Caries, pulp and periodontal disease: tracing a sinus tract: practice question

A Dentistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dentistry · Caries, pulp and periodontal disease: tracing a sinus tract

Sample item

A patient has a persistent gum-level sinus tract near a lower molar and the source is not clear. What is the best way to identify the tooth responsible?

ATake a bitewing radiograph of the areaBPalpate the tooth with a periodontal probe onlyCTest for a positive response to heat on the nearest toothDRadiograph taken with a gutta-percha point threaded into the tract

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Radiograph taken with a gutta-percha point threaded into the tract

A gutta-percha cone inserted into the sinus tract is radiopaque, and when a radiograph is taken it follows the tract to its origin, usually the apex of the infected tooth. Vitality tests then confirm the tooth is non-vital.

Option by option

A. Take a bitewing radiograph of the area
Bitewings show crowns and crestal bone and may miss the apical region.
B. Palpate the tooth with a periodontal probe only
Probing alone cannot follow the channel to the apex.
C. Test for a positive response to heat on the nearest tooth
Heat response is unreliable for locating a sinus and does not trace the tract.
D. Radiograph taken with a gutta-percha point threaded into the tract (correct)
Correct. The radiopaque cone follows the tract back to the source of infection.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Dentistry question

What is the answer to this Dentistry question?

The best answer is D, Radiograph taken with a gutta-percha point threaded into the tract. A gutta-percha cone inserted into the sinus tract is radiopaque, and when a radiograph is taken it follows the tract to its origin, usually the apex of the infected tooth.

Why is "Take a bitewing radiograph of the area" not the answer?

Bitewings show crowns and crestal bone and may miss the apical region.

Why is "Palpate the tooth with a periodontal probe only" not the answer?

Probing alone cannot follow the channel to the apex.

Why is "Test for a positive response to heat on the nearest tooth" not the answer?

Heat response is unreliable for locating a sinus and does not trace the tract.

What concept does this question test?

It tests Caries, pulp and periodontal disease: tracing a sinus tract in Dentistry. Vitality tests then confirm the tooth is non-vital.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Caries, pulp and periodontal disease: tracing a sinus tract?

Learn the dental formula, eruption ages and tooth structure once, as tables. Then use the flashcards and the other Dentistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.