TITANIUM AND ZIRCONIA PARTICLE RELEASE FROM IMPLANT SURFACES DURING ER: YAG LASER DECONTAMINATION

Abstract

Introduction: The prevalence of implant treatment has increased tremendously over the past few decades. In the process of either treating peri-implantitis or during the implant maintenance phase, it has been noted that certain implant decontamination methods may generate particles from implant surfaces. This may result in potential for disease exacerbation and irreversible damage to the implant surface. Although the Er: YAG (erbium-doped yttrium aluminum garnet) laser has been considered to have the best properties for the decontamination of the implant surface, there is limited data on the amount of titanium and zirconia particles that can be generated and released in the process. Purpose: The aim of this in vitro study was to investigate the possible generation of titanium and zirconia particles when the Er:YAG laser is used as a tool for implant decontamination and to assess for any possible surface alterations that may have resulted from the use of the Er:YAG laser. Materials and Methods: Six (N=6) Ti-Zirconium alloy (Roxolid®; Straumann® USA) and six (N=6) yttra-stabilized tetragonal zirconia (PURE® Ceramic; Straumann® USA) machined material discs, as well as two (N=2) expired Ti sandblasted acid-treated implants (Ti SLA® Implant; Straumann USA) and two (N=2) expired acid-etched zirconium-dioxide ceramic implants (PURE® Ceramic ZLA® Implant; Straumann® USA) were irradiated with the Er:YAG laser (LiteTouchTM) using the gentle treatment mode for implant decontamination for 30 and 60 seconds. The coolant water generated during laser irradiation was collected and filtered through polycarbonate track etch (PCTE) hydrophilic membrane filters using a vacuum filtration assembly unit. The PCTE membranes were then analyzed for presence of titanium and zirconia particles using a Field Emission Gun Scanning Electron Microscope (FEG-SEM). The elemental composition of the particles was compared with that of the implants and discs using Energy-dispersive X-ray spectroscopy (EDS). The surfaces of the discs and implants were also inspected for morphological alterations. The average surface roughness (Ra, Ry, Rz) of the discs before and after laser application were measured using a 2-dimensional surface profilometer. A paired sample t-test was used for statistical analysis to compare the surface roughness values before and after laser application. Results: No titanium or zirconia particles were collected after laser irradiation of the material discs after laser irradiation. Titanium and zirconia particles were detected after laser irradiation on the implants. There were no surface topographical alterations evident at higher magnification for the titanium and zirconia material discs, and implants after laser irradiation. There was a statistically significant decrease in all surface roughness parameters measured (Ra, Ry, Rz) after 60 seconds of laser irradiation for the zirconia discs. Conclusions: Within the limitations of this study, the Er:YAG laser used in gentle treatment mode for implant decontamination resulted in no visible damages to the titanium and zirconia implant surfaces. There were some titanium and zirconia particles produced during the laser irradiation on implants but no produced over discs. Additional in-vitro and clinical studies will have to be conducted to assess the clinical significance of these particles.