Contaminated implant surfaces: an in vitro comparison of implant surface coating and treatment modalities for decontamination.

The relationship between implant surfaces and decontamination treatments was studied in vitro to determine which implant surfaces were most effectively decontaminated, and which treatment was most effective for treating a particular implant surface. The implants used in the study were press fit cylindrical titanium units with machined, plasma sprayed, and hydroxyapatite-coated surfaces. Radioactive endotoxin (125I-LPS) was prepared from Porphyromonas gingivalis (ATCC 33277). Implants were coated with 125I-LPS and treated by burnishing with a cotton pellet soaked in water, citric acid solution (CA), or 0.12% chlorhexidine (CHX); or treated with an air-powder abrasive (AIR). Radioactivity was determined after each of two treatment cycles. The results for each implant surface were analyzed using ANOVA to determine differences between treatments. The remaining 125I-LPS after two treatment cycles were: for machined implants AIR < CA, with AIR = water = CHX and water = CHX = CA; for plasma sprayed implants AIR < water = CHX = CA; for hydroxyapatite implants AIR = CA < water < CHX. In evaluating treatment modalities, it was found that machined implants were decontaminated more effectively than the other surfaces by all treatments; the exception was citric acid treatment which was equally effective on either machined or hydroxyapatite surfaces. These results indicate that machined implants (without surface coating) are most readily decontaminated by a variety of methods; this characteristic should be considered, since long-term success of implants may involve treating periimplantitis. Further, the results indicate that air abrasives are effective for decontaminating implant surface, with the exception that hydroxyapatite coated surfaces can be treated equally with air abrasives or citric acid.