Trends over Time in Dental Caries status in Urban and Rural Thai Children.

Background: Historically, the prevalence of dental caries was higher in urban areas than rural areas of Thailand. This study aim to examine the time trends in caries status in children in Thailand.

Material and Methods: Linear regression was used to examine trend of dental caries prevalence and mean number of teeth with caries, filled and missing due to caries (dmft/DMFT) in urban and rural, of 3-, 5-6 and 12-year olds from seven Thailand National Oral Health Surveys conducted approximately every 5 years from 1977 to 2012.

Results: There were declines in the caries prevalence and mean dmft/DMFT in every age group. Significant results were observed in the mean dmft of 3 year-olds and the mean DMFT of 12 year-olds ( p = 0.03 and p =0.05, respectively). A significant trend of declining prevalence of dental caries was observed in urban children ages 5-6 ( p =0.002), along with urban 12 year-olds ( p <0.001). A declining trend of mean dmft for 3 and 5-6 year-olds, and mean DMFT for 12 year-olds was observed in both rural and urban areas, but significant results were shown in urban 3 and 5-6 year-olds ( P =0.04, and p <0.001, respectively), and urban 12 year-olds ( p =0.001). For restoration outcome, both urban and rural of all age groups have an increasing trend of mean ft/FT index.

Conclusions: There have been differences over time in the prevalence and quantity of dental caries between urban and rural school children. A significant reduction was observed in urban areas. More effort needs to be given to supply rural areas in order to have fair and equal access of all citizens to oral health care. Key words: Dental caries, prevalence, children, Thailand, rural, urban, time trend, national survey.