Six-year survival and clinical performance of glass hybrid restorations following selective caries removal in teeth with molar incisor hypomineralization: a prospective cohort study

Objectives This study aimed to evaluate the clinical success and long-term survival of glass hybrid restorations in permanent first molars affected by molar incisor hypomineralization (MIH) following selective caries removal (SCR) over a six-year follow-up period. Materials and methods This prospective cohort study included a total of 134 MIH-affected molars in 58 children (mean age 8.94 +/- 1.41 years) restored with glass hybrid materials after SCR. Clinical outcomes were assessed at baseline and at 6, 12, 18, 24, and 72 months using modified USPHS criteria. Kaplan-Meier survival analysis and Cox proportional hazards regression with robust standard errors were conducted to evaluate restoration survival and identify potential predictors. Results The overall estimated mean survival time of restorations was 59.82 +/- 1.50 months. The survival probabilities for mild and severe lesions at six-year were 24.3% and 11.1%, respectively. Multivariate Cox proportional hazards regression with robust standard errors indicated that lesion severity, medium lesion extension, and large lesion extension had a statistically significant impact on restoration survival (p < 0.001 for all). While survival was satisfactory up to 2-3 years, a marked decline was observed over time, particularly in severely affected molars. Conclusions Glass hybrid restorations demonstrated acceptable clinical performance in MIH-affected molars in the short to medium term but showed significant limitations in long-term survival.