Community dentistry: xylitol: 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 · Community dentistry: xylitol

Sample item

A school programme gives chewing gum to reduce caries. Which sweetener reduces Streptococcus mutans because it cannot be fermented?

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

The answer and the reasoning

B. Xylitol

Xylitol is a five-carbon polyol that oral bacteria cannot ferment, and it interferes with S. mutans metabolism, lowering counts. Chewing also stimulates saliva.

Option by option

  • A. Glucose

    Glucose is readily fermented.

  • B. Xylitol (correct)

    Correct. Xylitol is non-fermentable and cariostatic.

  • C. Fructose

    Fructose is fermentable and cariogenic.

  • D. Sucrose

    Sucrose is the most cariogenic sugar.

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.

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Questions about this Dentistry question

What is the answer to this Dentistry question?

The best answer is B, Xylitol. Xylitol is a five-carbon polyol that oral bacteria cannot ferment, and it interferes with S.

Why is "Glucose" not the answer?

Glucose is readily fermented.

Why is "Fructose" not the answer?

Fructose is fermentable and cariogenic.

Why is "Sucrose" not the answer?

Sucrose is the most cariogenic sugar.

What concept does this question test?

It tests Community dentistry: xylitol in Dentistry. mutans metabolism, lowering counts. Chewing also stimulates saliva.

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 Community dentistry: xylitol?

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.