Distribution of initial caries lesions in relation to fixed orthodontic therapy. A systematic review and meta-analysis

BACKGROUND: Initial caries lesion (ICLs) adjacent to orthodontic brackets are the most common side effect of orthodontic treatment with fixed appliances. The reported prevalence is uncertain and varies considerably across studies, from 27% to 97%. OBJECTIVES: This paper was designed to evaluate and synthesize the available evidence on the prevalence and incidence rates of ICLs in relation to orthodontic treatment. Selection criteria: The review (Prospero protocol CRD42023412952) included randomized and non-randomized clinical trials of interventions, cohort studies, and cross-sectional studies, published after 1990 on the prevalence or incidence of ICLs during or after orthodontic treatment with fixed appliances. Search methods: Pubmed, Scopus, and Embase databases were searched from 1990 until 01 May 2023. The risk of bias assessment was performed with RoB 2 and ROBINS-I tool and the Joanna Briggs Institute Critical Appraisal Checklist. Data collection and analysis: The proportion of individuals with ICLs, reported as the number/percentage of individuals/teeth with ICLs or mean number of ICLs per subject, were used to synthesize results. RESULTS: The search yielded a total of 468 papers; 21 studies were included in the systematic review, 2 of which were not included in the meta-analysis. The prevalence rate 95%CI of ICLs was 0.57% 0.48; 0.65 in 1448 patients, 0.22% 0.14; 0.33 in 11583 teeth, with a mean number of lesions equal to 2.24 1.79; 2.70 in 484 patients evaluated. The incidence rate of new carious lesions developed during orthodontic treatment was 0.48% 0.33; 0.63 in 533 patients, 0.15% 0.08; 0.26 in 1890 teeth with a mean number of ICLs equal to 2.29 1.12; 3.46 in 208 patients evaluated. LIMITATIONS: Although the high number of included studies and the overall good quality, there was a significant heterogeneity in the collected data. CONCLUSION: The prevalence and incidence rates of ICLs in subjects undergoing orthodontic treatment are quite high and raise some concerns in terms of risk assessment of orthodontic treatment. ICLs represent an alarming challenge for both patients and professionals. Effective caries prevention strategies during treatment need to be considered and implemented where appropriate.