DANB GC EXAM– QUESTIONS AND ANSWERS | VERIFIED AND
WELL DETAILED ANSWERS PLUS RATIONALES | GUARANTEED
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1. A dental assistant is reviewing patient records to ensure all medical histories are current
before treatment begins. Which of the following conditions represents a critical medical
alert that requires immediate consultation with the treating dentist prior to administering
local anesthesia containing a vasoconstrictor?
A. Mild seasonal allergic rhinitis
B. Controlled stage 1 hypertension
C. Unstable angina or recent myocardial infarction within the past six months
D. History of mild childhood asthma with no recent attacks
ANSWER: C. Unstable angina or recent myocardial infarction within the past six months
Unstable angina and recent myocardial infarction are critical cardiovascular
contraindications for vasoconstrictors like epinephrine, as they significantly increase cardiac
workload and risk acute cardiac events. Mild conditions do not pose the same high-risk
threshold.
2. During a routine composite restoration procedure, the dentist asks the dental assistant to
prepare the phosphoric acid etchant. What is the primary clinical objective of applying a
37% phosphoric acid etchant to enamel prior to bonding?
A. To create microscopic irregularities and microporosities in the enamel surface for mechanical
interlocking of the resin bonding agent
B. To chemically bond the composite resin directly to the dentin tubules without a primer
C. To permanently bleach the underlying tooth structure to a lighter shade
D. To neutralize any existing bacteria inside the pulp chamber
ANSWER: A. To create microscopic irregularities and microporosities in the enamel
surface for mechanical interlocking of the resin bonding agent
Acid etching dissolves microscopic inorganic components of enamel, creating an irregular
surface topography that allows low-viscosity resin to flow into the pores and create a strong
mechanical bond. It does not bond chemically to dentin or bleach teeth.
,3. A patient presents with acute throbbing pain in a mandibular molar. Clinical and
radiographic examinations reveal irreversible pulpitis. Which of the following procedures
is indicated to manage this condition definitively?
A. Direct pulp capping with calcium hydroxide
B. Scaling and root planing
C. Root canal treatment (endodontic therapy) or extraction
D. Placement of a temporary sedative filling without pulpal intervention
ANSWER: C. Root canal treatment (endodontic therapy) or extraction
Irreversible pulpitis means the dental pulp is inflamed beyond healing; therefore, definitive
treatment requires removing the diseased pulp tissue entirely via root canal therapy or tooth
extraction. Sedative fillings alone are insufficient.
4. When assisting with a crown preparation on tooth #30, the dentist uses a high-speed
handpiece with a diamond bur. What is the primary operational purpose of the water
spray emitted by the high-speed handpiece?
A. To cool the tooth structure and prevent thermal pulpal trauma from frictional heat generated
by high-speed rotation
B. To lubricate the internal gears of the handpiece turbine
C. To wash away excess saliva so the patient can swallow comfortably
D. To increase the setting time of composite resin materials
ANSWER: A. To cool the tooth structure and prevent thermal pulpal trauma from
frictional heat generated by high-speed rotation
High-speed handpieces generate intense frictional heat that can permanently damage the
dental pulp if water coolant is not continuously sprayed on the tooth structure during cutting.
5. A dental assistant is mixing zinc phosphate cement for permanent crown cementation.
The manufacturer’s instructions state to mix the powder in small increments over an
extended slab area. What is the primary chemical reason for this technique?
A. Zinc phosphate setting is an exothermic reaction; mixing slowly on a cool glass slab
dissipates heat and extends working time
B. It accelerates the setting reaction so the crown hardens instantly
,C. It turns the liquid cement into a gel consistency immediately
D. It prevents the powder from absorbing moisture from the room air
ANSWER: A. Zinc phosphate setting is an exothermic reaction; mixing slowly on a cool
glass slab dissipates heat and extends working time
Zinc phosphate cement releases significant heat as it sets. Utilizing a cool glass slab and
incorporating powder in small increments helps dissipate this heat, controlling setting time
and preventing premature hardening.
6. Which of the following instruments is classified as a hand-cutting instrument specifically
designed to bevel the gingival margins of a class II cavity preparation?
A. Enamel hatchet
B. Gingival margin trimmer
C. Spoon excavator
D. Ball burnisher
ANSWER: B. Gingival margin trimmer
Gingival margin trimmers are specifically angled and calibrated to place bevels on gingival
enamel margins in proximal box preparations. Spoon excavators remove decay, and hatchets
cleave enamel.
