Calculus is a mix of minerals (calcium and phosphate) and organic material. This organic material consists of bacteria which cause caries, due to their acid waste products.

Is it possible that in calculus these bacteria can be fossilated by adoption/exchange of minerals?

If that is the case could this calculus form a layer around the teeth so that it prevents the bacteria in the dental plaque from causing caries?

  • 1
    You said "This organic material consists of bacteria, which by there acid waste products cause caries". How can the organic material in calculus cause caries and prevent caries at the same time? Commented Jun 14, 2018 at 8:41
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    That just exactly the question, whether this is possible or not
    – Marijn
    Commented Jun 14, 2018 at 8:49
  • 3
    Marijn, I find this very hard to read/understand (the language, sentence composition..). Would you mind to edit?
    – Jan
    Commented Jun 14, 2018 at 8:55

2 Answers 2


Yes, the presence of calculus prevent the demineralization of the surface of the tooth. This is a common finding during routine scaling or calculus removal, where usually the underlying enamel is intact.

Also, there is a paper about this issue: Evidence for putting the calculus: caries inverse relationship to work who found

caries prevalence is highly significantly lower in calculus-prone than in calculus-free subjects

You can found the detailed explanation on the Fejerskov's Textbook of Dental Caries, and the principal ideal is: if you have calculus means that the intraoral enviroment is saturated with minerals and with pH levels above 5.0, hence demineralization of enamel is very difficult if not not feasible at all.

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    Wonderful find. – But. That might be read as: calculus is a good thing, or a sign of favourable conditions? Keep it present? (You illustrate one particular mechanism, but I'd like to see more of a complete picture on this). Commented Jun 14, 2018 at 19:21
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    Your statement in bold says that the mouth environment with high pH and high mineral saturation is associated with 1) calculus and 2) lower risk of caries. This means, that they are the pH and minerals in the mouth that prevent caries and not the calculus.
    – Jan
    Commented Jun 15, 2018 at 8:35

Yes, it is according to Keyes and Rams (2016)

Results: Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin.


Keyes, P. H., & Rams, T. E. (2016). Dental calculus arrest of dental caries. Journal of oral biology (Northborough, Mass.), 3(1). PMCID: PMC4950958 PDF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4950958/pdf/nihms761315.pdf

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