450 nm diode laser: A new help in oral surgery

Evaluation of Non-cross-linked Hyaluronic Acid on Oral Wound Healing After Diode Laser and Scalpel Incisions

Background

The aim was to assess the impact of non-cross-linked hyaluronic acid (HA) injections on the healing of intraoral wounds from 3 types of incisions.

Methods

A total of 36 Wister albino rats were included in this research. The rats were randomly assigned to 1 of 6 groups: the first group underwent a scalpel incision in the buccal mucosa with HA injection. The second group received a laser incision using a 976-nm diode laser with HA injection, whereas the third group was subjected to a laser incision with a 450-nm diode laser with HA injection. The fourth group underwent scalpel incision only, the fifth group received a 976-nm laser incision only, and the sixth group received a 450-nm laser incision only. Biopsies were collected at baseline, as well as on the third and seventh days, to assess wound healing using hematoxylin and eosin and Masson trichrome staining.

Results

Group 3 exhibited the most pronounced results on the third and seventh days after surgery, with collagen formation noted alongside well-organized granulation tissue that contributed to improved and expedited wound healing.

Conclusions

In this low-volume experimental study, HA injections in wounds made with a 450-nm diode laser demonstrated encouraging outcomes, enhancing the healing process and resulting in quicker recovery.

Blue laser-assisted depigmentation of gingiva using non-ablative technique

Diode lasers are one of the most widely used modalities in soft tissue dental surgery. Recent advancements have expanded the clinically useful emission spectrum of diode lasers to include the blue light region, corresponding to wavelengths such as 445 and 450 nm. The melanin present in hyperpigmented gingiva acts as a chromophore and absorbs laser energy, thus facilitating the denaturing of melanin-containing cells in the gingiva. This paper presents a case of ethnicity-related gingival hyperpigmentation that was successfully treated using a 445 nm blue wavelength soft tissue diode laser by non-ablative technique. The treated area showed no recurrence of pigmentation up to 9 months postoperatively.

Investigation of Changes in the Reflection Spectrum of Human Blood When Exposed to Laser Radiation With Wavelengths of 450 or 980 nm

OBJECTIVES

This study aimed to determine and explain changes in the reflectance spectrum of human blood in vitro when exposed to laser radiation at wavelengths of 450 or 980 nm.

METHODS

Reflectance spectra of venous blood samples were measured before and after exposure to a single pulse of 450 or 980 nm laser radiation. A numerical optical model based on the Monte Carlo method was applied.

RESULTS

Laser irradiation at 450 and 980 nm caused the most significant changes in the reflectance spectrum around 600 nm, associated with alterations in blood oxygen saturation. The maximum efficiency of reducing oxygen saturation was 0.20%/W for 980 nm and 0.72%/W for 450 nm, likely due to differences in blood absorption at these wavelengths.

CONCLUSIONS

The greatest change in intensity reflectance spectra and oxygen saturation of human venous blood occurs when exposed to laser radiation at 450 nm, not at 980 nm.

Thermal Effects on Dental Pulp during Laser-Assisted Bleaching Procedures with Diode Lasers in a Clinical Study

Background In the current cosmetics industry, bleaching is often associated with lasers. However, such treatment also harbors risks. Tooth death is observed at pulpal temperature increases ≥5.6 °C. Therefore, it seems important to investigate the effects of using different lasers. The aim of this study was to determine pulpal temperature increases at different laser parameters during bleaching by modeling a realistic environment and to compare the temperature recording using a thermocouple and thermal camera. The authors assumed that there are laser settings for the lasers used at which the pulpal temperature increases are <5.6 °C and that the temperature recordings with thermocouples and thermal cameras differ only minimally. Methods Human teeth were used, which were extracted for dental reasons. During experiment, teeth were bleached conventionally and by laser activation at 940 nm, 445 nm, and 970 nm. The temperature in the pulp was recorded using thermocouples. In a second setup, longitudinally halved teeth were bleached, while the temperature in the pulp was recorded with a thermocouple and thermal camera. Descriptive statistics were used. The significance level is 0.05. Results In addition to conventional bleaching, temperature increases <5.6 °C were observed for bleaching at 940 nm 1.5 W, at 445 nm 0.3 W, and at 970 nm 0.5 W. For bleaching procedures using 940 nm 7 W, 940 nm 2 W, 445 nm 0.5 W, and 970 nm 1 W, the temperature increase was ≥5.6 °C. Significant differences (p < 0.05) were found in the maximum temperature increases (°C) between all groups. Temperature recordings using a thermocouple and thermal camera differed by about 2.3 °C. The working hypotheses were confirmed. Conclusion With laser bleaching, attention must be paid to the type of laser, its power, and the time in order to avoid excessive overheating of the dental pulp.

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).

Wound healing after therapy of oral potentially malignant disorders with a 445-nm semiconductor laser: a randomized clinical trial

OBJECTIVES

Oral potentially malignant disorders (OPMDs) are the most clinically relevant precursor lesions of the oral squamous cell carcinoma (OSCC). OSCC is one of the 15 most common cancers worldwide. OSCC is with its high rate of mortality an important cause of death worldwide. The diagnosis and therapy of clinically relevant precursor lesions of the OSCC is one of the main parts of prevention of this malignant disease. Targeted therapy is one of the main challenges concerning an oncologically safe tissue removal without overwhelming functional and aesthetic impairment.

