Enamel Most Important MCQs

1 - All are true about the striae of retzius except___________?

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A. Constitute the rest lines with in the enamel rods

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B. Have high inorganic content

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C. They are areas of increased porosity

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D. Allow the movement of water and small ions

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Have high inorganic content

2 - All are true regarding the enamel spindles except____________?

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A. Produced by ameloblasts

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B. Found in the region of cusps

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C. Surrounded by inter prismatic enamel

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D. Terminate as rounded process

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Produced by ameloblasts

3 - Ameloblasts is______________?

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A. A cell from which tooth enamel is formed:

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B. A tissue from which tooth erupts

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C. A tumour of the jaw

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D. Pertaining to dentin

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A cell from which tooth enamel is formed:

4 - Among the following the structure that is most calcified is_______________?

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A. Enamel lamella

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B. Enamel rod

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C. Enamel spindle

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D. Enamel tuft

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Enamel rod

5 - Approximately how many enamel rods will be present in a maxillary molar ?

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A. 5 million

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B. 7 million

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C. 9 million

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D. 12 million

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12 million

6 - Blunt cell processes seen on the developing ameloblasts are celled as________________?

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A. Tomes fibres

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B. Tomes layer

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C. Tomes processes

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D. Odontoblastic processes

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Tomes fibres

7 - calcification in enamel starts at____________?

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A. Enamel matrix

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B. Root

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C. CEJ

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D. DEJ

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DEJ

8 - Chronological hypoplasia is_____________?

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A. Hypoplasia of local origin

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B. Hypoplasia of systemic origin

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C. Hypoplasia of hereditary origin

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D. None of the above

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Hypoplasia of systemic origin

9 - Dark bonds that are present in enamel rods at intervals of 4 μms are______________?

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A. Neonantal bands

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B. Cross striations

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C. Striae of Retzius

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D. Hunter-Schregar bands

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Cross striations

10 - Dentino enamel junction is_________________?

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A. Non-scalloped

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B. Straight

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C. Scalloped and the convexities are directed towards dentin

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D. Scalloped and the convexities are directed towards enamel

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Scalloped and the convexities are directed towards dentin

11 - Enamel can act in a sense like a_______________?

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A. Permeable membrane

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B. Impermeable membrane

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C. Semipermeable membrane

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D. Infrapermeable membrane

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Semipermeable membrane

12 - Enamel is laid down______________?

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A. Mainly by odontoblasts

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B. Mainly by ameloblasts

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C. Only on odontoblasts

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D. Only by ameloblasts

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Only by ameloblasts

13 - Enamel rods at the cervical area at the occlusal edge and incisal lip in permanent teeth are______________?

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A. Straight

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B. Shallow

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C. Bent

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D. Curved

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Bent

14 - Enamel spindles are formed by______________?

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A. Cracks

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B. Ameloblasts

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C. Odontoblasts

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D. Hypocalcified rods

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Odontoblasts

15 - Enamel tufts are_______________?

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A. Thin tuft like structure extending from enamel surface of dentin enamel junction

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B. Tuft like structure arising from dentin-enamel junction towards enamel surface

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C. Odontoblastic processes extending into enamel

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D. None of the above

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Tuft like structure arising from dentin-enamel junction towards enamel surface

16 - Following is not an external manifestation of enamel________________?

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A. Enamel tufts

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B. Enamel lamella

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C. Incremental lines of enamel

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D. Enamel cuticle

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Enamel tufts

17 - Formation of dentin by odontoblasts begins in_______________?

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A. Morphogenic stage

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B. Organizing stage

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C. Desmolytic stage

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D. Formative stage

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Organizing stage

18 - Hertwig's root sheath is formed from______________?

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A. Stratum inter medium

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B. Stellate reticulum

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C. Outer enamel epithelium

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D. Cervical loop

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Cervical loop

19 - Hunter Schreger band are____________?

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A. Dark and light bands of enamel seen in longitudinal ground section

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B. Dark and light bands of enamel seen in horizontal ground section

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C. Dark and light brands of dentin seen in longitudinal section

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D. Dark and light bands of dentin seen in horizontal

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Dark and light bands of enamel seen in longitudinal ground section

20 - Incremental lines of Retzius appear_____________?

