Residents of South Korea living in areas with newer water fluoridation programs had significantly fewer dental visits for caries and lower overall dental care costs than those in areas without water fluoridation, according to a new study.
Researchers sought to measure the impact community water fluoridation would have in nonmetropolitan areas of that country. The results were published in BMC Oral Health (November 8, 2016).
"In the regions with water fluoridation programs, the duration of the program had an inverse association with the number of dental visits per year," wrote the study authors, led by Myung-Soo Cho and Kyu-Tae Han.
Cho is from the department of health policy and management, and Han is from the department of public health, both at the Graduate School of Public Health at Yonsei University in Seoul.
Providing more evidence
While previous studies have shown positive effects of water fluoridation on oral health, concerns in the South Korea have grown about possible negative effects of community water fluoridation. This has especially been the case as water fluoridation has been expanded recently in some Korean nonmetropolitan areas.
These concerns have made it more difficult to implement new fluoridation programs, so the researchers conducted the current study to provide additional evidence of water fluoridation's positive public health effects.
The study examined the relationship between dental care utilization and the implementation of new water fluoridation programs in South Korea from 2003 to 2013. The researchers compared patient data from 164 nonmetropolitan areas, since water fluoridation programs were rarely added in metropolitan areas during those years.
The study included data from 472,250 patients in the National Health Insurance Service National Sample Cohort who were first diagnosed with dental caries in 2003 through 2013. The cohort was a random sample of 1,025,340 individuals, around 2.2% of the South Korean population in 2002. Individuals diagnosed with dental caries before 2003 were excluded to ensure that only newly diagnosed patients were included.
Just over 10% of total patients in the study lived in an area with community water fluoridation at baseline. Over an average follow-up period of 9.1 years, significantly fewer patients who lived in an area with fluoridation had dental care visits for dental caries compared with those without fluoridation (46.98% versus 48.66%; p < 0.0001). Additionally, the average number of dental care visits and costs were lower among patients in the areas with water fluoridation (p < 0.0001).
The association between the presence of a water fluoridation program and the number of dental visits was greater for patients who had not had a dental visit during the previous year compared with those who had. In addition, the longer a fluoridation program had been in place was associated with fewer dental visits per year. These results were similar to the findings of previous studies, including in other countries.
The study results suggest that water fluoridation programs had a major role in reducing the incidence of dental caries as a primary rather than secondary prevention, the authors noted.
Changing public perception
Previous studies have found that factors such as lifestyle, types of toothpaste, and frequency of toothbrushing can affect oral health outcomes, although the current study did not consider these factors. The study also did not examine fluoride levels in the water or fluoride consumption per individual. Other limitations of the study include possible underestimation of dental care expenditures and not including adverse effects of water fluoridation.
Despite these drawbacks, the authors concluded that their findings could be helpful in countering the negative public perception of water fluoridation programs in South Korea and also in combating high out-of-pocket dental care costs.
"The implementation of such programs would be effective for individuals who managed their dental care well without clinical symptoms," they wrote.