Effect of mechanical polishing and 35% hydrogen peroxide application on DIAGNOdent measurements in stained occlusal fissures: a randomized split-mouth clinical study

DIAGNOdent laser fluorescence measurements may be confounded by extrinsic staining in occlusal fissures, and the effect of common surface-preparation protocols on these readings remains unclear. The aim of this study was to compare the effects of mechanical polishing and 35% hydrogen peroxide application on DIAGNOdent Pen measurements in stained occlusal fissures. In this randomized split-mouth clinical study, 126 posterior teeth from 24 participants were evaluated. Opposing jaws received either mechanical polishing with a fluoride-free prophylaxis paste for 30 s or 35% hydrogen peroxide gel for 15 min. DIAGNOdent scores were recorded at baseline, after air–water spray cleaning and drying, and after the assigned procedure. Digital bite-wing radiographs obtained at baseline as a complementary diagnostic assessment. Data were analyzed using linear mixed-effects models and Wilcoxon signed-rank tests. Air–water spray cleaning and drying did not significantly change DIAGNOdent values in either group (bleaching: p = 0.355; polishing: p = 0.516). Post-procedure scores increased significantly after bleaching ( p = 0.023) and polishing ( p < 0.001). The mean score change was significantly greater after polishing than bleaching (18.4 ± 26.0 vs. 4.6 ± 19.3; p < 0.001). Both surface-preparation protocols may help reveal underlying fissure characteristics. However, as residual materials may affect DIAGNOdent scores, post-procedure evaluations should be interpreted cautiously alongside clinical and radiographic findings. ClinicalTrials.gov NCT07763470. Registered 07/08/2026 (first submitted date) – Retrospectively registered, https://clinicaltrials.gov/study/NCT07763470 .