LAUSR

OBJECTIVE To evaluate the influence of fluoride varnish (FV) therapies or resin infiltration (RI) to maintain the structural integrity of Molar Incisor Hypomineralization (MIH) affected teeth. METHODS Fifty-one children aged 6-12 years with at least one incisor and one first permanent molar with yellow/brown MIH opacities were included. Patients were randomly allocated into three groups: FV - Fluoride Varnish (Duraphat); FV + etch - Fluoride Varnish (Duraphat) after enamel etching with 37% phosphoric acid; or RI - Resin Infiltration system (Icon). Opacities were monitored for 18-months. The primary outcome was the loss of integrity due to post-eruptive enamel breakdown (PEB). Covariables included sex, age, DMFT index, opacity colour, plaque, number of MIH-affected teeth and surfaces. Fisher's Exact was used to test the association of treatments with PEB, the Kaplan-Meyer method analysed the survival rates and Cox-regression determined which covariables would predict failure (α = 0.05). RESULTS From a total of 235 teeth, the PEB rate for RI (6.1%) was significantly lower than FV (17.9%; OR 3.0, 95%CI 1.07, 8.48) and FV + etch (17.3%; OR 3.1, 95%CI 1.13, 8.73). DMFT index >3, brown opacities, cusp involvement, and age between 6-8 years predicted PEB (p < 0.05). CONCLUSIONS Resin infiltration positively influenced the structural integrity maintenance of MIH-affected teeth by decreasing the risk of enamel breakdown after18 months follow-up. Registry of Clinical Trials (XXXXX). CLINICAL RELEVANCE Resin infiltration proved to be a more efficacious intervention to maintain the structural integrity of MIH-affected teeth than fluoride varnish therapies.