Effects of different settings for 940 nm diode laser on expanded suture in rats

Objectives: To evaluate the effects of the Indium Gallium Arsenide Phosphoride (InGaAsP) diode laser at different energy levels on orthopedically expanded midpalatal sutures of rats. Materials and Methods: Eighty Wistar rats were randomly divided into four groups: a control group and low-, moderate-, and high-level laser groups with amounts of energy irradiated at 0 J, 18 J, 42 J, and 60 J, respectively. Each group was divided into two subgroups (n = 10) according to the schedule of sacrifice (7 and 21 days). Laser application (940 +/- 10 nm, 0.1 W) was completed twice weekly until sacrifice. The number of osteoblasts (OB), osteocytes (OC), and vessels (V); area of connective tissue (CT); inflammation (IN); and newly formed bone (NB); as well as the ratio of newly formed bone to the total bone area (N/T) were evaluated statistically at a significance level of P < .05. Results: For the low-level laser group, OB, NB, and N/T were significantly higher, and CT was lower, on both the 7th and 21st days. The amount of OC was significantly higher in the low-level laser group compared with the control group on the 7th day and the control and high-level laser groups on the 21st day. The IN was significantly higher for the high-level group on the 21st day compared with other groups. Both the moderate-level and high-level laser groups possessed fewer vessels than the low-level laser group on the 21st day. Conclusions: The InGaAsP laser at the low dosage induced a favorable effect on bone formation in the orthopedically expanded midpalatal suture of rats.