Fluoride is one of the electronegative elements that risk human health at concentrations lower and higher than the standard (0.5 – 1.0 mg/l). About 200 million people from 25 countries are exposed to highly fluoride-contaminated groundwater sources. Excess fluoride exposure exhibits an extraordinary degree of uniformity in its dental and skeletal manifestations, a highly advanced irreversible stage. Dental fluorosis occurs during the initial age of 0-12 years when the body tissues are developing. Dental fluorosis is followed by Skeletal fluorosis, a cripling stage where the calcification of bones causes the severe bone deformity, spinal compression, and elevated risk of bone fractures in adults. Hence, a clinical study was conducted in Dongargaon village in Chandrapur district in India. The village was previously reported to be contaminated with Fluoride in drinking water.

Fifty-seven human subjects (24 female and 33 male) from the Dongargaon village of Chandrapur District (India), in the age group of 35–55 (mean age 45 years) were recruited for the fluorosis study with their written consent. These subjects were exposed to fluoride through drinking water for at least 15 years. The spot urine of selected adults and water samples from all drinking water sources were collected for a fluoride assessment. The fluoride concentration in drinking water and urine samples was determined using the USEPA fluoride ion selective electrode method. The fluoride concentration in drinking water samples varied from 0.64-6 mg/l, exceeding the WHO ­­permissible limit (1.5 mg/l). The urinary fluoride concentration ranged from 0.5- 7.9 mg/l. 

Dental fluorosis was diagnosed using the Dean index. The shape and size of teeth and extent of discoloration were recorded. The clinical examination indicated that 3.5% (2/57) of the exposed population are at grade 0, 33.33% are at grade 0.5 (19/57), 33.33% are at grade I (19/57), 19.29% (11/57) are at grade II and 10.52% (6/57) are at grade III.  

Skeletal fluorosis stages were graded based on an anterior-posterior and lateral X-ray view of the lumbo-sacral spine including the pelvic girdle. Their bone X-ray images show typical clinical features of skeletal fluorosis. The radiological findings indicated that 36.84 % of the exposed population are at stage 0 (21/57), 21.05% are at stage I (12/57), 40.35% are at stage II (23/57) and 1.75 % are at stage III (1/57).

Extensive interim questionnaires concerning lifestyle and medical issues followed by physical tests indicated that 45.61% exposed population are unable to lift coins without bending their knees, 28.07% are unable to touch their chest with the chin and 3.5 % are unable to fold their elbow, stretch the arm sideways, and touch the back of the head. The pivotal study demonstrated a significant correlation between skeletal fluorosis and age. In view of extensive clinical surveys concerning the health of fluoride-exposed populations and assessments of fluoride concentrations in drinking water, and urine, it is evident that long-term fluoride exposure through the drinking water has dramatically caused skeletal and dental fluorosis. Existing epidemiologic research should be combined with current knowledge of toxicodynamic mechanisms gained from in-vitro and in-vivo studies. The improved risk assessment will necessitate interdisciplinary participation from the earliest stages of problem conceptualization through risk characterization and management.

Keywords:  Skeletal fluorosis, Dental fluorosis, X-ray