Restorative interventions and management of primary and permanent molars affected by molar incisor hypo-mineralization: a systematic review

PURPOSE: To systematically review clinical and radiographic success rates of various restorative interventions on hypo-mineralized second primary molars (HSPM) and first permanent molars (FPMs) with molar incisor hypo-mineralization (MIH) and their impact on pulp and periodontal health and patient's oral health-related quality of life (OHRQoL). METHODS: Seven electronic databases were searched for studies published up to September 2025. Selection of eligible studies and data extraction was performed by independent and previously calibrated review authors. Methodological quality of included studies was assessed using the appropriate tool according to the study design. RESULTS: 20 papers (19 for MIH and 1 for HSPM) were included. Mean overall clinical success rate for MIH-affected FPMs ranged from 84% at 12 months to 83% at 36 months. The lowest values were obtained for glass-ionomer cements at 12 months (53%) and the highest for fabricated ceramic restorations at 18 months and Preformed Metal Crowns (PMCs) at 24 months (100%). Treatment of MIH-affected FPMs did not significantly aggravate pulp and periodontal health nor improve OHRQoL. Clinical and methodological heterogeneity and the unclear risk-of-bias in most studies did not allow for meta-analyses. The single study on HSPM showed a high success rate of PMCs placed using the Hall technique although approximately 1/3 of the cases presented deterioration of the gingival condition. CONCLUSION: Within the limitations of this systematic review, clear recommendations based on solid evidence for the best restorative approach for HSPM and MIH-affected FPMs cannot be drawn.