Bactericidal effects of different laser systems on bacteria adhered to dental implant surfaces: an in vitro study comparing zirconia with titanium

Abstract Objectives: The purpose of this study was to examine in vitro the anti‐bacterial efficacy of two different laser systems (CO 2 and diode) applied to Streptococcus sanguinis or Porphyromonas gingivalis cells in suspensions or adhered to zirconia or titanium dental implant materials, with two different surfaces each. Materials and methods: Bacteria were irradiated at two different power settings with either a CO 2 (λ=10,600 nm) or a diode laser (λ=810 nm). The lower mode is used clinically (for CO 2 100 J/cm 2 , diode 50 J/cm 2 ) and the higher may alter the materials' surface (for CO 2 1200 J/cm 2 , diode 150 J/cm 2 ). After irradiation, the number of viable bacteria was determined by culture. Results: Planktonic cells of both species were more resistant to the laser irradiations than bacteria that adhered to surfaces. Adhered P. gingivalis were effectively killed at both wavelengths λ=10,600 and 810 nm even at the lower settings, independent of the material. S. sanguinis cells that adhered to either zirconia surface were effectively killed by the CO 2 laser at the lower setting of 100 J/cm 2 . However, the higher settings of both lasers were needed to reduce S. sanguinis that adhered to titanium surfaces. The CO 2 laser at the lower setting and the diode laser at the higher setting effectively reduced the viability of S. sanguinis or P. gingivalis that adhered to zirconia surfaces. Conclusions: Under irradiation conditions known not to alter zirconia implant surfaces in vitro , both CO 2 laser (100 J/cm 2 ) and the diode laser (150 J/cm 2 ) effectively reduced the viability of adhered S. sanguinis or P. gingivalis . To cite this article: Hauser‐Gerspach I, Stübinger S, Meyer J. Bactericidal effects of different laser systems on bacteria adhered to dental implant surfaces: an in vitro study comparing zirconia to titanium. Clin. Oral Impl. Res . 21 , 2010; 277–283. doi: 10.1111/j.1600‐0501.2009.01835.x