A. 0.4 mm
B. 0.3 mm
C. 0.2 mm
D. 0.7 mm
✅ The correct answer is option A. 0.4 mm.
Oral Histology
62. Incremental lines of retzius are seen in______________?
A. Enamel
B. Dentin
C. Cementum
D. Pulp
✅ The correct answer is option A. Enamel.
63. Cellular cementum is____________?
A. First formed cementum
B. Less calcified than acellular type
C. More calcified than acellular type
D. Less irregular
✅ The correct answer is option B. Less calcified than acellular type.
64. A purine which is found in saliva is_______________?
A. Uric acid
B. Thymine
C. Adenosine
D. Hypolithinium
✅ The correct answer is option C. Adenosine.
65. Blood supply of ameloblast for most of its life cycle comes form_______________?
A. Dental papilla
B. Reduced enamel organ
C. Dental Sac
D. Dental pulp
✅ The correct answer is option C. Dental Sac.
66. Ratio of diameter of enamel rods in the DEJ to the enamel surface is______________?
A. 1:4
B. 1:1
C. 1:2
D. 2:1
✅ The correct answer is option B. 1:1.
67. Movement of tooth to close the intermaxillary gap during eruption is due to____________?
A. Physiological tooth migration
B. Active eruption
C. Passive eruption
D. None of the above
✅ The correct answer is option B. Active eruption.
68. Mirgration of odontoblasts into dentinal tubules occurs during ________________?
A. Cavity preparation
B. Dehydration
C. Water irrigation
D. None of the above
✅ The correct answer is option A. Cavity preparation.
69. Organic portion can be separated from the mineral by_____________?
A. Incineration/organic chelation
B. Decalcification
C. Devitrification
D. Combustion
✅ The correct answer is option A. Incineration/organic chelation.
70. The average diameter of coronal dentinal tubules near the pulp is____________?
A. 0.2-0.5 microns
B. 2-3 microns
C. 0.2-0.3 microns
D. 7 microns
✅ The correct answer is option B. 2-3 microns.