Effect of diode lasers with wavelength of 445 and 980 nm on a temperature rise when uncovering implants for second stage surgery: An ex-vivo study in pigs

Background. Many surgical procedures in soft tissue are performed using diode lasers. Recently, a novel diode laser operating at 445 nm wavelength was introduced in dentistry. Objectives. The aim of our study was to evaluate the time of surgery and an increase in temperature of titanium implants during its uncovering using 445 and 980 nm wavelengths. Material and methods. The research included 45 pig mandibles (n = 45). The specimens were randomly divided into 3 groups (n = 15) according to the laser irradiation mode and wavelength; G1 - 445 nm laser, power: 3 W, continuous wave (CW), distance: 2 mm, power density: 7460 W/cm(2), fiber: 320 mu m, noncontact mode; G2 - 445 nm laser (power: 2 W, CW, power density: 4970 W/cm(2), fiber: 320 mu m, contact mode; G3 (control) - 980 nm laser, power: 2.5 W, CW, power density: 15920 W/cm(2), fiber: 200 mu m, contact mode. The temperature was measured with a 2 K-type thermocouples (a P1 at collar and a P2 at mid height of the implant). Results. The mean temperature rises measured by the P1 thermocouple were 16.9 degrees C, 36.1 degrees C and 21.6 degrees C in the G1, G2 and G3 group, respectively. Significant differences in temperature rise were found between the G1 and G2 group (p = 0.0007) and the G2 and G3 group (p = 0.01). The mean temperature rises measured by the P2 thermocouple were 1.8 degrees C, 1.4 degrees C and 5.6 degrees C in the G1, G2 and G3 group, respectively. Significant differences in temperature rise were found between the G1 and the G2 or G3 group (p = 0.0001). The significant differences among the study groups in average time necessary for uncovering the implants amounted to 69.7, 54.4 and 83.6 s, respectively (p < 0.05). Conclusions. The application of the 445 nm diode laser in non-contact mode reduced the temperature rise of the implants. The additional pulse intervals during laser irradiation with wavelength of 445 nm when operating in contact mode are needed.