Biochemical changes on the repair of surgical bone defects grafted with biphasic synthetic micro-granular HA + β-tricalcium phosphate induced by laser and LED phototherapies and assessed by Raman spectroscopy

Abstract

This work aimed the assessment of biochemical changes induced by laser or LED irradiation during mineralization of a bone defect in an animal model using a spectral model based on Raman spectroscopy. Six groups were studied: clot, laser (λ = 780 nm; 70 mW), LED (λ = 850 ± 10 nm; 150 mW), biomaterial (biphasic synthetic micro-granular hydroxyapatite (HA) + β-tricalcium phosphate), biomaterial + laser, and biomaterial + LED. When indicated, defects were further irradiated at a 48-h interval during 2 weeks (20 J/cm per session). At the 15th and 30th days, femurs were dissected and spectra of the defects were collected. Raman spectra were submitted to a model to estimate the relative amount of collagen, phosphate HA, and carbonate HA by using the spectra of pure collagen and biomaterials composed of phosphate and carbonate HA, respectively. The use of the biomaterial associated to phototherapy did not change the collagen formation at both 15 and 30 days. The amount of carbonate HA was not different in all groups at the 15th day. However, at the 30th day, there was a significant difference (ANOVA, p = 0.01), with lower carbonate HA for the group biomaterial + LED compared to biomaterial (p < 0.05). The phosphate HA was higher in the groups that received biomaterial grafts at the 15th day compared to clot (significant for the biomaterial; p < 0.01). At the 30th day, the phosphate HA was higher for the group biomaterial + laser, while this was lower for all the other groups. These results indicated that the use of laser phototherapy improved the repair of bone defects grafted with the biomaterial by increasing the deposition of phosphate HA.

Photobiomodulation: lasers vs. light emitting diodes?

“…The results of these studies are shortly presented in tables 4, 5 and 6, respectively. The tables are not comprehensive, since we excluded a few papers due to difficulties in interpreting either the methods or the results [45–48].…”

Effects of photobiomodulation on bone defects grafted with bone substitutes: A systematic review of in vivo animal studies

“…Eight studies were excluded as they were based on utilization of autogenous bone grafts for bone repair and regeneration [24, 27, 36–41] (inter‐reviewer agreement, κ = 0.94). Thus, out of the fifty‐three full text articles, fifteen articles were excluded due to the above mentioned reasons and 38 articles were included and analyzed in the present systematic review [42–79]. All the included articles were in vivo animal studies.…”

“…In thrity‐three papers, the experiments were conducted on Wistar rats (male and/or female) [42–73, 79]. The Sprague–Dawley rats were used, as experimental models in two studies [75, 76], whereas, the New Zealand rabbits were the experimental models in three studies [74, 77, 78] (Table 1).…”

Examination of the Effect of the Combined Use of Nd: YAG Laser Irradiation and Mechanical Force Loading on Bone Metabolism Using Cultured Human Osteoblasts

“…5 On another study using a rat fracture model, there were reports that Nd: YAG laser and diode laser irradiation promoted bone healing 6,7 and that diode laser irradiation promoted bone grafting in rats and in vitro experiments. 8,9 Also, another study reports that Nd: YAG laser irradiation promoted osteoblast differentiation, 10 red laser irradiation caused fibroblast proliferation, 11 and diode laser irradiation caused osteoblast proliferation. 12 In the field of orthodontic dentistry, pain relief 13,14 during tooth movement by laser irradiation and the acceleration of tooth movement have been reported.…”