Temperature Changes at the Implant-Bone Interface During Simulated Surface Decontamination with an Er:YAG Laser

Purpose: This study investigated temperature changes at the implant-bone interface during simulated implant surface decontamination with an Er:YAG laser. Materials and Methods: Stepped cylinder implants with three different surfaces (titanium plasma sprayed, sandblasted and acid etched, and hydroxyapatite coated) were placed in bone blocks cut from freshly resected pig femurs. An artificial periimplant bone defect with a size of 6 mm2 provided access for laser irradiation in the coronal third of the implant. A 540-µm periimplantitis application tip was used at a distance of 0.5 mm from the implant surface. Pulse energy was varied between 60 and 120 mJ at 10 pps. The bone block was placed into a 37°C water bath to simulate in vivo thermal conductivity and diffusitivity of heat. K-type thermocouples connected to a digital meter were used to register temperature changes at three levels of the periimplant bone. Results: The temperature at the implantbone interface did not exceed 47°C after 120 seconds of continuing laser irradiation. Temperature elevations were significantly higher at the hydroxyapatite-coated implants than in the two titanium surface groups (P .001). Conclusion: Decontamination of implant surfaces by means of the Er:YAG laser did not excessively heat the periimplant bone within the energy range investigated. This technique therefore seems clinically safe, at least when used with the surfaces studied.