Development and physical-chemical and biological characterization of new titanium surfaces modified with strontium, calcium, and osteogenic biomolecules in vitro

Abstract

The clinical failure of dental implants can occur due to inadequate osseointegration. Poor osseointegration induces mobility, inflammation, and bone resorption, leading to treatment failure. Due to systemic challenges related to insufficiency and/or poor quality of peri-implant bone tissue, which can compromise osseointegration, the development of titanium surfaces with an osteogenic and osteoconductive activity that favors early osseointegration is opportune. The development of implant surfaces with ability to modulate bone turnover in the direction of osteogenesis in order to rapidly achieve lasting osseointegration is necessary to improve even more the clinical success rate of implant surgeries, prolong implant life and extend its applicability in challenging clinical situations. In this context, implants with osteogenic capacity loaded with Calcium (Ca), Strontium (Sr) and osteogenic biomolecules can bring promising results. In this study, we intend to evaluate the effect of the addition of Ca, Sr, and osteogenic biomolecules - dexamethasone, ascorbic acid beta-glycerophosphate, on a commercially pure titanium surface. To incorporate these elements, the coatings will be treated under hydrothermal conditions. X-ray diffraction (XRD), scanning electron microscopy (SEM), confocal laser scanning microscopy, contact angle/surface free energy, inductively coupled plasma atomic emission spectrometry, corrosion resistance, and electrochemical stability will be used in the physicochemical characterization of the surface. Pre-ostoblastic cells from the MC3T3-E1 lineage will be used to evaluate the biocompatibility and biological behavior of the surfaces. Adhesion, spreading and cell morphology will be evaluated by SEM and direct fluorescence; cell viability with Alamar Blue® and activity of the enzyme Alkaline Phosphatase by colorimetric method. In addition, the gene expression of 84 osteogenic markers will be evaluated by PCR Array. Statistical analyzes will be performed in GraphPad Prism 5.0 software using parametric or non-parametric tests for independent data and more than two samples (ANOVA or Kruskal-Wallis test, respectively, in the case of normal sample distribution and homogeneity of variances), followed by multiple comparison tests, where applicable. The significance level adopted is going to be 5%.