Caries, pulp and periodontal disease: plaque bridge organism: 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.

Try it

Dentistry · Caries, pulp and periodontal disease: plaque bridge organism

Sample item

In the development of dental plaque, early colonisers such as Streptococcus sanguinis attach to the pellicle. Which Gram-negative organism acts as the bridge that allows late colonisers such as Porphyromonas gingivalis to join the biofilm?

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

The answer and the reasoning

C. Fusobacterium nucleatum

Fusobacterium nucleatum co-aggregates with both early Gram-positive colonisers and late Gram-negative anaerobes, so it acts as a bridging species in mature plaque. It supports the shift to the pathogenic flora of periodontitis.

Option by option

  • A. Streptococcus mutans

    S. mutans is a cariogenic early coloniser with no role as the periodontal bridge.

  • B. Candida albicans

    Candida is a fungus and not a bridging member of subgingival plaque.

  • C. Fusobacterium nucleatum (correct)

    Correct. F. nucleatum links early and late colonisers by co-aggregation.

  • D. Lactobacillus casei

    Lactobacilli are associated with advanced caries lesions and not with plaque bridging.

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.

More Dentistry questions

Questions about this Dentistry question

What is the answer to this Dentistry question?

The best answer is C, Fusobacterium nucleatum. Fusobacterium nucleatum co-aggregates with both early Gram-positive colonisers and late Gram-negative anaerobes, so it acts as a bridging species in mature plaque.

Why is "Streptococcus mutans" not the answer?

S. mutans is a cariogenic early coloniser with no role as the periodontal bridge.

Why is "Candida albicans" not the answer?

Candida is a fungus and not a bridging member of subgingival plaque.

Why is "Lactobacillus casei" not the answer?

Lactobacilli are associated with advanced caries lesions and not with plaque bridging.

What concept does this question test?

It tests Caries, pulp and periodontal disease: plaque bridge organism in Dentistry. It supports the shift to the pathogenic flora of 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: plaque bridge organism?

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.