NDEB (National Dental Examining Board of Canada)
Exam
2026-2027 • 200 Questions • 100% VERIFIED
Introduction
This assessment serves as a definitive examination evaluation resource for candidates preparing
for the NDEB (National Dental Examining Board of Canada) Exam (2026-2027) Comprehensive
Assessment. Designed to evaluate comprehensive clinical competence, diagnostic judgment, and
evidence-based treatment planning, this question bank rigorously addresses key content domains
mapped to the official NDEB blueprint. Key domains evaluated include Operative Dentistry,
Endodontics, Periodontics, Oral and Maxillofacial Surgery, Oral Pathology, Orthodontics, Pediatric
Dentistry, Prosthodontics, Dental Pharmacology, and Canadian Dental Ethics. Mastery of these
clinical disciplines is essential for achieving national certification, securing provincial licensure, and
executing ethical, high-quality patient care across dental operations in Canada.
Question 1: During the preparation of a Class II amalgam cavity, what is the primary purpose of
creating an occlusal cavosurface margin angle of 90 degrees?
A) To maximize the strength of both the dental amalgam and the adjacent enamel margin.
B) To increase the chemical adhesion of amalgam to dentin.
C) To allow easy placement of composite resin liners.
D) To eliminate the need for matrix band placement.
Correct Answer: A) To maximize the strength of both the dental amalgam and the
adjacent enamel margin.
Rationale: Dental amalgam is a brittle material with low edge strength. A 90-degree
cavosurface margin angle provides a butt-joint margin, preventing thin, weak overhangs of
amalgam or unsupported enamel rods that would otherwise fracture under occlusal forces.
Question 2: Which factor has the greatest influence on minimizing polymerization shrinkage stress
(C-factor) during direct composite resin restorations?
A) Using a high-intensity halogen light for 5 seconds.
B) Incremental placement of composite resin in layers less than 2 mm thick.
C) Applying air-driven handpieces at maximum speed.
D) Etching dentin for 60 seconds with phosphoric acid.
Correct Answer: B) Incremental placement of composite resin in layers less than 2 mm
thick.
Rationale: Incremental placement of composite resin reduces the Configuration Factor (C-
factor)—the ratio of bonded to unbonded surfaces—thereby reducing volumetric
polymerization contraction stress, microleakage, and post-operative sensitivity.
,Question 3: What is the primary mechanism by which 37% phosphoric acid etching prepares
enamel for adhesive resin bonding?
A) Dissolving the organic collagen matrix in enamel.
B) Promoting chemical chelation with calcium ions.
C) Selectively dissolving hydroxyapatite crystals to create microscopic surface irregularities for
mechanical resin tags.
D) Neutralizing intraoral salivary enzymes.
Correct Answer: C) Selectively dissolving hydroxyapatite crystals to create microscopic
surface irregularities for mechanical resin tags.
Rationale: Acid etching with 37% phosphoric acid selectively dissolves hydroxyapatite crystals
from enamel rods, producing microscopic microporosities into which low-viscosity resin
bonding agent flows and polymerizes, creating mechanical micro-retentive tags.
Question 4: Which property renders conventional glass ionomer cements (GIC) uniquely beneficial
in patients with high caries risk?
A) High compressive strength equal to dental amalgam.
B) Rapid setting time under moisture contamination.
C) Superior translucency matching feldspathic porcelain.
D) Long-term fluoride release and capacity to recharge fluoride from intraoral fluoride sources.
Correct Answer: D) Long-term fluoride release and capacity to recharge fluoride from
intraoral fluoride sources.
Rationale: Conventional glass ionomer cements release fluoride continuously into adjacent
tooth structure over extended periods and absorb fluoride from toothpaste/mouthwashes
('recharging'), providing a cariostatic effect at restoration margins.
Question 5: What material is indicated for direct pulp capping when a tiny mechanical exposure of
healthy pulp tissue occurs in a clean, isolated cavity preparation?
A) Mineral Trioxide Aggregate (MTA) or Calcium Silicate-based cement.
B) Zinc Phosphate cement.
C) Unfilled bis-GMA resin bonding agent.
D) Zinc Oxide Eugenol (ZOE) impression paste.
Correct Answer: A) Mineral Trioxide Aggregate (MTA) or Calcium Silicate-based cement.
Rationale: Mineral Trioxide Aggregate (MTA) or calcium silicate-based cements are
biocompatible, stimulate dentin bridge formation by odontoblasts, maintain a tight seal, and
promote pulpal healing following mechanical exposure.
Question 6: When placing a Class II composite restoration, what is the main function of a wooden
wedge placed interproximally below the gingival margin?
A) Etching the adjacent root surface.
, B) Slightly separating adjacent teeth and compressing the matrix band tightly against the
gingival margin to prevent overhangs.
C) Polishing the composite resin surface.
D) Inactivating oral bacteria in the gingival sulcus.
Correct Answer: B) Slightly separating adjacent teeth and compressing the matrix band
tightly against the gingival margin to prevent overhangs.
Rationale: Interproximal wedges separate adjacent teeth slightly (compensating for matrix
band thickness) and seal the matrix band flush against the gingival cavosurface margin,
preventing material overhangs and ensuring proper proximal contact.
Question 7: According to Caries Management by Risk Assessment (CAMBRA) guidelines, which
clinical finding classifies a patient immediately into the high caries risk category?
A) Presence of dark staining in occlusal fissures without cavitation.
B) Wearing a removable acrylic nightguard.
C) Visible cavitation or radiographic dentinal caries lesions present within the past 3 years.
D) Drinking fluoridated municipal tap water.
Correct Answer: C) Visible cavitation or radiographic dentinal caries lesions present
within the past 3 years.
Rationale: Under CAMBRA protocols, disease indicators such as active cavitated lesions,
radiographic dentinal caries, or carious lesions within the preceding 36 months automatically
categorize a patient as high caries risk.
Question 8: What etiology describes non-carious loss of tooth structure at the cervical area caused
by heavy eccentric occlusal loading and microfracture of enamel rods?
A) Attrition.
B) Abrasion.
C) Erosion.
D) Abfraction.
Correct Answer: D) Abfraction.
Rationale: Abfraction is the loss of cervical tooth structure resulting from occlusal flexure and
mechanical stress concentration, leading to microfracture of enamel and dentin at the cervical
fulcrum.
Question 9: Which cavity preparation feature provides primary retention form for an Class II
amalgam restoration in a permanent molar?
A) Occlusally converging vertical internal walls.
B) Beveling the cavosurface margin to 45 degrees.
C) Undercutting the enamel margin with a diamond disc.
D) Applying a thick layer of cavity varnish.
Correct Answer: A) Occlusally converging vertical internal walls.
, Rationale: Primary retention form for amalgam restorations is achieved by creating vertical
walls (buccal and lingual) that converge slightly toward the occlusal surface, preventing vertical
dislodgement of the restoration.
Question 10: What function does a silane coupling agent perform during the adhesive cementation
of a feldspathic porcelain veneer?
A) Bleaching intrinsic dentin discoloration.
B) Forming a chemical bond between inorganic silica in porcelain and organic resin in cement.
C) Accelerating the light-curing unit output.
D) Preventing postoperative pulpal inflammation.
Correct Answer: B) Forming a chemical bond between inorganic silica in porcelain and
organic resin in cement.
Rationale: Silane coupling agents contain bifunctional molecules that bond chemically to
inorganic silicon dioxide in etched porcelain on one end and to the organic resin matrix of
composite cement on the other.
Question 11: What is the primary advantage of resin-modified glass ionomer (RMGI) over
conventional glass ionomer cement?
A) Complete elimination of fluoride release.
B) Ability to bond to gold alloys without etching.
C) Immediate light-cured setting, higher early physical strength, and lower moisture sensitivity
during setting.
D) Higher radiopacity than dental amalgam.
Correct Answer: C) Immediate light-cured setting, higher early physical strength, and
lower moisture sensitivity during setting.
Rationale: RMGI incorporates photo-cured resin monomers into the glass ionomer matrix,
providing instant initial set upon light activation, improved early fracture toughness, and
reduced susceptibility to early moisture contamination.
Question 12: Which etching time parameter is recommended for dentin when using a total-etch
(etch-and-rinse) bonding system to avoid collagen collapse?
A) 60 seconds.
B) 45 seconds.
C) 30 seconds.
D) 15 seconds.
Correct Answer: D) 15 seconds.
Rationale: Over-etching dentin beyond 15 seconds removes mineral content too deeply,
exposing thick collagen networks that cannot be fully penetrated by bonding resin, leading to
hybrid layer defects and post-op sensitivity.
