Effect of different bleaching regimens on the flexural strength of hybrid composite resin.
BACKGROUND
The entire effects of different bleaching regimens on the mechanical properties of composite resins have remained unknown. The purpose of this study was to evaluate the effects of different bleaching regimens on the flexural strength (FS) of hybrid composite resins.


METHODS
In this in vitro study, 80 bar-shaped specimens of hybrid composite resins were fabricated and randomly divided into four groups, 20 specimens in each group. First group (C) was considered as control. The other groups were treated by home bleaching (HB) agent, in-office bleaching (IB) agent, and the combination regimens (HIB), respectively. The FS was evaluated by three-point bending test by using a Universal Testing Machine. All data were analyzed by using Statistical Package for the Social Sciences (SPSS) software version 18, analysis of variance (ANOVA), and Turkey's post hoc statistical tests (α = 0.05).


RESULTS
The maximum mean value of FS was seen in HB group with significant differences to other groups (P < 0.05). Also, the minimum FS was observed in group HIB.


CONCLUSIONS
Application of different bleaching regimens does not have any adverse effect on the FS of hybrid composite resins. However, the administration of HB regimens seemed to have lesser negative impact on the FS.
Dental Materials Research Center, Department of Restorative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
Atiyeh
A
Feiz
Department of Material Engineering, Islamic Azad University, Isfahan, Iran.
Noushmehr
N
Samanian
Private Practice, Isfahan, Iran.
Amin
A
Davoudi
Post-graguate Student, Department of Operative Dentistry, School of Dentistry, Shahid Sadoughi University Medical Sciences, Yazd, Iran.
Hamid
H
Badrian
Composite resin; flexural strength (FS); home bleaching (HB); in-office bleaching (IB)