Histopathology of Dental Caries MCQs
👉 Histopathology of Dental Caries Lecture
1. Enamel caries is initiated:
A) Beneath dental plaque deposits ✓
B) At the dentinoenamel junction
C) Inside dentin
D) In pulp
2. The earliest clinical sign of smooth surface caries is:
B) White spot lesion ✓
A) Brown cavitation
C) Black pit
D) Fractured enamel
3. Smooth surface caries commonly occurs on:
B) Gingival third of buccal/lingual surfaces ✓
A) Occlusal pits
C) Incisal edges
D) Root surface
4. Histologically, smooth surface caries shows:
A) Loss of interprismatic substance ✓
B) Hypermineralized enamel
C) Normal incremental lines of Retzius
D) Thickened pulp
5. Pit and fissure caries lesion shape:
B) Triangular, apex at tooth surface ✓
A) Cone-shaped, apex toward DEJ
C) Circular
D) Rectangular
6. In pit and fissure caries, early dentin involvement is:
B) Common due to thin enamel ✓
A) Rare
C) Impossible
D) Only in primary teeth
7. Which histological zone in enamel is most porous?
B) Translucent zone ✓
A) Surface zone
C) Dark zone
D) Body of lesion
8. The zone that always appears dark under polarized light is:
B) Dark zone ✓
A) Surface zone
C) Body of lesion
D) Translucent zone
9. The zone with highest fluoride concentration is:
A) Surface zone ✓
B) Translucent zone
C) Dark zone
D) Body of lesion
10. Recognizing white spot lesions allows:
B) Preventive and remineralization therapy ✓
A) Immediate extraction
C) Root canal therapy
D) Ignoring caries
11. The apex of smooth surface caries lesion points:
B) Toward DEJ ✓
A) Toward pulp
C) Toward enamel surface
D) Toward cementum
12. Caries progression in enamel primarily involves:
B) Demineralization of enamel ✓
A) Protein degradation
C) Collagen breakdown
D) Tubule sclerosis
13. Accentuated incremental lines of Retzius are seen in:
B) Enamel caries ✓
A) Advanced dentinal caries
C) Cementum caries
D) Pulpitis
14. A clinical “catch” on explorer is characteristic of:
B) Pit and fissure caries ✓
A) Smooth surface caries
C) Dentin sclerosis
D) Transparent dentin
15. Final stage of enamel caries shows:
B) Rough, demineralized enamel ✓
A) Transparent tubules
C) Normal enamel
D) Odontoblastic proliferation
16. Dentinal caries is faster than enamel caries because:
B) Dentin offers less resistance to acid ✓
A) Dentin has fewer tubules
C) Pulp is non-vital
D) Enamel is soft
17. Color of dentinal caries is usually:
B) Brown ✓
A) White
C) Transparent
D) Bluish
18. Dentinal sclerosis refers to:
B) Calcification of dentinal tubules ✓
A) Demineralization of enamel
C) Fatty degeneration of pulp
D) Cleft formation
19. Transparent dentin forms when:
A) Tubules are fully filled with calcified material ✓
B) Enamel is decalcified
C) Pulp necrosis occurs
D) Incremental lines of Retzius are accentuated
20. Pioneer bacteria are found:
B) In a few initial tubules ✓
A) In all tubules
C) Only in enamel
D) Only in pulp
21. Fatty degeneration of Tome’s fibers:
B) Predisposes to sclerosis ✓
A) Occurs in enamel
C) Causes cavitation
D) Is unrelated to caries
22. Microbial pattern near dentin surface is:
B) Acidophilic bacteria ✓
A) Proteolytic bacteria
C) Viral infection
D) Fungal infection
23. Microbial pattern in deeper dentin:
B) Proteolytic bacteria ✓
A) Acid-loving bacteria
C) Gram-negative cocci
D) Enamel rods
24. Advanced dentinal changes include:
A) Tubule decalcification ✓
B) Incremental lines of Retzius
C) Enamel opacity
D) Surface remineralization
25. Liquefaction foci are:
B) Ovoid necrotic areas along dentinal tubules ✓
A) Cavities in enamel
C) Transparent enamel rods
D) Healthy dentin
26. Triangular dentin lesions have apex pointing:
B) Toward pulp ✓
A) Toward enamel
C) Toward gingiva
D) Toward DEJ
27. Leathery necrotic dentin is:
B) Necrotic dentin after decalcification and proteolysis ✓
A) Soft, demineralized enamel
C) Transparent dentin
D) Cementum layer
28. Clefts in dentin:
B) Run perpendicular to tubules ✓
A) Run parallel to tubules
C) Are only in enamel
D) Are filled with odontoblasts
