Commission on Dental Competency
Assessments Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationales 2027 Q&A | Instant
Download Pdf
Question 1
A patient presents with a deep carious lesion on a vital permanent tooth.
The tooth is asymptomatic, and the pulp is not exposed after caries removal.
Which restorative material is most appropriate for protecting the remaining
dentin near the pulp?
A. Zinc phosphate cement
B. Calcium hydroxide or a suitable hydraulic calcium-silicate liner
C. Amalgam without a liner
D. Temporary zinc oxide-eugenol only
Answer: B. Calcium hydroxide or a suitable hydraulic calcium-silicate liner
,Rationale: A pulp-protective liner may be indicated in selected deep areas
when the remaining dentin is very thin. Hydraulic calcium-silicate
materials are commonly used because of their biocompatibility and ability
to support reparative dentin formation.
Question 2
Which instrument is primarily used to detect calculus deposits and explore
tooth surfaces for caries or irregularities?
A. Periodontal probe
B. Explorer
C. Spoon excavator
D. Gingival margin trimmer
Answer: B. Explorer
Rationale: An explorer is designed for tactile detection of calculus, caries,
defective margins, and surface irregularities. A periodontal probe is
primarily used to measure probing depths and assess periodontal tissues.
Question 3
During periodontal probing, a healthy periodontal sulcus generally
measures:
,A. 0–1 mm
B. 1–3 mm
C. 4–6 mm
D. 7–9 mm
Answer: B. 1–3 mm
Rationale: Healthy gingival sulci generally measure approximately 1–3 mm
when measured with a periodontal probe. Deeper measurements may
indicate periodontal pocketing or other pathology, depending on clinical
findings.
Question 4
Which local anesthetic technique is most commonly required to anesthetize
a mandibular first molar?
A. Posterior superior alveolar nerve block
B. Inferior alveolar nerve block
C. Greater palatine nerve block
D. Nasopalatine nerve block
Answer: B. Inferior alveolar nerve block
Rationale: The inferior alveolar nerve block anesthetizes the mandibular
teeth on the injected side, including the molars, although supplemental
anesthesia may sometimes be necessary.
, Question 5
What is the primary purpose of rubber dam isolation during restorative
treatment?
A. Increase saliva production
B. Improve moisture control and patient protection
C. Eliminate the need for local anesthesia
D. Increase occlusal contact
Answer: B. Improve moisture control and patient protection
Rationale: Rubber dam isolation provides a relatively dry operating field,
improves visibility and access, and helps protect the patient from
aspiration or swallowing of instruments and restorative materials.
Question 6
Which matrix system is particularly useful for restoring a posterior Class II
composite resin?
A. Circumferential matrix or sectional matrix system
B. Mylar strip only
C. Orthodontic band only
D. Impression tray
Answer: A. Circumferential matrix or sectional matrix system
Assessments Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationales 2027 Q&A | Instant
Download Pdf
Question 1
A patient presents with a deep carious lesion on a vital permanent tooth.
The tooth is asymptomatic, and the pulp is not exposed after caries removal.
Which restorative material is most appropriate for protecting the remaining
dentin near the pulp?
A. Zinc phosphate cement
B. Calcium hydroxide or a suitable hydraulic calcium-silicate liner
C. Amalgam without a liner
D. Temporary zinc oxide-eugenol only
Answer: B. Calcium hydroxide or a suitable hydraulic calcium-silicate liner
,Rationale: A pulp-protective liner may be indicated in selected deep areas
when the remaining dentin is very thin. Hydraulic calcium-silicate
materials are commonly used because of their biocompatibility and ability
to support reparative dentin formation.
Question 2
Which instrument is primarily used to detect calculus deposits and explore
tooth surfaces for caries or irregularities?
A. Periodontal probe
B. Explorer
C. Spoon excavator
D. Gingival margin trimmer
Answer: B. Explorer
Rationale: An explorer is designed for tactile detection of calculus, caries,
defective margins, and surface irregularities. A periodontal probe is
primarily used to measure probing depths and assess periodontal tissues.
Question 3
During periodontal probing, a healthy periodontal sulcus generally
measures:
,A. 0–1 mm
B. 1–3 mm
C. 4–6 mm
D. 7–9 mm
Answer: B. 1–3 mm
Rationale: Healthy gingival sulci generally measure approximately 1–3 mm
when measured with a periodontal probe. Deeper measurements may
indicate periodontal pocketing or other pathology, depending on clinical
findings.
Question 4
Which local anesthetic technique is most commonly required to anesthetize
a mandibular first molar?
A. Posterior superior alveolar nerve block
B. Inferior alveolar nerve block
C. Greater palatine nerve block
D. Nasopalatine nerve block
Answer: B. Inferior alveolar nerve block
Rationale: The inferior alveolar nerve block anesthetizes the mandibular
teeth on the injected side, including the molars, although supplemental
anesthesia may sometimes be necessary.
, Question 5
What is the primary purpose of rubber dam isolation during restorative
treatment?
A. Increase saliva production
B. Improve moisture control and patient protection
C. Eliminate the need for local anesthesia
D. Increase occlusal contact
Answer: B. Improve moisture control and patient protection
Rationale: Rubber dam isolation provides a relatively dry operating field,
improves visibility and access, and helps protect the patient from
aspiration or swallowing of instruments and restorative materials.
Question 6
Which matrix system is particularly useful for restoring a posterior Class II
composite resin?
A. Circumferential matrix or sectional matrix system
B. Mylar strip only
C. Orthodontic band only
D. Impression tray
Answer: A. Circumferential matrix or sectional matrix system
