Background: The aim of this study was to evaluate the effect of diode laser irradiation and bleaching materials on
the dentinal tubule diameter after laser bleaching.
Material and Methods: The dentin discs of 40 extracted third molar were used in this experiment. Each disc surface
was divided into two halves by grooving. Half of samples were laser bleached at different wavelengths with
two different concentrations of hydrogen peroxide. Other half of each disc with no laser bleaching remained as a
negative control. Dentin discs were assigned randomly into four groups (n=10) with following hydrogen peroxide
and diode laser wavelength specifications; Group 1 (30% - 810 nm), group 2 (30% - 980 nm), group 3 (46% - 810
nm) and group 4 (46% - 980 nm). All specimens were sent for scanning electron microscopic (SEM) analysis in
order to measure tubular diameter in laser treated and control halves. Data were analyzed by ANOVA and Tukey
test (p<0.05).
Results: A significant reduction in dentin tubule diameter was observed in groups 1, 2 and 4. There was no significant
difference between groups 1 and 2 and between groups 3 and 4 after bleaching.
Conclusions: The SEM results showed that diode laser was able to reduce dentin tubule diameter and its effect on
dentin was dependent on chemical action of bleaching material
