<prompt> Chronic flurosis is caused by drinking water with fluride content of:1-5 ppm5-10 ppm10 ppm10-15 ppm  <response>: Ans: c 10 ppm Ref: Maheswari, 3rd ed, p. 266; Davidson, 19th ed, p. 324Chronic flurosis is seen in localities where the water supply contains 10 ppm fluride Davidson.FlurosisIt is characterized by excessive deposition of calcium in bone soft tissues.Clinical features:Dental flurosis-- earliest sign offlurosis mottling of enamel - incisors of upper jaw.Skeletal flurosis-- pain in back joints, stiff spine, paraesthesias.Spastic paraparesis anaemia.Radiological findings:Spine: Calcification of posterior longitudinal ligament.Pelvis: Calcification of ischio pubic sacroiliac ligamentsForearm leg: calcification of interosseous membrane.Treatment: Defluridation of water Nalgonda techniqueDD of generalized osteosclerotic lesions:FlurosisEngelman diseasePaget diseaseRenal osteodystrophyOsteopetrosis marble bone diseaseSecondaries from prostate and other organs. 