This study was carried out to compare the ability of two in-office bleaching Systems (Philips Zoom White and Fläsh, Whitening Smile) to lighten teeth immediately, after one week and after one year. In addition, surface roughness of enamel was evaluated before and just after bleaching. Forty healthy human participants were selected. Three applications of the bleaching gel were done each time and the whole session duration was 45 minutes. The teeth shade was recorded using a digital camera and a contact-type intraoral spectrophotometer. An additional silicone-based impression material was used to record the upper anterior teeth' surface topography just before and after the bleaching session. Epoxy resin cast was gold-sputtered to be examined under vacuum using field emission scanning electron microscope attached to EDX Unit. Images were taken at representative areas at 500 X. The following results were found; ΔL, ΔA and ΔB showed no statistically significant difference between the ZOOM and Flash at the three-time intervals. In the flash group, ΔE 1976 and ΔE2000 increased significantly after one week. Flash showed a statistically significantly higher Δ H after one year and higher ΔC immediately after, after one week and after one year. Intragroup comparison showed no statistically significant difference between the different time intervals for all variables in the Zoom and Flash group. Both bleaching systems are effective in office bleaching systems and showed long term effect up to 1 year. The surface roughness of enamel was not altered following bleaching with either technique.