Are periodontitis and dental caries associated? A systematic review with meta-analyses

The epidemiological relationship between periodontitis and caries remains controversial, and evidence synthesis is currently lacking. Therefore, this systematic review was designed to answer the following PECO question: 'In human adults (P), do subjects suffering from periodontitis (E) have higher presence/number of untreated carious lesions and caries experience (O) than subjects not suffering from periodontitis (C)?'.

Observational studies that met specific inclusion criteria established to answer to the PECO question were included. Two review authors independently searched for eligible studies, screened the titles and abstracts, carried out the full text analysis, extracted the data and performed the risk of bias assessment. In case of disagreement, a third review author took the final decision during ad hoc consensus meetings. Data synthesis was carried out through random-effects meta-analyses.

A total of 18 studies on 21 cohorts, involving 135,018 participants, were included. Meta-analyses showed a significant association between periodontitis and the presence of at least one tooth with either untreated carious lesions (odds ratio [OR] = 1.63; 95% confidence interval [CI]: 1.32-2.01; p <.00; I²  = 83.0%) or caries experience (decayed and filled teeth ≥ 1) (OR = 1.27; 95% CI: 1.01-1.59; p = .038; I²  = 90.0%). Moreover, subjects with periodontitis exhibited a higher number of surfaces (difference in means [MD] = 0.86; 95% CI: 0.46-1.27; p <.001; I²  = 0.0%) and teeth (MD = 0.35; 95% CI: 0.28-0.42; p <.001; I²  = 69.6%) with untreated carious lesions, as well as a higher number of teeth with caries experience (standardized difference in means  [SMD] = 1.46; 95% CI: 0.15-2.78; p = .029; I²  = 98.9%) compared with those without periodontitis. Sensitivity analyses focusing on severe periodontitis as exposure mostly showed consistent results. Estimates for caries experience were only slightly attenuated in adjusted models compared with crude models. Subgroup analyses by caries location also indicated that periodontitis was associated only with root caries, while it was not with caries affecting the anatomical crown.

Periodontitis was found to be associated with the presence and number of treated/untreated root carious lesions. Therefore, caries-specific preventive measures (e.g., fluorides) should be considered for individuals with periodontitis.