Exam
2026-2027 • 200 Questions • 100% VERIFIED
Introduction
This assessment serves as a definitive examination evaluation resource for candidates preparing
for the NDEB (National Dental Examining Board of Canada) Exam (2026-2027) Comprehensive
Assessment. Designed to evaluate comprehensive clinical competence, diagnostic judgment, and
evidence-based treatment planning, this question bank rigorously addresses key content domains
mapped to the official NDEB blueprint. Key domains evaluated include Operative Dentistry,
Endodontics, Periodontics, Oral and Maxillofacial Surgery, Oral Pathology, Orthodontics, Pediatric
Dentistry, Prosthodontics, Dental Pharmacology, and Canadian Dental Ethics. Mastery of these
clinical disciplines is essential for achieving national certification, securing provincial licensure, and
executing ethical, high-quality patient care across dental operations in Canada.
Question 1: During the preparation of a Class II amalgam cavity, what is the primary purpose of
creating an occlusal cavosurface margin angle of 90 degrees?
A) To maximize the strength of both the dental amalgam and the adjacent enamel margin.
B) To increase the chemical adhesion of amalgam to dentin.
C) To allow easy placement of composite resin liners.
D) To eliminate the need for matrix band placement.
Correct Answer: A) To maximize the strength of both the dental amalgam and the
adjacent enamel margin.
Rationale: Dental amalgam is a brittle material with low edge strength. A 90-degree
cavosurface margin angle provides a butt-joint margin, preventing thin, weak overhangs of
amalgam or unsupported enamel rods that would otherwise fracture under occlusal forces.
Question 2: Which factor has the greatest influence on minimizing polymerization shrinkage stress
(C-factor) during direct composite resin restorations?
A) Using a high-intensity halogen light for 5 seconds.
B) Incremental placement of composite resin in layers less than 2 mm thick.
C) Applying air-driven handpieces at maximum speed.
D) Etching dentin for 60 seconds with phosphoric acid.
Correct Answer: B) Incremental placement of composite resin in layers less than 2 mm
thick.
Rationale: Incremental placement of composite resin reduces the Configuration Factor (C-
factor)—the ratio of bonded to unbonded surfaces—thereby reducing volumetric
polymerization contraction stress, microleakage, and post-operative sensitivity.
,Question 3: What is the primary mechanism by which 37% phosphoric acid etching prepares
enamel for adhesive resin bonding?
A) Dissolving the organic collagen matrix in enamel.
B) Promoting chemical chelation with calcium ions.
C) Selectively dissolving hydroxyapatite crystals to create microscopic surface irregularities for
mechanical resin tags.
D) Neutralizing intraoral salivary enzymes.
Correct Answer: C) Selectively dissolving hydroxyapatite crystals to create microscopic
surface irregularities for mechanical resin tags.
Rationale: Acid etching with 37% phosphoric acid selectively dissolves hydroxyapatite crystals
from enamel rods, producing microscopic microporosities into which low-viscosity resin
bonding agent flows and polymerizes, creating mechanical micro-retentive tags.
Question 4: Which property renders conventional glass ionomer cements (GIC) uniquely beneficial
in patients with high caries risk?
A) High compressive strength equal to dental amalgam.
B) Rapid setting time under moisture contamination.
C) Superior translucency matching feldspathic porcelain.
D) Long-term fluoride release and capacity to recharge fluoride from intraoral fluoride sources.
Correct Answer: D) Long-term fluoride release and capacity to recharge fluoride from
intraoral fluoride sources.
Rationale: Conventional glass ionomer cements release fluoride continuously into adjacent
tooth structure over extended periods and absorb fluoride from toothpaste/mouthwashes
('recharging'), providing a cariostatic effect at restoration margins.
Question 5: What material is indicated for direct pulp capping when a tiny mechanical exposure of
healthy pulp tissue occurs in a clean, isolated cavity preparation?
A) Mineral Trioxide Aggregate (MTA) or Calcium Silicate-based cement.
B) Zinc Phosphate cement.
C) Unfilled bis-GMA resin bonding agent.
D) Zinc Oxide Eugenol (ZOE) impression paste.
Correct Answer: A) Mineral Trioxide Aggregate (MTA) or Calcium Silicate-based cement.