29. Dentinal caries progresses faster than enamel due to:
A) Lower mineral content ✓
B) Bacterial absence
C) Tubule sclerosis
D) Surface remineralization
30. Color change in dentin is due to:
B) Pigments, protein breakdown, external stains ✓
A) Only protein breakdown
C) Enamel rods
D) Pulp calcification
👉 Histopathology of Dental Caries Lecture
31. The pulp-dentin complex functions as:
B) Structural & functional unit ✓
A) Non-vital structure
C) Enamel reinforcement
D) Plaque barrier
32. Early dentinal changes are more common in:
B) Chronic, slow caries ✓
A) Acute caries
C) Pit and fissure only
D) Root caries
33. Transparent dentin shows:
A) Soft intertubular dentin ✓
B) Hard enamel
C) Necrotic pulp
D) Cavitated enamel
34. Proteolytic bacteria predominate in:
B) Deeper dentin ✓
A) Enamel surface
C) Pulp only
D) Cementum
35. Acidophilic bacteria predominate in:
B) Near dentin surface ✓
A) Deeper dentin
C) Pulp chamber
D) Cementum
36. Tubule walls decalcify in:
B) Advanced dentinal caries ✓
A) Early dentinal caries
C) Surface enamel only
D) Healthy dentin
37. Sheath of Neumann swelling is seen in:
B) Advanced dentinal caries ✓
A) Enamel caries
C) Root cementum
D) Odontoblasts
38. Dentinal lesion shape is:
B) Triangular toward pulp ✓
A) Cone-shaped toward enamel
C) Circular
D) Rectangular
39. Tubule diameter increases in:
B) Advanced dentinal caries ✓
A) Early dentinal caries
C) Surface enamel only
D) Healthy dentin
40. Dentin cannot self-repair when:
A) Mineral content is low & collagen denatured ✓
B) Tubules are sclerotic
C) Enamel intact
D) Surface zone intact
41. Zone 1 dentin shows:
B) Fatty degeneration of Tome’s fibers; otherwise normal ✓
A) Bacterial invasion
C) Decalcification
D) Necrotic dentin
42. Zone 2 dentin:
B) Intertubular demineralization, tubules filled with Ca salts ✓
A) Tubules filled with bacteria
C) Decalcified dentin
D) Decomposed dentin
43. Zone 2 dentin can:
A) Remineralize ✓
B) Cannot repair
C) Always requires removal
D) Be necrotic
44. Zone 4 dentin:
B) Tubules filled with bacteria ✓
A) Normal dentin
C) Surface enamel only
D) Transparent dentin
45. Zone 5 dentin:
B) Necrotic, outermost, must remove ✓
A) Healthy dentin
C) Dentinal sclerosis
D) Early lesion
46. Bacteria are present in which zones?
C) Zone 4 & 5 ✓
A) Zone 1 & 2
B) Zone 3 only
D) All zones
47. Softened intertubular dentin is seen in:
A) Zone 3 ✓
B) Zone 2
C) Zone 4
D) Zone 1
48. Which zone is capable of remineralization?
A) Zone 2 ✓
B) Zone 4
C) Zone 5
D) Zone 3
49. Zone of bacterial invasion must:
B) Be removed during prep ✓
A) Be monitored only
C) Remineralize
D) Be ignored
50. Outermost decomposed dentin must:
B) Be removed completely ✓
A) Remain intact
C) Only be polished
D) Be filled with fluoride
51. Recognition of white spot lesions allows:
A) Conservative treatment ✓
B) Immediate RCT
C) Extraction
D) Ignoring caries
52. Cone-shaped lesion apex toward DEJ is seen in:
A) Smooth surface caries ✓
B) Pit & fissure caries
C) Dentinal caries
D) Pulpitis
53. Triangular lesion apex toward pulp is seen in:
B) Dentinal caries ✓
A) Enamel caries
C) Cementum caries
D) Root caries
54. Early enamel lesion under plaque:
A) White spot ✓
B) Black cavitation
C) Transparent dentin
D) Necrotic dentin
55. Enamel rods in pit & fissure caries:
A) Follow lesion direction ✓
B) Remain intact
C) Decalcify last
D) Form clefts
56. Advanced dentinal lesion may show:
A) Clefts perpendicular to tubules ✓
B) Transparent enamel
C) Incremental lines of Retzius
D) Surface remineralization
57. Histological zones help in:
A) Preventive care ✓
B) Ignoring lesions
C) Immediate extraction
D) Root canal therapy
58. Clinical “catch” on explorer indicates:
B) Pit & fissure caries ✓
A) Smooth surface caries
C) Dentinal sclerosis
D) Transparent dentin
59. Lesion progression knowledge helps:
A) Conservative caries management ✓
B) Aggressive extraction
C) Immediate RCT
D) Avoid fluoride
60. Dark zone in enamel under polarized light:
B) Always present ✓
A) Most porous
C) Least demineralized
D) Surface remineralized
