Laser Irradiation of Titanium and Ceramic Implants in Different in-Vitro-Conditions

Objectives: Different wavelengths have been used to decontaminate implant surfaces and stimulate wound healing. This experiment aimed to evaluate the thermal changes (ΔT) of pure titanium and ceramic dental implants during 445nm and 970nm diode laser irradiation in different in vitro conditions.
Methods: Two dental implants made of titanium and ceramic were placed into an organic bone analog and an intra-bony defect (4x4x5mm) was created at one site of each implant. Two thermocouples were used to record real-time temperature changes at the coronal part of the implant body (Tc), and the apex (Ta). A 445nm and 970nm diode laser with non-initiated tip and 320mm fiber was used to irradiate the defects for 30 seconds at 2W in continuous wave (c.w.) and pulsed non-contact mode. The experiment was done at room temperature (21.0°C±1) and in a water bath (37.0°C±1) simulating body temperature. The temperature changes were recorded and underwent statistical analysis (p< 0.05).
Results: At 21°C, the 445nm diode resulted in the highest ΔT coronally (29.6°C) and apically (6.70°C) for the titanium implant (p< 0.0001). In the same environment, the ceramic implant maintained ΔT values below the critical threshold after using the 970nm in c.w. (8.6°C) and pulsed mode (7.22°C). At 37°C, the 970nm diode laser in c.w. generated the most heat for the titanium implant (14.4°C, p< 0.0001). In pulsed mode, the 445nm diode laser showed the highest ΔT for the titanium implant (11.9°C), and for the ceramic implant, the ΔT was below the critical threshold for 445nm and 970nm (4.8°C and 3.52°C, respectively). Linear regression was used to compare the ΔT values, and the results were statistically significant (p< 0.0001).
Conclusions: Under in vitro conditions, the 445nm and 970nm diode lasers in pulsed mode seem to be safe on ceramic implants. However, these diode lasers should be used with caution on titanium implants.