Histological Effects of an Innovative 445 Nm Blue Laser During Oral Soft Tissue Biopsy

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.

Gingival overgrowth approached using recent mechanical and laser technologies: A case report

Gingival enlargement is a side effect of different drug classes, with calcium channel blockers being among the most often cited examples. Most often accompanied by a disruption in the oral biofilm, this form of gingival overgrowth, with histological signs of hyperplasia and hypertrophy, becomes a chronic inflammatory condition with the oral biofilm a primary cause. This periodontal disease is now classified as 'dental biofilm-induced gingivitis', and its preferred name is drug-influenced gingival expansion. The present study presented the case of a patient with gingival enlargement while being treated with nifedipine for cardiac disease. This patient had factors that contributed to the retention of bacteria, ranging from poor oral hygiene practices to poorly adapted prosthodontics. After reducing these factors, a multimodal treatment was conducted, including bacterial mechanical decontamination through guided biofilm therapy protocol, laser bacterial decontamination, and surgical laser gingivectomy. The patient was referred to their cardiologist for substituting the calcium channel blocker medication. Clinical evaluations followed each treatment step. At 12 months, the patient presented positive, stable results, with an improvement in gingival status (no gingival overgrowth in the area where all risk factors were eliminated and minimal overgrowth in the area where old poorly marginally adapted prosthodontics were kept in place and no/minimal signs of gingival inflammation).

450-nm blue diode laser: a novel medical apparatus for upper tract urothelial lesions

OBJECTIVE

To explore the feasibility, safety and effectiveness of the 450-nm blue diode laser (BL), novel blue laser in the treatment of upper tract urothelial carcinomas (UTUCs) and other lesions in a porcine model.

MATERIAL AND METHODS

For in vitro experiment, the ureter tissue was vaporised and coagulated with BL, green-light laser (GL) and Ho:YAG laser (Ho). The efficiency, width and depth of vaporisation, and depth of coagulation were recorded and compared. For in vivo experiments, four swines weighing 70 kg were used. In the acute group, different modes of operations were performed to evaluate the thermal damage, perforation and bleeding. In the chronic group, the overall appearance of the ureter and laser wound healing were observed by the naked eyes and H&E staining 3 weeks after surgery.

RESULTS

In in vitro study, the BL showed a higher efficiency of tissue vaporisation and less tissue coagulation for fresh ureter compared to GL and Ho. In the in vivo study, the power of BL set at 7 W was better, and the thickness of thermal damage varied with different surgery types in the range of 74-306 μm. After 3 weeks, the wound healed well static in vaporisation (SV), moving vaporisation (MV) and H&E staining indicated mucosal healing rather than scar healing.

CONCLUSION

5-10W blue diode laser achieved a higher efficiency of tissue vaporisation and less tissue coagulation in a porcine model, indicating its potential application in the endoscopic surgery of UTUC as an optional device with high performance and safety.

Use of a Fiberoptic-Laser Approach During Endoscopic Sinus Surgery: A Cadaver Feasibility Study

Aims

The aim of the present study is to evaluate the clinical applicability of laser energy during an oro-nasal endoscopic approach (ONEA) in the management of the anterior maxillary sinus wall.

Methods

An experiment on three adult human cadavers was performed to study the nasal cavities with angled rigid scopes and using the ONEA technique. In order to evaluate the effectiveness of laser energy on the bone, the drilling effect was compared to laser energy (1470 nm diode laser, continuous wave, power 8, 9 and 10 W).

Results

Compared to a rigid angled scope, the ONEA technique allowed complete visualization of the anterior wall of the maxillary sinus. Microscopic analysis of frontal bone revealed similar bone Exeresis with high-speed drilling (270.28 μm) and laser approaches (285.73-456.6 μm).

Conclusions

The laser ONEA technique is an innovative, mini-invasive, and safe approach to the anterior wall of the maxillary sinus. Additional study is warranted to further develop this technique.

