DRC Case Analysis & Practical Application 3 — Questions and Answers
Question 1: A patient's panoramic radiograph reveals a well-defined multilocular radiolucency in the posterior mandible with a 'soap bubble' appearance. The patient is 25 years old. What is the most likely diagnosis?
- Ameloblastoma (Correct answer)
- Dentigerous cyst
- Central giant cell granuloma
- Odontogenic keratocyst
Correct answer: Ameloblastoma
Ameloblastoma classically presents as a multilocular 'soap bubble' or 'honeycomb' radiolucency in the posterior mandible of young adults.
Question 2: When positioning a patient for a mandibular periapical radiograph using the bisecting angle technique, the vertical angulation should be directed:
- -5 degrees
- +15 degrees
- -15 degrees (Correct answer)
- +20 degrees
Correct answer: -15 degrees
The mandibular anterior region requires a negative vertical angulation of approximately -15 to -20 degrees in the bisecting angle technique to bisect the angle between the tooth and film.
Question 3: A 35-year-old patient's radiograph shows calcified deposits within the pulp chamber of tooth #19 that completely obliterate the chamber. The tooth tests vital. This finding is BEST described as:
- Pulp stone
- Pulp canal obliteration (Correct answer)
- Internal resorption
- Denticle
Correct answer: Pulp canal obliteration
Pulp canal obliteration (calcific metamorphosis) results in progressive calcification that fills the pulp chamber, often following trauma, while the tooth remains vital.
Question 4: During a panoramic examination, a patient with a high palatal vault causes the hard palate shadow to be superimposed over which structure on the radiograph?
- Condylar heads
- Maxillary anterior tooth roots (Correct answer)
- Mandibular incisors
- Mental foramen
Correct answer: Maxillary anterior tooth roots
A high palatal vault projects the hard palate shadow over the apices of the maxillary anterior teeth, potentially obscuring pathology.
Question 5: Radiographs of a 55-year-old patient show generalized increased radiopacity of the alveolar bone with a 'ground glass' pattern and expansion of the maxilla. Which systemic condition is most likely?
- Hyperparathyroidism
- Fibrous dysplasia (Correct answer)
- Paget's disease of bone
- Osteopetrosis
Correct answer: Fibrous dysplasia
Fibrous dysplasia produces a characteristic ground-glass radiographic appearance with bone expansion, commonly affecting the maxilla.
Question 6: A patient refuses to bite down fully on the bitewing tab, resulting in the crowns being cut off at the top of the image. What error occurred and what is the correction?
- Negative vertical angulation; increase to +10 degrees
- Film/sensor placed too high; reposition with occlusal plane at center
- Excessive positive vertical angulation; decrease angulation (Correct answer)
- Patient's head tilted; correct head position
Correct answer: Excessive positive vertical angulation; decrease angulation
When crowns are cut off superiorly, excessive positive vertical angulation is directing the beam too steeply downward; reducing the angulation corrects this.
Question 7: A radiograph shows a thin radiolucent line running obliquely through the root of tooth #14 without displacement of the root segments. The patient reports recent trauma. What does this most likely represent?
- External root resorption
- Horizontal root fracture (Correct answer)
- Artifact from grid lines
- Nutrient canal
Correct answer: Horizontal root fracture
A radiolucent line through the root following trauma is consistent with a root fracture; no displacement indicates the fracture fragments remain approximated.
DRC Case Analysis & Practical Application 3
A patient's panoramic radiograph reveals a well-defined multilocular radiolucency in the posterior mandible with a 'soap bubble' appearance.
The patient is 25 years old.
What is the most likely diagnosis?