Oral Candida colonisation and cariogenic bacteria in children and adolescents with cleft lip and/or palate: A systematic review and meta-analysis

Purpose Children with cleft lip and/or palate (CL/P) face a disproportionate cariogenic burden, yet the role of oral Candida and its partnership with cariogenic bacteria remains poorly quantified. This systematic review and meta-analysis synthesised observational evidence on oral Candida colonisation, cariogenic bacterial carriage, and clinical caries outcomes in non-syndromic CL/P, with GRADE-rated certainty. Methods Following PRISMA 2020 and the Cochrane Handbook (PROSPERO CRD420261402624), six databases were searched from inception to 27 May 2026. Eligible studies were observational designs enrolling children aged 0–18 years with non-syndromic CL/P versus non-cleft controls. Risk of bias used ROBINS-E. Random-effects meta-analyses (DerSimonian–Laird) pooled risk ratios (RR) for dichotomous outcomes and standardised mean differences (SMD) for continuous caries indices, with GRADE certainty. Results Ten studies (2011–2026; 421 CL/P vs 567 controls) were included. Oral Candida carriage was nearly threefold higher in CL/P (RR 2.94, 95% CI 2.04–4.22; I 2 = 23.4%; k = 4), with C. albicans predominant. High salivary Streptococcus mutans counts were similarly elevated (RR 2.74, 95% CI 1.42–5.27; I 2 = 0%), whereas Lactobacillus carriage showed no significant difference (RR 1.33, 95% CI 0.71–2.47). Caries indices were directionally higher in three of four datasets but highly heterogeneous (SMD 0.74; I 2 = 92.3%). GRADE certainty was Low to Very Low. Conclusion CL/P children carry elevated oral Candida and S. mutans burdens, supporting an early fungal–bacterial cariogenic shift. Candida assessment should be integrated into caries-risk evaluation from the deciduous-dentition stage within the multidisciplinary cleft pathway.