Dental caries and salivary alterations in patients with type 2 diabetes: A systematic review and meta-analysis

Introduction: The association between dental caries, salivary alterations, and type 2 diabetes (T2D) is inconclusive. This systematic review evaluated the caries status and salivary alterations in adults with T2D. Data: Observational studies (cross-sectional, case-control, or cohort studies) that evaluated the association between type 2 diabetes and dental caries and/or salivary changes were included. Sources: Systematic searches of PubMed/Medline, Web of Science, Embase, and the Cochrane Library for relevant literature published up to January 2024 were performed. Study selection: Ninety-eight studies were selected from the 1981 records obtained after screening the databases. Thirty-nine studies that met the eligibility criteria were included in the qualitative synthesis, and twenty-eight of the included studies were suitable for the quantitative synthesis (meta-analysis). Results: The meta-analysis showed that compared to non-diabetic individuals, type 2 diabetic individuals had higher DMFT (mean difference: 2.27; 95 % CI, 1.31 to 3.22; P < 0.00001). Moreover, type 2 diabetic individuals had lower salivary flow rate (standardized mean difference: -2.62; 95 % CI, -4.38 to -0.86; P = 0.003), salivary pH (standardized mean difference: -1.35; 95 % CI, -1.89 to -0.80; P < 0.00001) and salivary buffering capacity (standardized mean difference: -0.60; 95 % CI, -0.93 to -0.27; P = 0.0004). Whereas DMFT (mean difference: -2.15; 95 % CI, -6.47 to 2.17; P = 0.33) and salivary buffering capacity (standardized mean difference: -0.05; 95 % CI, -0.48 to 0.37; P = 0.80) were not significantly different between individuals with well-controlled diabetes and those with poorly-controlled diabetes. Conclusions: Type 2 diabetes may lead to an increased index of dental caries and a reduction in salivary flow rate, salivary pH, and salivary buffering capacity in adults. Clinical significance: Individuals with type 2 diabetes exhibit an elevated risk of dental caries and salivary alterations that facilitate the progression of dental caries. It is recommended that dentists and endocrinologists focus their attention on the oral health of this population.