A histological evaluation of the surgical margins from human oral fibrous-epithelial lesions excised with CO2 laser, Diode laser, Er:YAG laser, Nd:YAG laser, electrosurgical scalpel and cold scalpel

Histologic Evaluation of Effect of Three Wavelengths of Diode Laser on Human Gingival Margins

Introduction: Available evidence suggests that the response of the intervened tissue is directly linked to the effects generated by the cutting instrument used. To determine the histological findings in gingival tissue margins excised through gingivectomies performed using 450 nm, 940 nm, and 980 nm diode lasers. The present study aimed to determine the histological findings in gingival tissue margins excised through gingivectomies performed using 450 nm, 940 nm, and 980 nm diode lasers. Methods: Gingival tissue samples were collected from 30 patients who had undergone gingivectomy procedures. Each study group comprised 10 patients who willingly provided their samples after providing informed consent. The visualization of histological findings was facilitated through Hematoxylin-Eosin staining. Additionally, variables related to pain and hemostasis were assessed during the intraoperative period. Results: The incision quality was categorized as irregular across all three wavelengths. Histological examination of the epithelial tissue revealed the absence of carbonization and the preservation of cell morphology in over 50% of the resection margin in samples obtained with the 450 nm and 940 nm wavelengths. In the connective tissue, observations included carbonization, collagen coagulation, and basophilia, with the 980 nm wavelength demonstrating the highest percentage of samples displaying collagen coagulation in more than 50% of the resection margin. Conversely, the 450 nm wavelength exhibited the highest degree of preservation of the fibroblast structure. Conclusion: Based on a comprehensive analysis of the study results, it can be inferred that the 450nm and 940nm wavelength lasers tend to produce less thermal damage and better cell preservation when compared to the 980nm wavelength.

Histological implications of high-power laser use in the oral soft tissue lesions: a systematic review

The objective of this study was to describe the histological artifacts caused by high-power laser use compared to cold scalpel surgery in oral soft tissue lesions. Clinical studies that evaluated and compared histological artifacts resulting from the use of high-power lasers and cold scalpels in oral soft tissue lesions biopsies were retrieved from seven databases and four grey literatures, up to July 2022. The risk of bias was investigated using the ROBINS-I tool. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Seven studies were eligible for qualitative analysis. Based on the results obtained, those four studies had a low risk of bias, and three studies had an unclear risk of bias. The certainty of the evidence was classified as low. Limited evidence showed that epithelial artifacts such as loss of intraepithelial and subepithelial adhesions, accompanied by pyknotic, fusiform, and/or hyperchromic nuclei, were more common when a high-power laser device was used. Four articles reported that the use of high-power lasers did not interfere with the histopathological diagnosis of oral soft tissue lesions. Due to the heterogeneity of the data, a meta-analysis was not performed. Compared to the use of cold scalpels, histological artifacts, particularly those observed in epithelial tissue, are more common when high-powered lasers are used in oral lesions biopsies. The eligibility criteria and adequate indications of high-power lasers in different oral soft tissue lesion treatments must be respected to avoid tissue artifacts that impair precise histopathological diagnosis.

Evaluation of the Effectiveness of the Carbon Dioxide (CO2) Laser in Minor Oral Surgery: A Systematic Review

Introduction: Lasers in oral surgery have been extensively studied in recent years. Laser treatment is now a well-known technology that is frequently employed on oral soft tissues. The carbon dioxide (CO2) laser was one of the first soft tissue removal lasers. Because of the strong affinity of the CO2 laser to water, it is best used for removing, vaporizing, and coagulating these tissues. In minor oral surgery, CO2 laser therapy has shown advantages. Therefore, this study examined the CO2 laser use in minor oral soft tissue surgery. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards were followed in this study. A question for research encompassing the inclusion criteria for the participants, intervention, comparison, outcome, and study design (PICOS) was formulated. The search queries were entered into the PubMed/Medline, Scopus, and Embase databases. Consideration was given to publications published between January 1, 2018 and March 15, 2023. Results: The research included 37 studies after narrowing search results, eliminating duplicate titles, and conducting an eligibility review (three animal studies, seven case reports, three case series, and twenty-four clinical studies). CO2 lasers alone or in combination with other therapies successfully treated oral potentially malignant disorders (OPMDs), oral tumors, oral fibrous-epithelial lesions, gingival melanin hyperpigmentation, pyogenic granuloma, socket preservation, mucocele, high labial frenulum attachment, and so on. CO2 lasers reduced intra- and postoperative complications and adverse effects, improved postoperative functional results, ablated tissues with precision, and minimized disease recurrence and malignant transformation. Conclusion: Our study found that the CO2 laser in oral minor surgeries is successful, but further randomized clinical trials and multicenter studies are recommended to compare CO2 laser surgery to other treatments.

