title: Temperature changes induced by 809-nm GaAlAs laser at the implant-bone interface during simulated surface decontamination.
abstract: The aim of the study was to investigate temperature changes at the implant-bone interface during simulated implant surface decontamination with a 809-nm gallium-aluminium-arsenid (GaAlAs) semiconductor laser. Stepped cylinder implants with a diameter of 3.8 mm and a length of 11 mm with two different surfaces (sand-blasted and acid etched, and hydroxyapatite-coated) were inserted into bone blocks cut from freshly resected pig femurs. Access holes of 0.5 mm were drilled into the bone, to allow K-type thermocouples to contact periimplant bone in different parts of the cavity. An artificial periimplant bone defect provided access for laser irradiation in the coronal third. A 600-micrometer optic fiber was used at a distance of 0.5 mm from the implant surface. Power output varied between 0.5 and 2.5 W in the continuous wave mode. The bone block was placed into a 37 degrees C water bath in order to simulate in vivo thermal conductivity and diffusitivity of heat. Temperature elevations during irradiation were registered for a period of 120 s. In mean, the critical threshold of 47 degrees C was exceeded after 9.0 s at 2.5 W, 12.5 s at 2.0 W, 18.0 s at 1.5 W and 30.5 s at 1.0 W. Surface characteristics did not have a significant effect on temperature elevations. In an energy-dependent manner, implant surface decontamination with an 809-nm GaAlAs laser must be limited in time to allow the implant and bone to cool down. Clinical guidelines are presented to avoid tissue damage.
authors.affiliation: Department of Oral Surgery, Johannes Gutenberg-University Mainz, Mainz, Germany. matthiaskreisler@web.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Kreisler
authors.forename: Haitham
authors.initials: H
authors.lastname: Al Haj
authors.forename: Bernd
authors.initials: B
authors.lastname: D'Hoedt
mesh_terms: D000134:Acid Etching, Dental; D000535:Aluminum; D000818:Animals; D001152:Arsenicals; D001831:Body Temperature / Q000502:physiology / Q000528:radiation effects*; D001842:Bone and Bones / Q000503:physiopathology / Q000528:radiation effects*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D015921:Dental Implants; D017267:Dental Prosthesis Design; D004058:Diffusion; D017886:Durapatite / Q000737:chemistry; D005269:Femur; D005336:Fiber Optic Technology / Q000295:instrumentation; D005708:Gallium; D006358:Hot Temperature; D053685:Laser Therapy; D018709:Statistics, Nonparametric; D013242:Sterilization / Q000295:instrumentation*; D013499:Surface Properties; D013552:Swine; D013696:Temperature; D013814:Thermal Conductivity; D013821:Thermometers; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D001152:Arsenicals; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D014867:Water; D017886:Durapatite; D005708:Gallium; D000535:Aluminum