Thermodynamic effects of three different diode lasers on an implant-bone interface: an ex-vivo study with review of the literature.

The aim of this study is to assess the increase of temperature, following laser irradiation with 810nm and 980nm and 1064nm diode laser's wavelengths, of an implant, under conditions that more closely replicate those of the human body. A 4x14mm machined surface implant was placed in a porcine rib to replicate the conductivity of heat given by the bone. A peri-implant vertical defect 2mm wide and 2mm deep, to simulate bone resorption. Two thermocouples were positioned, crestally and apically, on the implant surface. The tip of the laser was kept 3mm away from the surface and continuously moved, in an up and down and side to side fashion, inside the defect for 60 seconds. Initial temperatures and the time needed to reach an increase of 10°C were recorded. The experiment was repeated, at room temperature and in a 37°C waterbath with the following settings: 0.6W, 0.8W, 1W continuous and repeated in pulsed. A critical increase of temperature of more than 10°C is reached with all lasers at 0.8W and 1W in continuous mode at room temperature. Only the 1064nm diode laser reached the critical increase at 0.8W in pulsed mode. No critical increase of temperature was registered with other settings and when the bone block was placed in a 37°C waterbath. The results of this study suggest that the use of these diode lasers does not cause a harmful increase in temperature when used under conditions similar to those of the human body.