CDT Dental Anatomy & Morphology Understanding 3 — Questions and Answers
Question 1: In permanent dentition, which tooth has the longest root relative to crown length?
- Maxillary central incisor
- Maxillary canine (Correct answer)
- Mandibular first molar
- Maxillary first premolar
Correct answer: Maxillary canine
The maxillary canine has the longest root of any tooth in the permanent dentition, contributing to its stability and anchorage value.
Question 2: Which surface of the mandibular first molar contains the distal pit?
- Occlusal surface near the distal marginal ridge (Correct answer)
- Distal surface at the cervical third
- Lingual surface distally
- Buccal surface at the occlusal third
Correct answer: Occlusal surface near the distal marginal ridge
The distal pit of the mandibular first molar is located on the occlusal surface adjacent to the distal marginal ridge.
Question 3: Which feature distinguishes the maxillary right central incisor from the left when viewed from the facial aspect?
- The distoincisal angle is more rounded on the side toward the midline
- The mesioincisal angle is more rounded than the distoincisal angle
- The distoincisal angle is more rounded than the mesioincisal angle (Correct answer)
- Both angles are identical
Correct answer: The distoincisal angle is more rounded than the mesioincisal angle
On maxillary central incisors, the mesioincisal angle is sharp and nearly 90°, while the distoincisal angle is more rounded, helping to distinguish left from right.
Question 4: What is the developmental groove that separates the mesiobuccal and distobuccal cusps on the mandibular first molar called?
- Central groove
- Buccal groove (Correct answer)
- Transverse groove
- Distobuccal groove
Correct answer: Buccal groove
The buccal groove of the mandibular first molar separates the mesiobuccal and distobuccal cusps on the buccal surface.
Question 5: Which of the following best describes the root trunk?
- The apical portion of each individual root
- The undivided portion of the root below the cervical line before furcation (Correct answer)
- The portion of the root embedded in alveolar bone
- The area of the root where the periodontal ligament attaches
Correct answer: The undivided portion of the root below the cervical line before furcation
The root trunk is the undivided section of a multi-rooted tooth's root structure that exists between the cervical line and the furcation.
Question 6: The oblique ridge on the maxillary first molar connects which two cusps?
- Mesiobuccal and distolingual cusps
- Distobuccal and mesiolingual cusps (Correct answer)
- Mesiobuccal and mesiolingual cusps
- Distobuccal and distolingual cusps
Correct answer: Distobuccal and mesiolingual cusps
The oblique ridge of the maxillary first molar is a transverse ridge connecting the distobuccal and mesiolingual cusps diagonally across the occlusal surface.
Question 7: How many roots does the mandibular second molar typically have?
- One
- Two (Correct answer)
- Three
- Four
Correct answer: Two
The mandibular second molar typically has two roots — a mesial and a distal root — similar to the mandibular first molar but with less divergence.
CDT Dental Anatomy & Morphology Understanding 3
In permanent dentition, which tooth has the longest root relative to crown length?