Films for a Patient Not Seen in Ten Years

Correct answer: B. A full mouth series

• A. A panoramic film is excellent for a broad survey — impactions, jaw pathology, sinus and condyle — but its resolution at the crestal bone and interproximal contacts is inadequate for periodontal assessment or caries detection.
• B. CORRECT. A FULL MOUTH SERIES is the ADA/FDA-recommended examination for a NEW adult patient with clinical evidence of generalized dental disease or a history of extensive treatment. It gives the periapical and interproximal bone detail needed to stage his periodontitis, which a panoramic film cannot provide at the level of individual teeth.
• C. A lateral cephalogram is an orthodontic and orthognathic tool for skeletal relationships. It has no role in this examination.
• D. Bitewings alone show interproximal caries and crestal bone but give no apical information, which is essential given his periodontal status and the anterior lesion.

Note: The prescribing rule: a new adult patient WITHOUT clinical evidence of disease gets posterior bitewings with selected periapicals or a panoramic. A new adult patient WITH generalized disease gets a full mouth series.

Correct answer: D. Vertical bitewings

• A. Horizontal bitewings are the standard for caries detection and for EARLY bone loss, but the limited vertical coverage is exactly the problem in advanced disease.
• B. A panoramic film shows generalized bone levels but with poor resolution, superimposition and magnification. It supplements but does not replace intraoral films for periodontal assessment.
• C. An occlusal film shows the arch in cross-section, useful for locating impacted teeth, sialoliths and expansion — not for crestal bone levels.
• D. CORRECT. VERTICAL BITEWINGS. The receptor is oriented with its long axis vertically, which captures far more crestal-to-apical bone height on a single film. With advanced bone loss, a horizontal bitewing simply cuts the image off before the base of the defect is reached — the vertical orientation is what allows the true depth of the defect to be seen along with the interproximal contacts.

Note: Vertical bitewings are the standard periodontal radiographic examination once probing depths exceed roughly 5–6 mm. Periapicals with a paralleling technique give the most accurate bone-level detail of all.

Correct answer: A. External resorption

• A. CORRECT. EXTERNAL resorption. It originates OUTSIDE the tooth, in the periodontal ligament, and is initiated here by chronic PRESSURE from the impacted third molar crown against the root surface. Sustained pressure recruits clastic cells to the root surface. Radiographically the defect is a saucer-shaped concavity on the root outline, and the canal outline remains visible and INTACT through it.
• B. Hypercementosis is excessive cementum DEPOSITION producing a bulbous root, the opposite process.
• C. Attrition is occlusal or incisal wear from tooth-to-tooth contact — a crown phenomenon, not a root one.
• D. Internal resorption originates from the PULP, requires vital pulp tissue and odontoclasts within the canal, and produces a balloon-like expansion of the CANAL itself. The canal outline is lost at the lesion, which is the key radiographic distinction.

Note: Distinguishing the two on film: EXTERNAL — canal outline traceable through the defect, and the lesion MOVES relative to the canal when the horizontal angle is changed. INTERNAL — canal outline lost, lesion stays centred on the canal. Other causes of external resorption: orthodontic force, trauma, periapical inflammation, cysts and tumours.

Correct answer: D. No treatment — periodic radiographic review only

• A. Root canal treatment on VITAL teeth is unnecessary and harmful. This is the classic trap: mistaking the radiolucent stage for periapical inflammation and endodontically treating healthy teeth. PULP TESTING is what prevents that error.
• B. Apicoectomy is likewise contraindicated, and for the same reasons.
• C. Surgical intervention is contraindicated. The dysplastic bone is hypovascular and heals poorly — biopsy or enucleation risks infection and a chronic non-healing defect.
• D. CORRECT. This is PERIAPICAL CEMENTO-OSSEOUS DYSPLASIA, and the critical finding is that the teeth are VITAL. It is a reactive, self-limiting fibro-osseous lesion of the periodontal ligament that passes through three stages — early osteolytic (radiolucent), intermediate cementoblastic (mixed), and mature (radiopaque with a thin radiolucent rim). It requires NO TREATMENT. Periodic radiographic observation is all that is needed.

Note: COD is most common in middle-aged Black women. The florid variant is multiquadrant and can be extensive; the same rule applies — leave it alone. Avoid extractions and implants in affected bone where possible.

Correct answer: A. The hyoid bone

• A. CORRECT. The HYOID BONE. It is a U-shaped bone suspended in the anterior neck at about the C3 level and is the only bone in the body that articulates with no other bone. On a PANORAMIC film it appears as a radiopacity superimposed over the mandible bilaterally, or occasionally in the midline. On a LATERAL CEPH it is clearly visible in profile below and behind the mandible, and its position is used in airway analysis. Being asked to identify the same structure on both projections is a common item pattern.
• B. The cervical spine appears as a vertical ghost in the midline of a panoramic film and clearly in profile on a ceph, but not as a discrete structure over the lower face.
• C. The styloid process is visible on both films too, but it is a slender spine projecting downward and forward from the temporal bone, near the mandibular ramus — a different shape and location entirely.
• D. The soft palate is soft tissue. It is visible on a lateral ceph as a soft-tissue shadow but is not a distinct radiopacity superimposed over the mandible on a pano.

Note: Other panoramic landmarks worth being able to name on sight: the hard palate, the inferior border of the maxillary sinus, the zygomatic arch, the pterygomaxillary fissure, the mandibular canal, the mental foramen, the coronoid process, the ear lobe shadow and the ghost image of the opposite mandible.

Correct answer: A. Panoramic radiograph

• A. CORRECT. The PANORAMIC film is the single most useful projection for suspected mandibular fracture. It displays the entire mandible in one image — symphysis, body, angle, ramus, coronoid and condyle — and reveals the multiple fracture sites that are so characteristic: because the mandible is a ring, a fracture at one point is very frequently accompanied by a second fracture elsewhere, classically a parasymphyseal fracture with a contralateral subcondylar fracture.
• B. The submentovertex projection shows the skull base, the zygomatic arches and the medial-lateral position of the condyles — useful for zygomatic arch fractures, not for the mandible generally.
• C. A lateral skull film superimposes the two sides of the mandible on each other, obscuring exactly what you need to see.
• D. A periapical shows fine detail of a small region but cannot survey the whole mandible, and cannot show the condyles at all.

Note: In practice, CT is the definitive imaging for facial trauma. But when the question offers only plain projections, panoramic is the answer for the mandible. Always look for a SECOND fracture.