The Impact of Laser Thermal Effect on Histological Evaluation of Oral Soft Tissue Biopsy: Systematic Review

The aim of the study is to review the literature to observe studies that evaluate the extent of the thermal effect of different laser wavelengths on the histological evaluation of oral soft tissue biopsies. An electronic search for published studies was performed on the PubMed and Scopus databases between July 2020 and November 2022. After the selection process, all the included studies were subjected to quality assessment and data extraction processes. A total of 28 studies met the eligibility criteria. The most studied laser was the carbon dioxide (CO₂) laser, followed by the diode laser 940 nm-980 nm. Six studies were focused on each of the Erbium-doped Yttrium Aluminium Garnet (Er:YAG), Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) lasers, and diode lasers of 808 nm and 445 nm. Three studies were for the Potassium Titanyl Phosphate (KTP) laser, and four studies were for the Erbium, Chromium-doped Yttrium, Scandium, Gallium, and Garnet (Er,Cr:YSGG) laser. The quality and bias assessment revealed that almost all the animal studies were at a low risk of bias (RoB) in the considered domains of the used assessment tool except the allocation concealment domain in the selection bias and the blinding domain in the performance bias, where these domains were awarded an unclear or high score in almost all the included animal studies. For clinical studies, the range of the total RoB score in the comparative studies was 14 to 23, while in the non-comparative studies, it was 11 to 15. Almost all the studies concluded that the thermal effect of different laser wavelengths did not hinder the histological diagnosis. This literature review showed some observations. The thermal effect occurred with different wavelengths and parameters and what should be done is to minimize it by better adjusting the laser parameters. The extension of margins during the collection of laser oral biopsies and the use of laser only in non-suspicious lesions are recommended because of the difficulty of the histopathologist to assess the extension and grade of dysplasia at the surgical margins. The comparison of the thermal effect between different studies was impossible due to the presence of methodological heterogeneity.

In vivo clinical and histological thermal effect of a 445 nm diode laser on oral soft tissues during a biopsy

Blue diode laser emits a 445 nm wavelength light, which is extremely effective with hemoglobin, and has an optimal hemostatic effect. This work analyzes its thermal effects and clinical efficacy, when used to perform excisional biopsies. Forty-two excisional biopsies were performed with the laser; then, the extent of perincisional thermal effects was evaluated and patients were followed up. Average alteration on epithelial tissue was 507.07 µm, and on connective tissue was 320.39 µm. In all the cases, it was possible to obtain a histological diagnosis. Diode lasers can be safely used to perform biopsies; various intra- and postoperative advantages were confirmed.

Assessment of Effects of Laser Light Combining Three Wavelengths (450, 520 and 640 nm) on Temperature Increase and Depth of Tissue Lesions in an Ex Vivo Study

Background: Lasers are widely used in medicine in soft and hard tissue surgeries and biostimulation. Studies found in literature typically compare the effects of single-wavelength lasers on tissues or cell cultures. In our study, we used a diode laser capable of emitting three components of visible light (640 nm, red; 520 nm, green; 450 nm, blue) and combining them in a single beam. The aim of the study was to assess the effects of laser radiation in the visible spectrum on tissue in vitro, depending on the wavelength and pulse width. Methods: All irradiations were performed using the same output power (1.5 W). We used various duty cycles: 10, 50, 80 and 100% with 100 Hz frequency. Maximum superficial temperature, rate of temperature increase and lesion depth were investigated. Results: Maximum superficial temperature was observed for 450 + 520 nm irradiation (100% duty cycle). The highest rate of increase of temperature was noted for 450 + 520 nm (100% duty cycle). Maximum lesion depth was observed in case of three-wavelength irradiation (450 + 520 + 640 nm) for 100, 80 and 50% duty cycles. Conclusions: The synergistic effect of two-wavelength (450 + 520 nm) irradiation was observed in case of maximum temperature measurement. The deepest depth of lesion was noted after three-wavelength irradiation (450 + 520 + 640 nm).