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

PURPOSE

To identify the surgical instrument that allows for optimal healing of tongue incisions.

METHODS

An Er:YAG laser was compared with different pulse energies to a conventional scalpel for the incision of mouse tongue tissues. Mice were sacrificed through cervical dislocation at 24, 48, and 72 h postoperatively, followed by extraction of their tongues for incision experiments. The healing of the incisions and expression of inflammation- and pain-related factors in the tongues were compared between the surgical procedure groups.

RESULTS

In laser-treated mice, tongue incisions healed the fastest when the laser output energy was 60 MJ per pulse. Macrophage chemotaxis toward the incisional area was triggered on the first postoperative day for the 60-MJ group, while the time for macrophage chemotaxis to the surgical area was later in the 80-MJ group. Tumor necrosis factor-alpha expression increased and then decreased in the 80-MJ group; however, it gradually decreased in the 60-MJ and conventional scalpel groups. Prostaglandin E2 expression increased and then decreased in the 80-MJ and conventional scalpel groups but gradually decreased in the 60-MJ group. The expression of transforming growth factor beta 1 gradually decreased in the 60-MJ and 80-MJ groups but gradually increased in the conventional scalpel group.

CONCLUSION

Compared with surgical procedures using conventional scalpels, those using an Er:YAG laser with appropriate pulse energies can inhibit inflammation in the incisional area and promote incision healing. The use of an Er:YAG laser with appropriate pulse energies can alleviate intraoperative and postoperative pain in the incisional area.

Laser nasal surgery (Review)

Laser nasal surgery has been an elusive subject in the last 10 to 15 years It was considered as a potential surgical staple for nasal surgery in the 1980s; however, it did not become one due to technical difficulties. Laser therapy has reemerged as an alternative to classical endoscopic surgery, and otorhinolaryngology surgeons are considering the benefits that it can offer. The advantages of this procedure are shorter hospitalization time, lack of nasal packing, high procedural precision with tissue sparing, and the unique capability of reducing both bacterial and fungal colonization at the level of the paranasal sinus. Therefore, laser therapy appears to be an invaluable tool for clinical practice. Due to the absence of a guaranteed cure for reoccurring nasal polyposis, laser therapy is worth investigating. For this therapy to evolve, an improved understanding of laser types and the effects that they produce is required. By investing in further developments of the equipment, the technique may become more widely used. With the current accelerated rate of technological evolution and robotic capabilities, laser nasal surgery may become a gold standard in future years. The aim of the present review is to evaluate whether it is worth investing in nasal laser surgery as a future alternative to current treatment standards.

Thermal damage and excision time of micro and super pulsed diode lasers: A comparative ex vivo analysis

OBJECTIVES

The primary aim of this ex vivo study was to evaluate thermal damage and cutting efficiency of micro and super pulsed diode lasers. The secondary aim was to suggest a guideline to perform simple surgical excisions adequate for histopathological evaluation.

MATERIAL AND METHODS

Ten groups of 10 specimens of pig tongues were excised using a blade (G1), a micro pulsed (G2-G9), and a super pulsed diode (G10) lasers. Different output power, pulse duration, pulse interval, and duty cycle were tested. Quantitative measures of thermal damage and excision times were recorded. Statistical analysis was performed at a significance level of 5%.

RESULTS

The control group (G1) presented no thermal damage. Within the laser groups (G2-G10), no statistically significant differences in depth of thermal damage (µm) were noted. G3 showed significantly less area of thermal damage (mm² ) when compared with G7 and G9 (p < .05). The median excision time of the control group and super pulsed diode laser group were significantly lower (p < .001) than the micro pulsed diode laser groups.

CONCLUSIONS

The cutting efficiency of the super pulsed diode laser is comparable to traditional blade, and with appropriate parameters, these lasers can produce predictable surgical outcomes with less collateral damage.

Histologic and Immunohistochemical Evaluation of Radiosurgery in Strabismus Surgery in a Rabbit Model

PURPOSE

The aim of this study was to evaluate the use of monopolar radiosurgery (MRS) assisted strabismus surgery and to compare its histologic and immunohistochemical wound healing outcomes with conventional surgery.

MATERIALS AND METHODS

Superior rectus muscle resection was performed on 30 white rabbits with three different surgical muscle cutting techniques: monopolar radiosurgery (MRS group), conventional scissors preceded by bipolar electrocautery (BEC group), and conventional scissors with no cauterization (control group). Degree of tissue injury, bleeding, inflammation, and fibrosis, as well as wound healing rate (CD68+ cell number), were evaluated.

