The influence of commercially pure Titanium (cpTi) coating with Ca and P incorporation produced by plasma electrolytic oxidation on low density bone: An in vitro, ex-vivo and in vivo study

Abstract

The medical and dental implants of titanium are frequently modified, especially its microstructure, obtaining better physical, chemical, and biological properties of the peri-implantar bone. Thus, the highest challenge current is to develop a surface on the topography of the implants to improve the bone healing on critical areas, mainly represented by bone with lower density. Therefore, this study will analyze the structural, molecular and healing parameters through a new coating method by plasma electrolytic oxidation (PEO) with Ca and P incorporation on the surface of the commercially pure titanium (cpTi) in low density bone. The structural characterization will be conducted on cpTi disks, which will be polished in a sequential granulation of sandpaper and then they will be submitted to the PEO method of Ca and P incorporation. The samples control will be treated with double etching-acid commercially available. After the texturing process, the disks will be analyzed in Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Difratography, Profilometry and Surface Free Energy (baseline). The animals used to the ex- in vivo and in vivo studies (Wistar female rats, n=10) will be divided into 3 groups: OBD Ovx (young rats - 6 months subjected to the ovariectomy for osteoporosis induction); ODN Sham (young rats - 6 months with normal bone density only induced at the same stress) and OBD Sen (old rats - 18 months with low bone density). The ex-vivo study will be conducted through culture of osteoblasts provided from calvaria bone of 60 female rats subjected to the same divisions as explained before (OBD Ovx, OBD Sen and ODN Sham). Thus, the total protein content, ALP activity and alizarin area will be analyzed. In the in vivo study, the same texturing methods performed on the disks will be carried out on the cpTi implants surface (2 x 4 mm) for placement in both tibias, for the following analyzes: reverse torque, PCR (OPG, RANKL, and OC), histological and histometric (Bone Implant Contact - BIC and Newly formed bone area - NB), microtomography (BV, BV/TV, Tb.Th, Tb.Sp, and Tb.N), of bone dynamics by fluorochromes (calcein/alizarin), and immunohistochemistry (OPG, RANKL, and OC). All quantitative data will be submitted to the normality curve to establish the best statistical test (parametric or nonparametric), considering P<0.05 significance level. Key-words: Osteoporosis, bone regeneration, Cell Culture Techniques, dental implants. (AU)