Implant surface modifications and osseointegration

Abstract

Osseointegration and osteogenic differentiation are important determinants of clinical outcomes involving implants in orthopaedics and dentistry. Implant surface microstructure and hydrophilicity are known to influence these properties. Recent research has focused on several modifications of surface topography and chemistry aimed at improving bone formation to achieve faster and better healing. Topographically modified titanium implant surfaces, like the sandblasted, large-grit, acid-etched (SLA) surface and chemically modified hydrophilic SLA (modSLA) surface, have shown promising results when compared with smooth/ polished titanium surfaces. Although most studies consider an average roughness (Ra) of 1–1.5 μm to be favourable for bone formation, there is no consensus regarding the appropriate roughness and chemical modifications necessary to achieve optimal osseointegration. Studies on microstructurally modified surfaces have revealed intricate details pertaining to the molecular interactions of osteogenic cells with implant surfaces. The in vivo and in vitro findings from these studies highlight the ability of modified titanium surfaces to support the establishment of a native osteogenic niche for promoting bone formation on the implant surfaces. Improved osteogenic properties of modified surfaces are evidenced in vitro by the differential regulation of the molecular transcriptome on such surfaces. Recent studies indicate that post-transcriptional modulators like microRNAs also play an important role in osteogenic regulation on implant surfaces. In this chapter, we discuss the current concepts and considerations in orthopaedic and dental implant research and the new knowledge in the field, which will assist in the development of novel approaches and designs of future implant devices.