Safety
The lethal dose for a 70 kg (154 lb) human is estimated at 5–10 g.Fluorides, particularly aqueous solutions of sodium fluoride, are rapidly and quite extensively absorbed by the human body.Fluorides interfere with electron transport and calcium metabolism. Calcium is essential for maintaining cardiac membrane potentials and in regulating coagulation. High ingestion of fluoride salts or hydrofluoric acid may result in fatal arrhythmias due to profound hypocalcemia. Chronic over-absorption can cause hardening of bones, calcification of ligaments, and buildup on teeth. Fluoride can cause irritation or corrosion to eyes, skin, and nasal membranes.Sodium fluoride is classed as toxic by both inhalation (of dusts or aerosols) and ingestion. In high enough doses, it has been shown to affect the heart and circulatory system. For occupational exposures, the Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health have established occupational exposure limits at 2.5 mg/m3 over an eight-hour time-weighted average.In the higher doses used to treat osteoporosis, plain sodium fluoride can cause pain in the legs and incomplete stress fractures when the doses are too high; it also irritates the stomach, sometimes so severely as to cause peptic ulcer disease. Slow-release and enteric-coated versions of sodium fluoride do not have significant gastric side effects, and have milder and less frequent complications in the bones.
However, when the tooth concerned will undergo endodontic treatment such as root canal treatment, presence of large pulp stones will be clinically significant.Large pulp stones in the pulp chamber might block the access to canal orifices and prevent the exploring dental instruments from passaging down the canal. In these cases, burs or even ultrasonic instrumentation can be used to remove the blocking pulp stones. During the removal process, sodium hypochlorite which has dissolving action can also be used as a synergistic effect. == References ==