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- blackness of the film
- ability to stop transmitted light from passing through
- D=log10 Io/It
- Density difference between image areas
- depends upon subject contrast and film contrast.
ability to record separate images of small objects which are placed very close together
- horizontal: both TMJ’s
- vertical: inferior border of the mandible and the superior aspects of the temporal component of the TMJ
- 1. trauma, 3rd molars, pathosis
- 2. tooth development (especially mixed dentition)
- 3. developmental anomalies
- 4. Edentulous patients
- 5. Patients who cannot open mouth or do not tolerate intra-oral procedures
- 1. Single image of facial structures including maxilla and mandible
- 2. Relatively low patient dose
- 3. Relative convenience, ease, and speed which procedure may be performed
- Does not reveal fine anatomic detail such as:
- 1. early alveolar bone loss
- 2. incipient dental caries
- 3. analysis of trabecular bone changes
Focal trough and planes
- 1. Sagittal plane
- 2. Frontal plane
- 3. Horizontal plane
- 4. Causes of distortion
MANDIBLE (CORTEX AND MEDULLARY BONE)
- Starting with right condyle, follow the complete borders of mandible.
- Is the border intact, well corticated, thin, scalloped, expanded, etc.?
- Review additional corticated surfaces, e.g. mandibular canals, mental foramina, genial tubercles, external oblique ridge etc., keeping in mind the various superimpositions and artifacts frequently seen.
- Examine the trabecular pattern of the bone in the ramus, body, and alveolar portions of the mandible. Is the trabecular pattern in each area within the normal range? Normal cancellous trabeculations are fine,irregular, lace-like spicules of bone.
- Try to define distinct individual trabeculations. This pattern may be altered in pathological and post-surgical states, and in normal physiological and post-surgical states, and in normal physiological aging.
- Examine bone for lucencies or opacities in periapical, central or peripheral areas.
- Compare contralateral sides for significant changes
- outline of the “head” of the condyle.
- Observe flattening,erosions, or fractures. The condyle should be in a mild translatory location since the patient is required to bite in an anterior edge-to-edge relationship.
- Can only demonstrate gross changes of the TMJ.
- Any joint space relationships or mild to moderate osseous changes must be evaluated using additional radiographic techniques (e.g., transcranial, or tomography of the TMJ).
MAXILLA (CORTEX AND MEDULLARY BONE)
- a. Starting with the right lateral pterygoid plate trace the outline of the maxillary alveolar areas (tuberosity, alveolar crest, etc). Review the normal anatomy of the area, remembering the thinness of the bone in the incisive fossa areas; tuberosities (often sparsely trabeculated), alveolar bone, inferior border of nasal fossa and region of the anterior nasal spine.
- b. Examine the zygomatic arches on each side starting with the glenoid fossa noting the articular eminence, zygomatico-temporal sutures, and the zygomatic process of the maxilla in cross section as it represents part of the lateral wall of the
- maxillary sinus.
- symmetrical and similar in lucency
- alveolar and zygomatic processes pneumatized
- Do shadows of the inferior turbinates blur across the sinuses?
- Is there evidence of mucous retention cysts, mucoperiosteal thickening or are other radiopacities present?
- Locate the borders (anteriorly and inferiorly) and
- the inferior turbinates.
- Rule out mucoperiosteal thickening and soft tissue lesions, such as nasal polyps.
continuity of the zygomatic arch from the glenoid fossa anteriorly to the lateral wall of the maxilla. Note the zygomatico-temporal suture located in the mid-portion.
- Define the shadows of the tongue and the borders of the hard and soft
- palate. The naso- and oro-pharyngeal airways are usually seen to be superimposed bilaterally across the mandibular rami.
SOFT TISSUE AND ADDITIONAL STRUCTURES
- Note any deviation from normal in the following structures:
- a. The soft tissue of the ear lobe can usually be seen lateral to the
- posterior border of the ramus and superimposed over the styloid process.
- b. Check soft tissue of the neck for calcifications, foreign bodies, or e.g., alterations in contour, soft tissue below the inferior mandibular border,
- and posterior to the mandibular rami.
- c. The styloid process can often be seen lateral to the posterior border of the ramus. The stylo-hyoid ligament, if calcified, will extend inferiorly
- and medially toward the lesser horn of the hyoid bone.
- d. The hyoid bone is usually depicted below the inferior border of the mandible. Note that this midline structure is projected bilaterally.page 5
- e. Examine the orbits if present in the radiograph. The infra-orbital rim can usually be seen. The infra-orbital canals will commonly be well outlined, although the infra-orbital foramina are less often visualized.
- f. Examine the lateral pterygoid plates and pterygomaxillary fissures.
- g. Examine the upper cervical spine.