Chinese Journal of Dental Research, 03/2018

Oral disease patterns change over time and it is important to conduct epidemiological surveillance population surveys regularly to monitor the situation. The overall objectives of the present survey were: (1) to describe the oral health status of Chinese children and adults in the 2015-2016 4th National Oral Health Survey; (2) to investigate the oral health knowledge, attitudes, and behaviours among children and adults; (3) to explore the association among sociodemographic characteristics, oral health behaviours, and the oral health status of Chinese children and adults. A national oral health survey was conducted among a representative sample of Chinese children and adults. Local residents from the five age groups - 3 to 5 years, 12 to 15 years, 35 to 44 years, 55 to 64 years, and 65 to 74 years - were selected. A multi-stage cluster sampling method was adopted for the identification of participants. All 31 provinces, autonomous regions and municipalities of the mainland of China were included. All participants were clinically examined and information on their oral health status, including oral mucosal lesions, dental caries experience, periodontal health status, dental fluorosis, and dental prosthesis status, was collected according to the procedures and criteria recommended by the World Health Organization (WHO). A calibration training programme and quality control procedures were conducted to ensure the reliability of the findings. Information on sociodemographic background, oral health behaviours, knowledge and attitude was also collected from all five age groups through a questionnaire survey. Keywords: China, epidemiology, methodology, the 4th National Oral Health Survey

Objective: To investigate the prevalence and severity of dental caries among pre-school children in China as part of the 4th National Oral Health Survey. Methods: The sampling process was conducted with a multistage stratified cluster method. A total of 40,360 children aged between 3 and 5 years were recruited for this study. Each participant was clinically assessed according to the 5th edition of the oral health survey's basic methods recommended by the World Health Organization (WHO) and their parents or grandparents completed a questionnaire at a face-to-face interview. The status of dental caries was shown in the form of the mean dmft and the prevalence of dental caries. The logistic regression analysis was performed to study the relationships between the prevalence of dental caries and the selected variables. Results: The prevalence of dental caries was 50.8%, 63.6% and 71.9% for 3-, 4- and 5-year-olds, respectively. The mean dmft was 2.28, 3.40 and 4.24, respectively. Logistic regression analysis showed that children who were mixed-fed had a higher chance of staying free of dental caries; children who had dessert before going to bed were associated with a higher probability of caries. Conclusion: The status of dental caries among preschool children in China is on the increase. The preschoolers' dental caries status related to their breastfeeding conditions within the first 6 months of life and their snacking habits. Keywords: China, dental caries, preschool children, epidemiology, the 4th National Oral Health Survey

Objective: To investigate the dental caries status of teenagers in China by means of analysing national data from the 4th National Oral Health Survey of China. Methods: Data for 12- to 15-year-olds participated in the 4th National Oral Health Survey of China were used for statistical analysis. Children who were recruited in the survey completed a dental examination and filled in a questionnaire. Social demographic factors, oral hygiene behaviours, sugar consumption habits, status of dental service utilisation, and pit-and-fissure sealant history were compared between adolescents with caries experiences and those without. For decayed, missing and filled permanent teeth (DMFT) and each of its components, mean values were statistically tested to see if significance existed between or among different categories of all involved variables. Results: In total, data from 27,821, 30,961, 30,691 and 29,128 Chinese 12-, 13-, 14-, and 15-year-olds respectively, were analysed. Social demographic factors, sugar consumption and dental service utilisation showed statistical significance when compared between those with and without dental caries experience in the 12- and 15-year-old groups. Certain categories of these factors above also had important influence on the mean value of the number of decayed teeth (DT), filled teeth (FT) and DMFT, and they might be potential determinants of dental caries experience of permanent teeth for teenagers. Conclusion: Dental caries in 12- and 15-year-old Chinese adolescents was impacted by certain social demographic and dental behavioural factors, which could provide some implications for policy makers and dental public health professionals when attempting to enhance oral health status for those teenagers in the early stages of permanent dentition. Keywords: adolescents, dental caries, dental behaviour, social demographic factor, the 4th National Oral Health Survey

Objective: To investigate the periodontal health status and associated factors of adolescents aged 12 to 15 years old in China. Methods: A cross-sectional national oral health survey was conducted in 2015-2016. The multi-stage stratified cluster sampling was used to select participants in all 31 provinces, autonomous regions and municipalities in the mainland of China. Each participant received a clinical assessment including periodontal bleeding and calculus, and 15-year-old adolescents received additional examinations including for periodontal pocket depth and attachment loss, using the latest criteria from the Oral Health Survey Basic Methods, as recommended by the World Health Organization (WHO). A self-answered structured questionnaire was designed to collect the data of background information and associated risk factors. Results: A total of 118,514 adolescents (14.0 ± 1.09 years old) completed all the oral examinations and the questionnaire. The prevalence of periodontal bleeding and calculus was 61.0% and 67.3% respectively. In the group of 15 year olds, 6.5% adolescents had periodontal pocket and 0.5% had attachment loss. Molars were often involved and, furthermore, calculus also occurred on lower incisors. The periodontal status of adolescents became worse as they grew up. The condition of girls was significantly better than boys. Conclusion: This survey illustrated a brief picture of periodontal status of adolescents in China showing that gingival bleeding and calculus were very common and frequent. Further actions on oral health education were necessary, especially for those in lower socio-economic classes. Keywords: adolescent, calculus, gingival bleeding, periodontal, the 4th National Oral Health Survey

