Ch. 42 RHS Slides

Extraoral radiographs are useful in

evaluating large areas of the skull and jaws but are not recommended for detection of subtle changes, like caries or early periodontal changes

what type of x-ray is cone beam computed tomography (CBCT) (intra/extraoral?)

extraoral

Panoramic imaging allows the dentist to ________on a single image

view the entire dentition and related structures

Panoramic imaging allows the dentist to view the entire dentition and related structures in how many images

one single image 

panoramic images were not recommended for________

diagnosing dental caries or periodontal disease or lesions because of the overlapping of posterior contact areas

full-featured digital panoramic units with a special ___-arm

C

Can panarox do bitewing? good or bad?

yes and its fine but better to use bitewing paralleling

Panoramic digital images produced with these machines can show____________

small interproximal carious lesions

patient receives less radiation exposure on panorex compared with the full-mouth survey. (true or false)

True

Two types of panoramic machines 

• Film-based imaging

• Direct digital imaging

The main difference between direct digital panoramic imaging and film-based panoramic imaging is the __________

image receptor

does direct digital use senor array or film? is the image produced right away or does it have to develop? 

Digital units use a sensor array rather than film, and the image is produced immediately on the computer monitor rather than on film after processing

True or False- In panoramic imaging, both the film/sensor and the tubehead rotate around the patient

True

Focal trough is an __________

imaginary three-dimensional curved zone in which structures appear clear on a panoramic radiograph

the vertical angulation of the panoramic tubehead is or is not adjustable

is not

for pano each head positioner consists of a _________________

chin rest, a notched bite-block, a forehead rest, and lateral head supports or guides

what can be adjusted in pano- mA, kVp, time

only mA and kVp. exposure time cannot be changed for panorex

what are ghost images

If all metallic or radiodense objects are not removed before exposure, a “ghost” image results

Do you use thyroid collar and lead apron when taking panorex

no thyroid collar yes lead apron 

what happens if a patient’s lips arent closed on the bite-block during exposure of a panoramic film. 

 dark radiolucent shadow that obscures the anterior teeth

during panorex the tongue must be in contact with _______ during exposure of a panoramic film. what happens if not? 

the palate; a dark radiolucent shadow that obscures the apices of the maxillary teeth

the positioning of the patients chin is also called

positioning of the Frankfort plane

If the Frankfort plane is incorrect and the patient’s chin is positioned too high or is tipped upward:

• Hard palate and the floor of nasal cavity will appear superimposed over the roots of the maxillary teeth

• Detail in the maxillary incisor region will be lost

• Maxillary incisors will appear blurred and magnified

• A “reverse smile line” will be apparent on the radiograph

If the Frankfort plane is incorrect and the patient’s chin is positioned too low or is tipped downward:

• The mandibular incisors will appear blurred

• Detail in the anterior apical regions will be lost

• The condyles will not be visible

• An “exaggerated smile line” will be apparent on the radiograph

If the patient’s anterior teeth are positioned too far back on the bite-block or posterior to the focal trough, the anterior teeth appear___________

“fat” and out of focus on the radiograph

If the patient’s anterior teeth are not positioned in the groove on the bite-block and are too far forward or anterior to the focal trough, the teeth appear________

“skinny” and out of focus

If the patient is not standing or sitting with a straight spine, the cervical spine appears ______________

as a radiopacity in the center of the film and obscures diagnostic information

whats the problem

wearing earrings 

what is the problem 

thyroid collar

whats the problem 

lips arent closed and tongue isnt on palate 

whats the problem

chin too high

whats the problem

chin too low

whats the problem

patient’s anterior teeth are positioned too far back on the bite-block

whats the problem

patient’s anterior teeth are not positioned in the groove on the bite-block and are too far back wider teeth

whats the problem

patient’s anterior teeth are not positioned in the groove on the bite-block and are too far forward or anterior to the focal trough- skinny

whats the problem 

patient is not standing or sitting with a straight spine

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During a cone beam CT examination, the arm rotates around the patient’s head in a _____________

complete 360-degree rotation

While doing CT cone beam, it takes anywhere from _______ (how many) two-dimensional (2D) images that the software collects

200 to 600

CBCT gives a 2D or 3D or 1D image

3D

what does CBCTThe proper placement of implants

• The proper placement of implants

• The extraction of impacted teeth

• Determining the exact location of the mandibular nerve prior to surgery

The most common skull radiographs used in dentistry include:

• Lateral cephalometric projection 

• Posteroanterior projection 

• Temporomandibular joint projection

best x-ray for oral surgery

skull radiorgraphy

Lateral Cephalometric Projection used for 

evaluate facial growth and development, trauma, disease, and developmental abnormalities

Lateral Cephalometric Projection showsPosteroanterior Projection 

shows the bones of the face and skull as well as the soft tissue profile

Posteroanterior Projection  used to 

evaluate facial growth and development, trauma, disease, and developmental abnormalities

Posteroanterior Projection shows

This projection shows the frontal and ethmoid sinuses, the orbits, and the nasal cavities