Dental Caries And Fluoride Levels In Water And Milk In 13-15 Year Old Adolescent Population In Dakshina Kannada District, India

Introduction

Dental caries is a major dental disease affecting a large population of the world. It causes pain and discomfort thus impairing the quality of life. Also, it imposes a huge financial burden on health service programmes. Fluoride as a cariostatic agent has been long studied and clinically proven as well. Increased use of fluoride as a systemic and topical agent has led to the decline of dental caries¹.

Recommended fluoride level in community drinking water is 1ppm ².

Fluoride's role in caries prevention is well documented. Fluoride concentration adjustment for caries control first began in 1945-46 in United States and Canada in the drinking water supplying four communities^3-6.

Dakshina kannada district has no centralised water supply. Hence community water fluoridation in not feasible, therefore milk fluoridation can be considered. Milk being an important source of both macro- and micronutrients and a staple in diet for children, it is thought to be an appropriate medium. Fluoride is as easily absorbed from milk as from water².

Systemic fluoride affects teeth during the developmental stages. It gets incorporated into the hydroxyapatite crystals forming fluorapatite which is more resistant to acid dissolution. This is a pre-eruptive effect. It also has a local post-eruptive effect as it is a component of saliva⁷.

Thus the aim of the present study was to determine the fluoride levels in water and milk in Dakshina Kannada district and co-relate it with dental caries in adolescent population.

Materials and Methods

Results:

Interobserver reliability test showed kappa value of 0.8 which is excellent agreement with statistical significance.

The range of fluoride levels in waters samples was 0.01 to 0.17 ppm and that of milk samples was 0.176 to 1.38 ppm. Table 1 shows the fluoride levels of water samples collected from different areas of Dakshina Kannada District.

15 students were consuming milk since less than last 5 years hence they were excluded. Fluoride levels observed were in range of 0.176 to 1.38 ppm within the milk samples tested. Increase in milk fluoride level showed decrease in DMFT scores except for the fresh cow milk with 0.3 ppm fluoride levels where maximum mean DMFT score was found (Table 2). One way ANOVA showed no significance association between DMFT score and milk fluoride level (p=0.2).

Discussion:

The present study has provided an interesting insight into milk, water fluoride levels and caries experience among Dakshina Kannada District in adolescent students. The results will be helpful in motivating the milk or water fluoridation programmes at administrative level to decrease caries incidence from the study areas. These results will also serve as base-line data for the future comparisons.

Fluoride contents of drinking water and different sources of milk in Dakshina Kannada District are below WHO recommended levels. Natural water and milk fluoride levels reflect the overall fluoride availability in an environment². Hence we can conclude that there is scarcity of fluoride in overall environment of Dakshina Kannada District. Amongst all water samples, samples of filtered cooler water from public mall showed minimum fluoride levels while city well water showed maximum fluoride level. It suggests that, may be the filtration must have reduced the fluoride content. Being a coastal area, city well water showed maximum fluoride level. Amongst all milk samples, processed milk showed least fluoride levels. It may suggest Ultra Heat Treatment has reduced the fluoride levels in processed milk.

Systemic fluorides, if administered during period of tooth development i.e. 8 months intra uterine life to 8 years of age, promote the fluorapatite deposition. It results in harder and less soluble enamel surface which is less prone to caries. Also increased levels of fluorides have been found in saliva and gingival crevicular fluid after systemic fluoride consumption². At 13-15 age permanent dentition is recently developed. Effect of systemic fluoridation can be best judged at this age.

Relatively less number of students drinking cow's milk must have resulted high mean value of DMFT. Also, it may suggest that, the caries causative factors viz. more sugar intake, cariogenic dietary habits must have outweighed the milk fluoride levels in students consuming cow's milk. There was no significant difference between the fluoride levels of different milk samples. Hence we could not get statistically significant association between DMFT scores and change in milkfluoride levels.

Previous studies conducted in Dakshina Kannada district have shown dental erosion in 11% males and 8% females, abrasion in 18%males and 13% females & attrition in 30% males and 26% females ⁸, 30.9% prevalence of caries in premolars ⁹, 26% prevalence of dentinal hypersensitivity with lower anterior teeth ¹⁰, more than 50% prevalence of caries in first permanent molar¹¹ and 1.2% prevalence of root caries in overall population¹². A 5 years retrospective study in Dakshina Kannada District showed 36.06% prevalence for missing mandibular molar and 30.64% prevalence of missing maxillary first molar ¹³. All these results show that the overall scarcity of fluoride in Dakshina Kannada District has led to increased prevalence of tooth wear and carious lesions.

Conclusion:

Fluoride content of drinking water in South Kannada District is below WHO recommended levels. Therefore there is necessity of Milk fluoridation of School water fluoridation programme.