| Oral hygiene is an important part of health, dental decaies in children can cause local infection, pulpitis or periapical periodontitis, infectious diseases, and even cause systemic infections. Realizing the epidemic law of and the risk factors of dental caries can make effective control of children’s oral diseases, and can provide basis and guarantee to children’s oral health.The prevalence of dental caries fluctuates with the development of social economy and the biological science. With diverse social and economic development levels in various areas, regional difference bring about diversity and complexity of data collection, decision-making in regional oral health disease research, and it is indispensable to study fixed crowd to get systematic, continuous data. As the rapid development of China and deepen reform of the medicine system, children’s living habits, nutrition, medical service utilization, etc. will change, the prevalence of dental caries will be constantly changing. It is necessary to take the concept and research methods of disease surveillance to monitor and investigate children caries dynamically.[Objective]To master the epidemic law of deciduous teeth and permanent teeth caries in different dentition development stage, and analyse risk factors, and provide scientific basis for prevention of children’s oral disease.[Methods]Pre-schooler cohort, primary school students cohort and junior school student cohort were established in 54 counties of 9 provinces. The baseline survey was implemented from December 2010 to June 2011, and all the participants were followed by 2 years.12979 children were investigated at the baseline, in which 10703 were followed by 2 yeas. The follow-up rate were 71.1%,86.8% and 88.4% of pre-schooler cohort, primary school cohort and junior school cohort respectively. The major reasons for the withdraw were transfer and relocation.[Results]Part Ⅰ The growth of deciduous and permanent dentitionIn the cohort of pre-schoolers,20 deciduous teeth have already erupted in all children at the age of 3. And at the age of 5,13.2% of them got teeth fall out, mainly the mandibular incisors.In the cohort of primary school students, children remaining 17.7 teeth per capita at the age of 6,63.1% of them with mixed dentition have been checked out,75.3% of them have at least 1 the first permanent molar. After two years, children remaining 11.5 teeth per capita at the age of 8,99.5% of them with replacement of primary and permanent teeth have been checked out,8.4 per capita, mainly in mandibular incisors, maxillary incisors, mandibular lateral incisors and maxillary lateral incisor and some cuspid teeth, in 98.1% of them,4 of the first permanent molar have erupted into the mouth.In the cohort of junior school students, only 606 people have few deciduous teeth, and 3328 have no deciduous teeth at the age of 12, accounted for 15.0% and 82.5% respectively. By the end of follow-up,97.3% of them have completed all the replacement of primary and permanent teeth,93.9% of them have 28 permanent teeth at the age of 14.The distribution of mixed dentition in different regions, in urban or rural is of significant difference:More in the eastern part than in the central and western regions (P< 0.05), More in the city children than in the rural children (P< 0.05), and girls with mixed dentition is more than boys, the differences reduced gradually as children’s growing up.Part Ⅱ Prevalence rate and the risk factors of caries in different dentition development stageIn the cohort of pre-schoolers, the caries prevalence rate of 3 aged children is 40.9%, dmft is 1.62, the caries filling constituent ratio is 1.2%. Children in different regions, in urban or rural areas, in different social-economic status, and children who have different eating habits of sweets are in different caries susceptibility level (P<0.05):children are more suffering in the western region, in rural area, in poor family economic conditions, and those who eat sweet foods more than 2 times a day, and those who often eating sweets after gargle or before bedtime are apt to get caries.In the cohort of primary school students, the caries prevalence rate of 6 aged children is 71.2%, dmft is 3.85, and the caries filling constituent ratio is 6.1%. Children in urban or rural areas, in different social-economic status, and children who have different sweets eating habits and brushing habits are in different caries susceptibility level (P<0.05):children are more suffering in the western region, in rural area, in poor family economic conditions, those who eat sweet foods more than 2 times a day, and those who often eating sweets after gargle or before bedtime, and those who never brush teeth are apt to get caries.In the cohort of junior school students, the permanent tooth caries prevalence rate of 12 aged children is 40.8%, dmft is 0.95, and the caries filling constituent ratio is 13.6%. The caries prevalence rate of the first permanent molar is 36.1%, for the second permanent teeth is 9.5%. Children in different