Exam 2026 | 100 Advanced Questions &
Answers with Detailed Rationales |
CRDTS Dental Licensing Exam Prep &
Study Guide
1. A patient presents for a posterior composite restoration on a mandibular
first molar. After rubber dam isolation, the clinician notices contamination
of the prepared cavity with saliva immediately before adhesive application.
What is the most appropriate next step?
A. Air-dry the cavity and continue with bonding
B. Apply additional bonding agent over the contaminated adhesive
C. Re-etch or otherwise recondition the surface according to the adhesive system
and repeat the bonding procedure
D. Place the composite directly over the contaminated adhesive
Answer: Re-etch or otherwise recondition the surface according to the adhesive
system and repeat the bonding procedure
,Rationale: Salivary contamination can compromise adhesive performance. The
contaminated surface should be managed according to the specific bonding
system rather than simply adding more adhesive.
2. During preparation of a Class II composite restoration, the proximal box
extends slightly subgingivally. Which factor is most critical for obtaining a
predictable restoration?
A. Increasing the occlusal convergence
B. Establishing adequate isolation and a controllable restorative margin
C. Eliminating all enamel at the marginal ridge
D. Using a thicker composite increment
Answer: Establishing adequate isolation and a controllable restorative margin
Rationale: Moisture control and access to the cervical margin are critical for
adhesive restorations. An inaccessible or contaminated margin substantially
increases the risk of postoperative problems and recurrent caries.
3. A patient has a deep carious lesion approaching the pulp but no
spontaneous pain, percussion sensitivity, or lingering thermal pain. Which
treatment strategy is generally most appropriate when the pulp is judged
vital and the lesion can be managed without exposing the pulp?
A. Immediate pulpectomy
B. Complete excavation regardless of pulp exposure risk
C. Selective caries removal with preservation of affected dentin near the pulp
D. Extraction
Answer: Selective caries removal with preservation of affected dentin near the
pulp
Rationale: In a vital tooth with no signs of irreversible pulpal disease, selective
removal can reduce the risk of pulp exposure while allowing definitive sealing of
the lesion.
, 4. A mandibular molar requires a full-coverage crown. Which feature of the
preparation most directly improves resistance form?
A. Excessively tapered axial walls
B. Short preparation with rounded occlusal anatomy
C. Adequate axial wall height with minimal appropriate taper
D. Removal of all proximal tooth structure
Answer: Adequate axial wall height with minimal appropriate taper
Rationale: Resistance form is enhanced by adequate preparation height and
appropriately parallel opposing walls. Excessive taper reduces the ability of the
preparation to resist lateral and rotational forces.
5. A maxillary anterior crown is planned for a patient with a high smile line.
Which margin location is generally preferred when esthetics and
periodontal health can both be maintained?
A. Deep subgingival placement in all cases
B. Supragingival placement whenever clinically possible
C. Extension to the alveolar crest
D. Placement directly on the epithelial attachment
Answer: Supragingival placement whenever clinically possible
Rationale: Supragingival margins facilitate isolation, impression accuracy,
hygiene, and periodontal health. Subgingival placement should be used only
when clinically indicated, such as for esthetics or retention.
6. A patient reports sharp pain to cold that disappears immediately after the
stimulus is removed. Radiographic examination reveals a deep restoration
without periapical pathology. Which pulpal diagnosis is most consistent
with this presentation?
A. Symptomatic irreversible pulpitis
B. Asymptomatic apical periodontitis
, C. Reversible pulpitis
D. Pulp necrosis
Answer: Reversible pulpitis
Rationale: Brief, non-lingering thermal pain is characteristic of reversible pulpal
inflammation when other clinical findings support pulpal recovery.
7. A patient experiences lingering spontaneous pain, particularly at night,
from a mandibular molar. Cold testing produces intense pain that persists
after removal of the stimulus. What is the most likely diagnosis?
A. Normal pulp
B. Reversible pulpitis
C. Symptomatic irreversible pulpitis
D. Pulp necrosis
Answer: Symptomatic irreversible pulpitis
Rationale: Spontaneous pain and prolonged thermal response are classic
findings associated with irreversible pulpal inflammation.
8. During endodontic treatment, an instrument separates in the apical third of
a curved canal. The patient has no acute symptoms, and the canal was
previously negotiable. What should primarily guide management?
A. Automatic extraction
B. Immediate surgical removal in every case
C. Canal anatomy, infection status, fragment location, and ability to disinfect the
remaining canal
D. Ignoring the fragment without documenting it
Answer: Canal anatomy, infection status, fragment location, and ability to
disinfect the remaining canal
Rationale: Instrument separation does not automatically mandate extraction or
surgery. Prognosis depends heavily on whether adequate disinfection can be
achieved and whether the fragment interferes with treatment.