RESULTS

In CS group, hemorrhage scores were significantly higher than those in the other groups (MRS group: Z = 5.182; p < 0.001 and BEC group: Z = 4.463; p < 0.001) and MRS group had lower scores than BEC group; however, the difference was not significant (Z = 1.423; p = 0.211). The tissue injury score in BEC group was higher when compared with MRS, and the difference was statistically significant (p = 0.028). Median inflammation scores at days 1 and 21 were lowest in MRS group, but the difference was not statistically significant among groups (day 1; p = 0.115, day 21; p = 0.095). The median fibrosis score was higher in the control group, when compared with MRS, and the difference was statistically significant (muscle-sclera; p = 0.011 and muscle-conjunctiva: p = 0.003). The macrophage score (number of CD68+ cells) was lowest in CS group; however, the difference was not significant (p = 0.657).

CONCLUSIONS

Monopolar radiosurgery is a novel method for strabismus surgery and provides equivalent hemostasis effects and wound healing properties, compared with conventional methods, and enhances surgeon comfort, as muscle incisions are made in one step with clean surgical area.

Phonosurgery: A review of current methodologies

Cold-steel has served as the gold standard modality of phonosurgery for most of its history. Surgical laser technology has revolutionized this field with its wide use of applications. Additional modalities have also been introduced such as coagulative lasers, photodynamic therapy, and cryotherapy. This review will compare the surgical modalities of cold steel, surgical lasers, phototherapy and cryotherapy. The mechanism of action, tissue effects and typical uses will be addressed for each modality.

Treatment of Wound Healing with Sequential Therapy to Accelerate Recovery and Inhibit Scar Hyperplasia: A Case Report

Study Design/Patients and Methods

A 19-year-old male was reported to have a postoperative facial trauma suture as a result of being involved in a car accident. Red light-emitting diode (LED) therapy (20 min, 96 J/cm², 633 nm), Botulinum Toxin Type A 36 IU injection, BroadBand Light and Er:YAG laser at various stages of wound healing were applied as the sequential therapy.

Results

Since the correction was promptly apparent and acceptable, the treatment proved secure and efficacious for repairing wound healing.

Conclusion

Clinically sequential therapy has demonstrated marked improvement in our case. Scar sequential therapy may offer a new strategy for wound healing recovery.

Uncovering and Autonomous Eruption of Palatally Impacted Canines-A Case Report

The impaction of permanent maxillary canine is a common clinical occurrence, and it is observed in 2% of patients who require orthodontic treatment. This case report describes a new orthodontic-surgical approach through the use of CO₂ laser, for the exposure of the palatally impacted canines. A 13-year-old female referred to our observation to make an orthodontic examination because of the maxillary primary canines’ persistence in upper arch. Orthopanoramic X-ray showed impaction of both permanent maxillary canines. The family history revealed that the patient’s mother had the same orthodontic problem. Cone Beam Computer Tomography (CBCT) was requested to plan the surgical-orthodontic treatment. Surgical exposure of the impacted canines was performed using a CO₂ laser and subsequent periodontal pack application. No orthodontic devices were applied for impacted teeth traction on dental arch. Canines’ movement was monitored at 1, 8 and 16 weeks post-surgery with photo and intraoral scanner CS3500 (CS3500^®, Carestream Health, Atlanta, GA, USA). When canine crowns were completely erupted on palatal side, the alignment in the arch with indirect bonding technique was performed. Complete disimpaction of canine crowns was obtained in only four months. As reported in the literature, this case confirms that impacted canines’ exposure to CO₂ laser has advantages if compared with traditional surgery: no bleeding during and after the procedure, decontaminant effect on the surgical area, no suture, and a fast spontaneous eruption. Conclusions: The pre-orthodontic uncovering and autonomous eruption of palatally impacted maxillary canines provides simplified, predictable, and more aesthetic outcomes. Furthermore, a significant positive factor is that there is no need to carry out the orthodontic traction of the impacted element, undoubtedly better compliance by the patient during the next alignment phase with the fix orthodontic appliance.

Histological Ex Vivo Evaluation of the Suitability of a 976 nm Diode Laser in Oral Soft Tissue Biopsies

INTRODUCTION

Laser-induced thermal effects can preclude a safe histological evaluation of biopsy resection margins. The aim of this study was to evaluate the suitability of a 976 nm diode laser in oral soft tissue biopsies in an ex vivo study.

