BACKGROUND There is little data regarding the effect of tooth whitening on microhardness of white spot lesions. This study was conducted to investigate the effect of home-bleaching and laser-assisted in-office bleaching on microhardness of demineralized enamel. MATERIAL AND METHODS Forty bovine incisors were selected and immersed in a demineralizing solution for 12 weeks to induce white spot ...

Introduction: Bleaching treatments may negatively affect the surface quality of composite restorations existing in the mouth. This study sought to assess the effect of 16% and 35% carbamide peroxide on microhardness of silorane-based versus two methacrylate-based composite resins. Methods: A total of 54 discs were fabricated from FiltekP90 (P90), FiltekZ350XT(Z350) Enamel and Filtek Z250(Z25...

Abstract The essence of the low-temperature pyrolysis process presented below is processing contaminated bleaching earth, resulting in a purified high calorific oil with an average level 45.5 MJ / kg and synthesis gas that can be used to heat reactor. For research purposes, proprietary low-pressure reactor system direct cooling hydrocarbon vapors was used. main advantages method are limitation ...

Abstract We study the spontaneous out-of-plane bending of a planar untwisted ribbon composed nematic polymer networks activated by change in temperature. Our theory accounts for both stretching and energies, which compete to establish equilibrium. show that when equilibrium is attained these energy components obey complementarity relation: one maximum where other minimum. Moreover, we identify ...

objective: the aim of this study was to evaluate and compare the effect of dental surface treatment with er:yag , nd:yag ,co2 lasers and sodium ascorbate to recently laser bleached enamel by scanning electron microscope (sem). methods: 15caries-free extracted human third molars were selected for this study. the samples were bleached by heydent jw power activated by diode laser 810 nm. after 7 d...

Coral reefs are highly vulnerable to bleaching under elevated temperature. Since 2002, NOAA Coral Reef Watch has used a bleaching threshold based on global sea surface temperatures to provide operational bleaching warnings. Recent studies suggest that modifications to the current global bleaching prediction method may result in higher predictive power. Here, we present a method for comparing fo...

This study on Evaluation of Discharged Untreated Wastewater from Pulping and Bleaching operations in a Bamboo Based tissue Paper Making Plant Nigeria was conducted mainly to evaluate the pollutant loads present wastewater produced during paper making progression. The samples were obtained examined find out pollutants they contain by checking availability some physicochemical parameters using st...