Repair of Surgical Bone Defects Grafted with Hydroxylapatite + β-TCP and Irradiated with λ=850 nm LED Light

Abstract

The treatment of bone loss due to different etiologic factors is difficult and many techniques aim to improve the repair, including a wide range of biomaterials and recently, photobioengineering. This work aimed to assess by histological analysis the repair of bone defects grafted with biphasic synthetic micro-granular HA + β-TCP associated with LED phototherapy. Forty rats were divided into 4 groups (Clot, LED, Biomaterial and LED + Biomaterial) each subdivided into 2 subgroups according to the time of animal death (15 and 30 days). Surgical bone defects were prepared on the femur of each animal with a trephine drill. In animals of the Clot group the defect was filled only by blood clot, in the LED group the defect filled with the clot was further irradiated. In the animals of Biomaterial and LED + Biomaterial groups the defect was filled by biomaterial and the last one was further irradiated (λ=850±10 nm, 150 mW, Φ ~ 0.5 cm 2 , 20 J/cm 2 -session, 140 J/cm 2 -treatment) at 48-h intervals for 2 weeks. Following animal death, samples were taken and analyzed by light microscopy. Using the degree of maturation of the bone by assessment of the deposition/organization of the basophilic lines in the newly formed bone tissue, the LED + Biomaterial group was the one in a more advanced stage of bone repair process at the end of the experiment. It may be concluded that the use of LED phototherapy was effective in positively modulating the process of bone repair of bone defects in the femur of rats submitted or not to biomaterial grafting.

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

“…A study by Soares et al [65] utilized λ 850 nm LED PBM irradiation on bone defects grafted with HA and βTCP showed to be effective in positively modulating the process of bone repair in rat's femur bone defect submitted or not to biomaterial irradiation. Hence, this study has poorly reported the laser parameters in terms of energy, power density and treatment duration [65]. Another study by Soares et al showed the influence of the LED (λ 78nm) and laser (λ 850 ± 10 nm) PBM on surgical bone defects repair whether augmented with or without biphasic synthetic micro-granular HA + βTCP.…”

3rd Symposium of Lasers In Dentistry

“…We highlight the laser light used for laser phototherapy (LPT). Over the past 20 years, experimental protocols have been proposed for a considerable number of procedures involving bone repair in animals and humans [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. These protocols are now also used as an aid to an efficient repair of mineralized tissues, as LPT accelerates bone repair by directly affecting, in different ways, the new bone formation.…”

“…Fibroblast proliferation and its increased activity have been previously detected in individuals and cultures of irradiated cells and are responsible for the high concentration of collagen fibers observed in the irradiated bone. Our previous studies indicate that the effective result of LPT is observed when the treatment is performed in the initial stages of repair, when a large cell proliferation occurs [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Vascular responses to LPT have also been suggested as one of the possible mechanisms responsible for the positive clinical results observed.…”

“…Destacamos a luz laser usada para fototerapia a laser (FTL). Ao longo dos últimos 20 anos, protocolos experimentais foram propostos para um número considerável de procedimentos envolvendo a reparação do osso em animais e humanos [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Esses protocolos agora são usados também como auxílio para um reparo eficiente de tecidos mineralizados, pois a FTL acelera o reparo ósseo afetando diretamente, de diversas maneiras, a nova formação óssea.…”

“…A proliferação fibroblástica e a sua atividade aumentada foram detectadas anteriormente em indivíduos e culturas de células irradiadas e são responsáveis pela grande concentração de fibras de colágeno observadas no osso irradiado. Nossos estudos anteriores indicam que o resultado efetivo da FTL é observado quando o tratamento é realizado nos estágios iniciais do reparo, quando ocorre uma grande proliferação celular [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] A Terapia fotodinâmica (PDT) tem sido muito utilizada em Periodontia com o objetivo de promover a redução dos microrganismos periodontais principalmente como coadjuvante ao tratamento periodontal não cirúrgico e cirúrgico, ou para o tratamento de bolsas residuais [1]. Consiste no uso de compostos fotossensibilizadores excitados por luz com comprimento ressonante gerando espécies reativas de oxigênio que são citotóxicas para vários tipos de microrganismos Estudos experimentais em animais, tem demonstrado que a PDT isolada ou quando associada a terapia periodontal mecânica é capaz de controlar a perda óssea alveolar, reduzir a extensão do processo inflamatório e da progressão da doença periodontal, controlar a atividade osteoclastogênica, regulando o metabolismo ósseo e promovendo a redução de periodontopatógenos na periodontite experimentalmente induzida, tanto em animais normais [2,3] como em animais modificados sistemicamente [4,5,6].…”