Biological Effects of Modifications of Titanium Implant Surfaces

Modifications in Titanium (Ti) implant surfaces have a significant effect on early biofilm formation and the success of the implant. The adsorption of biological molecules to the implant surface may determine the outcome of the procedure. Thus, interactions between serum, salivary and bacterial products with Ti implants of different surfaces need to be further investigated. Objectives: We examined the effect of chemical and physical properties of modified Ti surfaces, on the adsorption of biological components, such as plasma proteins and oral bacteria. Methods: Ti discs with three types of surface modifications were compared: Machined, Acid etched and Sandblast & Acid etched (SLA). Physical and chemical characterizations of the surfaces were performed via scanning electron microscopy, examination by atomic force microscope and characterization of the Titanium oxide layer by X-ray photoelectron spectroscopy. Evaluation of the adsorption of serum proteins to Ti surfaces was performed by ELISA. Confocal laser scanning microscope was used to investigate protein coat, bacterial adhesion, and the interactions between them. Results: SLA treated Ti surfaces were found to have high roughness values and a thicker TiO2 layer as compared to acid etched and machined surfaces. Adsorption of serum proteins to the SLA treated Ti surfaces, was found to be up to 4-time fold higher than the other treated surfaces. Furthermore, SLA treated Ti surfaces exhibited significantly higher bacterial adhesion and a different pattern of coating as compared to the other surfaces. Serum albumin coat reduced the bacterial adhesion to all surfaces and specifically the SLA surface. Conclusions: The preferential adsorption of biological components to SLA treated Ti surfaces may be explained by the physical and chemical characteristics of that modified surface. Further studies, to correlate osseointegration of modified Ti implants in animals and human subjects are underway.

Supported in part by the Israeli Health Ministry