regions, in urban or rural areas, of different gender, and children who have different eating habits of sweets are in different caries susceptibility level, and girls are apt to get permanent caries (P<0.05): children are more suffering in the western region, in rural area, those who eat sweet foods more than 2 times a day, and those who often eating sweets after gargle or before bedtime are also apt to get permanent caries.Part Ⅲ Incidence rate of caries in different ageIn the cohort of pre-schoolers,1882 children have occurred at least 1 new caries, the 2-year cumulative incidence rate is 65.6%. During the period of 3-4 years old and 4-5 years old, the annual incidence rate of caries is 45.3% and 50.0% respectively, the dmft increased by 1.00 annually. Incidence of mandibular second milk molars, mandibular first milk molars and maxillary incisor are the top three of dentition incidence, on average,12.8%,12.2% and 10.2% respectively. The relative risk of caries incidence between who have caries and caries free children at base line is 1.677 (95% CI:1.593-1.766)In the cohort of primary school studentst,2860 children have occurred at least 1 new caries, the 2-year cumulative incidence rate is 75.2%. During the period of 6-7 years old and 7-8 years old, the annual incidence rate of caries is 54.1% and 53.7% respectively, the dmft increased by 0.1 annually. Incidence of maxillary second milk molars, maxillary first milk molars and mandibular first milk molars are the top three of dentition incidence, on average,12.3%,10.2% and 9.9% respectively. Incidence of first permanent molar significantly increased, averaged 4.5%. The relative risk of caries incidence between who have caries and caries free children at base line is 1.749 (95%C1:1.643-1.861)In the cohort of junior school students,1766 children have occurred at least 1 new caries, the 2-year cumulative incidence rate is 43.8%. During the period of 12- 13 years old and 13-14 years old, the annual incidence rate of caries is 24.2% and 30.6% respectively, the dmft increased by 0.23 annually. Incidence of mandibular first permanent molars, mandibular second permanent molars, and the maxillary first permanent molar are the top three of dentition incidence, on average,8.1%,7.2% and 4.3% respectively. The relative risk of caries incidence between who have caries and caries free children at base line is 2.175 (95%CI: 2.024-2.336)[Conclusion]Early children caries start early and develop rapidly, and accumulate with age gradually. Distribution has apparent regional differences. Maxillary central incisor and primary molar teeth are apt to be decayed at this period. We should focus on the implementation of early prevention and control measures by implement the primary prevention and focus on the health education on parents about children’s oral health care knowledge and the training of daily children’s oral health care practice, and improve the feeding habits and breast-feeding habits to reduce the caries bacteria transmission from mother to children, and advocating baby teeth care and brushing as early as possible.With the accumulation of time, the prevalence rate of caries at early dental transitional period is high, and followed by a high incidence rate. The milk molar and the first permanent molar are apt to be decayed at this period. We should pay attention to the mixed dentition development and the protection of young permanent teeth. For those who have deciduous teeth caries, we should observe the eruption of children permanent teeth and incidence of permanent teeth caries, especially the first permanent molar. Providing guidance for them to build a good habit of brushing and sweets. Group preventive strategy, such as school based or community-based pit and fissure sealant can be applied.For children who just meet permanent dentition, caries prevalence is low, but the incidence is high. The first permanent molar and the second permanent molars are apt to be decayed at this period. This group have independent learning ability and health behavior habits. We should strengthen school oral health education and advocate timely caries filling, to reduce the risk of new caries attributed to previous dental caries.Living in western region, in the rural areas and with poor economic level are environmental factors of caries. Eating much sweet food daily and eat them after gargle or before bedtime are the common main cause of caries in each age stage. Caries experience is the most important indication of the future risk of caries.Caries prevention call for sustainability, systematic study of public health. Under the current social and economic development in our country, children’s oral health prevention measures in different regions should adjust to local conditions. Based on the existing oral health status, we can explore other monitoring methods that is more timely and accurately for caries disease, such as parents report or self report, to make further study of caries pathogenesis. |
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