Bone tissue microscopic findings related to the use of diode laser (830etam) in ovine mandible submitted to distraction osteogenesis

Abstract

Purpose: To analyze the microscopic characteristics of the effect of Gallium-Aluminum Arsenid diode laser (GaAlAs830ηm) applied during the activation and consolidation period to ovine mandibles submitted to distraction osteogenesis. Methods: Eighteen sheep underwent surgery in order to have bone distractors implanted in the left side of the jaw area. They were divided into three groups: 1 -Control; 2 -Laser irradiation during the activation period; 3 -Laser irradiation during the fixation period. The irradiation was carried out in five sessions, on every other day, with 4,0J/cm 2 doses applied to four pre-established areas, totaling 16J per session. After four days of latency under post-operative care, ten days of distractor activation (at 1mm/day) and twenty-one days of fixation the animals were sacrificed and the devices removed for microscopic analysis. Results: The groups that received laser irradiation (GaAlAs) presented a greater amount of mineralized bone trabeculae when compared to the Control Group. Despite that, cartilaginous tissues were also found in Group 2. Conclusion:The laser has been more favorable when used in the consolidation period, after bone elongation. Key words: Lasers. Bone lengthening. Wound healing. Sheep. RESUMOObjetivo: Avaliar as características microscópicas do efeito do laser diodo de Arsenieto de Gálio-Alumínio (AsGaAl830ηm), aplicado no período de ativação e consolidação de mandíbulas de ovelhas submetidas a distração osteogênica. Métodos: Dezoito ovinos foram submetidos a procedimento cirúrgico para colocação de distrator ósseo em região de mandíbula do lado esquerdo, sendo divididos em três grupos: 1 -Controle; 2 -Irradiação de laser no período de ativação; 3 -Irradiação de laser no período de contenção. As irradiações foram feitas em cinco seções em dias alternados, com doses de 4,0J/cm 2 em quatro pontos pré-determinados, somando 16J por seção. Após quatro dias de latência no pós-operatório, 10 dias de ativação do distrator (1 mm/dia) e 21 dias de contenção os animais foram mortos e as peças removidas para análise microscópica. Resultados: Os resultados foram que os grupos irradiados com laser (AsGaAl) apresentaram maior disposição de trabéculas ósseas mineralizadas em relação ao grupo controle, contudo, no Grupo 2 foi observada a presença de tecido cartilaginoso. Conclusão: O laser atuou de forma mais favorável quando utilizado no período de consolidação, após o alongamento ósseo. Descritores: Lasers. Alongamento ósseo. Cicatrização de feridas. Ovinos.

A preliminary study of hardness and modulus of elasticity in sheep mandibles submitted to distraction osteogenesis and low-level laser therapy

“…On the other hand, when applied during the latency and activation period, laser therapy caused a decrease in hardness and modulus of elasticity values, with a consequent delay in bone calcification. The results obtained in sheep D (LLLT applied during the bone consolidation period), namely hardness of 414.4 MPa and modulus of elasticity of 12.3 GPa (Table 1), are compatible with the results described by Cerqueira et al (18) and Kreisner et al (19), who also reported positive results in terms of bone regeneration and new bone formation in mandibles submitted to distraction osteogenesis and LLLT in the bone consolidation period. Sheep E (control) was not submitted to LLLT.…”

“…The lowest modulus of elasticity and hardness results were found in sheep C, which used the distractor for 33 days and was submitted to LLLT in the activation period. These findings may suggest that the application of LLLT during the activation period in fact provokes a delay in bone healing, a hypothesis that is reinforced by the marked presence of cartilage tissue and endochondral ossification observed in specimens irradiated with LLLT during the activation period, as proposed by Cerqueira et al (18). Although the use of distraction osteogenesis has become increasingly common, it can cause significant discomfort to the patient, especially when external devices are used, possibly leading to infections, paresthesia, hypertrophic scars and social difficulties (14).…”

The effects of grapeseed extract and low level laser therapy administration on the liver in experimentally fractured mandible

“…LLLT is among the techniques used to facilitate the recovery process in bone tissue during recent years. Conducted studies analyzed the therapeutic action of LLLT in the first connective tissue and it was determined that in time LLLT reduced inflammation, stimulated fibroblast proliferation and collagen production, increased local micro-vascularization and bone mineralization, and implant osteointegration by stimulating osteoblastic activity, and it was proven that these properties of laser had positive effects on bone recovery (27)(28)(29).…”

Low Level Laser Applications in Periodontology

“…Son zamanlardaki birçok çalışmada da DDLT'nin kemik oluşu-munu uyarıcı etkileri üzerine çalışmalar devam etmektedir. Yapılmış araştırmalar DDLT'nin kemik mineralizasyonunda ve osteoblast hücrelerin sayılarında arttırıcı etkisini göstermektedir (68)(69)(70)(71). DDLT'nin diş çekiminden sonra alveolar tamirde önemli rol aldığı, osteoblast kültürle-rinde, çoğalma, farklılaşma ve kalsifikasyon sürecini etkilediği gösterilmiştir (72).…”