Effect of low-level laser therapy irradiation and Bio-Oss graft material on the osteogenesis process in rabbit calvarium defects: a double blind experimental study.

This study aims to assess the effect of low-level laser therapy (LLLT) irradiation and Bio-Oss graft material on the osteogenesis process in the rabbit calvarium defects. Twelve white male New Zealand rabbits were included in this study. Four 8-mm diameter identical defects were prepared on each rabbit's calvarium. One site was left as an untreated control (C), the second site was filled with Bio-Oss (B), the third site was treated with laser irradiation (L), and the fourth site treated with Bio-Oss and laser irradiation (B + L). In the laser group, a diode laser (wavelength 810 nm, output power 300 mW, irradiation mode CW, energy density 4 J/cm2) was applied immediately after surgery and then one other day for the next 20 days. After 4 and 8 weeks, the animals were sacrificed and histological and histomorphometric examinations were performed and the data were subjected to Friedman and repeated measurements ANOVA tests. Significant differences were not found regarding inflammation severity, foreign body reactions, and vitality of newly formed bone on 4th and 8th week after operation. The mean amount of new bone was 15.83 and 18.5% in the controls on the 4th and 8th week; 27.66 and 25.16% in the laser-irradiated group; 35.0 and 41.83% in Bio-Oss and 41.83 and 47.0% in the laser + Bio-Oss treated specimens with significant statistical differences (p <0.05). Application of LLLT in combination with Bio-Oss® can promote bone healing. Therefore, LLLT may be clinically beneficial in promoting bone formation in skeletal defects.

Improvement of dermal burn healing by combining sodium alginate/chitosan-based films and low level laser therapy.

This paper aimed to evaluate the improvement of burn wounds healing by sodium alginate/chitosan-based films and laser therapy. Natural polymers with different biological activities are widely used as film dressings to improve wound healing. Lasers arrays accelerate the healing repair of soft tissue injuries. Burn procedures were performed on the backs of 60 male rats assigned into six groups: untreated (CTR), dressed with cellulose films (CL), dressed with sodium alginate/chitosan-based films (SC), laser-irradiated undressed wounds (LT), laser-irradiated wounds with cellulose (CLLT) and sodium alginate/chitosan-based films (SCLT). Laser therapy was applied for 7 days. Animals of each group were euthanised 8 and 14 days after the burn procedures. The inflammatory reaction was significantly more intense in the CTR group than in the irradiated groups after 8 and 14 days. Laser therapy stimulated myofibroblastic differentiation in 8 days, with or without dressing films. Combined laser therapy and both dressings improved epithelisation, blood vessels formation and collagenization, promoted rapid replacement of type III for type I collagen and favored the better arrangement of the newly formed collagen fibres. The combination of laser therapy and sodium alginate/chitosan-based dressing improves burn healing, apparently by modulating the epithelisation, blood vessels formation and collagenization processes.

The effect of the association of NIR laser therapy BMPs, and guided bone regeneration on tibial fractures treated with wire osteosynthesis: Raman spectroscopy study.

Bone fractures are lesions of different etiology; may be associated or not to bone losses; and have different options for treatment, such as the use of biomaterials, guided bone regeneration, techniques considered effective on improving bone repair. Laser therapy has also been shown to improve bone healing on several models. The association of these three techniques has been well documented by our group using different models. This study aimed to assess, through Raman spectroscopy, the incorporation of calcium hydroxyapatite (CHA approximately 958 cm(-1)) on the repair of complete tibial fractures in rabbits treated with wire osteosynthesis (WO); treated or not with laser therapy; and associated or not with the use of BMPs and/or Guided Bone Regeneration. Complete tibial fractures were created in 12 animals that were divided into four groups: WO; WO+BMPs; WO+laser therapy; and WO+BMPs+laser therapy. Irradiation started immediately after surgery; was repeated at every other day during 2 weeks; and was carried out with lambda 790 nm laser light (4 J/cm(2) per point, 40 mW, phi approximately 0.5 cm(2), 16J per session). Animal death occurred after 30 days. Raman spectroscopy was performed at both the surface and the depth of the fracture site. Statistical analysis showed significant difference on the concentrations of CHA between surface and depth. The analysis in each of the areas showed at the depth of the fracture significant differences between all treatment groups (p<0.0001). Significant differences were also seen between WO+BMPs+laser therapy and WO (p<0.001) and WO+laser therapy (p<0.001). At the surface, significant difference was seen only between the treatment groups and the non-fractured subjects (p=0.0001). However, no significant difference was seen between the treatment groups (p=0.14). It is concluded that the use of NIR laser therapy associated to BMPs and GBR was effective in improving bone healing on the fractured bones as a result of the increasing deposition of CHA measured by Raman spectroscopy.