Determine the effect of Low-Level Laser Therapy on pain, swelling, and trismus after impacted mandibular third molar surgery

Dental surgeries are always associated with pain and swelling for several consecutive days. Recent articles have shown conflicting results in the use of new techniques such as low-power lasers to treat postoperative pain and swelling. This study aimed to evaluate the reduction of pain, swelling, and trismus after surgery of the third molar-impacted tooth after the use of a low-power laser.

This study was a randomized, single-blind, split-mouth clinical trial involving patients who were referred to the special clinic of Birjand Dental School from December 2021 to June 2021 and required bilateral removal of the occluded third molars. Immediately after surgery, the patient was given a radiation laser with a wavelength of 780 nm and a power of 70 MW for 30 seconds at a dose or power density of 52.5 j/cm2. The extent of swelling and trismus was assessed by measuring the dimensions of the face and the amount of mouth opening as well as the amount of pain on the second and seventh days after surgery. Statistical analysis was performed using the Wilcoxon and Mann–Whitney U test by SPSS (Version 21) at the significant level of (5 %).

The intensity of pain and swelling decreased significantly over time and the amount of trismus increased significantly during the seventh day compared to the second day (p.value<0.05). The amount of pain on the 7th day after surgery in the group without laser was 1.98±0.26 and the amount of pain in the group with laser was 0.85 ± 0.92 which was not statistically significant between the two groups (value>0.05). The amount of trismus on 7-day was 38.79 ±9.94 and on the side, with laser, it was no significant difference. The distance between the tragus and the corner of the lip on day 7 after surgery was 110.03 ± 5.77 mm and in the laser group was 109.66 ±5.67 mm, no significant difference was observed between the two groups. The distance between the gonium and the outer corner on day 7 after surgery was 98.84 ±7.24 mm in the laser group and 98.21± 6.93 mm in the non-laser group and no significant difference was observed.

The use of low-power laser reduced the pain, reduce postoperative swelling, and trismus caused by surgery but this reduction was not significant. Therefore, it is suggested that the study method should be changed and the sample size must be increased in further studies.