Analysis of epidemiological trends of and associated factors for tooth loss among 35- to 44-year-old adults in Guangdong, Southern China, 1995–2015: a population-based cross-sectional survey

BACKGROUND: Tooth loss is a known marker of oral and systemic health, but large-scale population-based and cross-sectional multi-year comparative studies on tooth loss have yet to be much studied in China. This study explores the changing trends in tooth loss status and the associated factors influencing the prevalence of tooth loss over the past two decades in Guangdong, Southern China. METHODS: Data from three cross-sectional, representative oral epidemiological surveys in Guangdong Province were analyzed, including 400 in 1995, 720 in 2005, and 288 in 2015, for a total of 1408 participants. Sample selection is based on the National Census of China published by the National Bureau of Statistics. In this study, each year, the number of missing teeth (MT) and the prevalence of tooth loss (MT > 0) were calculated. Basic demographic information, socioeconomic status, caries and periodontal status, personal lifestyle factors, and dental health care behaviors were analyzed by multivariate logistic regression to estimate their associations with tooth loss. Statistical significance was evaluated with 2-sided tests with a significance level of P < 0.05. RESULTS: This study found that the mean number of missing teeth and the prevalence of tooth loss among adults aged 35–44 years in Guangdong Province did not change significantly in the first decade (1995–2005) but decreased significantly in the second decade (2005–2015) (0.94 and 40.8% in 1995, 0.99 and 42.9% in 2005, and 0.63 and 33.3% in 2015, respectively). The mean number of MT by tooth position was highest for the first and second molars, and both were larger in the mandible than in the maxilla. In 1995, populations with low educational attainment and the presence of caries or periodontal pocket (periodontal probing depth ≥ 4 mm) were associated with a higher chance of MT > 0. In 2005, those with low educational attainment, the presence of caries, and 40–44 years old were associated with a higher chance of MT > 0. Moreover, in 2015, females, rural residents, and those with caries or periodontal pocket were associated with a higher chance of MT > 0. CONCLUSIONS: Although tooth retention has improved recently (2005–2015) and the preventive effect of education level on tooth loss has increased over time, efforts to prevent tooth loss in adults need to be strengthened. Particular attention should be given to preventive interventions for women, rural residents, and those suffering from caries or periodontal pocket.