Osseointegration interfaces

Biomaterial scientists and engineers are currently investigating novel formulations and modifications of existing materials that elicit specific, timely, and desirable responses from surrounding cells and tissues to support the osseointegration of the next generation of orthopedic and dental biomaterials (Ratner, 1992). Enhanced deposition of mineralized matrix at the bone-implant interface provides crucial mechanical stability to implants. Proactive orthopedic and dental biomaterials could consist of novel formulations that selectively enhance osteoblast function (such as adhesion, proliferation and formation of calcium-containing mineral) while, at the same time, minimize other cell (such as fibroblast) functions that may decrease implant efficacy (e.g., fibroblast participation in callus formation and fibrous encapsulation of implants in vivo). 

The timeline of basic steps occurring at a bioconductive interface during osseointegration of an implant in the presence of an osseoconductive calcium phosphate coatings can be summarised as follows ... 

Figure 3.7 Dynamic behaviour of the inter- capsule that prevents osseointegration and face between a metallic implant (at left) and will cause implant loosening (Kasemo and bony tissue (at right). The inset shows that Lausmaa, 1991). ( With permission by Uni-sometimes connective tissue is being formed versity of Toronto Press.) at the interface resulting in a fibrous tissue...

Osseointegration A term developed by RI. Branemark and his colleagues indicating the ability of host bone tissues to form a functional, mechanically immobile interface with the implant. Originally described for titanium only, several other materials are capable of forming this interface, which presumes a lack of connective tissue (foreign body) layer. 

Zhou R, et al. Synergistic effects of surface chemistry and topologic structure from modified microarc oxidation coatings on Ti implants for improving osseointegration. ACS Appl Mater Interfaces 2015 7(16) 8932—41. 

The success rate of dental implants increased dramatically during the 1980s [9]. Improved materials, selection of appropriate materials, and advanced technology have resulted in an improved implant/bone interface attachment that is responsible for the increased success. Success of dental implants is measured by the absence of mobility, no ra-diolucency between the bone and implant, and no other adverse symptoms or problems. The most successful dental implant today is the endosseous implant where the implant is anchored into the bone and osseointegrated. Success rates can be as high as 95 % over a five-year period Titanium and Ti-6Al-4V are the most widely used materials for the implants. The effects of surface treatment on the surface oxides of titanium have been shown [72,73]. Titanium was the material of choice for Branemark, who correlated the dental implant surface preparation and purity with the histology results of the interfacial bone [74]. 

Maintaining a reliable and long-lasting osseointegration in between the implant-bone interface is the first step of the success of any bone-anchored facial prosthesis. Of 142 implants that were used on 50 patients, osseointegration was observed in 95.7% of nonirradiated patients and 81.6% in irradiated ones, presenting radiotherapy as a potential factor which reduces the rate of osseointegration [30]. 

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