Tooth eruption and caries patterns in the first permanent molars of 6–8-year-old schoolchildren in Shenzen, China

Abstract

AbstractBackground:The caries patterns of the first permanent molars (FPMs) among schoolchildren had not been adequately evaluated, and researchers paid no attention to the distributions of fully-erupted FPMs number and proportion in Shenzhen children.Objective:To quantitatively assess the eruption stages and dental caries patterns of the FPMs for the total students as well as the subgroups.Methods:A 3-year school-based epidemiological investigation was undertaken by dentists to examine the eruption stages and dental caries patterns of the FPMs, involved the second-grade students from 132 primary schools in Baoan District of Shenzhen, China.Results:Among 95809 schoolchildren aged 6–8 years, 86.51% individuals had fully erupted the Tooth #16, 87.15% for #26, 89.30% for #36, and 88.81% for #46 (c2=475.033,P<0.001); 80.65% children had all 4 erupted FPMs, with a higher rate among girls than boys (83.37%vs78.43%;P<0.001). The prevalence of FPMs caries among all students was 13.58% for Tooth #16, 13.53% for #26, 21.02% for #36, and 21.13% for #46 (c2=3322.810,P<0.001). The overall prevalence of dental caries on the FPMs was 28.58%, with a higher prevalence among girls than boys (31.97%vs25.68%;P<0.001). With increasing age, the FPMs caries prevalence increased (24.89% for 6 years-old, 28.70% for 7 years-oldχχ, and 34.65% for 8 years-old). Mean Decayed-Missing-Filled-Teeth score on FPMs was 0.652, with a decayed component of 0.646 (99.08%) and a filled component of 0.006.Conclusions:Most schoolchildren aged 6–8 years have fully erupted the FPMs, with a relatively high prevalence of FPMs caries in Shenzhen.