MATERIALS AND METHODS

A 976 nm diode laser (Solase®, Lazon Medical Laser, China) has been used in the contact mode, using a 400 μm fiber tip, at different parameters from 4 to 6 W in the continuous wave (CW), with a fluence between 3184 and 4777 J/cm2, and pulsed wave (PW) mode, with a fluence between 318,4 and 477,7 J/cm2, to obtain 30 samples from fresh pig cadaver tongues. All specimens were subdivided into 6 groups (from A to F), and each group consisted of 5 samples. Two sections were obtained from each sample. A histological analysis was performed using an optical microscope at magnifications of 5x and 10x. Statistical analysis was carried out using Kruskal-Wallis and Dunn's tests.

RESULTS

The results showed that histological readability was optimal in all the samples. The thermal damage was negligible in all groups. The average thermal damage was 208.40 ± 133.81 μm in the epithelial tissue and 330.14 ± 147.45 μm in the connective tissue. The statistical analysis showed no differences between the groups (p > 0.05).

CONCLUSION

A 976 nm diode laser demonstrated good surgical effectiveness that provoked little peripheral damage in the cut edges and allowed a safe histological diagnosis. Clinical Relevance. In oral pathology, many times, there is fear in using the laser to remove some lesions due to its thermal effect on the tissues close to the lesion. This effect is always present in the use of the laser, but the intent is to minimize this effect to have as little alteration as possible on the surrounding tissues.

Clinicopathological Features of Patients Nominated for Head and Neck Biopsies: A One-Year Series

Background Head and neck lesions, which are predominantly benign, were widely reported. Some of these tumors are potentially neoplastic and others are non-neoplastic. Therefore, this study aimed to assess the clinicopathological features of patients nominated for head and neck biopsies. Methodology In this study, data regarding head and neck biopsies were retrieved from the Department of Pathology at King Khalid Hospital, Hai'l, Northern Saudi Arabia. Data referring to head and neck biopsies of patients who were diagnosed during the period from January 2018 to December 2018 were included. Results The initial clinical presentations were stated for 50/64 (78.1%) head and neck lesions, 12/64 (18.8%) head and neck cysts, 1/64 (1.6%) keloid, and 1/64 (1.6%) ischemia. With regard to the biopsy's site, most were taken from the nose followed by oral cavity, scalp, ear, face, and eye, constituting 19/64 (29.7%), 15/64 (23.4%), 9/64 (14.1%), 5/65 (7.8%), 4/64 (6.2%), and 3/64 (4.7%), respectively. Conclusion Head and neck benign lesions, predominantly inflammatory lesions, are common in Northern Saudi Arabia. Accurate identification of these lesions is important during histopathological diagnosis, as some have pathological features that mimic some potentially neoplastic lesions.

Quantitative determination of cut efficiency during soft tissue surgery using diode lasers in the wavelength range between 400 and 1500 nm

Within the scope of this ex vivo study, the cut efficiency was investigated with eight diode laser wavelengths in the range from 400 to 1500 nm. Incisions on porcine gingiva samples were generated in CW-mode at a power range of 0.5–4 W using a bare fiber (∅ = 320 μm) in contact and non-contact mode at a cut speed of 2 mm/s. Cut depths, cut widths, and thermal damages were recorded based on histological sections and were evaluated via measurement masks. Moreover, with respect to the controllability of a therapeutic measure, an efficiency factor was defined. At powers above 2 W, for 445 nm, the maximum cut depth was 820 μm and 344 μm for 810 nm, respectively. At all wavelength and power ranges, the cut width averaged 125 μm. At minimum output power (0.5 W), the spatial expansion of the thermal damage in the tissue surface layer corresponds in the blue/green wavelength range from the very beginning of the laser impact to the fiber core diameter. It could be shown that increases in the diode laser power output do not correlate to the same extent with the incision depth nor with thermal damage to tissue.

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).

Efficacy of laser monotherapy or non-surgical mechanical instrumentation in the management of untreated periodontitis patients. A systematic review and meta-analysis

Objective

To evaluate and compare the effects of laser monotherapy with non-surgical mechanical instrumentation alone in untreated periodontitis patients.

Materials and methods

A focused question was formulated based on the Population, Intervention, Comparison, Outcome, and Study design criteria (PICOS): in patients with untreated periodontitis, does laser mono-therapy provide adjunctive effects on pocket probing depth (PPD) changes compared with non-surgical instrumentation alone? Both randomized controlled clinical trials (RCTs) and controlled clinical trials (CCTs) were included. The results of the meta-analyses are expressed as weighted mean differences (WMD) and reported according to the PRISMA guidelines.

