Efeitos da fotobiomodulação na osseointegração de implantes dentários em ratos diabéticos: avaliação em microtomografia computadorizada

Abstract

This study aimed to investigate the effects of photobiomodulation with low-level laser light on the process of osseointegration of dental implants in diabetic rats using micro computed tomography (micro-CT). An in vivo experimental study was carried out, using 24 male rats of the species Ratthus norvegicus, class Mammalia, order Roedentia, strain Wistar, aged between 60 and 90 days and mass between 270-300 grams. Type II diabetes was chemically induced by intraperitoneal injection of a single dose of 40mg / kg of streptozotocin. On the fifth day after induction, only animals that had fasting blood glucose above 300mg / dl were included in the study. The animals were randomly divided into four experimental groups: Red group (λ = 660nm, 100mW, 2J, 20 seconds); Infrared group (λ = 808nm, 100 mW, 2J, 20 seconds); Combined group (λ = 660nm + λ = 808nm, 100 mW, 4J, 20 seconds); control group (simulated therapy). After anesthetic induction, incision, divulsion, access to the bone bed and drilling with milling were performed under irrigation with saline. The first application of laser light was performed immediately after bone milling, at a central point in the implant receiving bed. Then the implants were installed in the right tibial metaphysis. After suturing the tissues, the second application of laser light was performed, in five points: one in the center of the incision, another in 1 cm to the right of this central point, another 1 cm to the left of the central point, one point on the external surface and another on internal tibia. The photobiomodulation protocol was repeated every 48 hours, for a period of 28 days, totaling 14 sessions. After the 28-day experimental period, the animals were euthanized and the tibiae were sent for analysis of the trabecular bone microarchitecture by micro-CT, using the parameters: Percentage of bone volume (BV/TV); Bone surface (BS); Trabecular number (Tb.N); Trabecular thickness (Tb.Th), Trabecular separation (Tb.Sp) and Connectivity density (Conn.D). Parametric tests, analysis of variance (ANOVA one-way) and post-hoc Tukey tests were used to assess bone morphology and density (α = 5%). It was observed that the Percentage of bone volume (p = 0.002) and the average Number of bone trabeculae (p = 0.008) were higher in the combined group compared to the infrared, red and control groups. The parameters Bone surface, Trabecular thickness, Trabecular separation and Density of connectivity did not show any significant difference between the proposed groups (p> 0.05). Through this study, it was possible to conclude that photobiomodulation with low intensity laser light with simultaneous emission of two wavelengths (660nm and 808nm), favored the osseointegration of dental implants in diabetic rats.