7. A patient in the dental chair suddenly exhibits signs of severe respiratory distress,
wheezing, and swelling of the lips and tongue shortly after receiving penicillin. Which
emergency medication should the dentist administer immediately?
A. Nitroglycerin sublingually
B. Epinephrine intramuscularly or subcutaneously
C. Aspirin chewable tablets
D. Glucose gel orally
ANSWER: B. Epinephrine intramuscularly or subcutaneously
Anaphylaxis is a life-threatening allergic reaction characterized by bronchospasm and
angioedema. Epinephrine is the primary, life-saving emergency drug used to reverse
anaphylactic shock.
, 8. Which of the following impression materials undergoes a physical change from a sol to a
gel state during setting and is classified as a reversible hydrocolloid?
A. Polyether
B. Addition silicone (polyvinyl siloxane)
C. Agar impression material
D. Irreversible hydrocolloid (alginate)
ANSWER: C. Agar impression material
Agar is a reversible hydrocolloid that transitions physically between sol and gel states based on
temperature changes. Alginate is irreversible because its setting involves a chemical reaction.
9. During a Class II amalgam restoration on tooth #14, the dentist places a Tofflemire
matrix retainer and band. What is the primary function of the wedge placed in the gingival
embrasure?
A. To widen the tooth permanently so it never shifts
B. To adapt the matrix band tightly against the gingival cavosurface margin, preventing
overhangs and establishing proper interproximal contact
C. To hold the rubber dam in place on adjacent teeth
D. To deliver fluoride directly into the interdental papilla
ANSWER: B. To adapt the matrix band tightly against the gingival cavosurface margin,
preventing overhangs and establishing proper interproximal contact
Wedging separates teeth slightly to compensate for the thickness of the matrix band and firmly
presses the band against the gingival margin to prevent excess restorative material
(overhangs) from extruding.
10. Which of the following classification of carious lesions involves the pits and fissures of
the occlusal surfaces of posterior teeth, as well as the buccal and lingual surfaces?
A. Class I
B. Class II
C. Class III
D. Class V
WELL DETAILED ANSWERS PLUS RATIONALES | GUARANTEED
PASS | LATEST EXAM UPDATE | EXAM PREP | STUDY GUIDE |
PRACTICE TEST| DOWNLOAD INSTANT PDF
1. A dental assistant is reviewing patient records to ensure all medical histories are current
before treatment begins. Which of the following conditions represents a critical medical
alert that requires immediate consultation with the treating dentist prior to administering
local anesthesia containing a vasoconstrictor?
A. Mild seasonal allergic rhinitis
B. Controlled stage 1 hypertension
C. Unstable angina or recent myocardial infarction within the past six months
D. History of mild childhood asthma with no recent attacks
ANSWER: C. Unstable angina or recent myocardial infarction within the past six months
Unstable angina and recent myocardial infarction are critical cardiovascular
contraindications for vasoconstrictors like epinephrine, as they significantly increase cardiac
workload and risk acute cardiac events. Mild conditions do not pose the same high-risk
threshold.
2. During a routine composite restoration procedure, the dentist asks the dental assistant to
prepare the phosphoric acid etchant. What is the primary clinical objective of applying a
37% phosphoric acid etchant to enamel prior to bonding?
A. To create microscopic irregularities and microporosities in the enamel surface for mechanical
interlocking of the resin bonding agent
B. To chemically bond the composite resin directly to the dentin tubules without a primer
C. To permanently bleach the underlying tooth structure to a lighter shade
D. To neutralize any existing bacteria inside the pulp chamber
ANSWER: A. To create microscopic irregularities and microporosities in the enamel
surface for mechanical interlocking of the resin bonding agent
Acid etching dissolves microscopic inorganic components of enamel, creating an irregular
surface topography that allows low-viscosity resin to flow into the pores and create a strong
mechanical bond. It does not bond chemically to dentin or bleach teeth.
,3. A patient presents with acute throbbing pain in a mandibular molar. Clinical and
radiographic examinations reveal irreversible pulpitis. Which of the following procedures
is indicated to manage this condition definitively?
