Laser-induced alterations in rat oral mucosa.

The alterations during healing in laser and scalpel incised palate and tongue mucosa were studied in 37 Spraque-Dawley rats by taking specimens for light and electron microscopic inspection immediately and 4, 7, 11 and 21 days after the treatments. The laser incision differed from the conventional incision: it was horizontally broader, more superficial, not bleeding and contained some charred and necrotic tissue particles; there were more inflammatory cells during healing, and the healing was slightly retarded. The damaged area around the laser incision was very narrow. In EM, the lasered areas showed total cell disruption with no morphologic details seen at the treated site. Adjacent to those sites, charred-appearing particles were seen scattered and embedded also in the connective tissue. The most resistant cell organelles against laser-caused disruption were desmosomes and nuclear membranes. After 21 days' observation the ultrastructural study still revealed cell damage even though the reepithelialization as such seemed to be complete.