en دهان و دندان Oral and Maxillofacial پژوهشي Research <ul> <li style="text-align: justify;"><strong>Introduction:</strong> Dental surgeries are always associated with pain and swelling for several consecutive days. Recent articles have&nbsp;shown conflicting results in the use of new techniques such as low-power lasers to treat postoperative pain and swelling. This study&nbsp;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.</li> <li style="text-align: justify;"><strong>Method:</strong> This study was a randomized, single-blind, split-mouth clinical trial involving patients who were referred to the special&nbsp;clinic of Birjand Dental School from December 2021 to June 2021 and required bilateral removal of the occluded third molars.&nbsp;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&nbsp;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&nbsp;and the amount of mouth opening as well as the amount of pain on the second and seventh days after surgery. Statistical analysis was&nbsp;performed using the Wilcoxon and Mann&ndash;Whitney U test by SPSS (Version 21) at the significant level of (5 %).</li> <li style="text-align: justify;"><strong>Results:</strong> The intensity of pain and swelling decreased significantly over time and the amount of trismus increased significantly during&nbsp;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&nbsp;laser was 1.98&plusmn;0.26 and the amount of pain in the group with laser was 0.85 &plusmn; 0.92 which was not statistically significant between&nbsp;the two groups (value>0.05). The amount of trismus on 7-day was 38.79 &plusmn;9.94 and on the side, with laser, it was no significant&nbsp;difference. The distance between the tragus and the corner of the lip on day 7 after surgery was 110.03 &plusmn; 5.77 mm and in the laser&nbsp;group was 109.66 &plusmn;5.67 mm, no significant difference was observed between the two groups. The distance between the gonium and&nbsp;the outer corner on day 7 after surgery was 98.84 &plusmn;7.24 mm in the laser group and 98.21&plusmn; 6.93 mm in the non-laser group and no&nbsp;significant difference was observed.</li> <li style="text-align: justify;"><strong>Conclusion:</strong> The use of low-power laser reduced the pain, reduce postoperative swelling, and trismus caused by surgery but this&nbsp;reduction was not significant. Therefore, it is suggested that the study method should be changed and the sample size must be&nbsp;increased in further studies.</li> </ul> <h1></h1> Low-Level Light Therapy, Third Molar, Tooth Extraction, Trismus, Pain, Edema 137 144 http://jsurgery.bums.ac.ir/browse.php?a_code=A-10-318-1&slc_lang=en&sid=1 Narjes Akbari narges_akbare4021@yahoo.com 10031947532846009150 10031947532846009150 No Associate Professor of Oral & Maxillofacial Medicine, Department of Oral & Maxillofacial Diseases, School of Dentistry, Infectious Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran Marzieh Mohamadimoghadam mohamadi_moghadam@yahoo.com 10031947532846009151 10031947532846009151 Yes Department of Periodontics, School of Dentistry, Birjand University of Medical Sciences, Birjand, Iran Amir Mohammad Chaji chajiamirmohammad@gmial.com 10031947532846009152 10031947532846009152 No Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran