Objective: High-intensity laser therapy (HILT) combined with photobiomodulation therapy (PBMT) using a diode or CO2 laser was administered after extraction of the left first molar in rats. Effects on socket preservation (preservation of the alveolar bone and healing time after extraction) were evaluated histopathologically. Background: Irradiation using a diode or CO2 laser has been shown to hasten wound healing, but the effects remain controversial. Methods: Five-week-old male Wistar rats that underwent extraction of the left maxillary first molar were divided into three groups: diode laser irradiation (diode group), CO2 laser irradiation (CO2 group), and no laser irradiation (control group). HILT (27 J) was performed immediately after tooth extraction to enhance blood coagulation, followed by PBMT (0.7 J) 1 day later to enhance healing. Tissues, including the extraction socket, were removed en bloc 3, 5, 7, 10, and 21 days postextraction to determine the morphological characteristics of wound healing and the distribution of myofibroblasts involved in scar formation. Results: In the diode and CO2 groups, new bone formation and cancellous bone maturation were observed at an early stage of wound healing. The number of myofibroblasts was significantly lower in the laser treatment groups than the control (p < 0.001), and both treatment groups had a significantly higher alveolar crest height (p < 0.01), with almost no concavity in the mucosa of the extraction wound. Conclusions: Combined HILT and PBMT following tooth extraction hastened wound healing and preserved alveolar crest height, suggesting a role in socket preservation.
Keywords: carbon dioxide laser; diode laser; enhanced healing process; myofibroblast; scar tissue; socket preservation; tooth extraction.