[Effect of the soft laser on gingival connective tissue. I--Effect on fibroblasts. Histoenzymology and electron microscopy study].

The effect of soft-laser upon human gingival fibroblasts was studied after an initial biopsy followed by irradiation and numerous biopsies performed 5 mn, 15 mn, 1 hour and 24 hours after irradiation. In addition, control biopsies were performed in the same way on a non-irradiated gingival area. One hour after irradiation and up to 24 hours later, the enzymatic activities of the fibroblasts were obvious: oxidative enzymes, leucine aminopeptidase, and considerable Brachet's test highly positive (RNA). By transmission electron microscopy were changes were found in these fibroblasts. They were more numerous and their cytoplasmic organelles were increased (mitochondria, rough endoplasmic reticulum). An abundant granular material as well as collagen fibrils were accumulated along their cytoplasmic membrane. On the whole, from the 1st hour on following irradiation by soft-laser a stimulation of metabolic activity of the fibroblasts (oxidative activities, proteic synthesis) was observed with increased production of collagen.