抄録
The aim of this study was to evaluate histologically the anti-inflammatory reaction following Nd: YAG laser irradi ation in surgical mandibular defects of rats.
Fifteen rats were used in this study and the experimental period was one, three, or seven days. The rats were given a general anaethetic, and the mandibule was exposed using a skin-mucosal flap. In each animal, a surgical defect of 2×2 mm was created at the inferior border of the mandible bilaterally. In the experimental group (Exp), Nd: YAG laser was irradiated to the bone defect and the inside of the skin-mucosal flap under saline water (3.0 W, 30 seconds, 3 times). In the control group (Cont), no intervention was made following surgery. At day 1, 3 and 7, each group of 5 animals was sacrificed. Undecalcified sections were made, stained with tolidine blue, then subjected to histological analysis and planimetric measure ments.
Histological observation revealed that the tissue component inside surgically created bone defects was fibrous connective tissue that was dense and almost regularly aligned in Exp, but the fibrous connective tissue was dense and irregularly aligned in Cont. In Exp, the connective tissue corresponding to the line considered both bone edges (irradiated skin-mucosal flap) was dense and irregularly aligned at day 1, but it was loose and almost regularly aligned at day 7. In Cont, it was loose and regularly aligned at day 1, but was dense and irregularly aligned at day 7. In Exp, the bone edges were observed to be convexo concave and a densely stained area but were not osteoclast and resorption cavity observed during the experimental period. However, in Cont, they were not observed to be convexo concave and densely stained area.
The results of planimetric measurements indicated that there was no statistically significant difference in the areas of surgi cally created bone defects in both Exp and Cont (p>0.05). In addition, there was no statistically significant difference in the number of inflammatory cells in both Exp and Cont during the experimental period (p>0.05).
This study suggested that the anti-inflammatory effect following Nd: YAG laser irradiation is not a quantitative change of the number of inflammatory cells but a qualitative change associated with a histological change caused by laser irradiation.
