DRC DRC Anatomy & Radiographic Landmarks 2 — Questions and Answers
Question 1: The periodontal ligament space on a radiograph is identified as a:
- Thin radiolucent line surrounding the tooth root (Correct answer)
- Radiopaque band adjacent to cementum
- Dense cortical border of the alveolus
- Trabecular bone pattern near the root
Correct answer: Thin radiolucent line surrounding the tooth root
The periodontal ligament space appears as a thin, uniform radiolucent line surrounding the tooth root between the lamina dura and the root surface.
Question 2: On a bitewing radiograph, the alveolar crest in a healthy adult should be located approximately how far apical to the cementoenamel junction (CEJ)?
- 1–2 mm (Correct answer)
- 4–5 mm
- 6–7 mm
- 0.5 mm or less
Correct answer: 1–2 mm
In a healthy periodontium, the alveolar crest is normally located 1–2 mm apical to the CEJ on bitewing radiographs.
Question 3: Which radiographic landmark in the maxillary anterior region appears as an oval or heart-shaped radiolucent area between the central incisor roots?
- Incisive foramen (Correct answer)
- Nasal fossa
- Median palatal suture
- Anterior nasal spine
Correct answer: Incisive foramen
The incisive foramen (nasopalatine foramen) appears as an oval or heart-shaped radiolucency located between the roots of the maxillary central incisors.
Question 4: The genial tubercles are radiographic landmarks found in which location?
- Midline of the mandible near the lingual surface (Correct answer)
- Lateral borders of the mandibular ramus
- Below the mandibular premolars
- Superior to the mandibular condyle
Correct answer: Midline of the mandible near the lingual surface
The genial tubercles appear as a ring-shaped radiopaque structure at the midline of the mandible on the lingual surface, near the apex of the central incisors.
Question 5: On a panoramic radiograph, the soft palate and uvula may appear as:
- A radiopaque ghost shadow in the midline (Correct answer)
- Radiolucent areas in the maxillary sinus
- Dense cortical bands near the condyle
- Trabecular patterns in the mandible
Correct answer: A radiopaque ghost shadow in the midline
The soft palate and uvula can project as a radiopaque soft-tissue shadow in the midline area of the panoramic image, often overlying the maxillary teeth region.
Question 6: Which radiographic landmark of the mandible appears as a diagonal radiopaque line extending from the molar region toward the anterior border of the ramus?
- External oblique ridge (Correct answer)
- Internal oblique ridge
- Mylohyoid ridge
- Coronoid process
Correct answer: External oblique ridge
The external oblique ridge appears as a prominent diagonal radiopaque line on the lateral surface of the mandible extending from the molar region toward the ramus.
DRC DRC Anatomy & Radiographic Landmarks 2
The periodontal ligament space on a radiograph is identified as a: