In-Office Bleaching Techniques: Laboratory Investigation of the Effect on Color Change and EnamelMicromorphology

Objectives: This study was conducted to evaluate and compare the effect of different in-office bleaching techniques on color change and enamel surface micromorphology.
Materials and Methods:Three different bleaching agents(one light-activated and two chemical-activated) were selected for this study. Sixty sound human permanent maxillary central incisors were selected andfixedin cylinder plastic mold (2 cm width and 1cm height) fabricated with using self- polymerized acrylic resin.Teeth were assigned into two groups according to the test conductedon, color test group (n=30), and themicro-morphology test group(n=30). Each group was further classified into three subgroups(n=10) according to the bleaching material used. The subgroups of each bleaching material were tested for enamel color change assessment usingaspectrophotometer and for surface  micromorphology assessment by a non-contact optical profilometer before and after bleaching application. Data for each test wastabulated and statistically analyzed.
Results: Regarding color change analysis,all tested bleaching materials were effective on tooth color whitening,there was statistical significant differenceinthe mean value of all tested groups (P=0.011). With higher mean values recorded for Zoom group followed by Dash and Boost groups. Regarding the results of surface micromorphology, all the tested bleaching materials showed no statistical significant difference in enamel surface roughness after bleaching(P=0.591).
Conclusions: All thetestedin-officebleaching systemswere effectivelywhiten teeth, with light-activated systemexhibited higher whitening potential than chemical-activatedbleaching systems, with insignificant changein enamel micromorphology.