INBDE Radiology & Diagnosis Practice
Exam 2026 | 100 Advanced Questions &
Answers with Detailed Rationales |
Integrated National Board Dental
Examination Prep & Study Guide
1. A 42-year-old patient presents with intermittent pain associated with the
mandibular first molar. A periapical radiograph shows a poorly defined
radiolucency at the apex. The tooth has a large restoration and does not
respond to cold testing. Which diagnosis best explains the radiographic
finding?
A. Condensing osteitis
B. Chronic apical abscess
C. Symptomatic irreversible pulpitis
D. Periapical cemento-osseous dysplasia
Answer: Chronic apical abscess
Rationale: A nonvital tooth associated with a periapical radiolucency and
clinical evidence of infection is most consistent with apical periodontitis
,progressing to a chronic apical abscess. The poorly defined radiolucency reflects
inflammatory bone destruction.
2. A radiograph demonstrates a well-circumscribed, unilocular radiolucency
surrounding the crown of an unerupted mandibular third molar and
extending along the cervical region. Which lesion is most likely?
A. Odontogenic keratocyst
B. Dentigerous cyst
C. Ameloblastoma
D. Traumatic bone cyst
Answer: Dentigerous cyst
Rationale: A dentigerous cyst characteristically attaches at the cemento-enamel
junction and surrounds the crown of an unerupted tooth. Large lesions can
extend considerably within the mandible.
3. A patient has a painless, slowly enlarging posterior mandibular swelling.
Imaging reveals a multilocular “soap-bubble” radiolucency with root
resorption and cortical expansion. Which diagnosis is most likely?
A. Simple bone cyst
B. Ameloblastoma
C. Periapical cyst
D. Central giant cell granuloma
Answer: Ameloblastoma
Rationale: A multilocular expansile radiolucency in the posterior mandible with
root resorption is highly characteristic of conventional ameloblastoma.
4. A mandibular molar demonstrates a diffuse radiopaque lesion surrounding
the roots, with the tooth remaining vital. The patient has no symptoms.
Which diagnosis is most likely?
A. Condensing osteitis
B. Cementoblastoma
,C. Focal cemento-osseous dysplasia
D. Hypercementosis
Answer: Focal cemento-osseous dysplasia
Rationale: Focal cemento-osseous dysplasia commonly occurs in middle-aged
adults, frequently in the posterior mandible, and progresses from radiolucent to
mixed and radiopaque stages. Associated teeth generally remain vital.
5. A radiograph shows a “sunburst” periosteal reaction associated with an
aggressive mandibular lesion. Which diagnosis should be strongly
considered?
A. Osteosarcoma
B. Fibrous dysplasia
C. Periapical cemento-osseous dysplasia
D. Odontoma
Answer: Osteosarcoma
Rationale: A sunburst pattern represents aggressive periosteal bone formation
and is classically associated with osteosarcoma. Widening of the periodontal
ligament space may also be an important early radiographic clue.
6. Which radiographic finding is most suggestive of early osteosarcoma of the
jaws?
A. Uniform narrowing of the periodontal ligament
B. Symmetric widening of the periodontal ligament space
C. Periapical sclerosis surrounding multiple vital teeth
D. Complete loss of the lamina dura throughout the dentition
Answer: Symmetric widening of the periodontal ligament space
Rationale: Widening of the periodontal ligament space, particularly when
irregular or asymmetric, can be an early sign of jaw osteosarcoma and should
prompt further investigation when clinically appropriate.
, 7. A panoramic image shows a radiopaque mass attached to the root of a vital
mandibular first molar, surrounded by a thin radiolucent halo. The patient
reports localized pain and swelling. What is the most likely diagnosis?
A. Hypercementosis
B. Cementoblastoma
C. Complex odontoma
D. Idiopathic osteosclerosis
Answer: Cementoblastoma
Rationale: Cementoblastoma is fused to the tooth root and is typically
surrounded by a radiolucent rim. Pain and expansion may occur, helping
distinguish it from asymptomatic hypercementosis.
8. A radiolucent lesion is discovered incidentally between the roots of the
mandibular canine and first premolar. The teeth are vital. The lesion is
small, well circumscribed, and heart-shaped on some projections. Which
diagnosis is most likely?
A. Lateral periodontal cyst
B. Globulomaxillary cyst
C. Periapical cyst
D. Odontogenic keratocyst
Answer: Lateral periodontal cyst
Rationale: A lateral periodontal cyst is typically a small, well-defined
radiolucency along the lateral root surface of a vital tooth, commonly in the
mandibular canine-premolar region.
9. A patient with generalized aggressive periodontitis undergoes full-mouth
radiographic evaluation. Which radiographic finding most strongly indicates
horizontal bone loss?
