Photothermal Effects of Defocused Initiated Versus Noninitiated Diode Implant Irradiation

摘要

Background: Diode lasers have been used for implant decontamination. However, the use of initiated or noninitiated tips remains unevaluated to verify potential photothermal risks. Objective: To assess the photothermal effects of defocused-initiated versus noninitiated irradiation. Materials and methods: A dental implant (3.5 × 11 mm) was placed into an artificial bone, an infrabony defect was created to simulate a four-wall peri-implant defect. Irradiation was performed using pulsed diode lasers of 940, 975, and 980 nm. The laser tips were positioned parallel to the implant (maximum 2W pulsed mode). The implant was irradiated for 30 sec using noninitiated, cork-, and blue paper-initiated tips. Temperature differences were observed at the apical and coronal regions of the implant. The data were statistically evaluated and compared using one-way analysis of variance and Tukey tests. Results: The average temperature increase and the amount of time that it took to yield the critical temperature were comparable at the coronal level for the 940 and 975 nm diode lasers ( p   0.05). For the 980 nm laser, blue-initiated tip had the highest temperature increase (22.4°C), followed by cork (18.8°C) and noninitiated tip (17.3°C). The critical threshold at the coronal portion for the 980 nm laser was reached in 11.5, 8.79, and 6.46 sec for the blue paper-, cork-, and noninitiated tips, respectively. The 975 and 980 nm lasers had average temperature increases, comparable among the blue paper-, cork-, and noninitiated tips at the apical level ( p   0.05). Apically, for the 940 nm, the noninitiated tip had the highest temperature increase (5.57°C), followed by the cork- (4.96°C) and blue paper-initiated tip (4.54°C). Conclusions: The initiator does not affect the temperatures produced during implant decontamination although noninitiated diode lasers may overheat (within 30 sec) than initiated tips. There is minimal risk of overheating at the apical portion. It seems that the 940 nm diode is the safest of the evaluated laser systems.