process is influenced by the susceptibility of the tooth surface, the bacterial profile, the quantity and of saliva, and the presence of fluoride which promotes remineralization and inhibits the demineralization of the tooth structure. Caries is a dynamic process involving alternating periods of demineralization and remineralization. How- ever, the majority of lesions in permanent teeth advance relatively slowly, with an average lesion taking at least 3 years to progress through enamel to dentine (Mejare et al. 1998). In populations with low DMF/dmf levels, the majority of carious lesions are confined to the occlusal surfaces of the molar teeth. At higher DMF/dmf levels, smooth surfaces may also be affected by caries (Sheiham and Sabbah 2010).