Efeito da fotobiomodulação laser no reparo de defeitos ósseos em fêmur de ratos preenchidos ou não com cimentos à base de silicato de cálcio

Abstract

Restorative cements based on calcium silicate are considered transforming biomaterials in Dentistry because they induce the formation of mineralized tissue, contributing to tissue repair and regeneration. Other therapeutic resources such as laser photobiomodulation can be associated with these cements, in an attempt to speed up the regenerative process due to the induction of several chemical reactions. Therefore, the aim of the present study was to evaluate the effect of laser photobiomodulation (λ 780nm) in the repair of bone defects in the femur of rats filled or not with different cements based on calcium silicate (BioMTA and Biodentine). For this, 52 rats underwent surgery to create a standardized bone defect measuring 2 mm in diameter in the upper third of the lateral surface of the left femur of each rat. After making the bone defect, the animals were divided into 06 groups: BioMTA (n=10); Biodentine (n=10); Clot (n=6); BioMTA Laser (n=10); Biodentine Laser (n=10); Laser clot (n=6), according to the filling of the defect. Laser photobiomodulation (λ780 nm, P = 70 mW, continuous emission, Ф = 0.5 cm2, 20.4 J/cm² per session, t= 300 s, 142.8 J/cm2 per treatment) was performed immediately after the surgical procedure, and every 48 hours for 15 days. To obtain tissue samples, the animals were euthanized according to the experimental period of 15 and 30 days after surgery. The surgical specimen removed was sent for histological analysis by light microscopy. The specimens were processed, evaluated by means of descriptive and comparative analysis, and the data were submitted to Fisher's exact statistical test (p=0.05). In the 15-day experimental period, there was greater bone neoformation in the BioMTA group (p<0.05) when compared to the others and a decrease in the inflammatory infiltrate criterion when the groups with laser photobiomodulation were compared to the others. In the 30-day period, there was no statistical difference in the bone neoformation criterion, however there was a greater osteoblastic paving (p<0.05) in the Biodentine Laser group when compared to the others. It was possible to conclude that the association of calcium silicate-based cements with laser photobiomodulation allowed a decrease in the inflammatory infiltrate and greater collagen deposition in a period of 15 days. And in 30 days, increased osteoblastic paving and decreased inflammatory infiltrate in the association of laser photobiomodulation and Biodentine cement.