A. Seventh and eight years
B. Seventh and ninth years
C. Seventh and tenth years
D. Seventh and Twelfth years
✅ The correct answer is option D. Seventh and Twelfth years.
Oral Anatomy
What is the thickness of the layer of primsless enamel found in primary teeth_____________?
A. 25 μm
B. 50μm
C. 75μm
D. 100μm
✅ The correct answer is option A. 25 μm.
Mesiolingual grooves may be found on which of the following permanent teeth ______________?
A. Mandibular second molars
B. Mandibular first premolars
C. Maxillary first molars
D. Maxillary canines
✅ The correct answer is option B. Mandibular first premolars.
The zygomatic bone does not articulate with________________?
A. Frontal bone
B. Maxillary bone
C. Nasal bone
D. Temporal bone
✅ The correct answer is option C. Nasal bone.
Rounded protuberances on the incisal edges of newly erupted permanent incisors are____________?
A. Mamelons
B. Tubercles
C. Enamel pits
D. Cingulum
✅ The correct answer is option A. Mamelons.
Generally , contact areas between posterior teeth are located in which directions from the centr of the proximal surface ____________?
A. Facially and occlusally
B. Facially and gingivally
C. Lingually and gingivally
D. Lingually and occlusally
✅ The correct answer is option A. Facially and occlusally.
The most constant and valuable trait to differentiate among maxillary first, second and third molars i____________?
A. Number of roots
B. Depth of central fossae
C. Comparative size of the cusp of carabelli
D. Relative position of the distolingual grooves
✅ The correct answer is option D. Relative position of the distolingual grooves.
The faciolingual angulation of the upper central incisor is approximately___________________?
A. 20°
B. 28°
C. 33°
D. 38°
✅ The correct answer is option B. 28°.
During the development of a tooth, sound coalescence of the lobes results in_____________?
A. Grooves
B. Fissures
C. Cusps
D. All of the above
✅ The correct answer is option A. Grooves.
The biting forces at molar region during mastication is_______________?
A. 20 to 55 pounds
B. 30 to 75 pounds
C. 50 to 75 pounds
D. 90 to 200 pounds
✅ The correct answer is option D. 90 to 200 pounds.