Comparative study on the incision healing of the palatal mucosa by using Er:YAG laser or traditional scalpel in the SD rats

The aim of this study was to compare the histology of wound healing following incisions with the scalpel or the Er:YAG laser in the palatal mucosa of SD rats. Two types of wounds were performed with the stainless steel scalpel or the Er:YAG laser in the palatal mucosa of SD rats, while the adjacent untreated palatal mucosa was chosen as control. Rats were sacrificed on day 1, day 3, day 7, and day 30 post-surgery. Biopsy samples from each wound were examined and the expression of IL-1ß and TGF-ß1 was determined by enzyme-linked immunosorbent assay (ELISA). The early postoperative incision of the scalpel group had obvious bleeding and swelling, while the laser wound mainly covered the surface of white pseudomembrane. The infiltration of neutrophils and lymphocytes in the stroma of the scalpel incision was more than that of the laser group. Compared to the laser group, 1 and 3 days after operation, the TGF-β1 content of the scalpel group were significantly increased (P = 0.032 and 0.019). Seven days after operation, the TGF-β1 content of two groups was decreased. TGF-β1 expression of control group was obviously increased (P > 0.05); 1, 3, and 7 days after operation, the traditional scalpel amount of IL-1β expression was significantly higher than that of control group (P = 0.000, 0.000, and 0.001). Postoperative day 1, IL-1β expression of laser group and control group had no significant difference (P = 0.572). Three days after operation, IL-1β expression of laser incision was increased and was significantly higher than that in control group (P = 0.032), however lower than the scalpel group (P = 0.03). Seven days after operation, the IL-1β expression of two groups had no significant difference (P = 0.333); however, the IL-1β expression of two groups were significantly higher than that of the control group (P = 0.02 and 0.001). Compared to the traditional scalpel, the incision of Er:YAG laser has smaller inflammation reaction, more pseudomembrane coverage, and minimal damage of the mucoperiosteal tissue.