Resin infiltration versus other minimally invasive treatments for demarcated opacities in molar-incisor hypomineralization: a systematic review

Introduction: Demarcated opacities of molar-incisor hypomineralization are a frequent aesthetic concern in children and adolescents. Resin infiltration has been proposed as a minimally invasive alternative to microabrasion, bleaching and restorative approaches, but its comparative effectiveness remains unclear. Methods: A systematic review following PRISMA 2020 was conducted. PubMed, OpenAlex and Crossref were searched for clinical and image-based studies published between 2015 and 2023 that compared resin infiltration with other minimally invasive approaches for masking demarcated opacities in molar-incisor hypomineralization. Risk of bias was assessed with RoB 2 and ROBINS-I, and findings were synthesized narratively. Results: Of 237 records, 10 studies were included. Resin infiltration reduced the color difference between the opacity and sound enamel in every comparative study; the difference was 4.07 units after infiltration versus 7.35 after placebo, and resin infiltration outperformed fluoride varnish at all time points. Complete masking was rare, and partial masking predominated, reported in 95.65% of infiltrated teeth in one study. Most studies were small, short and at serious risk of bias. Conclusions: Resin infiltration reduces but rarely fully conceals demarcated opacities in molar-incisor hypomineralization, with short-term results generally superior to placebo and fluoride varnish. Direct randomized comparisons against microabrasion are lacking, and the evidence does not yet support one protocol over another.