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Updated: Dec 11, 2025

Author Spotlight: Establishing an Accurate Microhardness Testing Protocol for Craniofacial Tissues
Published on: April 26, 2024
Analysis of enamel structure and mineral density after different bleaching protocols using micro-computed tomography
Derya Surmelioglu1, Eda Didem Yalcin2, Kaan Orhan3
1Department of Restorative Dentistry, Faculty of Dentistry, Gaziantep University, Gaziantep, Turkey.
Objective:
This study aims to investigate the effect of three different bleaching applications on structural integrity, mineral volume (MV) and density of the enamel by using micro-computed tomography (Micro-CT) and evaluate the colour effectiveness using CIEDE2000.
Materials And Methods:
Twenty-four maxillary premolar teeth were divided into three groups (n = 8) (group 1: 40% HP gel with erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser activation; group 2: 40% HP gel with diode laser activation; group 3: 16% CP gel). Bleaching protocols were applied and colour alteration was obtained. Data were calculated with CIEDE2000 before and after bleaching. A Micro-CT was used to scan the specimens before and after the bleaching application. Statistical analysis was performed by ANOVA.
Results:
No significant difference was observed between the groups for colour changes (p > .05). Micro-CT analysis showed significant differences in structural thickness, structural separation, mineral density and MV for the different ROIs before and after bleaching for all groups (p<.05).
Conclusions:
All of the bleaching methods represented similar efficiency. However, bleaching with Er,Cr:YSGG laser was less harmful to enamel in comparison with other bleaching methods. The present results may be useful for establishing a numerical standard for the change in bleaching with laser systems in dental hard tissues.

