4th National Oral Health Survey Research Articles

The 4th National Oral Health Survey in the Mainland of China: Background and Methodology.

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.

The Prevalence and Associated Risk Indicators of Dental Fluorosis in China: Findings from the 4th National Oral Health Survey.

To explore the prevalence and associated risk indicators of dental fluorosis in the mainland of China. 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. 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. 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.

Oral Health Status of 12-year-olds from Regions with and without Coverage of the National Oral Health Comprehensive Intervention Program for Children in China.

To investigate the oral health status and related factors of 12-year-olds from regions with and without coverage of the National Oral Health Comprehensive Intervention Program in China by means of analysing national data from the 4th National Oral Health Survey. Data of 12-year-olds participating 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. Oral health status, pit-and-fissure sealant history, oral hygiene behaviours, sugar consumption habits, status of dental service utilisation, and oral health knowledge were compared between children from regions with and without coverage of the national programme. For the number of decayed, missing and filled permanent teeth (DMFT) and its components, as well as the number of teeth with pit-and-fissure sealants, mean values were statistically tested to see if significance existed between regions covered by the national programme and uncovered regions, whereas caries prevalence and percentage of pit-and-fissure sealants presented were also compared. Data from 27,821 12-year-old children were analysed, among whom 7,726 were from regions covered by the national programme and 20,095 were from uncovered regions. Statistical significance was found in caries experience and activity, pit-and-fissure sealant history, sugar consumption habits, utilisation of dental services and oral health knowledge when compared between the covered and uncovered regions. Prevalence of dental caries and indices for caries experience and activity was lower in regions covered by the national programme than those not covered, while the percentage of pit-and-fissure sealants presented and the number of teeth with pit-and-fissure sealants exhibited higher in the covered regions. This remained the same even if we focused only on the first molars instead of the full dentition. The National Oral Health Comprehensive Intervention Program for Children in China potentially contributed to better oral health status, behaviour and knowledge in 12-year-old children. The expansion and extension of coverage of the national programme was expected to be beneficial for improving oral health status in children, as well as constructing teams of oral and dental workforce and working mechanisms in some underdeveloped regions.

Status of Tooth Loss and Denture Restoration in Chinese Adult Population: Findings from the 4th National Oral Health Survey.

To investigate the status of tooth loss and denture restoration in Chinese adults, analyse the changing trend and provide fundamental data for oral health policy. According to the protocol of the 4th National Oral Health Survey, a multistage stratified random cluster-sampling method was used to enrol adult subjects aged 35 to 44, 55 to 64 and 65 to 74 years in all 31 provinces, municipalities and autonomous regions of the mainland of China. The status of tooth loss and denture restoration was investigated. SPSS20.0 software was used for statistics analysis. Among the 13,464 subjects investigated, 13.8% had complete dentition, 84.4% had dentition defects, and 1.8% was edentulous. Urban subjects showed a significantly higher proportion of complete dentition than those in rural (P = 0.02), and males showed the statistically higher proportion of complete dentition than females (P = 0.01). The mean of remaining teeth was 26.1 ± 6.90, which in urban areas was significantly higher than in rural areas (P < 0.01). The means of remaining teeth were 29.6 ± 2.3, 26.3 ± 6.1, and 22.5 ± 8.7 in the 35 to 44, 55 to 64 and 65 to 74 age groups, respectively. The detection rate of fixed partial dentures (FPD) was statistically higher in urban than in rural areas and in males than that in females (P < 0.01). The detection rate of removable partial dentures (RPD) was statistically higher in urban areas than in rural locations (P < 0.01). However, the detection rates of irregular denture and unrepair of tooth loss were both significantly lower in urban than in rural areas (P < 0.01). The rate of restoration of tooth loss was 41.6% in Chinese adults. Although the tooth loss and denture restoration status recorded in the survey was improved compared with the results of 10 years ago, more efforts need to be made on strengthening oral health promotion, particularly for elderly people and those living in rural areas.

Utilisation of Oral Health Services and Economic Burden of Oral Diseases in China.

