The association between black stain and lower risk of dental caries in children: a systematic review and meta-analysis

BACKGROUND: Previous literature shows that children with dental black stain might be less susceptible to dental caries. The aim of this study was to systematically review the available literature to determine whether black stain presence could influence the prevalence or severity of dental caries in primary dentition. METHODS: A systematic search of PubMed, Web of Science, Scopus, Google Scholar, OpenGrey, and Egyptian Universities Libraries Consortium was conducted up to December 2020. Quality assessment was done using a modified version of Down’s and Black checklist. Meta-analyses were performed to assess the association between dental black stain and: (i) Likelihood of developing dental caries/being caries-free (ii) Number of teeth affected by dental caries (iii) Number of tooth surfaces affected. RESULTS: The database search yielded 2164 results, 14 of which matched the eligibility criteria. The meta-analysis showed that the likelihood of developing caries (Fixed effect model: OR [95% CI]: 0.67 [0.54; 0.82]; I(2)=37%; τ(2)=0.05), number of teeth affected (Random effects model: MD [95% CI]: –0.98 [–1.54; -0.42]; I(2)=79%; τ(2) =0.44), and number of surfaces affected (Random-effects model: MD [95% CI]: –2.34 [–4.23; -0.44]; I(2)=85%; τ(2) =2.93), were all lower in children with black stain. CONCLUSIONS: It is suggested that dental black stain is associated with lower dental caries experience in children with primary dentition. However, it is questionable whether black stain has a protective effect against dental caries, or whether children at low risk of dental caries are more likely to develop BS because their oral microbiome favors BS-forming organisms. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s42506-022-00107-3.