Fluoride concentration in drinking water in Shahroud (Northern Iran) and determination of DMF index in 7 year old children

&nbsp; Background : Fluorine is an essential micronutrient for human health, serving to strengthen the apatite matrix of skeletal tissues and teeth. In regions where the fluoride (F&minus;) concentration of water is naturally low (<0.5 mg/l), some communities have chosen to add this constituent to their drinking water to strengthen teeth and to minimize cavities P.B. Maithani, R. Gurjar, R. Banerjee, B.K. Balaji, S. Ramachandran and R. Singh, Anomalous . The aim of this study was to determine fluoride concentration in drinking water in shahroud city at the northern part of Iran as well as determination of DMF value in 7 year old children, for a duration of 6 years. &nbsp; Materials and Methods: In this descriptive study, 138 students aged 7 were chosen randomly from Shahroud schools and were followed up for a duration of 6 years (2004-2009). They were examined by a dentist for determining the numbers of decayed, missing and filled permanent teeth. Also 120 samples were taken from drinking water in the city and Ion-selective method was used for measureing fluoride concentration. Determination of both DMF index and fluoride mean concentration was repeated for six years from 2004 to 2009. &nbsp; Results: Fluoride concentrations were between 0.45 to 0.75 mg/L and DMF index was between 3.18 to 3.81. There was a significant difference between both DMF index and fluoride mean concentrations in different years. Conclusions: DMF index obtained in our study was higher than the index reported for the whole country (1.2-2.6mg/L).