The Effect of Photodynamic Therapy on Post-extraction Third Molar

Overview

The extraction of lower third molars is one of the most frequent procedures in oral surgery. For this reason, the extraction of these teeth generally requires a surgical approach involving the elevation of a mucoperiosteal flap and osteotomy to allow the use of elevators and removal of tooth in pieces or as a whole depending on the situation. As a result, it is a more invasive procedure than simple dental extraction, which leads a more challenging healing period for the patient, with complications such as pain, swelling, and trismus. Literature studies suggest that the peak of pain reported by patients occurs 3-5 hours after the local anesthetic wears off, while swelling reaches its maximum in the first 24-48 hours before gradually decreasing. In the first hours following the surgery, in addition to symptom onset, reparative mechanisms begin, contributing to the healing of the post-extraction site. Independent of the use of bone grafts, antimicrobial photodynamic therapy (aPDT) has been introduced to enhance healing and for disinfection of the extraction site5,6. aPDT uses a non-thermal photochemical reaction which promotes the excitation of a nontoxic dye (photosensitizer) by light at an appropriate wavelength. This causes an interaction with molecular oxygen and acts by damaging biomolecules selectively and destroying bacterial membranes7. The efficacy of this therapy in reducing bacterial load has been demonstrated in literature, and it has been widely used in patients with periodontitis or peri-implantitis since several years8. Although the primary use of antimicrobial photodynamic therapy seems to be related to periodontal and peri-implant diseases, its use in oral surgery to disinfect the socket and reduce the risk of complications related to bacterial contamination of the surgical site should not be underestimated9. Furthermore, the biostimulator effect of the laser can promote tissue healing after surgery through vasodilation, activation of microcirculation, and enhancement of tissue metabolism, thus reducing the recovery time for the patient10. There are still a few papers in literature that evaluate the effect of aPDT on post-operative healing after wisdom tooth extractions. This study aimed to investigate the effect of aPDT on the healing of soft and hard tissues and on post-surgical discomfort in subjects undergoing mandibular third molar extraction. The null hypothesis is that aPDT has no beneficial effects compared to spontaneous healing.

Patients in need of unilateral mandibular third molar extraction were randomly assigned to test or control group before surgery. In the test, a photoactive substance activated with laser light (20 mW, 660 nm) was applied to the post-extraction site for 60 seconds before suturing, to promote healing and disinfection. The control group did not receive any laser applications after tooth removal.