Developmental enamel defects and their relationship with caries in adolescents aged 18 years.

Randomly selected 1,611 individuals aged 18 years formed a nationally representative sample from all provinces of Poland. Developmental defects of the enamel (DDE) and caries were assessed using the modified DDE index, molar incisor hypomineralisation (MIH) Treatment Need Index (MIH-TNI), FDI and WHO criteria by 22 trained and calibrated dentists. T-test was used for comparing group means. A simple and multiple logistic regression tests were used to assess the relationship between DDE and caries severity expressed as DMFT (p < 0.05). The prevalence of DDE was 13.7%. Demarcated opacities (DEO) were the most frequent (9.65%); 4% had diffuse opacities (DIO) and 1.5% had hypoplasia. MIH was diagnosed in 0.6% patients. The prevalence of caries was 93.2%, with mean DMFT of 6.50 ± 4.22. The DMFT value was 7.52 ± 4.77 in the group of patients with demarcated opacities (DEO); 7.85 ± 4.74 with diffuse opacities (DIO) and 7.56 ± 4.57 with enamel hypoplasia, respectively. There was a significant relationship between caries severity and DDE (p < 0.001), DEO (p = 0.001) and DIO (p = 0.038), and between DDE and DMFT index (p < 0.001). The results obtained in the study proved the significant relationship between DDE and DMFT in 18-year-olds, the assessment of which was the aim of the study.