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A. As lines in the enamel running at right angles to the enamel surface

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B. As lines in the dentin running at right angles to the dentino-enamel junction

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C. In enamel and follow the apposition pattern

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D. In dentin and follow the appositional pattern

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In enamel and follow the apposition pattern

21 - Incremental lines of retzius are seen in______________?

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A. Enamel

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B. Dentin

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C. Cementum

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D. Pulp

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Enamel

22 - Inorganic content of enamel is about______________?

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A. 0.35

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B. 0.5

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C. 0.04

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D. 0.96

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0.96

23 - Interwining of the enamel rods at the cusp timps and the incisal edges of a tooth is called______________?

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A. Enamel spindles

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B. Gnarled enamel

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C. Incremental lies of woven

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D. Incremental lines of retzius

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Gnarled enamel

24 - Ionic exchange between enamel surface and environment______________?

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A. Does not take place once enamel surface and invironment

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B. Stops after 2 years of eruption

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C. Continues till adult life

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D. Continues through out life

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Continues through out life

25 - Length of enamel rods is_____________?

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A. Greater than the thickness of enamel

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B. Less than the thickness of enamel

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C. Equal to the thickness of enimal

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D. None of the above

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Greater than the thickness of enamel

26 - Maximum amount of phosphate is seen in_______________?

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A. Bone

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B. Enamel

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C. Gingiva

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D. Dentin

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Enamel

27 - Metalloprotienases are used in which stage of the amelogenesis_____________?

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A. Organising

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B. Formative/ Secretory

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C. Protective

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D. Desmolytic

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Formative/ Secretory

28 - Moth eaten appearance of of enamel is seen in____________?

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A. Odontodysplasia

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B. Amelogenisis stage

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C. Desmolytic stage

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D. Mottled enamel

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Odontodysplasia

29 - narled enamel is seen in_____________?

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A. Proximal surface of tooth

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B. Cervical region of tooth

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C. Cusp tips of tooth

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D. All of the above

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Cusp tips of tooth

30 - Neonatal line is also referred to as______________?

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A. Retzius line

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B. Line of cross striations

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C. Incremental lines

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D. Line of enamel tufts

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Incremental lines

31 - Neonatal lines are found in all of the following except____________?

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A. Enamel of primary incisors

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B. Enamel of permanent canines

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C. Enamel and dentin of permanent first molars

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D. Dentin of permanent mandibular incisors

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Enamel of permanent canines

32 - Neonatal lines are seen in_______________?

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A. Enamel of deciduous incisiors

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B. Enamel of permanent incisors

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C. Enamel of premolars

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D. Dentin of all teeth, as if is formed first

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Enamel of deciduous incisiors

33 - Non acidic, nonionic protein which helps in enamel mineralization _______________?

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A. Tuftelin

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B. Sheathlin

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C. Enamelin

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D. Amelogenin

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Amelogenin

34 - Nutritional supply of the ameloblasts during most of their life cycle is from the_____________?

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A. Dental pulp

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B. Odontoblastic processes

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C. Dental sac

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D. Reduced dental organ

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Dental sac

35 - On microscopic examination enamel rods have___________?

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A. Key hole appearance in cross section

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B. Paddle appearance in cross section

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C. Lanullate appearance in cross-section

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D. None of the above

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Key hole appearance in cross section

36 - perikymata are the external surface manifestations of_____________?

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A. Enamel rods

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B. Incremental lines of retzius

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C. Nasmyth's membrane

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D. Pellicle

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Incremental lines of retzius

37 - Ratio of diameter of enamel rods in the DEJ to the enamel surface is______________?

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A. 0.044444444444

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B. 0.042361111111

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C. 0.043055555556

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D. 0.084027777778

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0.042361111111

38 - Shape of enamel rod is______________?

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A. Key hole or paddle shaped

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B. Square

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C. Round

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D. None of the above

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Key hole or paddle shaped

39 - Specific gravity of enamel is_____________?

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A. 2.8

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B. 3.8

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C. 4.8

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D. 2.3

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2.8

40 - Synthesis of enamel matrix proteins occurs in the________________?

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A. Outer enamel epithelium

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B. Ameloblast

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C. Stratum intermedium

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D. Stratum granulosum

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Ameloblast

41 - The average width of enamel rods is______________?

