Caries, pulp and periodontal disease: lactobacilli in caries: 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: lactobacilli in caries

Sample item

In a deep carious cavity, which organisms are mainly responsible for progression of the lesion through dentine?

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

The answer and the reasoning

C. Lactobacilli

Streptococcus mutans initiates enamel caries, whereas lactobacilli, being highly acidogenic and aciduric, predominate in advanced dentine lesions. Counts of lactobacilli are used as a marker of caries activity.

Option by option

  • A. Veillonella

    Veillonella uses lactic acid and is not a main cause of progression.

  • B. Streptococcus salivarius

    S. salivarius is a commensal that is not a principal cariogenic species.

  • C. Lactobacilli (correct)

    Correct. Lactobacilli drive progression of the lesion within dentine.

  • D. Actinomyces israelii

    Actinomyces israelii is associated with root caries and actinomycosis, not the main progression flora.

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 C, Lactobacilli. Streptococcus mutans initiates enamel caries, whereas lactobacilli, being highly acidogenic and aciduric, predominate in advanced dentine lesions.

Why is "Veillonella" not the answer?

Veillonella uses lactic acid and is not a main cause of progression.

Why is "Streptococcus salivarius" not the answer?

S. salivarius is a commensal that is not a principal cariogenic species.

Why is "Actinomyces israelii" not the answer?

Actinomyces israelii is associated with root caries and actinomycosis, not the main progression flora.

What concept does this question test?

It tests Caries, pulp and periodontal disease: lactobacilli in caries in Dentistry. Counts of lactobacilli are used as a marker of caries activity.

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: lactobacilli in caries?

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.