Evaluation of the effects of low-level laser applications with intra-oral appliance on condylar growth in rats

A growth center of the mandible that stimulates to its effective length and height is mandibular condyle. Forward positioning of mandible is followed by adaptive remodelling in the mandibular condyle cartilage and glenoid fossa. The aim of this study was to evaluate the effects of low-level laser applications with intra-oral appliance on condylar growth in rats. The sample consisted of 48 rats, weighing between 260 and 280 gr, divided randomly into four groups. Group 1 was the control group, group 2 was the appliance group, group 3 was the 8 j laser irradiation with appliance group and group 4 was the 10 j laser irradiation with appliance group. Experimental rats were stimulated with low-level laser in the temporomandibular joint region bilaterally for 15 times in 30 days. Morphological changes in mandible was checked with lateral radiographs before and after the applications. After euthanasia, histological specimens were analyzed histomorphometrically at the anterior and posterior aspects of mandibular condyle, including the condylar cartilage and subchondral bone. According to lateral radiograph results growth of mandibles in experimental groups was significantly more than that in the control group. Histomorphometric results also revealed a significant difference between experimental groups and the control group. Group 3 and group 4 showed that the stimulatory effects of low level laser therapy are dose-dependent. We concluded that low-level laser irradiation with the chosen parameters can stimulate condylar growth and cause mandibular advancement.