1. Which of the following structures is not of ectodermal origin:
A. Hunter-schreger bands
B. Enamel spindles
C. Enamel tufts
D. Enamellamellae
3. Which of the following tissues have no reparative capacity :
A. Enamel
B. Dentin
C. Cementum
D. Periodontal ligament
4. The enamel has no capacity of self -repair because
A. It has only a small percent of organic content
B. Its formative cells are lost once it is completely formed
C. It is essentially a keratin tissue and has no blood vessels
D. It has no direct connection with the active cells of the dental pulp
5. The type of fibrous element in enamel is :
A. T ono filament
B. Keratin like fibre
C. Collagen fibre
D. Vimentin filament
6. Calcification in enamel starts at :
A. Enamel matrix
B. Root
C. CEJ
D. DEJ
7. Specific gravity of enamel is :
A. 2.8
B. 3.8
C. 4.8
D. 23
8. Inorganic content of enamel is about
A.3%
B.2%
C. 4%
D. 96%
9. Length of enamel rods is
A. Greater than the thickness of enamel
B. Less than the thickness of enamel
C. Equal to the thickness of enamel
D. None of the above
10. The diameter of the rod is
A. 4 Jlm
B. 9 Jlm
C. 7 Jlm
D. 2 Jlm
11. Which of the following statement is correct
A. In cross sections enamel rods appear hexagonal and resembles fish scales
B. The bodies of rods are near occlusal and incisal surfaces, where as the tails point cervically
C. The appatite crystals are parallel to bodies and deviate 65° from the tails.
D. All of the above
12. True about direction of enamel rods
A. They originate at right angle to dentin surface
B. They are almost vertical near the incisal edge (or) cusp tip areas
C. In the cervical third of deciduous crowns they are almost horizontal in direction
D. In cervical region of permanent teeth, they deviate in apical direction
E. All of the above
13. Thin leaf like structures that extend from enamel surface in to DEJ are
A. Enamel spindles
B. Enamellamella
C. Enamel tufts
D. Perikymata
14. Dentino enamel junction is
A. Non-scalloped
B. Straight
C. Scalloped and the convexities are directed towards dentin
D. Scalloped and the convexities are directed toward enamel
15. Hertwig's root sheath is formed from
A. Stratum inter medium
B. Stellate reticulum
C. Outer enamel epithelium
D. Cervical loop
16. Perikymata are the external manifestations of
A. Enamel rods
B. Incremental lines of retzius
C. Nasmyth's membrane
D. Pellicle
17. The percentage of inorganic matter in fully developed enamel is about
A. 66%
B. 76%
C. 86%
D. 96%
18. The enamel of the posterior teeth is thickest at
A. Cervical third of buccal surface
B. Middle third of buccal surface
C. Middle third of lingual surface
D. Occlusal surface
19. Enamel tufts are
A. Thin tuft like structure extending from enamel surface to dentin-enamel junction
B. Tuft like structure arising from dentin¬enamel junction towards enamel surface
C. Odontoblastic processes extending into enamel
D. None of the above
20. Following is not an external manifestation of enamel
A. Enamel tufts
B. Enamellamella
C. Incremental lines of enamel
D. Enamel cuticle
21. 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
22. Interwining of the enamel rods at the cusp tips and the incisal edges of a tooth is called
A. Enamel spindles
B. Gnarled enamel
C. Incremental lines of woven
D. Incremental lines of retzius
23. Incremental lines of retzius are seen in
A. Enamel
B. Dentin
C. Cementum
D. Pulp
24. All are true regarding the enamel spindles except
A. Produced by ameloblasts
B. Found in the region of cusps
C. Surrounded by inter prismatic enamel
D. Terminate as rounded process
25. Neonatal lines are found in all of the following except
A. Enamel of primary inc 'sors
B. Enamel of permanent canines
C. Enamel and dentin of permanent first molars
D. Dentin of permanent mandibular incisors
2.The formative cells of which of the following dental tissues disappear once tissue is formed
Enamel
Dentin
Periodontal ligament
Cementum