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A. 10mm

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B. 5mm

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C. 2mm

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D. 0.5mm

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5mm

42 - The class of low molecular weight calcium binding proteins seen predominantly in developing enamel are_____________?

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A. Enamelin

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B. Amelogenin

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C. Tuftelin

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D. Ameloplakin

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Amelogenin

43 - The diameter of the rod is______________?

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A. 4 μ m

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B. 9 μ m

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C. 7 μ m

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D. 2 μ m

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4 μ m

44 - The enamel has no capacity of self repair because______________?

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A. It has only a small percent of organic content

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B. Its formative cells are lost once it is completely formed

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C. It is essentially a keratin tissue and has no blood vessels

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D. It has no direct connection with the active cells of the dental pulp

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Its formative cells are lost once it is completely formed

45 - The enamel of the posterior teeth is thickest at____________?

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A. Cervical third of buccal surface

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B. Middle third of buccal surface

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C. Middle third of lingual surface

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D. Occlusal surface

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Occlusal surface

46 - The formative cells of which of the following dental tissues disappear once tissue is formed___________?

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A. Enamel

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B. Dentin

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C. Periodontal ligament

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D. Cementum

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Enamel

47 - The key hole, pattern appearance in the cross section is feature of______________?

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A. Aprismatic enamel

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B. Prismatic enamel

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C. Intertubular dentin

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D. Intratubular dentin

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Prismatic enamel

48 - The percentage of inorganic matter in fully developed enamel is about____________?

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A. 0.66

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B. 0.76

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C. 0.86

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D. 0.96

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0.96

49 - The shallow furrows on the enamel surface, where stria of Retzius end are known as _______________ ?

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A. Cracks

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B. Pellicle

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C. perikymata

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D. Enamel lamellae

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perikymata

50 - The small ridges, perikymata, seen on facial surfaces of canines are the result of_____________?

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A. Hyperplasia

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B. Hypoplacification

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C. Normal development

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D. Interstitial development

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Normal development

51 - The striking difference between enamel and other mineralized tissues is______________?

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A. Presence of high percentage of organic matrix

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B. Presence of incremental lines

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C. Enamel has high reparative capacity

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D. Most of organic component is lost during mineralization

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Most of organic component is lost during mineralization

52 - The thickness of prismless enamel in diciduous teeth is______________?

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A. 25 μ m

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B. 50 μ m

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C. 75 μ m

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D. 100 μ m

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25 μ m

53 - The type of fibrous element in enamel is_____________?

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A. Tono filament

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B. Keratin like fibre

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C. Collagen fibre

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D. Vimentin filament

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Keratin like fibre

54 - Thin leaf like structures that extend from enamel surface in to DEJ are____________?

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A. Enamel spindles

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B. Enamel lamella

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C. Enamel tufts

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D. Perikymata

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Enamel lamella

55 - True about direction of enamel rods______________?

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A. They originate at right angle to dentin surface

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B. They are almost vertical near the incisal edge (or) cusp tip areas

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C. In the cervical third of deciduous crowns they are almost horizontal in direction

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D. All of the above

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All of the above

56 - Which of the following is correct about enamel crystals ?

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A. Same as dentin crystals

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B. Contains organic portion in the center

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C. Roughly texagonal in shape

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D. Their diameter is about 5 microns in size

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Roughly texagonal in shape

57 - Which of the following statement is correct_________________?

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A. In cross sections enamel rods appear hexagonal and resembles fish scales

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B. The bodies of rods are near occlusal and incisal surfaces, where as the tails point cervically

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C. The apatite crystals are parallel to bodies and deviate 65° from the tails

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D. All of the above

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All of the above

58 - Which of the following statement is false______________?

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A. Resorption of roots of deciduous incisors and canines begins on their lingual surfaces

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B. Resorption of roots of deciduous molars begins on their inner surfaces

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C. Shedding of deciduous teeth is delayed in the absence of their successor teeth

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D. None of the above

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None of the above

59 - Which of the following structures is not of ectodermal origin_______________?

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A. Hunter schreger bands

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B. Enamel spindles

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C. Enamel tufts

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D. Enamel lamellae

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Enamel spindles

60 - Which of the following tissues have no reparative capacity______________?

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A. Enamel

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B. Dentin

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C. Cementum

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D. Periodontal ligament

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Enamel

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