The Effect of Photobiomodulation Therapy in Different Doses on Bone Repair of Critical Size Defects in Rats: A Histomorphometric Study

Andrea Carvalho De Marco; Letícia Cavassini Torquato; Paulo Roberto Gonçalves; Tatiana Camacho Ribeiro; Camilla Moretto Nunes; Daniella Vicensotto Bernardo; Mônica Fernandes Gomes; Maria Aparecida Neves Jardini; Mauro Pedrine Santamaria

doi:10.34172/jlms.2021.53

The Effect of Photobiomodulation Therapy in Different Doses on Bone Repair of Critical Size Defects in Rats: A Histomorphometric Study

J Lasers Med Sci. 2021 Sep 26:12:e53. doi: 10.34172/jlms.2021.53. eCollection 2021.

Authors

Andrea Carvalho De Marco¹, Letícia Cavassini Torquato¹, Paulo Roberto Gonçalves², Tatiana Camacho Ribeiro², Camilla Moretto Nunes¹, Daniella Vicensotto Bernardo², Mônica Fernandes Gomes³, Maria Aparecida Neves Jardini¹, Mauro Pedrine Santamaria¹

Affiliations

¹ Department of Diagnosis and Surgery - Division of Periodontology, São Paulo State University (UNESP), Institute of Science and Tecnology, Campus São José dos Campos, Sao Paulo, Brazil.
² Sao Jose dos Campos, Sao Paulo, Brazil.
³ Department of Biosciences and Oral Diagnosis, São Paulo State University (UNESP), Institute of Science and Technology, Campus São José dos Campos, Sao Paulo, Brazil.

Abstract

Introduction: Photobiomodulation therapy (PBM) appears to induce osteogenesis and stimulate fracture repair; because of its capacity, it is considered a promising treatment, but the characteristics of response to different radiation doses must be investigated through in vivo studies to establish their safety and effectiveness. Thus, this paper aims to analyze the effects of the PBM at different doses on the repair of critical bone defects through histological and histomorphometric analyses. Methods: Sixty 90-day-old adult rats (Rattus norvegicus, albinus, Wistar) weighing approximately 300 g were used. Critical bone defects of 5 mm in diameter were performed in their calvaria. The animals were randomly separated into 5 groups: C-Blood clot, L15-PBM 15J/cm², L30-PBM 30 J/ cm², L45-PBM 45 J/cm², L60-PBM 60 J/cm². Each group was subdivided according to observation periods of 30 and 60 days with 6 rats in each subgroup. Low-level gallium aluminum arsenide (GaAlAs) lasers were used at a 660 nm wavelength, 30 mW and 0.04 cm² in area. The PBM was applied over 5 points; 4 points of application were distributed on the edges while one point of application was located in the center of the bone defect. PBM occurred right after the procedure. In 30 and 60 days, the animals were euthanized by anesthesia overdose and the analyses were performed. The data were analyzed statistically by the ANOVA, together with the Tukey test, whose significance level was 5%. Results: As regards the treatment factor, the highest percentage of bone neoformation was achieved by group L45-60. The group with the highest closure, despite not having a statistically significant difference with the other doses, was 45 J with only 0.49 mm between edges. Conclusion: Thus, the present study allowed concluding that the highest percentage of bone neoformation area was achieved at 45 J/cm² in 60 days; that is, it was significantly effective in comparison with other doses.

Keywords: Bone Regeneration; Lasers; Low-Level Light Therapy; Rats.