Biological consideration in operative dentistry - Copy

🔥 EXAM-PROOF MCQ BANK
During cavity preparation, preparation of 1 mm² of dentin exposes approximately:
a) 5,000–10,000 dentinal tubules
b) 10,000–20,000 dentinal tubules
c) 30,000–45,000 dentinal tubules
d) 50,000–70,000 dentinal tubules

Answer: c

Which of the following is considered the MOST important factor protecting the pulp?
a) Smear layer
b) Remaining dentin thickness
c) Coolant use
d) Handpiece speed

Answer: b

A remaining dentin thickness of 0.5 mm reduces pulpal irritation by approximately:
a) 50%
b) 60%
c) 75%
d) 90%

Answer: c

Which histopathological response is considered an EARLY reversible pulpal change?
a) Necrosis of cell-rich zone
b) Displacement of odontoblastic nuclei into dentinal tubules
c) Fibrosis of pulp
d) Complete odontoblast destruction

Answer: b

Heat generation during cavity preparation is directly proportional to:
a) Speed only
b) Pressure only
c) Pressure and contact time
d) Coolant usage

Answer: c

The MOST harmful handpiece speed in deep dentin without coolant is:
a)

Answer: c

Which factor does NOT contribute to thermogenesis?
a) Friction
b) Pressure
c) Contact surface area
d) Dentin permeability

Answer: d

Excessive pressure during cutting may lead to:
a) Reduced bacterial penetration
b) Pushing microorganisms into pulp
c) Decreased heat generation
d) Increased smear layer formation

Answer: b

Threshold pressure for pulpal irritation is approximately:
a) 100 g
b) 150 g
c) 226.7 g
d) 300 g

Answer: c

Deep cavity preparation results in:
a) Decreased pulpal reaction
b) Increased use of rotary instruments
c) Increased need for liners and bases
d) Reduced risk of irritation

Answer: c

Dentin desiccation causes pulpal irritation due to:
a) Inward fluid movement
b) Outward fluid movement
c) Bacterial invasion
d) Loss of smear layer

Answer: b

Which is a cause of dentin desiccation?
a) Use of water coolant
b) Hypertonic chemicals
c) Low-speed cutting
d) Thick dentin

Answer: b

Vibration or eccentric movement of bur leads to:
a) Controlled cutting
b) Reduced heat
c) Microcracks formation
d) Increased dentin thickness

Answer: c

Calcio-traumatic response is characterized by:
a) Uniform dentin formation
b) Dark blue dentin near pulp
c) Complete pulp necrosis
d) Absence of predentin

Answer: b

Pin insertion causes trauma primarily because:
a) Dentin is highly elastic
b) It exceeds elastic limits of dentin
c) It reduces heat
d) It decreases pressure

Answer: b

The smear layer is:
a) Highly organized structure
b) Cellular layer
c) Amorphous microcrystalline debris
d) Bacterial biofilm

Answer: c

Removal of smear layer results in:
a) Decreased permeability
b) No change
c) Increased dentin permeability
d) Reduced tubule exposure

Answer: c

Which material has minimal pulpal irritation and induces reparative dentin?
a) Zinc phosphate
b) Amalgam
c) Calcium hydroxide
d) Composite resin

Answer: c

The main function of cavity varnish is:
a) Thermal insulation
b) Reparative dentin formation
c) Reduce microleakage
d) Increase adhesion

Answer: c

Eugenol in ZOE provides:
a) Acidic irritation
b) Bactericidal destruction
c) Sedative and bacteriostatic effect
d) Heat insulation only

Answer: c

Zinc phosphate cement is highly irritating due to:
a) Neutral pH
b) High alkalinity
c) High initial acidity
d) Low thermal conductivity

Answer: c

Zinc polycarboxylate cement has low irritation because:
a) Small molecular size
b) High toxicity
c) Large molecular size limiting diffusion
d) Persistent acidity

Answer: c

Amalgam irritation in deep cavities is mainly due to:
a) Polymerization shrinkage
b) Mercury ion penetration
c) Low thermal conductivity
d) Alkaline pH

Answer: b

Composite resin causes pulpal irritation due to:
a) Lack of curing
b) Polymerization shrinkage and heat
c) Low thermal expansion
d) High pH

Answer: b

Subgingival extension of cavity is indicated EXCEPT:
a) Caries removal
b) Esthetics
c) Finishing margins
d) Routine preparation

Answer: d

Over-contouring restorations leads to:
a) Increased gingival stimulation
b) Food stagnation
c) Reduced plaque accumulation
d) Gingival strengthening

Answer: b

Under-contouring restorations results in:
a) Reduced pressure
b) Excessive food pressure on gingiva
c) Plaque elimination
d) No gingival effect

Answer: b

Improper contact and embrasures lead to:
a) Reduced caries risk
b) Food impaction
c) Improved occlusion
d) Gingival healing

Answer: b

Overhang of restorations causes:
a) Enamel strengthening
b) Gingival inflammation and bone resorption
c) Reduced plaque
d) Increased occlusal stability

Answer: b

Surface roughness of restorations leads to:
a) Smooth plaque flow
b) Reduced bacterial adhesion
c) Plaque retention and gingival irritation
d) Improved gingival health

Answer: c