ABSTRACT
To analyze the effects of bleaching agent on enamel structure and to characterize the morphological and chemical changes in enamel due to bleaching. Experimental study. School of Chemical and Material Engineering [SCME], NUST Islamabad from Feb to May 2013. Ten recently extracted pre molars between the 12-22years age group were randomly assigned into two groups. Group one was a non-bleached control group with sound enamel. Group two was bleachedwith Everbrite In office tooth whitening system after specimen preparation, surface morphology was observed under SEM [scanned electron microscope] and AFM [Atomic force microscope]. Thedetrimental effects of hydrogen per-oxide on enamel were evident in bleached specimens under SEM, and AFM analysis. There were significant surface alterations found in the bleached specimens as compared to control group. However salivary buffering potentials could overcome the demineralizing effect of bleaching gel
ABSTRACT
The aim of this study was to measure the linear shrinkage of alginate impression material in various disinfecting solutions. The two different alginates used were Blue Print Cremix [Dentsply, USA] and Hydrogum [Ivoclar vivadent, Liechtenstein] which are commercially available, whereas the two disinfectants used to measure the shrinkage of the alginates immersion materials were Perform I.D. [Schulke and Mayr, Germany] and sodium hypochlorite [Laboratories Rivadis, France]. Distilled water was used as control and air was used to simulate clinical situation. At the end of one hour Blueprint Cremix showed more shrinkage than Hydrogum in distilled water, 1% Na Hypochlorite and Perform I.D. Whereas, in air Hydrogum showed more shrinkage than BluePrint Cremix. Immersion of the two alginates in disinfecting solutions has similar effect of net shrinkage, how-ever the effect is more pronounced for BluePrint Cremix. Effect of disinfecting solutions on the dimensional stability of alginate impression material