Free Enamel MCQs with Answers

• A. Periodontal ligament
• B. Dentin
• C. Enamel
• D. Cementum

Explanation: Ameloblasts are the formative cells of enamel and disappear after enamel formation.

• A. None of the above
• B. Paddle appearance in cross section
• C. Lanullate appearance in cross-section
• D. Key hole appearance in cross section

Explanation: In cross-section, enamel rods commonly show a keyhole or paddle-like outline, with the head toward the incisal or occlusal surface.

• A. Constitute the rest lines with in the enamel rods
• B. Have high inorganic content
• C. They are areas of increased porosity
• D. Allow the movement of water and small ions

Explanation: Striae of Retzius are incremental, relatively hypomineralised lines that have increased porosity and can permit movement of water and…

• A. Does not take place once enamel surface and invironment
• B. Stops after 2 years of eruption
• C. Continues through out life
• D. Continues till adult life

Explanation: After eruption, enamel continues to exchange ions with saliva and the oral environment throughout life.

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

Explanation: The incremental growth lines called the striae of Retzius are characteristic of enamel.

• A. Enamel tufts
• B. Enamel lamella
• C. Incremental lines of enamel
• D. Enamel cuticle

Explanation: Enamel tufts are hypomineralised structures that arise at the dentinoenamel junction and extend inward, so they are not an external…

• A. Dark and light bands of enamel seen in horizontal ground section
• B. Dark and light bands of enamel seen in longitudinal ground section
• C. Dark and light brands of dentin seen in longitudinal section
• D. Dark and light bands of dentin seen in horizontal

Explanation: Hunter-Schreger bands are alternating dark and light bands produced by changes in the direction of enamel rod groups.

• A. 66%
• B. 76%
• C. 86%
• D. 96%

Explanation: Fully developed enamel is approximately 96% inorganic by weight, mainly hydroxyapatite, with only small organic and water components.

• A. Amelogenin
• B. Sheathlin
• C. Enamelin
• D. Tuftelin

Explanation: Amelogenin is the major non-acidic enamel matrix protein and helps regulate enamel crystal growth and mineralization.

• A. Same as dentin crystals
• B. Contains organic portion in the center
• C. Roughly texagonal in shape
• D. Their diameter is about 5 microns in size

Explanation: Enamel crystals are roughly hexagonal in cross-section, unlike the less regularly arranged crystals of dentin.

• A. Bone
• B. Gingiva
• C. Enamel
• D. Dentin

Explanation: Enamel is the most highly mineralized tissue in the body, so it contains the greatest proportion of phosphate among these choices.

• A. Dentin of all teeth, as if is formed first
• B. Enamel of permanent incisors
• C. Enamel of premolars
• D. Enamel of deciduous incisiors

Explanation: The neonatal line marks the abrupt change in mineralization associated with birth and is prominent in the enamel of primary teeth.

• A. Cusp tips of tooth
• B. Cervical region of tooth
• C. Proximal surface of tooth
• D. All of the above

Explanation: Gnarled or twisted enamel occurs where enamel rods change direction markedly, especially at cusp tips and incisal edges.

• A. 50 μ m
• B. 25 μ m
• C. 75 μ m
• D. 100 μ m

Explanation: The prismless enamel layer in primary teeth is a thin superficial layer of approximately 25 micrometres.

• A. Straight
• B. Shallow
• C. Bent
• D. Curved

Explanation: In permanent teeth, enamel rods are bent in the cervical region and near occlusal or incisal edges rather than following a uniformly…

• A. As lines in the enamel running at right angles to the enamel surface
• B. As lines in the dentin running at right angles to the dentino-enamel junction
• C. In dentin and follow the appositional pattern
• D. In enamel and follow the apposition pattern

Explanation: Lines of Retzius are incremental growth lines in enamel that record the appositional rhythm of ameloblast activity.

• A. Odontoblasts
• B. Ameloblasts
• C. Cracks
• D. Hypocalcified rods

Explanation: Enamel spindles are extensions of odontoblast processes that become trapped across the dentino-enamel junction during enamel formation.

• A. Hyperplasia
• B. Normal development
• C. Hypoplacification
• D. Interstitial development

Explanation: Perikymata are shallow grooves or ridges on the enamel surface that represent the external endings of the incremental lines of Retzius.

• A. A tumour of the jaw
• B. A tissue from which tooth erupts
• C. A cell from which tooth enamel is formed:
• D. Pertaining to dentin

Explanation: Ameloblasts are specialized epithelial cells that secrete and form the enamel matrix during amelogenesis.

• A. None of the above
• B. Square
• C. Round
• D. Key hole or paddle shaped

Explanation: In cross-section, most enamel rods have a keyhole or paddle-shaped outline, with a rounded head and a narrower tail.