INBDE Comprehensive Practice Exam
2026 | 100 Questions & Answers with
Detailed Rationales | Integrated
National Board Dental Examination
Prep & Study Guide
1. A 52-year-old patient presents with spontaneous, lingering pain to cold in
the mandibular first molar. Radiographs show no obvious periapical
radiolucency. The tooth is not tender to percussion. Which pulpal diagnosis
is most appropriate?
A. Normal pulp
B. Reversible pulpitis
C. Symptomatic irreversible pulpitis
D. Pulp necrosis
Answer: Symptomatic irreversible pulpitis
Rationale: Lingering spontaneous thermal pain is characteristic of irreversible
pulpal inflammation. A normal periapical radiograph does not exclude
,significant pulpal disease, particularly in early stages before apical tissue
changes develop.
2. A patient has a mandibular first molar with a large occlusal restoration. The
tooth is painful to biting and to release of pressure. Which condition should
be strongly suspected?
A. Reversible pulpitis
B. Cracked tooth syndrome
C. Chronic apical abscess
D. Hypercementosis
Answer: Cracked tooth syndrome
Rationale: Pain on biting or, particularly, on release of biting pressure is strongly
associated with a cracked tooth. The crack may allow movement of dentin
segments and pulpal irritation even when conventional radiographs appear
normal.
3. A 45-year-old patient has generalized attachment loss, probing depths of 5–
7 mm, bleeding on probing, and radiographic horizontal bone loss. Which
finding most strongly indicates periodontitis rather than gingivitis?
A. Gingival erythema
B. Bleeding on probing
C. Clinical attachment loss
D. Plaque accumulation
Answer: Clinical attachment loss
Rationale: Periodontitis is defined by inflammation associated with loss of
periodontal attachment and supporting bone. Gingivitis does not cause
permanent attachment loss.
4. A patient with severe chronic periodontitis has a molar with probing depths
of 8 mm and furcation involvement extending completely through the
furcation. What is the appropriate furcation classification?
,A. Grade I
B. Grade II
C. Grade III
D. Grade IV
Answer: Grade III
Rationale: Grade III furcation involvement represents a through-and-through
furcation that is clinically detectable with a probe but may not necessarily be
visible because of soft-tissue coverage. Grade IV additionally involves clinically
visible furcation because of gingival recession.
5. A patient presents with a painless, well-circumscribed unilocular
radiolucency surrounding the crown of an unerupted mandibular third
molar and attached near the CEJ. What is the most likely diagnosis?
A. Odontogenic keratocyst
B. Dentigerous cyst
C. Radicular cyst
D. Periapical cemento-osseous dysplasia
Answer: Dentigerous cyst
Rationale: A dentigerous cyst characteristically surrounds the crown of an
unerupted tooth and attaches near the cemento-enamel junction. It is one of the
most common developmental odontogenic cysts.
6. A 19-year-old patient has a radiolucent lesion associated with an unerupted
mandibular canine. The lesion contains small radiopaque flecks resembling
miniature teeth. Which diagnosis is most likely?
A. Ameloblastoma
B. Odontoma
C. Odontogenic myxoma
D. Central giant cell granuloma
Answer: Odontoma
, Rationale: Odontomas are hamartomatous odontogenic lesions containing
dental hard tissues. Compound odontomas often contain multiple tooth-like
structures and commonly occur in the anterior maxilla.
7. A 24-year-old patient has a multilocular "soap-bubble" radiolucency in the
posterior mandible with expansion and root resorption. Which diagnosis is
most likely?
A. Ameloblastoma
B. Periapical cyst
C. Condensing osteitis
D. Simple bone cyst
Answer: Ameloblastoma
Rationale: Conventional ameloblastoma frequently occurs in the posterior
mandible and can produce a multilocular soap-bubble or honeycomb
radiographic appearance, with cortical expansion and root resorption.
8. Which odontogenic tumor is particularly associated with an unerupted
tooth and frequently occurs in younger patients?
A. Adenomatoid odontogenic tumor
B. Cementoblastoma
C. Ameloblastoma
D. Odontogenic fibroma
Answer: Adenomatoid odontogenic tumor
Rationale: Adenomatoid odontogenic tumors commonly occur in adolescents
and young adults, frequently around an unerupted canine. They may contain
fine radiopaque calcifications within a radiolucent lesion.
9. A patient develops a rapidly enlarging painless mandibular swelling.
Imaging demonstrates a destructive "sunburst" periosteal reaction. Which
malignancy should be suspected?