Objective: To explore the prevalence and associated risk indicators of dental fluorosis in the mainland of China. Methods: Data for this study was obtained from the 4th National Oral Health Survey in China, conducted from 2015 to 2016. The sample population was 12-year-old school students. Study participants were selected using a multi-stage, stratified random sample selection procedure using a sampling frame compiled from geographical distribution of China. The level of dental fluorosis was determined using the Dean index recommended by the World Health Organization (WHO). A structured questionnaire was distributed to all the subjects in schools. Participants completed a questionnaire with assistance from staff. A bivariate analysis was performed using the chi-square test. Logistic regression was performed to evaluate the association between dental fluorosis and the independent variables. Results: A total of 27,495 students were evaluated, of which 13,650 (49.6%) were male. Overall, dental fluorosis was found in 13.4% of participants; 6.3% had very mild fluorosis, 4.3% had mild fluorosis, 2.3% had moderate fluorosis, and 0.5% had severe fluorosis. The community fluorosis index was 0.28. In the final logistic regression model students from rural areas (RR:1.582, 95%CI 1.473-1.700), students whose fathers had low education (RR:1.429, 95%CI 1.230-1.661 & 1.184, 95%CI 1.026-1.365), and those students with sibling (RR:1.537, 95%CI 1.414-1.671) were more significantly associated with dental fluorosis. Conclusion: As a whole, China has a low dental fluorosis prevalence. Rural areas were the key places for the prevention of dental fluorosis. More prevention measures should be conducted on the children whose fathers were of lower education and who were not an only child. Keywords: dental fluorosis, prevalence, risk indicator, the 4th National Oral Health Survey

Objective: To investigate the dental caries status and related factors in Chinese elderly people, using data from the 4th National Oral Health Survey of China. Methods: In this cross-sectional study, a multistage, cluster strategy was used to recruit 4,431participants (2,222 male and 2,209 female) aged 65 to 74 years from all 31 provinces, autonomous regions and municipalities of the mainland of China. The survey was performed according to the diagnostic standard proposed by the World Health Organization (WHO). Socio-demographic information was collected with a closed questionnaire. Results: The caries prevalence in 65 to 74-year-olds was rather high; the report shows it was 98.0% (DMFT ≥ 1) among elderly people in China. The mean DMFT, DT, MT and FT was 13.33 ± 9.32, 3.33 ± 4.17, 9.50 ± 8.66 and 0.49 ± 1.41, respectively. The filling rate was very low, assessed as 12.8%. The number of DMFT related to gender, residential district type, educational level, level of annual household income, toothbrushing frequency, consumption frequency of desserts, attitudes to oral health and oral health-related knowledge. Conclusion: The prevalence of dental caries in Chinese elderly people is rather high and a lot of decayed teeth still need to be filled and suitable prevention and treatment for this group is urgently needed. Keywords: caries, elderly people, prevalence, risk factors, the 4th National Oral Health Survey

Objective: To investigate the differences in distribution of root caries and related factors between middle-aged and elderly people in China. Methods: In this cross-sectional study, a multistage, cluster strategy was used to recruit 4,410 participants (2,197 males and 2,213 females) aged 35 to 44 years and 4,431 participants (2,222 males and 2,209 females) aged 65 to 74 years from all 31 provinces, autonomous regions and municipalities of the mainland of China. The survey was conducted according to the basic methods proposed by the World Health Organization (WHO). Sociodemographic information, oral health behaviour, attitude and knowledge, history of dental prophylaxis and general health condition were collected with a closed questionnaire. Results: A great increase in the occurrence of root caries in Chinese adults from 35 to 44-year-old to 65 to 74-year-olds, with the prevalence (DFR ≥ 1) from 25.4% to 61.9% and with the mean DFR score from 0.54 ± 1.34 to 2.63 ± 3.75. Filling rates were also very low, only 1.8% and 3.0%, respectively. Females and residents of rural areas were more likely to suffer from root caries. In both the middle-aged group and the elderly group, root caries related to gender, education level, sweet food/drinks consumption, oral health knowledge and status of root surface explosion. In 35 to 44 year olds, toothbrushing is a significant protection factor (OR = 0.88, 95%CI 0.81 ~ 0.96), while using toothpicks is a risk factor (OR = 1.06, 95%CI 1.02 ~ 1.10). In 65 to 74 year olds, not having dental had scaling in the past 12 months is a risk factor (OR = 1.66, 95%CI 1.09 ~ 2.53). Conclusion: Root caries among middle-aged people and elderly people in China have different risk factors and need more attention in future research to develop proper prevention. Keywords: China, elders, middle-aged, risk factor, root caries, the 4th National Oral Health Survey