EVALUATION OF THE ACTION THAT TREATMENT WITH ANTIRESORTIVE DRUG CAUSES IN THE BONE TISSUE LOCATED AROUND IMPLANTS THAT HAVE ALREADY OSSEOINTEGRATED: HISTOMORPHOMETRIC STUDY IN RATS

Abstract

Anti-resorptive drugs, although quite effective in the treatment of skeletal-related events, can result in a serious adverse effect of great importance in dentistry, medication-related osteonecrosis of the jaws (MRONJ). This is a pathological condition whose treatment is long, complex, can fail and generate serious sequelae, many of which make rehabilitation difficult or impossible, considerably compromising the quality of life of patients. Recently, the number of cases of MRONJ associated with dental implants (DI) already osseointegrated and functioning in the oral cavity has increased substantially. Understanding the pathophysiological mechanisms involved in this condition is necessary, especially in order to establish effective prevention and treatment strategies. The aim of this study will be to evaluate the histological characteristics of the bone tissue located around DI that are already osseointegrated in the maxilla of senescent rats submitted to treatment with zoledronate after osseointegration has been achieved. In this study, 32 senescent female rats will be used. In the 0th week, the upper right first molar will be extracted and a titanium implant (length - 2.5 mm; diameter - 1.5 mm) will be installed in the dental extraction site previously occupied by its mesial root. In the 10th week the rats will be divided into two groups: VEI, treated with vehicle, and ZOL, treated with vehicle added from 100 ¼g/Kg of zoledronate. From the 10th to the 20th week, vehicle or zoledronate will be administered intraperitoneally every four days. In the 20th week the rats will be euthanized, an intraoral clinical evaluation will be carried out and the samples of the maxilla containing the implant will be dissected. Half of the samples from each experimental group will be submitted to ground-section histological processing for histometric analysis of the bone-implant contact. The other half of the samples from each experimental group will be submitted to conventional histological processing and hematoxylin-eosin staining, for histometric analysis of the percentage of total bone tissue (PTBT) and the percentage of non-vital bone tissue (PNVBT) in the peri-implant region. The results obtained will be submitted to statistical analysis with a significance level of 5%.