NDAEB Dental Sciences Foundations 3

Question 1

Which muscle is primarily responsible for elevating the mandible during the closing phase of mastication?

Accepted Answer

Masseter

Answer

The masseter is the most powerful muscle of mastication and is primarily responsible for elevating (closing) the mandible. It originates from the zygomatic arch and inserts on the lateral surface of the mandibular ramus.

Question 2

What is the function of the periodontal ligament in tooth support?

Accepted Answer

It acts as a shock absorber and anchors the tooth to alveolar bone through collagen fibers

Answer

The periodontal ligament (PDL) is a connective tissue structure that suspends the tooth in its socket, absorbs occlusal forces, and anchors the tooth to bone through Sharpey's fibers embedded in both cementum and alveolar bone.

Question 3

Which cells in the dental pulp are responsible for forming secondary and reparative dentin throughout the life of the tooth?

Accepted Answer

Odontoblasts

Answer

Odontoblasts line the periphery of the dental pulp and continue to produce secondary dentin throughout life. When stimulated by caries or trauma, they produce reparative (tertiary) dentin as a protective response.

Question 4

The temporomandibular joint (TMJ) contains a fibrocartilaginous disc. What is the primary function of this articular disc?

Accepted Answer

To divide the joint into superior and inferior compartments and distribute forces during jaw movement

Answer

The articular disc divides the TMJ into superior and inferior compartments, each with different movement functions. The disc distributes compressive forces across a larger area, protecting the bony surfaces during function.

Question 5

What is the critical pH at which enamel demineralization begins to occur in the oral cavity?

Accepted Answer

5.5

Answer

Enamel demineralization begins at approximately pH 5.5, known as the critical pH. Below this level, the oral environment becomes undersaturated with respect to hydroxyapatite, and mineral loss from enamel occurs.

(NDAEB) National Dental Assisting Examination Board Practice Test

(NDAEB) National Dental Assisting Examination Board Practice Test

NDAEB Dental Sciences Foundations 3