Prevalence of malocclusion in primary dentition in mainland China, 1988-2017: a systematic review and meta-analysis.

Malocclusion is a common oral disease affecting children with various reported prevalence rates. This meta-analysis aimed to determine the epidemiological characteristics of malocclusion among pre-schoolers in mainland China from 1988 to 2017. A total of 31 qualified papers describing 51,100 Chinese children aged 2-7 years were selected. The pooled malocclusion prevalence was 45.50% (95% confidence interval (CI): 38.08-52.81%) with 26.50% Class I (CI: 19.96-33.12%), 7.97% Class II (CI: 6.06-9.87%) and 12.60% Class III (CI: 9.45-15.68%) cases. The most common type of malocclusion was overbite (33.66%, CI: 27.66-39.67%), and the flush terminal type (47.10%, CI: 28.76-65.44%) was the most common in the terminal plane relationship. An increasing trend and wide variations across the country were observed. Additionally, there was no significant difference in malocclusion by gender (relative risk (RR) = 1.01, [0.96-1.06]) or urban/rural area (RR = 0.99, [0.82-1.20]). Although this study represents a narrow view of deciduous-dentition malocclusion in mainland China, the results provide sample evidence that can aid clinicians and policy makers towards early prevention and timely treatment.