Original Article Estimation of Fluoride Content of Drinking Water in Dharan Bandana Koirala1, Surya Raj Niraula2, Anup Ghimire3 1Department of Pedodontics and Preventive Dentistry, 2School of Public Health and Community Medicine, 3School of Public Health and Community Medicine; BP Koirala Institute of Health Sciences, Dharan, Nepal Abstract Introduction: Fluoride when present in drinking water at optimal level has been shown to promote oral health by preventing tooth decay. Dental caries represents a health problem that impacts on the medical, functional, nutritional and psychological status of patients in all the age groups. Fluoridation of public water supply is a safe, economical and effective measure to prevent dental caries. Objective: To estimate the level of fluoride present in drinking water supplies in all the wards of Dharan and to compare the fluoride concentration of its different water supply sources. Methods: One hundred water samples were collected from the various sources (ground water and surface water) and its different reservoirs along with random samples of 2-7 from all the wards of Dharan. The samples were then taken to the SEAM-N-MMA laboratory, Biratnagar to be tested for fluoride using the photometric method. Microsoft excel for data entry and SPSS 11.5 version for analysis were used. Significance of the variables was examined by Chi-square test. Results: The results of this study showed that in 96% of the samples taken, fluoride level was below the optimal. Only few samples met the lower range guideline value of Nepal (0.5 mg/l). Also, there was significant difference (p< 0.002) between the surface and consumer level fluoride. Conclusion: The fluoride content in drinking water supplies of Dharan was found to be below optimal level as per the national and WHO guideline values. Key Words: Dental caries, drinking water, fluoride Introduction In the 1940s, scientists discovered that people Fluoride is one of the most plentiful elements on who lived where drinking water supplies had earth and occurs naturally in water supplies in naturally occurring fluoride levels of varying amounts. When fluoride is present in approximately 1 part fluoride per million parts drinking water at optimal levels, it has been water or greater (> 1.0 ppm) had fewer dental shown to promote oral health by preventing caries than people who lived where fluoride tooth decay. Water systems are considered levels in drinking water were lower.1,2 naturally fluoridated when the natural level of Numerous reports documenting reduced dental fluoride is greater than 0.7 parts per million caries prevalence after exposure to fluoridated (ppm). When a water system adjusts the level of water supplies have appeared in a variety of fluoride to 0.7-1.2 ppm, it is referred to as water sources.3 These studies comparing fluoridated fluoridation. and non-fluoridated communities have reported decrease in the overall prevalence of dental Address for correspondence caries, and for summary scores of dental decay Dr. Bandana Koirala, Professor and Head Department of Pedodontics & Preventive Dentistry identified as the "DMF" for permanent teeth and BP Koirala Institute of Health Sciences, Dharan the "def" for primary teeth. These summary Email: [email protected] 88 Koirala B et al. Estimation of Fluoride Content of Drinking Water in Dharan JBPKIHS 2020; 3(1): 88-97 scores represent the cumulative caries fluoride from age six months to six years, and experience based on the number of decayed (D decreasing the level at which no or d), missing or extracted due to caries (M or e) supplementation is needed from 0.6 ppm to 0.7 or filled (F or f) tooth surfaces. Additional ppm. When drinking water levels of fluoride are studies have documented increased caries suboptimal, dietary supplementation should be prevalence following withdrawal of fluoride considered for preventing dental caries which is supplementation of drinking water.4,5 Frequent supported by the U.S. Preventive Services Task exposure to small amounts of fluoride each day Force.12 The prevalence of dental caries is 42% will best reduce the risk for dental caries in all at five years of age, increasing to more than the age groups, hence, it is recommended that 84% by age 17.13-15 The Health Care Financing all persons drink water with an optimal fluoride Administration estimates that 5% of the total concentration and brush their teeth twice daily health care expenditures (or $34 billion) is spent with fluoridated toothpaste.6 on dental services of which 13.2% (or $4.5 The action of fluoride on teeth involves both billion) is used for amalgam restorations.16 topical and systemic mechanisms. Fluoride acts Dental caries represents a health problem that to stabilize the hydroxyapatite matrix on internal impacts on the medical, functional, nutritional, and