Results

The search yielded 1268 records, out of which 8 articles could be included. With respect to PPD changes, a meta-analysis including 5 articles (n = 148) failed to identify statistically significant differences in favor of laser monotherapy for PPD change (WMD = 0.14 mm; 95% CI: − 0.04/0.32; z = 1.51; p = 0.132) nor for clinical attachment level (CAL) (WMD = 0.04 mm; 95% CI: − 0.35/0.42; z = 0.19; p = 0.850). Data on cost-effectiveness are lacking. One study reported patient-related outcome measures (PROMS).

Conclusions

In untreated periodontitis patients, laser monotherapy does not yield superior clinical benefits compared with non-surgical mechanical instrumentation alone.

Clinical relevance

In untreated periodontitis patients, mechanical instrumentation with hand and/or ultrasonic instruments remains the standard of care.

A Single Case Report of Granular Cell Tumor of the Tongue Successfully Treated through 445 nm Diode Laser

Oral granular cell tumor (GCT) is a relatively rare, benign lesion that can easily be misdiagnosed. Particularly, the presence of pseudoepitheliomatous hyperplasia might, in some cases, lead to the hypothesis of squamous cell carcinoma. Surgical excision is the treatment of choice. Recurrence has been reported in up to 15% of cases treated with conventional surgery. Here, we reported a case of GCT of the tongue in a young female patient, which was successfully treated through 445 nm diode laser excision. Laser surgery might reduce bleeding and postoperative pain and may be associated with more rapid healing. Particularly, the vaporization effect on remnant tissues could eliminate GCT cells on the surgical bed, thus hypothetically leading to a lower rate of recurrence. In the present case, complete healing occurred in 1 week, and no recurrence was observed after 6 months. Laser surgery also allows the possibility to obtain second intention healing. Possible laser-induced histopathological artifacts should be carefully considered.

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

Continuously evolving laser devices can be used in various fields; they are an alternative to the traditional cold blade surgery to perform biopsies of oral soft tissues. The aspect focused on in this paper is the possibility to use the 445 nm diode laser (Eltech K-Laser srl, Treviso, Italy) in complete safety, by evaluating its thermal effects during microscopy. A histological evaluation of the alteration of the peri-incisional edges on 10 samples was realized. All excisional biopsies were related to clinically unsuspected lesions and performed by the same expert operator. The surgical procedure was performed with the same laser parameters and the same pathologist evaluated the thermal effect on the samples. An average value of the detected tissue alteration was calculated; the average damage of the epithelium was 650.93 μm, while in the connective tissue it was 468.07 μm. In all the cases a clear diagnosis was possible, and no clinical complications were observed; so, the 445 nm diode laser proved to be a device that can be safely used for biopsies of clinically unsuspicious lesions. Due to the small number of cases, this in vivo preliminary experience needs to be extended.

Q-Switch Nd:YAG Laser-Assisted Decontamination of Implant Surface

Peri-implantitis (PI) is an inflammatory disease of peri-implant tissues, it represents the most frequent complication of dental implants. Evidence revealed that microorganisms play the chief role in causing PI. The purpose of our study is to evaluate the cleaning of contaminated dental implant surfaces by means of the Q-switch Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser and an increase in temperature at lased implant surfaces during the cleaning process. Seventy-eight implants (titanium grade 4) were used (Euroteknika, Sallanches, France). Thirty-six sterile implants and forty-two contaminated implants were collected from failed clinical implants for different reasons, independent from the study. Thirty-six contaminated implants were partially irradiated by Q-switch Nd:YAG laser (1064 nm). Six other contaminated implants were used for temperature rise evaluation. All laser irradiations were calibrated by means of a powermetter in order to evaluate the effective delivered energy. The irradiation conditions delivered per pulse on the target were effectively: energy density per pulse of 0.597 J/cm², pick powers density of 56 mW/cm², 270 mW per pulse with a spot diameter of 2.4 mm, and with repetition rate of 10 Hz for pulse duration of 6 ns. Irradiation was performed during a total time of 2 s in a non-contact mode at a distance of 0.5 mm from implant surfaces. The parameters were chosen according to the results of a theoretical modeling calculation of the Nd:YAG laser fluency on implant surface. Evaluation of contaminants removal showed that the cleaning of the irradiated implant surfaces was statistically similar to those of sterile implants (p-value ≤ 0.05). SEM analysis confirmed that our parameters did not alter the lased surfaces. The increase in temperature generated at lased implant surfaces during cleaning was below 1 °C. According to our findings, Q-switch Nd:YAG laser with short pulse duration in nanoseconds is able to significantly clean contaminated implant surfaces. Irradiation parameters used in our study can be considered safe for periodontal tissue.