Diode Laser Light Scattering and Temperature Changes Due to Anesthesia Injection in Bovine Tongue Mucosa.

Background and objective: Diode lasers are used in periodontal therapy. Parameters such as wavelength and application mode can affect the laser/tissue interactions, quality of incision, and final outcomes. This study set out to assess the temperature changes in tissue when diode lasers are used for incisions on tissues injected with local anesthetics. Materials and methods: Incisions were made on the surface of bovine tongue parallel to the tongue axis (ex vivo). The tissue was divided into three groups (lidocaine, saline, and a control group with no infiltration). Irradiation was performed with 810 and 980 nm diode lasers. Trials were further divided using noninitiated and initiated tips. A microprobe thermocouple was placed to evaluate the temperature changes. Linear mixed-model with Tukey adjustment was used to make comparisons and p < 0.05 was denoted as statistically significant. Results: The overall group comparisons reveal that the control group mean rise in temperature is lower than both the lidocaine group (p < 0.0001) and the saline group (p < 0.0001). When combining the data in and across each group, the average temperature rise that occurred for incisions made with initiated tips was significantly lower than incisions made with noninitiated tips (p < 0.0001). Combining the data of tip initiation shows that incisions made with a 980 nm laser produced lower temperature changes, than incisions made with an 810 nm laser (p < 0.0001). Conclusions: Infiltration of water-based liquids, such as local anesthetics or saline, causes an increase in tissue temperature during irradiation, especially when noninitiated tips are used. In addition, temperature significantly rises with the use of the 810 compared with the 980 nm diode laser. Therefore, to avoid photothermal damage to the tissue, the use of initiated tips is encouraged and local anesthetics in conjunction with 810 nm diode lasers should be minimized.

Temperature Change from Diode Lasers in Oral Mucosa: An Ex Vivo Study.

Objective: The aim of this ex vivo study was to assess the mean temperature change deep in tissue during diode laser (980 vs. 810 nm) irradiation using continuous and pulsed laser and initiated versus noninitiated tips. Background data: Previous studies have determined thermal effects of diode lasers on tissue damage but have yet to compare the incision qualities of 980 versus 810 nm diode lasers. Further studies need to be done to determine the efficiency of diode lasers to create a safer protocol for clinicians. Methods: Ninety-six incisions of 20 mm length were made in three bovine tongues using diode lasers (980 and 810 nm). Both continuous and pulsed modes were tested with initiated (using blue articulating paper) and noninitiated glass fibers (n = 12 per group). Thermocouples attached to LabChart® software were used to measure mean temperature changes. Mean, standard deviations, and p values were conducted for each group to test the statistical significance (p < 0.05). Results: Quality of incisions were better using the initiated tips for both laser wavelengths. Pulsed mode with 810 nm diode laser produced the least mean temperature change in tissue. Overall, both pulsed and continuous mode showed similar thermal effects on tissue. Conclusions: Within the limitations of this study, noninitiated tips are responsible for diffuse irradiation in tissue and are associated with tissue temperature increase during surgery. Low incision quality was observed using noninitiated tips. The temperature changes seem to be dependent on the laser wavelength and are higher for 980 nm compared with 810 nm pulsed diode laser.