Manifestation and characterization of enamel surface changes after fluoride-containing bleaching treatments

• Main Authors: Yu-Peng Lin, 林育朋
• Other Authors: Shu-Fen Chuang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/79102105015432693505

碩士 === 國立成功大學 === 口腔醫學研究所 === 97 === External tooth bleaching by peroxide-based home bleaching agents is a popular method to whiten discolored teeth. Carbamide peroxide (CP) is an oxidizing agent, consisting of hydrogen peroxide-urea compounds. Some studies found surface softening, mineral loss, increased susceptibility to erosion or caries, reduced fracture stability or a decrease in abrasion resistance on bleached dental hard tissues. Moreover, tooth sensitivity often occurs during the bleaching treatments. Therefore, investigations have been addressed on fluoride–containing CP that improved these disadvantages. It provoked the argument that adding fluoride to whitening systems may aid tooth remineralization. Although fluoride-containing CP bleaching gels are often used in the clinic. Additional fluoride is thought that it can protect tooth. The reason of improve negative effect are not clear. It may be fluoride compound form on tooth surface. The efficacy has not been thoroughly evaluated. The purpose of the present study was to evaluate the effects of fluoride concentration and CP concentration on the manifestations of surface enamel. In the present study, bovine incisors were treated by the fluoride-free bleaching gels and bleaching gels containing different concentrations of fluoride. These incisors were placed in a de-/ remineralization cycle to simulate conditions in oral cavity. Microhardness, Scanning Electron Microscope, Electron Spectroscopy for Chemical Analysis, Inductively Coupled Plasma-Optical Emission Spectrometry, Microscopes Raman Spectrometer and Profilemeter, were used. The result showed that teeth treated with bleaching gels containing high concentrations of fluoride exhibited higher microhardness, less erosion morphology and apatite destruction, less Ca-leaching, and potential surface deposition on enamel surface. Treating with the higher concentration CP with the same fluoride concentration generated lower microhardness, more erosion morphology but Ca-leaching were similar to the lower CP concentration ones. The present results were similar to other study using the citric acid for demineralization. However, these results showed the correlations between the fluoride concentration and the enamel surface changes. The clinic information provided by this study suggests that dentist should choose bleaching agents with suitable fluoride concentration to reduce demineralization after bleaching treatment, or avoid severe erosion and in patients with soft drinks habits.