REVIEW ON ROLE OF METAL SALT IN THE RE-MINERALIZATION OF DENTAL CARIES

Dental caries is a most common disease that affects large number of people. It is a worldwide public health problem, affecting numerous urban and rural communities. White-spot lesions (WSL) are the earliest macroscopic evidence of enamel caries. Typically, the enamel surface layer stays intact during subsurface demineralization, but, without treatment, will eventually collapse into a full cavity. Near-neutral pH of saliva is endowed with a natural buffering capacity. Natural demineralization of tooth at an early stage is reversed by saliva, which contains calcium ions, phosphate ions, buffering agents, fluoride, and other substances. The strategy for aided remineralisation is to have ions directly delivered to where and when they are needed the most. Several mechanisms are available for aided remineralisation. The most well known is the delivery of topical and systemic fluoride, which has been proven to be a highly effective measure for prevention of caries. However limitations and risks associated with the use of fluoride as a remineralising agent fuelled the need to develop newer non-toxic techniques that deliver calcium and phosphate ions directly into subsurface lesion and/or boost remineralising properties of saliva. Encouraging microscopic changes in the demineralized enamel surface following the treatment with different concentration of metal salts, involving zinc, strontium, magnesium, in addition to stannous fluoride, many metal salts are in use for the treatment of dental caries. Microscopic examination was conducted on teeth samples before and after pH-cycling procedure and following the treatment with the selected metal salt under polarized microscope (100X). The best obvious remineralisation was found following treatment with stannous fluoride, followed by zinc chloride. The stannous fluoride was the best in the remineralisation of initial caries, results for other metals seem to be promising if used for prevention of dental caries. Mineralization of teeth is determined by major inorganic elements as calcium, phosphorous in addition to other elements that occur in traces within tooth structure (Thylstrup and Fejerskov, 1996 Murry, 1996 Peter, 2004). Fluoride now a day is widely used either systemically or topically to increase resistance of teeth surface, it has been well documented as a major contributing factor in the decline of the incidence and severity of dental caries in many countries (Murry, 1996 Curzon,1999).So far fluoride has been considered to play an almost unique role in the prevention of dental caries however there is no reason to dismiss the role of other elements as being potential cariostatic agents. Different concentrations of different metal ions as zinc and copper have been tested for better effect on remineralisation in vitro (Dedhiya, et al., 1974 Fang et al., 1980). However controversy is present in the literature concerning their effectiveness in prevention of dental caries when used topically at effective concentrations (Torredo et al., 2004 Elzbieta et al., 2008 Curzon, 1983).