2026 | 100 Questions & Answers with
Detailed Rationales | Integrated
National Board Dental Examination
Prep & Study Guide
1. A 52-year-old patient presents with spontaneous, lingering pain to cold in
the mandibular first molar. Radiographs show no obvious periapical
radiolucency. The tooth is not tender to percussion. Which pulpal diagnosis
is most appropriate?
A. Normal pulp
B. Reversible pulpitis
C. Symptomatic irreversible pulpitis
D. Pulp necrosis
Answer: Symptomatic irreversible pulpitis
Rationale: Lingering spontaneous thermal pain is characteristic of irreversible
pulpal inflammation. A normal periapical radiograph does not exclude
,significant pulpal disease, particularly in early stages before apical tissue
changes develop.
2. A patient has a mandibular first molar with a large occlusal restoration. The
tooth is painful to biting and to release of pressure. Which condition should
be strongly suspected?
A. Reversible pulpitis
B. Cracked tooth syndrome
C. Chronic apical abscess
D. Hypercementosis
Answer: Cracked tooth syndrome
Rationale: Pain on biting or, particularly, on release of biting pressure is strongly
associated with a cracked tooth. The crack may allow movement of dentin
segments and pulpal irritation even when conventional radiographs appear
normal.
3. A 45-year-old patient has generalized attachment loss, probing depths of 5–
7 mm, bleeding on probing, and radiographic horizontal bone loss. Which
finding most strongly indicates periodontitis rather than gingivitis?
A. Gingival erythema
B. Bleeding on probing
C. Clinical attachment loss
D. Plaque accumulation
Answer: Clinical attachment loss
Rationale: Periodontitis is defined by inflammation associated with loss of
periodontal attachment and supporting bone. Gingivitis does not cause
permanent attachment loss.
4. A patient with severe chronic periodontitis has a molar with probing depths
of 8 mm and furcation involvement extending completely through the
furcation. What is the appropriate furcation classification?
,A. Grade I
B. Grade II
C. Grade III
D. Grade IV
Answer: Grade III
Rationale: Grade III furcation involvement represents a through-and-through
furcation that is clinically detectable with a probe but may not necessarily be
visible because of soft-tissue coverage. Grade IV additionally involves clinically
visible furcation because of gingival recession.
5. A patient presents with a painless, well-circumscribed unilocular
radiolucency surrounding the crown of an unerupted mandibular third
molar and attached near the CEJ. What is the most likely diagnosis?
A. Odontogenic keratocyst
B. Dentigerous cyst
C. Radicular cyst
D. Periapical cemento-osseous dysplasia
Answer: Dentigerous cyst
Rationale: A dentigerous cyst characteristically surrounds the crown of an
unerupted tooth and attaches near the cemento-enamel junction. It is one of the
most common developmental odontogenic cysts.
6. A 19-year-old patient has a radiolucent lesion associated with an unerupted
mandibular canine. The lesion contains small radiopaque flecks resembling
miniature teeth. Which diagnosis is most likely?
A. Ameloblastoma
B. Odontoma
C. Odontogenic myxoma
D. Central giant cell granuloma
Answer: Odontoma
, Rationale: Odontomas are hamartomatous odontogenic lesions containing
dental hard tissues. Compound odontomas often contain multiple tooth-like
structures and commonly occur in the anterior maxilla.
7. A 24-year-old patient has a multilocular "soap-bubble" radiolucency in the
posterior mandible with expansion and root resorption. Which diagnosis is
most likely?
A. Ameloblastoma
B. Periapical cyst
C. Condensing osteitis
D. Simple bone cyst
Answer: Ameloblastoma
Rationale: Conventional ameloblastoma frequently occurs in the posterior
mandible and can produce a multilocular soap-bubble or honeycomb
radiographic appearance, with cortical expansion and root resorption.
8. Which odontogenic tumor is particularly associated with an unerupted
tooth and frequently occurs in younger patients?
A. Adenomatoid odontogenic tumor
B. Cementoblastoma
C. Ameloblastoma
D. Odontogenic fibroma
Answer: Adenomatoid odontogenic tumor
Rationale: Adenomatoid odontogenic tumors commonly occur in adolescents
and young adults, frequently around an unerupted canine. They may contain
fine radiopaque calcifications within a radiolucent lesion.
9. A patient develops a rapidly enlarging painless mandibular swelling.
Imaging demonstrates a destructive "sunburst" periosteal reaction. Which
malignancy should be suspected?
