Morphological, histochemical and immunocytochemical study of CO2 and Er:YAG laser effect on oral soft tissues

The purpose of this study was to investigate the morphological, histochemical, and immunocytochemical
changes of the oral mucosa after CO2 or Er:YAG laser irradiation. Background Data: There have
been no comparative reports on CO2 and Er:YAG laser effects on human oral soft tissues. Materials and
Methods: Tissue preservation was studied in 40 oral biopsies of young patients obtained by CO2 and Er:YAG
laser surgery. Hematoxylin-eosin and Giemsa stains, PAS/diastase treatment, AE1 and AE2 cytokeratins,
MiB1/Ki67, and bcl-2 immunoreactions were performed on the laser cut edges on formalin fixed, paraffin embedded
biopsies. Results: CO2 laser biopsies show blisters, clefts and erosions of the epithelium. Intracellular
edema and lengthened nuclei were also seen. The glycogen content results decreased in CO2 laser biopsies.
Good expression for cytokeratins and cell-cycle proliferation markers were found in Er:YAG biopsies, on the
contrary the apoptosis marker was better expressed in CO2 laser biopsies. Conclusion: The results suggest
that Er:YAG laser may be routinely used in surgery, because of its minimal damage of the epithelial tissue, its
low inflammatory reaction, its quicker healing process and its lower risk of scarring.