external tooth surfaces.7,8 Topical and psychological status of patients in all the application of fluoride has been shown to age groups. Fluoridation of public water supply decrease levels of dental plaque bacteria.9 is a safe, economical and effective measure to Systemic fluoride is provided by fluoridated prevent dental caries. The Centers for Disease public water supplies, dietary supplements, food Control and Prevention (CDC) considered the and beverages. Sources of topical fluorides reduction in tooth decay from fluoridation as include fluoride-containing dentifrices, mouth one of the top public health achievements of the rinses and gels. When used appropriately, 20th Century.2 Very limited studies with minimal fluoride is both safe and effective in preventing coverage have been conducted in Nepal.17,18 and controlling dental caries. Though it is Therefore, the present study aimed to estimate proved that appropriate amount of fluoride the level of fluoride present in drinking water consumption helps in combating dental caries, supplies in all the wards of Dharan and to number of adverse effects have been seen with compare the fluoride concentration of its chronic ingestion of high doses on human health different water supply sources. of which dental fluorosis is the commonest.10 The American Academy of Pediatrics (AAP) Materials and Methods has issued a schedule for fluoride The study was conducted in Dharan supplementation.11 These recommendations take municipality- a city of Eastern Nepal. Dharan is account of the levels of fluoride contained in the located on the foothills of Himalayas in the primary drinking water supply as well as the age eastern region in the Sunsari District. Surface of the pediatric patient. Changes in the current water being the major source of water in AAP schedule include the elimination of Dharan, the ground water source meets the dry fluoride supplementation during the first six season demand through its five differently months, decreased doses of supplemental located wells. 100 water samples were collected 89 Koirala B et al. Estimation of Fluoride Content of Drinking Water in Dharan JBPKIHS 2020; 3(1): 88-97 from the various sources i.e., ground water and the same investigator and the collected samples surface water and its different reservoirs along stored in the icebox immediately. The samples with random samples of 2-7 from different were then taken to the SEAM-N-MMA wards of Dharan. laboratory, Biratnagar to be tested (using the The coding list was prepared. Water samples photometric method which allows a reliable were collected in sterilized plastic bottles determination of fluoride) on the same or the provided by the SEAM-N-MMA laboratory and next day. All the samples were stored in the according to the sample collection protocol by refrigerator if not taken to lab the same day. Data Management and Analysis: different sources. The probability of rejection of The corrected data was entered into the null hypothesis was set at ‘p’ value less than computer through Microsoft excel software and 5%. checked in every fifth entry and corrected if any Results false entry was seen. After purifying the data, it Fluoride content in source and consumer level was converted into SPSS 11.5 version software was below optimal and was found to be and analysis was done. significantly different. Table 1 and Table 2 Frequency and percentage were presented to represent the analyzed report. describe the nature and the characteristics of the variables. Corrected Chi-square test was used to assess the significant difference in between Table 1: Fluoride content of drinking water taken from source and consumer levels Fluoride Concentration (mg/l) Levels Total < 0.05 0.05- 0.49 >= 0.50 Source 11 11 2 24 45.8% 45.8% 8.4% 100.0% Consumer 10 64 2 76 13.2% 84.2% 2.6% 100.0% Total 21 75 4 100 21.0% 75.0% 4.0% 100.0% (Chi square = 12.46, df= 1, p< 0.002) In all the samples taken from the ground level, Of the remaining samples, 30%, 23%, and 15% fluoride content was seen to be below optimal. had fluoride levels of 0.1 mg/l, 0.2 mg/l, and 0.3 Out of the 16 samples taken from the surface mg/l, respectively. Only one sample had 0.4 sources, 12.5% of the samples were found to mg/l of fluoride. have optimal level of fluoride in the range of Since there is zero cell frequency in case of 0.55- 0.67 mg/l. At the consumer level, only ground source, we have only included surface 2.6% were within the lower optimal level (0.52 level and consumer level for the significance mg/l). The concentration of fluoride in the test. This test shows there was significant remaining samples is described as follows: 20% difference between the surface and consumer of the samples had fluoride level below levels of fluoride (Chi-square= 12.46, df= 1, p< 0.05mg/l.