To evaluate the use of oral health services, the economic burden of oral diseases and related influential factors in China. Using the multistage, stratified, equal proportion, random sampling method in the 4th National Oral Health Survey of China conducted in 2015 to 2016, residents aged 3 to 5 years, 12 to 15 years, 35 to 44 years, 55 to 64 years, and 65 to 74 years respectively were recruited, clinically examined and answered a questionnaire. Utilisation of oral health services were assessed in all the age groups and the economic burden of oral diseases in the past 12 months were assessed in the 3 to 5 years and 35 to 74 year-old groups. Chi-squared tests, t tests, correlation analysis and a one-way ANOVA were used to determine the relationships of different factors with utilisation of oral health services and the economic burden of oral diseases. In the subject groups - 3 to 5 years, 12 to 15 years and 35 to 74 years - the prevalence of the utilisation of oral health services in the past 12 months was 14.6% (5,876/40,353), 23.6% (27,936/118,592), and 20.1% (2,708/13,461), respectively. In all three groups, receiving dental treatment was the most common reason for subjects' recent dental visit. The average dental cost in the past 12 months was 403.43 CNY (median = 100) for 3 to 5-year-old children and 850.83 CNY (median = 300) for adults aged 35 to 74 years old. Area, education and annual household income per person were the socio-economic influential factors. Oral health status, oral hygiene and attitudes to and knowledge of oral health affected the utilisation of oral health services and the economic burden of oral diseases. The percentage of dental service utilisation was relatively low, and the economic burden was high. The related factors for both utilisation of oral health services and the economic burden of oral diseases included living in area, educational attainment, household income, perceived oral health status, and oral hygiene.

Report of the National Investigation of Resources for Oral Health in China.

To investigate the current status and distribution of resources for oral health in China, by means of analysing national data from the National Investigation of Resources for Oral Health. The National Investigation of Resources for Oral Health in China was performed in 2015, in parallel with the 4th National Oral Health Survey of China (2015 to 2016). A structured questionnaire on resources for oral health was used to collect the data of professional institutions and stomatological/dental workforce in each province. For each province, the local Investigation Group was responsible to summarise the status and distribution of institutions with stomatological/dental departments and stomatological/dental workforce. Descriptive analysis of resources for oral health was performed to learn about the number and percentage of each category both for each province and nationally. The ratio of number of stomatological/dental workforce to population was also calculated and compared with the criteria of the World Health Organisation (WHO). There were totally 75,399 stomatological/dental departments nationally in all professional institutions in the mainland of China, most of which were set in institutions of primary health care services. Institutions of private sectors accounted for a higher proportion (69.8%) which was over two-fold compared to that of public ones (30.2%). General hospitals were the major part of hospitals with stomatological/dental departments compared with stomatological/dental specialised hospitals. Stomatological/dental clinics were the majority of institutions of primary health care services, compared to community health care service centres/stations and township health care services. Amongst all professional institutions of public health with stomatological/dental departments, 35.0% were maternal and child health care services and 11.2% were institutions for prevention and control of oral diseases. The total number of stomatological/dental workforce in the country was 314,347, among whom 171,587 (54.6%) were stomatologists/dentists. The ratio of number of stomatologists/dentists to population was 1:7,768 nationally, which was lower than the WHO standard of 1:5,000. The National Investigation of Resources for Oral Health in China exhibited the current status and distribution of resources for oral health over the country, whereas insufficiencies of stomatological/dental workforce and institutions and inequalities of their distribution were found nationally. This could provide some policy suggestions for the health authorities in China to promote oral health in the Chinese population in the future.

Dental Caries Status and its Associated Factors among 3- to 5-year-old Children in China: A National Survey.

To investigate the prevalence and severity of dental caries among pre-school children in China as part of the 4th National Oral Health Survey. 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. 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. 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.

How Root Caries Differs between Middle-aged People and the Elderly: Findings from the 4th National Oral Health Survey of China.

To investigate the differences in distribution of root caries and related factors between middle-aged and elderly people in China. 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. 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). 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.

Periodontal Status of Chinese Adolescents: Findings from the 4th National Oral Health Survey.

To investigate the periodontal health status and associated factors of adolescents aged 12 to 15 years old in China. 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. 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. 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.