CARIES INCREMENT AMONG SCHOOLCHILDREN EXPOSED TO DIFFERENT FLUORIDE CONCENTRATIONS IN WATER: A FIVE-YEAR RETROSPECTIVE COHORT STUDY Previous studies have indicated that the cessation of community water fluoridation (CWF) leads to an increase in caries prevalence among schoolchildren. However, little is known about the rate of caries progression among schoolchildren exposed to different concentrations of fluoride in water. Hence, this study aimed to compare the mean caries increment in permanent dentition among Malaysian schoolchildren with partial exposure (in Pahang) and full exposure (in Perak) to CWF and determine its associated factors. This was a five-year retrospective cohort study using an analysis of secondary data of school dental records among schoolchildren exposed to different fluoride concentrations in the water supply. Children in Perak were exposed to CWF throughout life while children in Pahang were exposed to CWF for the first five to six years of their lives before it was discontinued. The children were followed retrospectively from 2015 (initially aged eight years old) to 2019 (12 years old). Relevant data such as demographic characteristics, caries experience and exposure to other clinical preventive dental treatments were extracted and analysed using SPSS 21.0. Descriptive, independent t-test and negative binomial regression were used to examine the data. The sample consisted of 462 school dental records in both states. The prevalence of schoolchildren with DMFT scores of 2 and ≥ 3 increased by 10.4% and 13.9%, respectively, in Pahang from 2015 to 2019, compared to 4.8% and 0.9% in Perak. The mean (M) and standard deviation (SD) of caries increment at tooth and surface levels in permanent dentition among schoolchildren in Pahang (M = 0.83, SD = ±1.50 and M = 1.00, SD = ±2.10) was significantly greater (p < 0.001) compared to Perak (M = 0.18, SD = ±0.53 and M = 0.22, SD = ±0.66) over the same period. After controlling for confounders, partial exposure to CWF remained a strong predictor for mean caries increment over a five-year study period. This study showed greater mean caries increment in permanent dentition among schoolchildren in Pahang after CWF ceased. Hence, the findings from this study could be used to assist policy makers to support reimplementation and continuation of CWF in Malaysia.

COST ANALYSIS OF COMMUNITY WATER FLUORIDATION IN KERIAN, PERAK There is limited information available regarding the cost of community water fluoridation (CWF) in Malaysia. Issues related to the cessation of CWF since 2012 in one of the states in Malaysia, were due to the cost of fluoride chemical and the privatisation of water treatment facilities (WTF). Hence, this study aims to estimate the total and per capita cost of the CWF programme in Kerian, Perak, from 2015 to 2019. This was a retrospective record review, analysing CWF expenditure data in two WTF and two dental clinics in Kerian, Perak, from 2015 to 2019, using a healthcare provider perspective. The data on the population coverage of CWF in Kerian was obtained from the Perak Dental Division. Activity-based costing followed CWF guidelines for implementation, operation and maintenance, monitoring, and evaluation activities. All cost items (capital, manpower, safety, maintenance, chemical, and transportation) were presented in MYR 2015 with a 3.0% discount rate. Over the five-year period, the cost of the CWF programme was estimated as follows: MYR 242,644.33 (20.4%) for programme implementation, MYR 796,627.93 (66.9%) for programme operation and maintenance, MYR 147,542.05 (12.4%) for programme monitoring, and the remaining MYR 3,508.20 (0.3%) for programme evaluation. The highest contributor to the CWF programme cost was the fluoride chemical; sodium fluorosilicate, at MYR 450,364.53 (37.8%). The population that received fluoridated water was 189,015. From 2015 to 2019, the CWF programme in Kerian, Perak, incurred an estimated total cost of MYR 1,190,322.51, with a cost per capita of MYR 6.30. This cost analysis enables oral health policymakers and WTF authorities to make informed decisions about investing in the CWF programme.