Objective: The purpose of this study was to investigate the effects of dent
in ablation using a carbon dioxide (CO2) laser emitted at 9.3 mu m by scann
ing electron microscopy (SEM) and confocal laser scanning microscopy (CLSM)
, Background Data: There have been no reports on effects of CO2 laser irrad
iation emitted at 9.3 Ecm on dentin by SEM and CLSM, Methods: Thirty extrac
ted human teeth showing no clinical signs of caries were used. All teeth we
re horizontally sectioned to approximately 200 mu m thickness and sections
were irradiated using a 9.3 pm CO2 laser at different parameters as follows
: 26 mi [energy density (ED) 53.0 J/cm(2)] and 30 mJ (ED 61.1 J/cm(2)), Aft
er laser irradiation, samples were treated with sodium hypochlorite, staine
d using rhodamine-123, and observed with CLSM followed by SEM procedures. R
esults: No craters or cracks were observed, but many small molten and rehar
dened particles were documented on the sample surface using SEM. Some small
cracks were seen in the subsurface layer, and some patent dentinal tubules
were detected using CLSM. Conclusion : These results suggest that laser ir
radiation at these parameters affected the sample surface only (less than 2
0 mu m) and would be less harmful to thermal damage of dental pulp for dent
in ablation.