A. Direct pulp capping with calcium hydroxide
B. Scaling and root planing
C. Root canal treatment (endodontic therapy) or extraction
D. Placement of a temporary sedative filling without pulpal intervention
ANSWER: C. Root canal treatment (endodontic therapy) or extraction
Irreversible pulpitis means the dental pulp is inflamed beyond healing; therefore, definitive
treatment requires removing the diseased pulp tissue entirely via root canal therapy or tooth
extraction. Sedative fillings alone are insufficient.
4. When assisting with a crown preparation on tooth #30, the dentist uses a high-speed
handpiece with a diamond bur. What is the primary operational purpose of the water
spray emitted by the high-speed handpiece?
A. To cool the tooth structure and prevent thermal pulpal trauma from frictional heat generated
by high-speed rotation
B. To lubricate the internal gears of the handpiece turbine
C. To wash away excess saliva so the patient can swallow comfortably
D. To increase the setting time of composite resin materials
ANSWER: A. To cool the tooth structure and prevent thermal pulpal trauma from
frictional heat generated by high-speed rotation
High-speed handpieces generate intense frictional heat that can permanently damage the
dental pulp if water coolant is not continuously sprayed on the tooth structure during cutting.
5. A dental assistant is mixing zinc phosphate cement for permanent crown cementation.
The manufacturer’s instructions state to mix the powder in small increments over an
extended slab area. What is the primary chemical reason for this technique?
A. Zinc phosphate setting is an exothermic reaction; mixing slowly on a cool glass slab
dissipates heat and extends working time
B. It accelerates the setting reaction so the crown hardens instantly
,C. It turns the liquid cement into a gel consistency immediately
D. It prevents the powder from absorbing moisture from the room air
ANSWER: A. Zinc phosphate setting is an exothermic reaction; mixing slowly on a cool
glass slab dissipates heat and extends working time
Zinc phosphate cement releases significant heat as it sets. Utilizing a cool glass slab and
incorporating powder in small increments helps dissipate this heat, controlling setting time
and preventing premature hardening.
6. Which of the following instruments is classified as a hand-cutting instrument specifically
designed to bevel the gingival margins of a class II cavity preparation?
A. Enamel hatchet
B. Gingival margin trimmer
C. Spoon excavator
D. Ball burnisher
ANSWER: B. Gingival margin trimmer
Gingival margin trimmers are specifically angled and calibrated to place bevels on gingival
enamel margins in proximal box preparations. Spoon excavators remove decay, and hatchets
cleave enamel.
7. A patient in the dental chair suddenly exhibits signs of severe respiratory distress,
wheezing, and swelling of the lips and tongue shortly after receiving penicillin. Which
emergency medication should the dentist administer immediately?
A. Nitroglycerin sublingually
B. Epinephrine intramuscularly or subcutaneously
C. Aspirin chewable tablets
D. Glucose gel orally
ANSWER: B. Epinephrine intramuscularly or subcutaneously
Anaphylaxis is a life-threatening allergic reaction characterized by bronchospasm and
angioedema. Epinephrine is the primary, life-saving emergency drug used to reverse
anaphylactic shock.
, 8. Which of the following impression materials undergoes a physical change from a sol to a
gel state during setting and is classified as a reversible hydrocolloid?
A. Polyether
B. Addition silicone (polyvinyl siloxane)
C. Agar impression material
D. Irreversible hydrocolloid (alginate)
ANSWER: C. Agar impression material
Agar is a reversible hydrocolloid that transitions physically between sol and gel states based on
temperature changes. Alginate is irreversible because its setting involves a chemical reaction.
9. During a Class II amalgam restoration on tooth #14, the dentist places a Tofflemire
matrix retainer and band. What is the primary function of the wedge placed in the gingival
embrasure?
A. To widen the tooth permanently so it never shifts
B. To adapt the matrix band tightly against the gingival cavosurface margin, preventing
overhangs and establishing proper interproximal contact
C. To hold the rubber dam in place on adjacent teeth
D. To deliver fluoride directly into the interdental papilla
ANSWER: B. To adapt the matrix band tightly against the gingival cavosurface margin,
preventing overhangs and establishing proper interproximal contact
Wedging separates teeth slightly to compensate for the thickness of the matrix band and firmly
presses the band against the gingival margin to prevent excess restorative material
(overhangs) from extruding.
10. Which of the following classification of carious lesions involves the pits and fissures of
the occlusal surfaces of posterior teeth, as well as the buccal and lingual surfaces?
A. Class I
B. Class II
C. Class III
D. Class V
