Bacterial inactivation/sterilization by argon plasma treatment on contaminated titanium implant surfaces: In vitro study

Background: Surface treatment by argon plasma is �widely used as t�he last step of t�he manufacturing process of titanium implant fixtures before their sterilization by gamma rays. The possibility of using such a technology in thedaily clinical practice is particularly fascinating. The aim of the present study was to assess the effects of the argonplasma treatment on different titanium implant surfaces previously exposed in vitro to bacterial contamination.Material and Methods: Sterile c.p. titanium implant discs with turned (T, Sa: 0.8μm), sandblasted/acid-etched(SAE, Sa: 1.3μm) and titanium plasma sprayed (TPS, Sa: 3.0μm) surface were used in this study. A strain of Aggregatibacter actinomycetemcomitans ATCC3718 was grown at 37°C under anaerobic conditions for 24 h and thentransferred on six discs for each of the three surface types. After 24 hours, a half of the contaminated discs (controlgroup) were directly used to evaluate the colony forming units (CFUs). The other half of the contaminated discs(test group) were treated in an argon plasma chamber for 12 minutes at room temperature prior to be analyzed forCFU counting. All assays were performed using triplicate samples of each material in 3 different experiments.Results: When the CFU counting was carried out on control discs, a total of 1.50x106±1.4x105, 1.55x106±7.07x104and 3.15x106±2.12x105 CFU was respectively assessed for T, SAE and TPS discs, without statistically significantdifferences among the three surfaces. On the contrary, any trace of bacterial contamination was assessed fortitanium discs treated in the argon plasma chamber prior to be analyzed, irrespectively to the implant surfacetested.Conclusions: Within the limit of this study, reported data suggested that the argon plasma technology could beefficiently used to decontaminate/sterilize previously infected titanium implant surfaces