纵向研究0-2岁婴幼儿变异链球菌群与早期婴幼儿龋的关系

Longitudinal study of mutant streptococci in relation to dental caries in 8-32 month old children

目的探讨8～32个月婴幼儿牙菌斑中变异链球菌群的定植情况,并分析其早期定植与龋病关系。方法收集广州市花都区新华镇225名8月龄婴幼儿,每半年复查一次,持续两年,至婴幼儿32月龄。复查内容包括龋病检查和前牙牙菌斑样本收集。WHO诊断标准用于龋病诊断,选择性培养基及生化实验用于变异链球菌群的分离鉴定。统计方法采用χ2检验或Fisher确切概率法。结果 8月、14月、20月、26月和32月龄变异链球菌群定植率分别为6.7%、31.2%、50.3%、61.0%和75.5%。其中,8月龄组有2名幼儿检出变异链球菌群未见乳牙萌出。变异链球菌群首次检出的平均年龄为(19.6±6.9)个月。婴幼儿乳牙变异链球菌群早期定植患龋率高于晚期定植,32月龄组差异有统计学意义(P=0.018)。结论变异链球菌群能在未萌牙口腔中检出,其定植率随年龄的增长而增加。变异链球菌群在前牙面的早期定植促进乳牙龋病的发生。

Objective To explore the presence of mutant streptococci and the early colonization of mutant streptococci in relation to dental caries in 8-32 month old children.Methods Dental caries was examined and dental plaque samples were collected in 225 children of 8 month old at Xinhua Town,Huadu District of Guangzhou at baseline,and the follow-ups were conducted every 6 months until the subjects were 32 months old.The criteria recommended by World Health Organization were used for the diagnosis of dental caries.Dental plaque samples were plated onto selective media for incubation and identification of mutant streptococci.Chi-square test or Fisher exact test was performed.Results The prevalence of mutant streptococci in children examined was 6.7%,31.2%,50.3%,61.0%,75.5%,at the age of 8,14,20,26 and 32 months,respectively.Two children detected mutant streptococci had no tooth eruption at month 8.The mean age of first detection mutant streptococci was（19.6±6.9） months.The children who were colonized early by mutant streptococci showed a higher number of decayed teeth than those colonized later,with statistical significance in the group of 32 months old.Conclusion Mutant streptococci can present in predentate infants and increase with age.The early colonization of mutant streptococci in anterior surface teeth promotes the occurrence of dental caries.