A. Bone height remains parallel to a line connecting adjacent CEJs
B. Bone loss occurs at a consistent angle across the affected teeth
Exam 2026 | 100 Advanced Questions &
Answers with Detailed Rationales |
Integrated National Board Dental
Examination Prep & Study Guide
1. A 42-year-old patient presents with intermittent pain associated with the
mandibular first molar. A periapical radiograph shows a poorly defined
radiolucency at the apex. The tooth has a large restoration and does not
respond to cold testing. Which diagnosis best explains the radiographic
finding?
A. Condensing osteitis
B. Chronic apical abscess
C. Symptomatic irreversible pulpitis
D. Periapical cemento-osseous dysplasia
Answer: Chronic apical abscess
Rationale: A nonvital tooth associated with a periapical radiolucency and
clinical evidence of infection is most consistent with apical periodontitis
,progressing to a chronic apical abscess. The poorly defined radiolucency reflects
inflammatory bone destruction.
2. A radiograph demonstrates a well-circumscribed, unilocular radiolucency
surrounding the crown of an unerupted mandibular third molar and
extending along the cervical region. Which lesion is most likely?
A. Odontogenic keratocyst
B. Dentigerous cyst
C. Ameloblastoma
D. Traumatic bone cyst
Answer: Dentigerous cyst
Rationale: A dentigerous cyst characteristically attaches at the cemento-enamel
junction and surrounds the crown of an unerupted tooth. Large lesions can
extend considerably within the mandible.
3. A patient has a painless, slowly enlarging posterior mandibular swelling.
Imaging reveals a multilocular “soap-bubble” radiolucency with root
resorption and cortical expansion. Which diagnosis is most likely?
A. Simple bone cyst
B. Ameloblastoma
C. Periapical cyst
D. Central giant cell granuloma
Answer: Ameloblastoma
Rationale: A multilocular expansile radiolucency in the posterior mandible with
root resorption is highly characteristic of conventional ameloblastoma.
4. A mandibular molar demonstrates a diffuse radiopaque lesion surrounding
the roots, with the tooth remaining vital. The patient has no symptoms.
Which diagnosis is most likely?
A. Condensing osteitis
B. Cementoblastoma
,C. Focal cemento-osseous dysplasia
D. Hypercementosis
Answer: Focal cemento-osseous dysplasia
Rationale: Focal cemento-osseous dysplasia commonly occurs in middle-aged
adults, frequently in the posterior mandible, and progresses from radiolucent to
mixed and radiopaque stages. Associated teeth generally remain vital.
5. A radiograph shows a “sunburst” periosteal reaction associated with an
aggressive mandibular lesion. Which diagnosis should be strongly
considered?
A. Osteosarcoma
B. Fibrous dysplasia
C. Periapical cemento-osseous dysplasia
D. Odontoma
Answer: Osteosarcoma
Rationale: A sunburst pattern represents aggressive periosteal bone formation
and is classically associated with osteosarcoma. Widening of the periodontal
ligament space may also be an important early radiographic clue.
6. Which radiographic finding is most suggestive of early osteosarcoma of the
jaws?
A. Uniform narrowing of the periodontal ligament
B. Symmetric widening of the periodontal ligament space
C. Periapical sclerosis surrounding multiple vital teeth
D. Complete loss of the lamina dura throughout the dentition
Answer: Symmetric widening of the periodontal ligament space
Rationale: Widening of the periodontal ligament space, particularly when
irregular or asymmetric, can be an early sign of jaw osteosarcoma and should
prompt further investigation when clinically appropriate.
, 7. A panoramic image shows a radiopaque mass attached to the root of a vital
mandibular first molar, surrounded by a thin radiolucent halo. The patient
reports localized pain and swelling. What is the most likely diagnosis?
A. Hypercementosis
B. Cementoblastoma
C. Complex odontoma
D. Idiopathic osteosclerosis
Answer: Cementoblastoma
Rationale: Cementoblastoma is fused to the tooth root and is typically
surrounded by a radiolucent rim. Pain and expansion may occur, helping
distinguish it from asymptomatic hypercementosis.
8. A radiolucent lesion is discovered incidentally between the roots of the
mandibular canine and first premolar. The teeth are vital. The lesion is
small, well circumscribed, and heart-shaped on some projections. Which
diagnosis is most likely?
A. Lateral periodontal cyst
B. Globulomaxillary cyst
C. Periapical cyst
D. Odontogenic keratocyst
Answer: Lateral periodontal cyst
Rationale: A lateral periodontal cyst is typically a small, well-defined
radiolucency along the lateral root surface of a vital tooth, commonly in the
mandibular canine-premolar region.
9. A patient with generalized aggressive periodontitis undergoes full-mouth
radiographic evaluation. Which radiographic finding most strongly indicates
horizontal bone loss?
A. Bone height remains parallel to a line connecting adjacent CEJs
B. Bone loss occurs at a consistent angle across the affected teeth
