Bactericidal efficacy of GaAlAs diode laser irradiation on titanium surfaces, using an ex vivo biofilm system

INTRODUCTION: Biological complications around dental implants, including peri-implantitis and peri-implant mucositis, result from host-modulated response to bacterial biofilm. Current treatment approaches for these conditions do not adequately decontaminate implant surfaces and instrumentation is likely to damage the implant surfaces. OBJECTIVE: The aim of this study was to evaluate the bactericidal effect of laser diode irradiation (GaAlAs 810 nm) on biofilms formed in vivo on titanium surfaces, and to determine optimal laser parameters for disinfection. Ten participants wore an intraoral appliance each containing six titanium discs (Ra = 0.5) for 96 hours to generate multispecies biofilms. Discs were irradiated (ex vivo) with a range of diode laser outputs. Discs were stained with fluorescent viability dyes and examined by confocal laser-scanning microscopy and by scanning electron microscopy. After 96 hours, biofilms containing various bacterial morphotypes covered the entire disc surfaces. RESULTS: Diode laser irradiation resulted in a dose-dependent bactericidal effect with maximal antimicrobial efficacy at = 75 J/cm2. At this setting, no viable bacteria were evident, however cellular remnants and intracellular matrix were apparent. No damage to the titanium surface was evident following exposure to = 150 J/cm2. CONCLUSION: Diode laser irradiation effectively kills natural biofilms without damage to the titanium surface but the consequences of non-viable biofilm remnants on tissue healing remains to be determined.