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

Abstract

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 ∼ 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 λ 790 nm laser light (4 J/cm2 per point, 40 mW, φ ∼ 0.5 cm2, 16 J 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.