The effect of Er:YAG laser treatment on biofilm formation on titanium and zirconia disc surfaces

Abstract

Background: Lasers represent a promising method for implant decontamination, but evidence on implant surface changes and subsequent biofilm formation is limited. This study aimed to assess the effect of erbium-doped yttrium aluminum garnet (Er:YAG) laser treatment on zirconia and titanium discs, and the differences in biofilm formation as a result of surface alterations. Methods: A two-stage (in vitro and in vivo) experiment utilizing Er:YAG laser on titanium and zirconia discs was performed. In vitro, surface alterations, roughness, and elemental-material weight differences following laser treatment were assessed using scanning electron microscopy and atomic force microscopy. In vivo, four participants wore custom-made intra-oral stents, embedded with laser-treated and untreated titanium and zirconia discs overnight. Biofilm-coated discs were stained using nucleic acid fluorescence dye and visualized using multiphoton confocal laser scanning microscopy. Biofilm 3D structure, biomass, thickness, and live-to-dead bacteria ratio were assessed. Results: Both titanium and zirconia discs treated with Er:YAG laser resulted in visual surface alterations, but showed no significant change in average surface roughness (titanium P = 0.53, zirconia P = 0.34) or elemental-material-weight (titanium, P = 0.98), (zirconia, P = 0.96). No significant differences in biofilm biomass, average thickness, and live-to-dead bacteria ratio of laser-treated titanium and zirconia discs were identified compared to untreated groups (titanium P > 0.05, zirconia P > 0.05). Generally, zirconia discs presented with a lower live-to-dead bacteria ratio compared to titanium discs, regardless of laser treatment. Conclusion: Er:YAG laser treatment of titanium and zirconia implant surfaces does not significantly affect surface roughness, elemental material weight, or early biofilm formation in the oral cavity.