ADC - Australian Dental Council Radiographic Interpretation and Diagnosis Questions and Answers

Question 1

An orthopantomogram (OPG) of an asymptomatic 18-year-old reveals a well-defined, corticated, unilocular radiolucency surrounding the crown of an unerupted mandibular third molar.
The lesion appears attached at the cementoenamel junction.
What is the most likely radiographic diagnosis?

Accepted Answer

Dentigerous Cyst

Answer

Ameloblastoma

Answer

Odontogenic Keratocyst (OKC)

Answer

Radicular Cyst

Question 2

Which of the following radiographic features is most suggestive of a benign lesion rather than a malignant one?

Accepted Answer

A well-defined, corticated margin

Answer

Ill-defined or ragged borders

Answer

A 'moth-eaten' or permeative appearance of bone

Answer

Evidence of cortical bone destruction and invasion into soft tissue

Question 3

A periapical radiograph of a maxillary first molar shows the palatal root superimposed over the distobuccal root. A second radiograph is taken with the X-ray tube head moved more mesially. In this new image, the palatal root now appears distinctly mesial to the distobuccal root. Based on the SLOB rule, what is the buccolingual position of the palatal root?

Accepted Answer

It is lingual (palatal) to the distobuccal root

Answer

It is buccal to the distobuccal root

Answer

Its position cannot be determined with this information

Answer

It is directly in line with the distobuccal root

Question 4

A routine panoramic radiograph of a 50-year-old asymptomatic male reveals a well-defined, ovoid radiolucency with a sclerotic border, located entirely inferior to the mandibular canal, near the angle of the mandible. What is the most likely diagnosis?

Accepted Answer

Stafne Defect (Static Bone Cavity)

Answer

Traumatic Bone Cyst

Answer

Residual Cyst

Answer

Odontogenic Keratocyst (OKC)

Question 5

Which of the following clinical situations presents the strongest justification for using Cone Beam Computed Tomography (CBCT) over conventional two-dimensional radiography for diagnosis and treatment planning?

Accepted Answer

Evaluating the precise three-dimensional position of a horizontally impacted maxillary canine and its relationship to the roots of adjacent incisors

Answer

Routine detection of interproximal caries in a patient with a low caries risk

Answer

Generalised assessment of periodontal bone levels for a new patient examination

Answer

Monitoring the healing of a small, uncomplicated periapical lesion following routine endodontic treatment

Question 6

A periapical radiograph of a mandibular incisor shows a diffuse, ill-defined radiolucency at the apex with a loss of the lamina dura. The patient is systemically unwell with a fever and reports severe, spontaneous pain. The tooth is non-vital and extremely tender to percussion. What is the most likely radiographic diagnosis?

Accepted Answer

Acute Periapical Abscess

Answer

Chronic Periapical Periodontitis (Granuloma)

Answer

Radicular Cyst

Answer

Condensing Osteitis