Molar-incisor hypomineralisation: long-term dental outcomes, dental anxiety, and quality of life in the fit futures longitudinal cohort study

PURPOSE: This longitudinal study aimed to evaluate long-term outcomes of teeth with molar-incisor hypomineralisation (MIH) and associations with dental anxiety and oral health-related quality of life (OHRQoL) in a cohort of Norwegians followed from adolescence to young adulthood. METHODS: Data were from the Fit Futures cohort study, including 518 participants with dental data at ages 16 and 27. MIH was assessed at age 16 using standardised criteria. Outcomes included caries experience, self-reported dental health, dental anxiety, OHRQoL, and dental avoidance. Descriptive and regression analyses were conducted, adjusting for sex and education. RESULTS: Teeth with severe MIH did not show higher levels of caries, tooth loss or endodontic treatment compared to unaffected teeth over the study period. Dental avoidance due to fear was more common among participants with severe MIH (20.0% vs 8.6% at age 27, p = 0.018). Severe MIH was not significantly associated with OHRQoL or dental anxiety score (OR = 0.85, 95% CI = 0.44, 1.67; and B = 0.87, 95% CI - 0.32, 2.07, respectively at age 27). Participants with no or mild MIH had lower dental anxiety scores over time (median 7.0 and 6.0 at ages 16 and 27, respectively, p < 0.001), unlike those with severe MIH (median 7.0 and 7.5 at ages 16 and 27, respectively, p = 0.829). CONCLUSION: Teeth with severe MIH showed no evidence of major deterioration into adulthood, and OHRQoL was similar between groups. However, dental avoidance due to fear was more common among those with severe MIH. Studies with larger cohorts and earlier MIH diagnosis are warranted to validate these findings.