Nd:YAG laser versus traditional scalpel. A preliminary histological analysis of specimens from the human oral mucosa

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.

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.

Treatment of Gingival Growth Due to Amlodipine Use With a 445-nm Diode Laser: A Case Report

Amlodipine is a widely used calcium channel blocker associated with gingival enlargement. The effects of amlodipine on gingival enlargement vary depending on the duration of drug use and the dose of the active substance. This report presents a 56-year-old male hypertensive patient who had been using amlodipine (5 mg/day orally, single dose) for the last two years. He presented with diffuse gingival enlargement, complaining of gingival swelling and bleeding. This case report demonstrates the treatment of gingival enlargement with a novel 445-nanometer (nm) blue light diode laser after drug change and oral hygiene, which resulted in permanent and satisfactory clinical results.

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.

The effects of Twinlight laser treatment on the titanium surface proliferation and osteogenic differentiation of mesenchymal stem cells

BACKGROUND

The study aimed to observe the effects of a Twinlight laser on the titanium surface proliferation of inflammatory Mesenchymal stem cells (MSCs), inflammatory cytokine expression, and osteogenic differentiation.

METHODS

The MSCs were collected from bone tissue of healthy individuals.The cellular inflammatory model was established with 1 μg/mL lipopolysaccharide (LPS).Under the cellular inflammatory model,divided into five groups: the normal control group (C); the inflammatory control group (L); Er:YAG laser group (L + E); Nd:YAG laser group (L + N); Er:YAG laser and Nd:YAG laser group (L + E + N). The treated cells were inoculated onto titanium disks.The normal and inflammatory MSCs on the surface of titanium surface were examined by CCK-8, scanning election microscopy (SEM), quantitative real-time polymerase chain reaction (qRT‑PCR) and other methods for their proliferation, growth pattern, expression of inflammatory factors Interleukin-6 (IL-6), Interleukin-8 (IL-8) and osteogenic genes Runx2 (Runt-related transcription factor 2) and alkaline phosphatase (ALP), providing the theoretical basis and experimental data for the Twinlight laser-assisted treatment of peri-implantitis. Statistical analyses were performed using a Student's t test with SPSS 17.0 software.

RESULTS

Through observation using SEM, the cell densities of the L + E + N, L + E, and L + N groups were similar, but cell bodies in the L + E + N group were fuller and each had more than two pseudopodia. The expression level of IL-6 mRNA in the L, L + N, L + E, and L + E + N groups was higher than in group C (P < 0.05), and the expression level of IL-8 mRNA in the L + E + N group was significantly lower than in group L (P < 0.0001). On day 7, the expression level of ALP mRNA in the L, L + N, L + E, and L + E + N groups was lower than in group C (P < 0.05). On day 14, there was no significant difference in the expression level of ALP mRNA among the L + N, L + E + N, and C groups (P > 0.05). On day 7, the expression level of RUNX2 mRNA in the L + E + N group was higher than in group L (P < 0.001). On day 14, the expression level of RUNX2 mRNA in the L + E + N group was higher than in group L (P < 0.01).

CONCLUSION

Twinlight laser treatment promoted cell proliferation, inhibited the expression of inflammatory cytokines, and effectively enhanced the osteogenic differentiation of cells on a titanium surface.

Development and evaluation of a scoring system for assessing incisions in laser surgery

The idea of laser surgery is nearly as old as the laser itself. From the first trials to modern laser surgery systems, it was and is the aim to selectively cut the tissue in the focus spot without causing harm to surrounding structures. This is only possible when the correct parameters for the surgical laser are chosen. Usually, this is done by parameter studies. However, the concrete evaluation scheme often differs between groups and more precise approaches require staining and microscopic evaluation. To overcome these issues, a macroscopic scoring system is presented and evaluated. It can be shown that the scoring system works well and, thus, a laser cut can be evaluated within a few seconds. At the same time, the whole cutting front is taken into account. The presented scoring system is evaluated by the intra class correlation (ICC). The final agreement between different raters is more than 0.7. Therefore, the scoring system can be used to optimize and evaluate the cutting process and it should be suitable for comparing the results between different groups. Definitely, it can be applied for scoring within a group to enable e.g., a profound statistical analysis for a parameter study.

