Outcomes of resin infiltration for white spot lesions at different time points: a systematic review and meta-analysis

BACKGROUND: White spot lesions (WSLs) are a common clinical finding with implications for both individuals and society. Several treatment approaches have been proposed, among which resin infiltration (RI) has emerged as a promising option. OBJECTIVE: Investigate clinical and patient-reported outcomes of RI on WSLs at different time points. SEARCH METHODS: Unrestricted literature searches were conducted in six databases for human studies until September 2025. SELECTION CRITERIA: Randomized and non-randomized clinical studies on patients with WSLs on at least one anterior tooth treated with RI assessing different clinical- and patient-reported outcomes with a minimum patient follow-up of 3 months. DATA COLLECTION AND ANALYSIS: Study selection, data extraction, and risk of bias assessment were performed in duplicate. Random-effects meta-analyses of pooled average changes between post-treatment and follow-up time points with their corresponding 95% confidence interval (CI) were performed, followed by sensitivity analyses. RESULTS: Thirty-four reports pertaining to 29 studies were included covering 544 patients (ages 7-40 years; 44% male on average) and 1495 teeth with WSLs. The risk of bias assessment revealed concerns mainly due to the small sample sizes, short follow-up periods, absence of blinded measurements, and lack of analysis of confounding factors or within-patient clustering. For most outcomes, RI showed inconsistent and heterogeneous effects. In the largest meta-analysis (six studies) comparing the standardized color difference (ΔE) between WSL and sound adjacent enamel from post-treatment to 6 months, the pooled average change was 0 (95% CI -0.42 to 0.41; P = .98), with high heterogeneity (I2 = 84%). A small meta-analysis showed significant improvements in patient satisfaction through a Visual Analogue Scale from post-treatment to 1 month (two studies; +11.9 mm; 95% CI +5.9 to +17.8 mm; P = .02), which diminished to non-significant levels at the 3 (P = .09), 6 (P = .20) and 12 months (P = .94). Twelve months post-treatment, no significant differences were seen for ΔΕ, fluorescence, patient satisfaction, or WSL area (P > .05). LIMITATIONS: Among the included studies, high between-study heterogeneity was observed for most outcome measures, while most studies featured small sample sizes and short follow-up times. CONCLUSIONS: RI for WSLs shows highly inconsistent effects, compounded by limited follow-ups, highlighting the need for larger and standardized studies with extended follow-up to better evaluate treatment outcomes of resin-infiltrated WSLs. REGISTRATION: PROSPERO CRD42024611702.