MATERIALS AND METHODS

In this randomized controlled trial, a newly introduced intraoral 445-nm semiconductor laser (2W; cw-mode; SIROLaser Blue, Dentsply Sirona, Bensheim, Germany) was used in the therapy of OPMDs. Duration and course of wound healing, pain, and scar tissue formation were compared to classical cold blade removal with primary suture by measuring remaining wound area, tissue colorimetry, and visual analogue scale. The study includes 40 patients randomized using a random spreadsheet sequence in two groups (n1 = 20; n2 = 20).

RESULTS

This comparative analysis revealed a significantly reduced remaining wound area after 1, 2, and 4 weeks in the laser group compared to the cold blade group (p < 0.05). In the laser group, a significantly reduced postoperative pain after 1 week was measured (p < 0.05).

CONCLUSION

Laser coagulation of OPMDs with the investigated 445-nm semiconductor laser is a safe, gentle, and predictable surgical procedure with beneficial wound healing and reduced postoperative discomfort.

CLINICAL RELEVANCE

Compared to the more invasive and bloody cold blade removal with scalpel, the 445-nm semiconductor laser could be a new functional less traumatic tool in the therapy of OPMDs. The method should be further investigated with regard to the identification of further possible indications.

TRAIL REGISTRATION

German Clinical Trials Register No: DRKS00032626.

Use of Blue and Blue-Violet Lasers in Dentistry: A Narrative Review

Introduction: Blue and blue-violet diode lasers (450 and 405 nm) seem to represent an interesting approach for several clinical treatments today. The aim of this narrative review is to describe and comment on the literature regarding the utilization of blue and blue-violet lasers in dentistry. Methods: A search for "blue laser AND dentistry" was conducted using the PubMed database, and all the papers referring to this topic, ranging from 1990 to April 2020, were analyzed in the review. All the original in vivo and in vitro studies using 450 nm or 405 nm lasers were included in this study. All the articles on the LED light, laser wavelengths other than 405 and 450 nm and using lasers in specialties other than dentistry, as well as case reports, guideline papers and reviews were excluded. Results: From a total of 519 results, 47 articles met the inclusion criteria and were divided into 8 groups based on their fields of application: disinfection (10), photobiomodulation (PBM) (4), bleaching (1), resin curing (20), surgery (7), periodontics (1), endodontics (1) and orthodontics (3). Conclusion: Blue and blue-violet diode lasers may represent new and effective devices to be used in a large number of applications in dentistry, even if further studies will be necessary to fully clarify the potentialities of these laser wavelengths.

In vitro evaluation of the safety and efficacy of a high-power 450-nm semiconductor blue laser in the treatment of benign prostate hyperplasia

A 450-nm blue laser may be suitable to treat benign prostate hyperplasia (BPH) due to its haemoglobin absorption characteristic. The present study compared a novel high-power 450-nm semiconductor blue laser with other lasers marketed for in vitro soft tissue ablation, to evaluate the safety and efficacy of the 450-nm laser in BPH surgery. With the in vitro tissues on an experimental platform in water, the vaporization efficiency and coagulation layer thickness of the novel 450-nm laser and commercially available 532-nm, 980-nm, and 1470-nm lasers were measured at the same power (120 W). The damage to the adjacent tissue and the working noise were also measured. The vaporization efficiency was proved to be 450-nm laser > 532-nm laser > 1470-nm laser > 980-nm laser. Comparison of coagulation layer thickness was as follow: 980-nm laser > 1470-nm laser > 532-nm laser > 450-nm laser. The degree of tissue damage caused by the 450-nm and 532-nm lasers increased with the decrease in distance and increase in time (these are safe when a sufficient distance and short irradiation time are maintained). The heating ability of 980-nm and 1470-nm lasers was much greater than that of 450-nm and 532-nm lasers. The working noise was lower in 450-nm and 1470-nm lasers. The novel 450-nm laser has the advantages of highly efficient tissue vaporization, creating a thin coagulation layer, and low working noise. These characteristics suggest that the novel 450-nm laser may be a promising choice for the surgical treatment of BPH.

Ex vivo histological analysis of the thermal effects created by a 445-nm diode laser in oral soft tissue biopsy

OBJECTIVE

The aim of this study was to evaluate, ex vivo, the histological effects of 445-nm diode laser (Eltech K-Laser srl, Treviso, Italy), during an oral soft tissue biopsy.

MATERIALS AND METHODS

Thirty samples from pig cadaver tongues were obtained, through five laser settings, in continuous and pulsed wave (CW and PW). Samples were divided into six groups of five pieces each. A control specimen was taken by a scalpel. All samples were examined with an optical microscope by a blinded pathologist. Thermal effects on epithelium and connective tissues were measured with LAS 4.8 software. Finally, a statistical evaluation was made using GraphPadPrism 7.0 software.

RESULTS

All specimens, except one, showed a damage lower than 1 mm. Readability was always optimal; there was a different thermal effect between epithelial and connective tissue and in CW and PW samples, confirmed by statistical analysis too.

CONCLUSIONS

A 445-nm diode laser creates a minimum thermal effect, that has no implications in the histological evaluation of benign lesions. In suspicious lesions, a safety margin of 1 mm, compared with a scalpel, is preferable.

CLINICAL RELEVANCE

A 445-nm diode laser has excellent surgical properties and can manage many arduous clinical cases, such as vascularized lesions. In the excision of suspected lesions, it is necessary to compare, case by case, clinical advantages to possible histological implications.