Histological evaluation of mouse tongue incisions after Er:YAG laser surgery with different pulse energies versus after conventional scalpel surgery

The features of the reparative regeneration of an oral mucosa wound created under the exposure of a laser at a wavelength of 445 nm (a pilot study)

In clinical practice, an innovative laser technology that provides contactless preparation of soft tissues with a wavelength of 445 nm has been introduced. This study aimed to investigate the morphological changes in the oral mucosa when exposed to laser radiation at a wavelength of 445 nm in the ablation mode.An experimental study was conducted to analyze the dynamics of reparative regeneration in the wound caused by that particular type of radiation, utilizing the procedure of lower lip frenuloplasty as an illustration. 48 sexually mature male laboratory rats were chosen as the research object. The procedure of preparing the oral vestibule was executed by employing a contactless laser beam with a wavelength of 445 nm and a power of 0.7 W in continuous mode (CW) and an uninitiated fiber.Histological examination showed that 25 min after the surgery, there were large areas of coagulation necrosis in the oral mucosa in the area affected by the blue laser. In 48 h, the area of necrosis decreased both in size and depth. By the 7th day after the surgery, the necrotic masses had grown into the connective tissue, while marginal regeneration of the epithelium was noted. By the 14th day, the wound surface was completely epithelialized, represented by fibrous scar tissue. Clinically, around the mandibular incisors, there was a wide area of attached keratinized gingiva.The findings of histological examination indicate a necrosis of coagulation type in the region of tissue ablation and also show the absence of phase II of the inflammatory response (the stage of exudation), which expedites the process of epithelialization of the oral mucosa wound.

Er:YAG Laser Therapy on Alveolar Osteitis After Mandibular Third Molar Surgery: A Randomized Controlled Clinical Study

Background: Alveolar osteitis (AO) or "dry socket" affects the quality of life of patients, and there is a high clinical demand for its effective treatment. Objective: To evaluate the effect of Er:YAG laser therapy (ErLT) on AO after mandibular third molar surgery. Methods: Eighty-three patients were randomly divided into Er (n = 43) and control groups (n = 40). In the Er group, the Er:YAG laser (2940 nm; AT Fidelis Fotona, Ljubljana, Slovenia) was used to irradiate the AO site directly in micro short-pulsed mode (pulse duration 0.1 ms, pulse energy 100 mJ, frequency 40 Hz, water 4, and air 2) until all debris and necrotic material had been removed, exposing fresh bone and soft tissue surfaces with blood exudation. The control group received mechanical therapy until the treated lesions resembled those in the Er group. Pain assessment was performed at baseline and on days 1-7 post-intervention using the visual analog scale (VAS). Wound healing was assessed using the wound healing index (WHI). The operating times of the two therapies were also recorded. Results: Group Er had lower VAS scores than the control group on days 1-3 (p = 0.00). There was no significant difference between the two groups on days 4-7 (p = 0.15). The WHI scores were better in the Er group than those in the control group (t = 2.65, p = 0.01), especially in terms of redness (t = 2.70, p = 0.01). There was no significant difference in the operating time between the two groups (t = 0.76, p = 0.45). Conclusions: Compared with mechanical therapy, ErLT for AO provides rapid pain relief and improved wound healing.