Influence of Different Air-Cooling Strategies on Laser-Induced Peri-Implant Temperature Development

Objectives: Lasers with a high energy output, such as the Er:YAG laser, can be used for the non-destructive removal of implant-supported ceramic restorations. However, this can induce a temperature increase in the surrounding tissue. The purpose of this study was to investigate the influence of different cooling strategies on peri-implant thermal changes.
Methods: The present study consisted of four test series (n=15), depending on the implant material (roxolid, titanium, zirconium-dioxide) and diameter. An ex-vivo model was chosen, consisting of a fresh bovine mandible, stored in water at 37°C to simulate the body temperature. According to the drilling protocols of the individual implant systems, the bone was prepared accordingly so that insertion of the implants with direct bone contact was possible. For two-piece implant systems, the implants were then restored with a prefabricated abutment; one-piece systems were left untouched. 300 laser pulses with an energy of 2.05 J were applied to the abutment area of each implant. To document the temperature development, three temperature electrodes were attached to each implant (marginal, central, apical). While no air cooling was used for the first five samples of each test series, two different air cooling strategies were used for the other ten samples, depending on the number of air blowers used. Finally, data obtained was analyzed statistically and graphically.
Results: The application of laser pulses without cooling showed the greatest temperature changes for all materials (marginal:25.8°C-41.8°C; central:12.4°C-17.8°C; apical:3.4°C-14.8°C). The use of air cooling resulted in significantly smaller temperature increases, regardless of how many air blowers were used: 1 air blower (marginal:1.8°C-5.6°C; central:0.6°C-3.4°C; apical:0.6°C-2°C); 2 air blowers (marginal:1.2°C-4.0°C; central:0.4°C-2.4°C; apical:1.2°C-1.4°C).
Conclusions: Considering the limitations of this ex-vivo study, it can be stated that air cooling, regardless of the cooling strategy, influences the peri-implant temperature development on the implants in such a way that no critical limits are exceeded.