NBDE Dental Anatomy and Occlusion 3 — Questions and Answers
Question 1: Which landmark on the maxillary central incisor crown is used to distinguish it from the lateral incisor?
- More prominent cingulum
- Sharper mesioincisal angle compared to the distoincisal angle (Correct answer)
- Greater overall crown width to length ratio
- Presence of a lingual fossa pit
Correct answer: Sharper mesioincisal angle compared to the distoincisal angle
The maxillary central incisor has a sharper, more right-angled mesioincisal angle compared to the more rounded distoincisal angle, unlike the lateral incisor.
Question 2: Centric relation is best defined as:
- Maximum intercuspation of the teeth
- The most retruded position of the mandibular condyles
- The position where condyles are in their most superior-anterior position in the glenoid fossa (Correct answer)
- The rest position of the mandible
Correct answer: The position where condyles are in their most superior-anterior position in the glenoid fossa
Centric relation is defined as the maxillomandibular relationship where the condyles are in their most superior and anterior position, braced against the articular eminence.
Question 3: Which cusp of the mandibular first molar is the largest?
- Mesiobuccal cusp (Correct answer)
- Distobuccal cusp
- Mesiolingual cusp
- Distolingual cusp
Correct answer: Mesiobuccal cusp
The mesiobuccal cusp of the mandibular first molar is the largest cusp on this tooth.
Question 4: The curve of Spee is best described as:
- The lateral curve seen in a frontal view of the dentition
- The anteroposterior curve following the buccal cusp tips from canine to last molar (Correct answer)
- The curve created by the incisal edges of anterior teeth
- The arc described by the lingual cusps of posterior teeth
Correct answer: The anteroposterior curve following the buccal cusp tips from canine to last molar
The curve of Spee is an anteroposterior (sagittal) curvature following the buccal cusp tips from the mandibular canine through the posterior teeth.
Question 5: A tooth with two roots and three canals is most likely which tooth?
- Mandibular first premolar
- Maxillary first premolar (Correct answer)
- Mandibular canine
- Maxillary lateral incisor
Correct answer: Maxillary first premolar
The maxillary first premolar most commonly has two roots (buccal and palatal) and three root canals, making it unique among premolars.
Question 6: The term 'working side' in lateral excursion refers to:
- The side toward which the mandible moves (Correct answer)
- The side away from which the mandible moves
- The side with the most tooth contacts
- The side with balanced occlusal contacts
Correct answer: The side toward which the mandible moves
The working side (also called the laterotrusive side) is the side toward which the mandible moves during lateral excursion.
Question 7: Which feature distinguishes the mandibular second molar from the first molar?
- Presence of a distal cusp making it a five-cusp tooth
- More symmetrical, cross-shaped occlusal groove pattern (Correct answer)
- Three roots instead of two
- A prominent buccal groove dividing two equal buccal cusps
Correct answer: More symmetrical, cross-shaped occlusal groove pattern
The mandibular second molar typically has a four-cusp design with a cross-shaped (+) occlusal groove pattern, making it more symmetrical than the first molar.
NBDE Dental Anatomy and Occlusion 3
Which landmark on the maxillary central incisor crown is used to distinguish it from the lateral incisor?