Expression of genes related to bone formation and resorption in early and late residual ridge resorption in human mandibles.

Abstract

After extraction of teeth, followed a phase of alveolar bone remodeling that can result in extensive loss of bone height of the jaws, specially in the lower jaw. The understanding of residual ridge resorption (RRR) can provide a scientific basis for improving therapeutic and restorative treatment for edentulous population. This project has as main objective to compare the expression pattern of genes related to bone formation and resorption in jaw bone tissue that have suffered from the extraction of remaining teeth in a period less than 02 months (in which the RRR is more intense) and more than five years (in which the RRR is less intense). As a secondary objective, these features will be analyzed for their possible associations with clinical variables of interest such as gender, age, use of prosthesis and radiographic data. The bone samples will be collected from 12 patients divided into two equal groups: one composed of individuals who have suffered tooth extraction in the area to be operated less than 02 months ago, and another for patients who had their last teeth extracted mandibular for over 05 years. All patients will have their clinical data recorded and panoramic radiographs of patients will be used to perform set for evaluation of anatomical features previously related to RRR. The RNA samples will be extracted using the Trizol protocol, following the manufacturer's recommendations. All RNAs used should have purity between 1.8 and 2.0 which will be verified through an integrity gel. The preparation of cDNA will be performed using the technique of RT-PCR using Superscript II enzyme. For quantitative analysis by PCR (RT-PCR in real time), all reactions are performed in optical 96-well plates for specific real-time PCR, using primers for 42 genes involved in bone metabolism. The data will be standardized based on the expression of more stable constitutive genes for the experimental condition proposed in this study and analyzed using the ”Ct. The comparison between groups for demographic and clinical variables and radiographic be evaluated using the x2 and Fisher tests. The gene expression data obtained in two experimental groups will be submitted to Student's t-test. All statistical tests will use a significance level of 5%.