FREE NBDE Dental Anatomy and Occlusion Questions and Answers

Question 1

A patient presents with a malocclusion where the mesiobuccal cusp of the maxillary first molar is positioned anterior to the buccal groove of the mandibular first molar. Additionally, their maxillary central incisors are retroclined and there is a deep overbite. According to Angle's classification, which of the following best describes this presentation?

Accepted Answer

Class II, Division 2 Malocclusion

Answer

Angle's Class II malocclusion is defined by the mesiobuccal cusp of the maxillary first molar occluding anterior to the buccal groove of the mandibular first molar. This class is further divided into two divisions. Division 2 is specifically characterized by retroclined (lingually inclined) maxillary central incisors and often presents with a deep overbite, which matches the patient's description. Class II, Division 1 involves proclined maxillary incisors, leading to a large overjet.

Question 2

Which of the following represents the most common eruption sequence for the permanent maxillary teeth?

Accepted Answer

First Molar, Central Incisor, Lateral Incisor, First Premolar, Second Premolar, Canine, Second Molar

Answer

The typical eruption sequence for permanent maxillary teeth begins with the first molar (around age 6), followed by the central incisor (age 7-8), lateral incisor (age 8-9), first premolar (age 10-11), second premolar (age 10-12), canine (age 11-12), and finally the second molar (age 12-13). While slight variations exist, the eruption of the first molar before the incisors is a key characteristic of the maxillary arch sequence.

Question 3

During a lateral excursive movement to the right, a patient's right canine is the only tooth that contacts its opposing tooth, causing all posterior teeth on both the right (working) and left (non-working) sides to separate. This type of occlusal scheme is known as:

Accepted Answer

Canine Guidance (Canine Protected Articulation)

Answer

Canine guidance, also known as canine protected articulation, is an occlusal scheme where, during lateral movements of the mandible, the maxillary and mandibular canines on the working side contact and guide the movement, causing the disocclusion (separation) of all posterior teeth. This is considered a protective mechanism for the posterior teeth from potentially damaging lateral forces. Group function would involve multiple posterior teeth on the working side contacting simultaneously.

Question 4

The oblique ridge on a permanent maxillary first molar is a prominent feature formed by the union of which two ridges?

Accepted Answer

Distobuccal cusp's triangular ridge and the Mesiolingual cusp's triangular ridge

Answer

The oblique ridge is a unique and defining characteristic of maxillary molars. It traverses the occlusal surface diagonally and is formed by the union of the triangular ridge of the distobuccal cusp and the distal ridge of the mesiolingual cusp. This ridge separates the central fossa from the distal fossa.

Question 5

A dental student is examining a patient's study models and notes an anteroposterior curve of the occlusal plane when viewed from the buccal aspect. This curve, which begins at the tip of the mandibular canine and follows the buccal cusp tips of the premolars and molars, is known as the:

Accepted Answer

Curve of Spee

Answer

The Curve of Spee is the anatomical curvature of the mandibular occlusal plane viewed in the sagittal plane (from the side). It extends from the canine tip posteriorly along the buccal cusp tips of the posterior teeth. The Curve of Wilson is the mediolateral curve viewed in the coronal plane (from the front). The Sphere of Monson is a three-dimensional concept combining both curves.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

FREE NBDE Dental Anatomy and Occlusion Questions and Answers