Osteointegration of biomimetic apatite coating applied onto dense and porous metal implants in femurs of goats

Abstract

Biomimetic calcium phosphate (Ca-P) coatings were applied onto dense titanium alloy (Ti6Al4V) and porous tantalum (Ta) cylinders by immersion into simulated body fluid at 37 degrees C and then at 50 degrees C for 24 h. As a result, a homogeneous bone-like carbonated apatitic (BCA) coating, 30 microm thick was deposited on the entire surface of the dense and porous implants. Noncoated and BCA-coated implants were press-fit implanted in the femoral diaphysis of 14 adult female goats. Bone contact was measured after implantation for 6, 12, and 24 weeks, and investigated by histology and backscattered electron microscopy (BSEM). After 6 weeks, bone contact of the BCA-coated Ti6Al4V implants was about 50%. After 12 and 24 weeks, bone contact was lower in comparison with the 6-week implantations at, respectively 24 and 39%. Regarding the BCA-coated porous Ta implants, bone contacts were 17, 30, and 18% after 6, 12, and 24 weeks, respectively. However, bone contact was always found significantly higher for BCA-coated dense Ti6Al4V and porous Ta cylinders than the corresponding noncoated implants. The results of this study show that the BCA coating enhances the bone integration as compared to the noncoated implants.

Organic–Inorganic Surface Modifications for Titanium Implant Surfaces

“…An ion-exchange reaction between the bioactive implant and surrounding body fluids results in the formation of a carbonate apatite layer on the implant that is chemically and crystallographically equivalent to the mineral phase in bone. The bone healing process is therefore enhanced by this biological apatite layer (38,39). The correlation between bioactivity and the formation of a carbonate apatite layer is often inverted for preliminary in vitro testing of the potential bioactivity of biomaterials.…”

“…Since then numerous reports have been published about the osteoconductive properties of CaP-coated implants (osteoconduction refers to the ability of a biomaterial to support the growth of bone over its surface). These CaP coatings are described to induce an increased bone-to-implant contact (38,(43)(44)(45), to improve the implant fixation (46), and to facilitate the bridging of small gaps between implant and surrounding bone (47,48). As an example of the osteoconductive properties of CaP coatings, Fig.…”

Osseointegration of polyethylene implants coated with titanium and biomimetically or electrochemically deposited hydroxyapatite in a rabbit model

“…In the current study, histomorphometric evaluation was selected because it is a reliable and well-defined method for which considerable work has been performed and numerous historical data are available [6,[8][9][10]. This study demonstrated that polyethylene implants coated with Ti-PVD and biomimetically or electrolytically deposited HA were able to develop osseointegration comparable to that of a plasma sprayed-HA coated titanium PE implant, that are largely used in hip arthroplasty.…”

Effets de la macro et de la nano-géométrie sur la stabilité primaire des implants

“…La fixation biologique des implants en titane au tissu osseux est plus rapide avec un revêtement en phosphate de calcium [7,8]. Ce revêtement donne un meilleur taux de réussite clinique à long terme par rapport aux implants en titane sans revêtement [7,9] et ceci est dû à un taux initial d'ostéointégration plus élevé [9].…”

“…L'ostéointégration des implants en titane à surface biomimétique de phosphate de calcium a évaluée dans des études pré-cliniques comparatives. Elles ont montré un contact os-implant plus élevé pour les implants avec une surface biomimétique de phosphate de calcium que pour les implants en titane non traité [8,10].…”