All Free Oral Histology MCQs with Answers

• A. Pulp
• B. Enamel
• C. Dentin
• D. Cementum

Explanation: Dentin forms the basic shape of the tooth and determines the outline of the crown and the size and configuration of the roots.

• A. Disturbance in dentinal tubules
• B. Fracture of the dentin
• C. Artifact in light microscopy
• D. Failure of coalescence of calcospherities

Explanation: Interglobular dentin forms when adjacent calcospherites fail to fuse during dentin mineralization, leaving hypomineralized areas between…

• A. Inter tubular dentin
• B. Mantle dentin
• C. Peritubular dentin
• D. Predentin

Explanation: Intertubular dentin lies between the dentinal tubules and constitutes most of the dentin bulk.

• A. With out but not with in the dentin
• B. Odontoblastic processes in dental tubules
• C. Type of sharpey's fibres
• D. Originate from tome's granular layer

Explanation: Tomes' fibers are the odontoblastic processes extending from odontoblasts into dentinal tubules.

• A. Reactionary dentin
• B. Secondary dentin
• C. Mantle dentin
• D. Indeed dermal tubules

Explanation: Korff's fibers are large collagen fibers associated with the formation of mantle dentin near the dentinoenamel junction.

• A. Sclerotic dentin
• B. Mantle dentin
• C. Predentin
• D. Osteodentin

Explanation: Osteodentin is an irregular form of tertiary dentin containing trapped cells within its matrix, resembling bone.

• A. Lamina limitans
• B. Lamina lucida
• C. Lamina propria
• D. Lamina densa

Explanation: The lamina limitans is the organic lining of the mineralized dentinal tubule and is associated with the tubular wall.

• A. Cementoblasts
• B. Odontoblasts
• C. Fibroblasts
• D. Osteoblasts

Explanation: Odontoblasts produce both primary and secondary dentin throughout tooth life.

• A. Enamel (anterior teeth)
• B. Enamel (Posterior teeth)
• C. Dentinoenamel junction
• D. Dentin

Explanation: The dentinoenamel junction is especially sensitive during cavity preparation because dentinal tubules begin beneath it and transmit…

• A. Direct activation of nerve endings
• B. Correlated with the innervation density of the dentin
• C. There is no transmission of stimulus across dentin
• D. Stimulus induced fluid flow

Explanation: Dentin sensitivity is explained by the hydrodynamic theory: stimuli produce movement of fluid within dentinal tubules, which excites…

• A. greater content of inorganic salts
• B. Lasser content of inorganic salts
• C. Greater stainability
• D. Greater content of large collagen fibres

Explanation: Peritubular dentin is more highly mineralized than intertubular dentin, so it has a greater inorganic salt content and narrows the…

• A. Smear layer
• B. Length of dentinal tubules
• C. Fluid convection
• D. Diffusion coefficient

Explanation: Smear layer, dentinal tubule length and the diffusion coefficient affect dentin permeability.

• A. 0.2-0.5 microns
• B. 7 microns
• C. 0.2-0.3 microns
• D. 2-3 microns

Explanation: Coronal dentinal tubules are widest near the pulp, with an average diameter of about 2 to 3 micrometres, and become narrower toward the…

• A. The diameter of dentin tubules ranges from 5 to 7μm
• B. Inner pulpal layer contains more dentinal tubules than outer dentin layer
• C. The diameter of dentinal tubule is more at pulpal layer than outer layer
• D. The bonding is more on the inner layer of dentin compared to outer surface

Explanation: Dentinal tubules are generally about 1 to 3 micrometres wide near the pulp, not 5 to 7 micrometres.

• A. Incremental deposition
• B. Crowding of odontoblasts
• C. Peritubular dentin
• D. Due to excess amount of organic component

Explanation: The S-shaped course of dentinal tubules results mainly from the crowding and changing movement of odontoblasts as they retreat toward the…

• A. Sclerotic dentin
• B. Reparative dentin
• C. Secondary dentin
• D. All of the above

Explanation: Secondary dentin is deposited physiologically after root completion and continues throughout life at a slow rate.

• A. Secondary dentin
• B. Primary dentin
• C. Sclerotic dentin
• D. Interglobular dentin

Explanation: In sclerotic dentin, mineral deposits progressively occlude and calcify the dentinal tubules, reducing permeability.

• A. Contour lines of owen
• B. Incremental lines of vonebner
• C. Incremental lines of retzius
• D. None of the above

Explanation: Contour lines of Owen are accentuated incremental lines in dentin produced when disturbances affect matrix formation or mineralization.

• A. Acellular cementum
• B. Bone
• C. Enamel
• D. None of the above

Explanation: Dentin is closely related to bone in composition and structure because both are mineralized connective tissues containing collagen and…

• A. Mantle dentin
• B. Circumpulpal dentin
• C. Predentin
• D. Secondary dentin

Explanation: Predentin is the thin, newly formed layer of dentin matrix nearest the pulp that has not yet undergone mineralization.