Caries, pulp and periodontal disease: CPITN probe: 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: CPITN probe

Sample item

A community survey uses the WHO periodontal probe. Which feature describes this probe?

AFlat blade of 5 mm with no markingsBBall tip of 2 mm with a red band at 10 mmCBall tip of 0.5 mm with a black band between 3.5 and 5.5 mmDSharp tip of 2 mm with markings at every millimetre

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

The answer and the reasoning

C. Ball tip of 0.5 mm with a black band between 3.5 and 5.5 mm

The WHO probe has a 0.5 mm ball tip and a black band from 3.5 to 5.5 mm, with rings at 8.5 and 11.5 mm. Light probing force of about 20 g is used.

Option by option

A. Flat blade of 5 mm with no markings
A flat blade is not a probe for pocket depth.
B. Ball tip of 2 mm with a red band at 10 mm
The ball tip is 0.5 mm, not 2 mm.
C. Ball tip of 0.5 mm with a black band between 3.5 and 5.5 mm (correct)
Correct. A 0.5 mm ball tip and black band characterise the probe.
D. Sharp tip of 2 mm with markings at every millimetre
A sharp tip could damage tissue and is not the WHO design.

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 C, Ball tip of 0.5 mm with a black band between 3.5 and 5.5 mm. The WHO probe has a 0.

Why is "Flat blade of 5 mm with no markings" not the answer?

A flat blade is not a probe for pocket depth.

Why is "Ball tip of 2 mm with a red band at 10 mm" not the answer?

The ball tip is 0.5 mm, not 2 mm.

Why is "Sharp tip of 2 mm with markings at every millimetre" not the answer?

A sharp tip could damage tissue and is not the WHO design.

What concept does this question test?

It tests Caries, pulp and periodontal disease: CPITN probe in Dentistry. 5 mm ball tip and a black band from 3.5 to 5.5 mm, with rings at 8.5 and 11.5 mm. Light probing force of about 20 g is used.

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: CPITN probe?

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.