Methods: Biofilm-coated 10 mm x 1 mm round titanium discs were; 1) treated with a diode laser (Odyssey, Ivoclar); 2,3) microetched with 27µm or 100µm Al2O3 particles; 4,5) treated with a diode laser then microetched with 27µm or 100µm Al2O3 particles; or (6) cleaned with a titanium brush (Straumann). All assays were performed in triplicate. The number of viable microorganisms was determined on one disc. The surface area covered by bacteria was assessed by scanning electron microscopy (SEM) on another disc and endotoxin levels were assessed on the third disc (ToxinSensor Gel Clot Endotoxin Assay, GeneScript). Untreated biofilm-coated discs were positive and sterile discs were negative controls. The number of viable microorganisms was also determined on sterile discs treated as above.
Results: All six treatments of biofilm-coated titanium discs eliminated viable microorganisms as determined by negative cultures. Diode laser treatment combined with Al2O3 microetching with either particle size completely eliminated biofilm while the other five treatments reduced the biofilm-coated surface area. All treatments eliminated endotoxin contamination except for the titanium brush treatment. Interestingly, treatments which altered the titanium surface - diode laser and Al2O3 microetching either alone or in combination - did not increase biofilm growth on sterile discs compared to positive controls.
Conclusions: The combined diode laser / Al2O3 microetching treatment was more effective than diode laser or Al2O3 microetching or titanium brush treatments alone in eliminating biofilms and endotoxin from titanium surfaces in vitro. The combined diode laser / Al2O3 microetching treatment may be useful in vivo in treating dental implants exposed to the oral environment as a result of peri-implantitis.