Bone Tissue Response to Porous and Functionalized Titanium and Silica Based Coatings

Abstract

BackgroundTopography and presence of bio-mimetic coatings are known to improve osseointegration. The objective of this study was to evaluate the bone regeneration potential of porous and osteogenic coatings.MethodologySix-implants [Control (CTR); porous titanium coatings (T1, T2); thickened titanium (Ti) dioxide layer (TiO2); Amorphous Microporous Silica (AMS) and Bio-active Glass (BAG)] were implanted randomly in tibiae of 20-New Zealand white rabbits. The animals were sacrificed after 2 or 4 weeks. The samples were analyzed histologically and histomorphometrically. In the initial bone-free areas (bone regeneration areas (BRAs)), the bone area fraction (BAF) was evaluated in the whole cavity (500 µm, BAF-500), in the implant vicinity (100 µm, BAF-100) and further away (100–500 µm, BAF-400) from the implant. Bone-to-implant contact (BIC-BAA) was measured in the areas where the implants were installed in contact to the host bone (bone adaptation areas (BAAs)) to understand and compare the bone adaptation. Mixed models were used for statistical analysis.Principal FindingsAfter 2 weeks, the differences in BAF-500 for different surfaces were not significant (p>0.05). After 4 weeks, a higher BAF-500 was observed for BAG than CTR. BAF-100 for AMS was higher than BAG and BAF-400 for BAG was higher than CTR and AMS. For T1 and AMS, the bone regeneration was faster in the 100-µm compared to the 400-µm zone. BIC-BAA for AMS and BAG was lower after 4 than 2 weeks. After 4 weeks, BIC-BAA for BAG was lower than AMS and CTR.ConclusionsBAG is highly osteogenic at a distance from the implant. The porous titanium coatings didn't stimulate bone regeneration but allowed bone growth into the pores. Although AMS didn't stimulate higher bone response, it has a potential of faster bone growth in the vicinity compared to further away from the surface. BIC-BAA data were inconclusive to understand the bone adaptation.

Orthopedic bioactive implants: Hydrogel enrichment of macroporous titanium for the delivery of mesenchymal stem cells and strontium

“…With this aim, cementless implant technology has evolved with the introduction of porous metallic materials to maximize bone ingrowth and bone-to-implant contact. [4][5][6][7] Among the different types of porous titanium, Trabecular Titanium TM (TT) is currently clinically used in acetabular cups and to fill cavitary and segmental bone defects. This macroporous titanium is characterized by multiple layers of hexagonal pores with a 640 lm diameter, 8 macroporosity that facilitates cell migration and bone deposition.…”

Titanium implants with modified surfaces: Meta-analysis of in vivo osteointegration

“…Implant design was as described in [16]: commercially pure Ti sheets (grade 2, thickness 1 mm, Goodfellow, UK), were laser-cut into Ø 4 mm discs and etched in a HF:HNO3 = 1:5 solution (specimens marked as "etched"). After autoclave sterilization, these discs were used both as substrate material and as the reference material for the in vivo tests.…”

“…Surgery and subsequent tissue processing were done as outlined by Chaudhari et al [16]. The animal handling and experimental protocol used in this study were approved by the Animal Ethics Committee of the KU Leuven and were performed according to the Belgian national legislation concerning the protection and wellbeing of animals (Approval ID: P122/2008).…”

“…The experimental bone model has been described in [16] and different histomorphometrical parameters used are summarized here. Fig.…”

Silica-Based and Borate-Based, Titania-Containing Bioactive Coatings Characterization: Critical Strain Energy Release Rate, Residual Stresses, Hardness, and Thermal Expansion

“…Different approaches have been taken towards re-designing DSA devices for improving patient outcomes; these approaches usually involve modification of the surface by sandblasting the device surface, titanium plasma-spraying, plasma-spraying with hydroxyapatite (HA), coating the implant with a titanium dioxide (TiO 2 ) layer through anodic oxidation, and applying a coating made from bioactive glass [4,5,6]. From these approaches, bioactive glasses have shown encouraging results over these other technologies when used as coatings [5]. …”