In vivo behavior and mechanical stability of surface-modified titanium implants by plasma spray coating and chemical treatments

The geometric design and chemical compositions of an implant surface may have an important part in affecting early implant stabilization and influencing tissue healing. In this study, in vivo behavior and mechanical stability in implants of three surface designs, which were smooth surface (SS), rough titanium (Ti) surface by plasma spray coating (PSC), and alkali- and heat-treated (AHT) Ti surface after plasma spray coating, were compared by histological and mechanical analyses. Surface morphologies of the implants were observed by optical microscopy and scanning electron microscopy. Chemical compositional surface changes were investigated by energy dispersive spectroscopy. The implants were inserted transversely in a dog thighbone and evaluated at 4 weeks of healing. At 4 weeks of healing after implantation in bone, the healing tissue was more extensively integrated with an AHT implant than with the implants of smooth (SS) and/or rough Ti surfaces (PSC). The bone bonding strength (pull-out force) between living bone and implant was observed by a universal testing machine. At 4 weeks' healing after implant placement in bone, the pull-out forces of the SS, PSC, and AHT implants were 235 (+/-34.25), 710 (+/-142.25), and 823 (+/-152.22) N, respectively. Histological and mechanical data demonstrate that appropriate surface design selection can improve early bone growth and induce an acceleration of the healing response, thereby improving the potential for implant osseointegration.