ABSTRACT
The implant surgery consists of two distinct techniques, the transmucosal, also known as "one-stage" and the "two-stage" technique. Lasers represent a possible aid in implant dentistry, especially in the two-stage technique and its main characteristics are represented by a decreased trauma to bone and soft tissues, a reduction of pain as well as a reduction of the risk of postoperative infections. The aim of this study was to analyze in an animal model the thermal elevation induced by four different laser wavelengths (diode, Nd:YAG, Er:YAG, KTP) during the implant uncovering. Four pig jaws were used to carry out this study. Five implants were placed in each anatomical specimen for a total of 20 fixtures. Four wavelengths (532, 810, 1,064 and 2,940 nm) were used to uncover the implants. Two thermocouples were used to measure temperature changes during laser irradiation at bone level, peri-implant tissues and on the fixture surface The thermocouples were connected with two probes of 1.5 mm in diameter, in order to simultaneously recording two temperature variations. Surface temperature was also checked during all procedures with a thermal camera (Thermovision A 800, Flyr Systems, Stockolm, Sweden) connected to a PC. The mean temperatures of each specimen (five fixtures) were calculated (TM1, mean temperature at the beginning; TM2, mean peak temperature). Furthermore, a record of the temperature at 1 min after the end of the surgical procedure was taken (mean: TM3). All the recorded values were statistically evaluated by one-way analysis of variance (ANOVA). The thermocouples recorded a lower increase in temperature for Er:YAG and KTP laser; Nd:YAG and diode laser produced similar increases characterized by higher values. The thermo-camera pointed out the lower increase for Er:YAG and higher for diode laser. KTP laser resulted faster in uncovering implants and diode laser was the one that needed more time. This ex vivo study showed that laser utilization with the recommended parameters gives no risks of dangerous thermal elevation to the tissues and implants.