Root Caries: Incidence and increment

shutterstock_34500700 - caries sign

With improvements in life expectancy and oral health older adults are retaining an increasing number of natural teeth. This potentially increases the risk of root cares becoming a significant public health problem with prevalence rates of between 9.8% to 71% and incidence rates of similar levels ( 12.4% to 77% )being reported.

The aims of this review were to assess

  1. What are the estimates of the root caries incidence and increment at the population level around the world?
  2. Are there any differences in the estimation of the root caries incidence and increments according to the length and types of studies?
  3. What are some possible sources of heterogeneity among root caries studies around the world?


Searches were conducted in the PubMed and Embase databases. Longitudinal studies on root caries incidence and increment published in English language were considered. Two reviewers independently screened studies, extracted data and assessed study quality using the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument [(MAStARI) . A pooled incidence and increment of decayed/filled root surfaces (DFS) was estimated and meta-regression analysis was performed by length of follow-up (<2 years; 2years; 3-4years and ≥5years) and study type (observational population-based and clinical trial).


  • 20 studies were included in the meta-analysis.
  • The overall quality of the studies was assessed as medium.
  • The annualised root caries incidence and increment are shown in the table
  Annualised Incidence (95%CI) Annualised Increment


All studies 18.25% (13.22%-23–28%) 0.45 (0.37–0.53)
Studies with less than 2 years follow-up 32.95% (29.13%–36.77%) 0.64 (0.38–0.89)
Studies with 5+ years follow-up 9.4% (3.32%–15.48%) 0.43 (0.21–0.64)
  •  The variance in root caries incidence estimate was explained by the length of the follow-up in the study (44.08%), baseline age (22.12%) and baseline root DFS (24.80%) in univariant analysis.
  • Variance of the root caries increment was explained by the length of the follow-up in the study (20.24%), root caries data adjustment (13.80%), source of participants (10.75%), baseline root DFS (2.83%) and number of exposed root surfaces (39.32%) respectively.


The authors concluded: –

Length of follow-up time is a factor influencing estimates of root caries incidence and increment. Longer follow-up was associated with lower estimates. This appeared to reflect a healthy participant or survivor bias. Root caries increased even among the healthier older adults.


While two major databases have been searched for this review limiting the inclusion criteria to English language studies only has the potential to exclude relevant studies.  An estimate for incidence and increments was produced and it is interesting to note the difference between the 2 and 5 years follow up estimates. The univariant analysis pointed to the length of follow up was seen to have an important influence on the findings with the authors considering that this might be due to a ‘healthy’ survivor bias. In the discussion the authors also highlight the problem with variation in the way in which root caries was reported which meant that several studies could not be included. With an increasingly elderly population with more teeth at potential risk of root caries having good quality data on the prevalence and incidence of caries will be important for its management.  Good quality studies reporting using common outcomes sets will be important to enable monitoring and comparison in the future.


Primary Paper

Hariyani N, Setyowati D, Spencer AJ, Luzzi L, Do LG. Root caries incidence and increment in the population – A systematic review, meta-analysis and meta-regression of longitudinal studies. J Dent. 2018 Jun 21. pii: S0300-5712(18)30175-1. doi: 10.1016/j.jdent.2018.06.013. [Epub ahead of print] Review. PubMed PMID: 29935998.

Other references

Dental Elf Root Caries Blogs




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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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