ABSTRACT
The aim of the present study was to determine the prevalence, severity of dental fluorosis and to identify the contributing factors to fluorosis among preparatory school children in Alexandria Gov-ernorate. To meet this aim, a cross-sectional sample was selected using a stratified sampling with proportional allocation technique. A total number of 1007 children, aged 12 to 13 years old, were randomly selected from 27 preparatory schools in all of Alexandria districts [urban and rural - private and public schools], and they were equally divided into males [505] and females [502] A questionnaire was used to collect fluoride exposure data. Only students who returned the questionnaire and their parents' consent were clinically examined on the next day for dental fluorosis, which was recorded by Dean's [1942] index. One hundred samples of drinking tap water for residents [since birth] were analyzed to measure the fluoride concentration For further confirmation of the fluoride analysis, 12 water samples were collected from all Alexandria water stations The results showed that the water fluoride level in Alexandria ranged from 0.30 to 0.90 mg/L, the highest water fluoride concentration was in Borg El-Arab district, which was attributed to presence of agricultural waste products that drained in the main water stream just before the water supply station Although this fluoride concentration in drinking tap water is considered optimal, however there is a trend towards increase in the prevalence of dental fluorosis [60.0% to 85.7%], particularly in Borg El-Arab district [85.7%], also in rural children [92.4%] than urban children [69.9%] and public schools [72.1%] than private [64.6%]. The most prevalent form of dental fluorosis was the very mild form. Fluorosis was proved to be more prevalent in maxillary than mandibular teeth and premolars were the teeth most affected. The multiple regression analysis proved that the most significant contributing factor for dental fluorosis was fluoridated toothpaste if used in large size on toothbrush's head and particularly if the child started brushing teeth with fluoridated toothpaste at an early age Also, fluoride supple-ments intake in the first 8 years of life and frequency of eating fish per week increased the probability of the child to have different degrees of dental fluorosis. The results suggested that fluorosis prevalence is increasing but can be put under control by monitoring fluoride level in drinking water and controlling hidden sources of fluoride intake by labeling juices and beverages, aboundenting the practice of dietary fluoride supplementation, and close parent supervision on the dispersion of fluoridated toothpastes by children