Influence of nicotine on osseointegration of implants installed in the tibia of rats: evaluation biomechanical, histological, immunohistochemical and histometric

Abstract

Smoking is an important risk factor in the occurrence of different degenerative pathologies. The literature reports that smokers are more prone to fractures and changes in bone regeneration, however, fails to document the behavior of implants in these cases. Thus, this study aims to evaluate the biomechanical point of view, histological, immunohistochemical and histometric the influence of low intensity laser on the osseointegration of implants installed in tibiae of rats systemically modified by nicotine. To do this, will be used 120 male rats were divided into 4 experimental groups of 30 animals each: Group I: sham group or control, surgical preparation of the alveolus for implant installation without any treatment prior to its installation site, Group II: sham + Laser surgical preparation of the alveolus for implant installation and application of low intensity laser prior to installation, Group III: Group nicotine, surgical preparation of the alveolus for implant installation without any treatment prior to its installation site, Group IV: Nicotine + Laser surgical preparation of the alveolus for implant installation and application of low intensity laser prior to installation. In all groups will be installed implants of 2.2 mm x 4 mm in both the tibia. The animals in groups III and IV will receive subcutaneous injections of nicotine (3mg/kg) twice daily, starting 30 days before installation of the implants, remaining until the end of the experiment according to the periods of euthanasia. The animals in groups I and II applications will receive normal saline solution for undergoing the same stress conditions. The alveoli are prepared with a surgical cutter mounted on 2 mm 20:1 contra angle and engine torque to the implant with 45 N and speed of 1490 rpm. The laser used is the Thera Lase (InGaAlP 660 nm) in continuous mode and in contact with the area, with power of 30 mW, energy of 0.14 J and energy density of 4.9 J/cm2. Ten animals of each experimental group will be euthanized at 15, 30 and 60 days after installation of implants. To evaluate the results of the analysis will be performed in reverse torque specimens to be evaluated histologically in decalcified sections, which are semi-serial thickness of 4 micrometers. The decalcified specimens not be used for histometric analysis. The events will be described and histopathological data values obtained by analysis of reverse torque, immunohistochemical and histometric will be evaluated statistically (p <0.05). (AU)