?

The dental radiographer must remember that images are taken to benefit the patient. Only diagnostic images benefit the patient. A diagnostic dental image is one that has been properly placed, exposed, and processed; errors in any one of these three areas may result in nondiagnostic images. In many instances, nondiagnostic images must be retaken. Retakes result in additional exposure of the patient to ionizing radiation, which does not benefit the patient.

When would the dental radiographer want to use the occlusal technique?

The occlusal technique is a supplementary imaging technique that is usually used in conjunction with periapical or bite-wing images. The occlusal technique is used when large areas of the maxilla or mandible must be visualized. The occlusal image is preferred when the area of interest is larger than a periapical receptor may cover or when the placement of periapical receptors is too difficult for the patient.

To what does the term paralleling technique refer?

The paralleling technique is one method that can be used to expose periapical receptors. This technique is based on the concept of parallelism. The receptor is placed in the mouth parallel to the long axis of the tooth being imaged. The central ray of the x-ray beam is directed perpendicular to the receptor and long axis of the tooth. A beam alignment device must be used to keep the receptor parallel with the long axis of the tooth. The patient cannot hold the receptor.

What is a beam alignment device? What types of beam alignment devices are used with the paralleling technique?

The paralleling technique requires the use of a beam alignment device to position the receptor parallel to the long axis of the tooth.. A beam alignment device is an instrument that is used to position an intraoral receptor in the mouth and hold the receptor in position during exposure. Beam alignment devices eliminate the need for the patient to hold the exposure during exposure. Some examples of beam alignment devices include: Rinn XCP instruments, Precision film holders, Stabe film holders, EEZEE-Grip film holder, and a Hemostat film holder. Some beam alignment devices are disposable and are designed for one-time use only. Other beam alignment devices can be bagged and sterilized for

Short teeth with blunted roots appear on the image when:

The vertical angulation is excessive

As you begin to mount a set of bite-wing images, you notice that the contacts on the left premolar exposure are overlapped. What common error occurred during exposure of this image? What type of correction is needed on the retake?

When overlapped contact appears on the image, incorrect horizontal angulation has occurred. The cause of this error is the central ray not being directed through the interproximal spaces. As a result, the proximal surfaces of adjacent teeth appear overlapped in the bite-wing image. Overlapped contacts prevent examination of interproximal areas. To prevent overlapped contacts on a bite-wing image, direct the x-ray beam through the interproximal regions. When the contacts are opened, a thin radiolucent line is seen between the proximal surfaces of the teeth. The use of Rinn bite-wing instruments minimizes errors in horizontal angulation.

Turberosity

a large, rounded, usually roughened process

ridge

a linear prominence or projection of bone

cervical burnout

a radiolucency often observed on the mesial and distal root surfaces near the cementoenamel junction. Appear between the edge of the enamel Cap-between the crest of the alveolar ridge

When the film is reversed, the image will be:

a.​light with a herringbone pattern

suture

an immovable joint (especially between the bones of the skull) a tiny rediocent line

cervical burnout

can be mistaken for decay; frequently seen on mandibular anteriors

An unexposed receptor appears

clear

cortical bone

compact bone the dense outer layer appears radiopaque

What do initials XCP represent?

extension cone paralleling

Which of the following images would most likely appear black?

film exposed to light​

What technique is used is used to locate the position of a tooth or object in the jaws?

localization technique

process

marked prominence or projection

The __________ is preferred when the area of interest is larger than a periapical receptor or when the placement of periapical receptors is too difficult for the patient.

occlusal image

When the occlusal technique is used, a _____ to stabilize the receptor.

patient gently bites on the surface of the receptor

What is the first step obtaining quality radiographs?

placement

spine

sharp, thornlike projection

An underexposed receptor results from:

​Inadequate exposure time

Long, distorted teeth appear on the image when

​The vertical angulation is excessive

cancellous bone

•The soft, spongy bone located between two layers of dense cortical bone •Appears primarily radiolucent •Trabeculae appear radiopaque, marrow