Quantitative Radiographic Assessment of Proximal Caries Lesions Treated with Resin Infiltration

Abstract Objective Resin infiltration is widely used for non‑cavitated proximal caries lesions, yet evidence from standardised, quantitative radiographic monitoring is limited. This study evaluated short‑term outcomes using a reproducible, image‑based workflow. Methods In this observational cohort, adults (n = 23; 118 proximal lesions) were managed with resin infiltration (Icon) plus oral-hygiene instruction (10 patients; 53 lesions) or oral-hygiene instruction alone (13 patients; 65 lesions). Standardised bitewing radiographs were obtained at baseline, 6, and 12 months. Lesion length and area were measured in ImageJ following a reproducible calibration protocol. Between-group and longitudinal effects were tested using repeated-measures analyses and generalised linear mixed models (GLMMs) with patient-level random intercepts. Results Over 12 months, mean lesion-length increase was 0.14 mm with infiltration versus 0.26 mm in controls. GLMMs showed significant effects of group, time, and baseline caries level, and a significant group×time interaction (p < 0.001; large effect), indicating diverging trajectories. The protective effect was most evident at enamel level; dentine-involving lesions were stabilised relative to controls. DMF-T was not independently significant (p ≥ 0.05). Conclusions Within a standardised quantitative radiographic workflow, resin infiltration was associated with less short-term radiographic progression than no treatment. Findings support lesion-level quantitative monitoring to inform micro-invasive management and follow-up scheduling.