Progression of molar incisor hypomineralization lesions over a 9-year period: results of the 6th German Oral Health Study (DMS • 6).

OBJECTIVES: Molar incisor hypomineralization (MIH) is a developmental defect of the dental hard tissues characterized by insufficient enamel mineralization. However, the natural course of this developmental enamel defect is unknown. This study aimed to assess changes in MIH severity over a 9-year period. METHOD AND MATERIALS: This longitudinal study included individuals who had participated in the Fifth German Oral Health Study (DMS V) in 2014 as 12-year-olds (baseline) and were reexamined in 2023 as 20-year-olds (follow-up). A total of 158 teeth from 366 adolescents with MIH defects at baseline were included, and MIH severity at baseline and follow-up was assessed according to the criteria of the European Academy of Pediatric Dentistry (EAPD). RESULTS: In 11.6% of the analyzed teeth, the MIH worsened during the follow-up period (cumulative progression), corresponding to a progression rate of 1.4 progressive events per 100 tooth-years. Detailed transition analysis showed that 88.1% of the teeth with demarcated opacities at baseline remained unchanged after 9 years. In 7.4% of the cases, an atypical restoration was observed in teeth that had previously presented with only discoloration. In addition, 60% of the enamel breakdown lesions observed at baseline were restored at follow-up. CONCLUSION: Mild MIH may remain stable over several years. However, the risk of requiring restorative treatment is high in teeth with posteruptive enamel breakdown. (Quintessence Int 2026;57(Suppl):S82-S88; doi: 10.3290/j.qi.b6955485).