Rationale: Mineral Trioxide Aggregate (MTA) or calcium silicate-based cements are
biocompatible, stimulate dentin bridge formation by odontoblasts, maintain a tight seal, and
promote pulpal healing following mechanical exposure.
Question 6: When placing a Class II composite restoration, what is the main function of a wooden
wedge placed interproximally below the gingival margin?
A) Etching the adjacent root surface.
, B) Slightly separating adjacent teeth and compressing the matrix band tightly against the
gingival margin to prevent overhangs.
C) Polishing the composite resin surface.
D) Inactivating oral bacteria in the gingival sulcus.
Correct Answer: B) Slightly separating adjacent teeth and compressing the matrix band
tightly against the gingival margin to prevent overhangs.
Rationale: Interproximal wedges separate adjacent teeth slightly (compensating for matrix
band thickness) and seal the matrix band flush against the gingival cavosurface margin,
preventing material overhangs and ensuring proper proximal contact.
Question 7: According to Caries Management by Risk Assessment (CAMBRA) guidelines, which
clinical finding classifies a patient immediately into the high caries risk category?
A) Presence of dark staining in occlusal fissures without cavitation.
B) Wearing a removable acrylic nightguard.
C) Visible cavitation or radiographic dentinal caries lesions present within the past 3 years.
D) Drinking fluoridated municipal tap water.
Correct Answer: C) Visible cavitation or radiographic dentinal caries lesions present
within the past 3 years.
Rationale: Under CAMBRA protocols, disease indicators such as active cavitated lesions,
radiographic dentinal caries, or carious lesions within the preceding 36 months automatically
categorize a patient as high caries risk.
Question 8: What etiology describes non-carious loss of tooth structure at the cervical area caused
by heavy eccentric occlusal loading and microfracture of enamel rods?
A) Attrition.
B) Abrasion.
C) Erosion.
D) Abfraction.
Correct Answer: D) Abfraction.
Rationale: Abfraction is the loss of cervical tooth structure resulting from occlusal flexure and
mechanical stress concentration, leading to microfracture of enamel and dentin at the cervical
fulcrum.
Question 9: Which cavity preparation feature provides primary retention form for an Class II
amalgam restoration in a permanent molar?
A) Occlusally converging vertical internal walls.
B) Beveling the cavosurface margin to 45 degrees.
C) Undercutting the enamel margin with a diamond disc.
D) Applying a thick layer of cavity varnish.
Correct Answer: A) Occlusally converging vertical internal walls.
, Rationale: Primary retention form for amalgam restorations is achieved by creating vertical
walls (buccal and lingual) that converge slightly toward the occlusal surface, preventing vertical
dislodgement of the restoration.
Question 10: What function does a silane coupling agent perform during the adhesive cementation
of a feldspathic porcelain veneer?
A) Bleaching intrinsic dentin discoloration.
B) Forming a chemical bond between inorganic silica in porcelain and organic resin in cement.
C) Accelerating the light-curing unit output.
D) Preventing postoperative pulpal inflammation.
Correct Answer: B) Forming a chemical bond between inorganic silica in porcelain and
organic resin in cement.
Rationale: Silane coupling agents contain bifunctional molecules that bond chemically to
inorganic silicon dioxide in etched porcelain on one end and to the organic resin matrix of
composite cement on the other.
Question 11: What is the primary advantage of resin-modified glass ionomer (RMGI) over
conventional glass ionomer cement?
A) Complete elimination of fluoride release.
B) Ability to bond to gold alloys without etching.
C) Immediate light-cured setting, higher early physical strength, and lower moisture sensitivity
during setting.
D) Higher radiopacity than dental amalgam.
Correct Answer: C) Immediate light-cured setting, higher early physical strength, and
lower moisture sensitivity during setting.
Rationale: RMGI incorporates photo-cured resin monomers into the glass ionomer matrix,
providing instant initial set upon light activation, improved early fracture toughness, and
reduced susceptibility to early moisture contamination.
Question 12: Which etching time parameter is recommended for dentin when using a total-etch
(etch-and-rinse) bonding system to avoid collagen collapse?
A) 60 seconds.
B) 45 seconds.
C) 30 seconds.
D) 15 seconds.
Correct Answer: D) 15 seconds.
Rationale: Over-etching dentin beyond 15 seconds removes mineral content too deeply,
exposing thick collagen networks that cannot be fully penetrated by bonding resin, leading to
hybrid layer defects and post-op sensitivity.
