Surface changes of implants after laser irradiation

Abstract

Periimplantitis is one of the major factors for the loss of dental implants. Due to the minor defense ability of the tissue surrounding the implant compared to natural teeth treatment of periimplantitis in the early stage is very important. Reducing bacteria with a laser might be the most successful step in therapy of periimplantitis. Aim of the study was to observe changes in surface morphology of seven different implants after irradiation with three different lasers. Two kinds of flat round samples were prepared by the manufacturers either identical to the body surface or to the cervical area of the corresponding implants. The samples were irradiated using different power settings. The lasers used were a CO 2 laser (Uni Laser 450P, ASAH Medico, Denmark; fiber guided, wavelength 10.6 μm, max. average power 8.3 W, soft-pulse and cw) an Er: YAG laser (KaVo Key Laser II, wavelength 2.94 μm, pulse duration 250 - 500 μs, pulse energy 60 - 500 mJ, pulse repetition rate 1 - 15 Hz, focus diameter 620 μm, air-water cooling; Biberach, Germany) and a frequency doubled Alexandrite laser (laboratory prototype, q-switched, fiber guided, wavelength 377 nm, pulse duration 1 μs, pulse repetition rate 30 Hz, water cooling). After irradiation the implant surfaces were investigated with a Scanning Electron Microscope. Ablation thresholds were determined. After CO 2 laser irradiation no changes in surface morphology were observed whereas using the pulsed Er: YAG or frequency doubled Alexandrite laser even at low energies loss of integrity or melting of the surface was observed. The changes in surface morphology seem to depend very strongly on the type of surface coating.