Caries, pulp and periodontal disease: red complex: 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: red complex

Sample item

A subgingival plaque sample from a 55-year-old with deep pockets is cultured. Which organism of the red complex is most strongly linked to chronic periodontitis?

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

The answer and the reasoning

D. Porphyromonas gingivalis

The red complex comprises Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. P. gingivalis is regarded as the keystone pathogen of chronic periodontitis.

Option by option

  • A. Streptococcus mutans

    S. mutans is the main organism of enamel caries.

  • B. Streptococcus sanguinis

    S. sanguinis is an early colonizer associated with health.

  • C. Actinomyces viscosus

    Actinomyces viscosus is an early plaque colonizer, and is linked to root caries.

  • D. Porphyromonas gingivalis (correct)

    Correct. P. gingivalis is a keystone pathogen of the red complex.

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 D, Porphyromonas gingivalis. The red complex comprises Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola.

Why is "Streptococcus mutans" not the answer?

S. mutans is the main organism of enamel caries.

Why is "Streptococcus sanguinis" not the answer?

S. sanguinis is an early colonizer associated with health.

Why is "Actinomyces viscosus" not the answer?

Actinomyces viscosus is an early plaque colonizer, and is linked to root caries.

What concept does this question test?

It tests Caries, pulp and periodontal disease: red complex in Dentistry. P. gingivalis is regarded as the keystone pathogen of chronic periodontitis.

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: red complex?

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.