DRC Case Analysis & Practical Application 2 — Questions and Answers
Question 1: A radiograph of a 45-year-old patient reveals a well-defined radiolucent lesion at the apex of a non-vital maxillary lateral incisor. The lesion measures 12mm in diameter. What is the MOST likely diagnosis?
- Periapical granuloma
- Periapical cyst (Correct answer)
- Lateral periodontal cyst
- Nasopalatine duct cyst
Correct answer: Periapical cyst
Periapical cysts are the most common odontogenic cysts and are associated with non-vital teeth; lesions larger than 10mm are more likely to be cysts than granulomas.
Question 2: During a full-mouth radiographic survey, the dental hygienist notices a horizontal radiolucent line crossing the roots of the mandibular molars. What artifact is most likely responsible?
- Ghost image
- Mach band effect (Correct answer)
- Double exposure
- Film crease artifact
Correct answer: Mach band effect
The Mach band effect is an optical illusion where a dark band appears at the junction of structures of differing densities, commonly seen crossing molar roots.
Question 3: A panoramic radiograph of a 12-year-old shows an impacted mandibular third molar bud superimposed over the inferior alveolar canal. Which additional imaging would best assess the spatial relationship?
- Periapical radiograph with paralleling technique
- Occlusal radiograph
- CBCT imaging (Correct answer)
- Bitewing radiograph
Correct answer: CBCT imaging
CBCT provides 3D spatial information to precisely determine the relationship between an impacted tooth and the inferior alveolar canal.
Question 4: A patient's bitewing radiograph shows loss of the distinct white line of the lamina dura around the mesial root of tooth #30. Which condition should be suspected?
- External resorption
- Periapical pathology (Correct answer)
- Hypercementosis
- Condensing osteitis
Correct answer: Periapical pathology
Loss of the lamina dura around a root apex is a radiographic sign of periapical inflammation or infection.
Question 5: On a periapical film of the maxillary molar region, a radiopaque structure with a root-like shape is seen superior to the apex of tooth #2. What is this most likely representing?
- Zygomatic process of the maxilla (Correct answer)
- Maxillary sinus floor
- Nasal spine
- Coronoid process of the mandible
Correct answer: Zygomatic process of the maxilla
The zygomatic process of the maxilla frequently appears as a U- or J-shaped radiopaque structure superimposed over the maxillary molar roots.
Question 6: A 60-year-old diabetic patient presents with generalized bone loss averaging 50% on radiographs and furcation involvement on all molars. This pattern is most consistent with:
- Localized periodontitis Stage III
- Generalized periodontitis Stage III or IV (Correct answer)
- Aggressive periodontitis
- Necrotizing periodontal disease
Correct answer: Generalized periodontitis Stage III or IV
Generalized bone loss exceeding 33% with furcation involvement on multiple teeth classifies as generalized periodontitis Stage III or IV under the 2017 classification.
Question 7: A radiograph reveals a crescent-shaped radiolucency at the cervical area on the facial surface of tooth #8. The tooth tests vital. What is the most likely cause?
- Internal resorption
- External cervical resorption (Correct answer)
- Caries
- Dens invaginatus
Correct answer: External cervical resorption
External cervical resorption appears as an irregular radiolucency at the cervical area originating from the outer root surface, often in a vital tooth.
DRC Case Analysis & Practical Application 2
A radiograph of a 45-year-old patient reveals a well-defined radiolucent lesion at the apex of a non-vital maxillary lateral incisor.
The lesion measures 12mm in diameter.
What is the MOST likely diagnosis?