A histological evaluation of the mice oral mucosal tissue wounds excised with diode laser, Er:YAG laser, and cold scalpel

Laser has been considered to show many favorable characteristics, including wound healing acceleration, hemostasis, biostimulation, and microbial inhibition. Previous studies have investigated the effect of laser treatment during the process of wound healing, with conflicting results. To date, there is still no unified conclusion on the effect and application principle of clinical laser therapy. This study evaluated the incision morphology, wound healing speed, and histological changes in mice oral mucosal wounds excised with diode laser, Er:YAG laser, and cold scalpel. The results showed that compared with the cold scalpel group, laser treatments caused more tissue thermal damage and carbonization, which led to a healing delay. However, lasers also showed some advantages, including hemostasis, regular incision, and immune response mobilization, suggesting that lasers may be beneficial in some specific cases, such as reducing intraoperative accidents and wound tissue laceration and controlling bleeding and postoperative infection. This study provides a theoretical basis for clarifying the effect of laser treatments and their clinical application principle.

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.

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.

High-level laser therapy versus scalpel surgery in the treatment of oral lichen planus: a randomized control trial

OBJECTIVE

To compare the clinical effectiveness of various types of high-level laser therapy (HLLT) toward scalpel excision for the surgical treatment of erosive oral lichen planus (OLP).

MATERIALS AND METHODS

The total number of 128 individuals were enrolled in the study. The 35 did not meet the inclusion criteria due to malignancy signs and presence of diabetes mellitus. In total, 8 were lost to follow-up, and 10 were excluded from the analysis, due to analgesics intake. This way 75 patients with the erosive form of OLP were analyzed in three intervention groups (Er:YAG, n = 19; Nd:YAG, n = 15; Er:YAG + Nd:YAG combination, n = 20) and one control group with scalpel excision (n = 21). The therapy effectiveness has been assessed based on the comparison of salivary interleukin (IL)-1β, IL-6 and interferon (IFN)-γ preoperative levels to 14, 30 days, and 2 years postoperation, as well as pain level and time of epithelization.

RESULTS

All HLLT groups demonstrated a significantly (p > 0.05) higher IL-1β, IL-6, IFNγ and pain level reduction and quicker epithelization toward the control group on the 30th day, except Nd:YAG in case of IFNγ level. The highest IL-1β, IFNγ and pain level reduction and quicker epithelization on the 30th day was observed in Er:YAG group, followed by Er:YAG + Nd:YAG combination, Nd:YAG respectively. However no significant difference was observed between the HLLT groups with regard to IL-6 level reduction. After a 2-year follow-up, no significant difference was observed between all study groups with regard to all variables.

CONCLUSION

HLLT yields a superior clinical outcome compared to the scalpel excision for the surgical treatment of oral lichen planus, whereby the Er:YAG has been proposed as the most effective laser type at the end of the first postoperative month.

CLINICAL RELEVANCE

For the surgical treatment of erosive OLP the Er:YAG laser may be a preferable treatment option compared to Nd:YAG and scalpel surgery.

TRIAL REGISTRATION

The present trial was registered retrospectively in the German Clinical Trials Register, as a member of WHO international clinical trials registry platform, on the 18.03.2020 with the following number: DRKS00020986.

Large-sized pleomorphic adenoma of the cheek treated with Nd:Yag laser: report of a case and review of the literature

Pleomorphic adenoma (PA) mostly involves parotid glands, while extra-parotid localizations are relatively uncommon. Particularly, PAs of the cheek minor salivary glands with a size larger than 4 cm are exceedingly rare, with only few cases reported. Surgical treatment of PA usually consists in radical excision. However, despite a presumptive radicality, recurrences, sometimes followed by malignant transformation, may occur. Here we report a case of a large-sized (6 cm) PA of the cheek minor salivary glands in a 70 year-old female patient, successfully treated through a conservative approach, based on the use of Nd:YAG Laser (λ=1064 nm). No recurrences were observed after a 2-year follow-up. A concise review of the literature, describing the features of 14 cases is also provided. Advantages of laser treatment include a precise cut, reduction of trauma on surrounding tissues, the possibility of a very good intraoperative hemostasis. Such features may sometimes allow to avoid general anesthesia, even for removal of big lesions. Post-operative course, in terms of pain and swelling, is usually better for intervention performed with laser, when compared to traditional surgery.

Key words:Oral surgery, oral pathology, pleomorphic adenoma, laser surgery, minor salivary glands, salivary glands tumors.

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.

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.

[Clinical application of laser in crown lengthening]

Crown lengthening is one of the most common surgeries in clinical practice. Under the premise of ensuring the biologic width, the adequate crown is exposed by resecting the periodontal soft tissue and (or) hard tissue to meet the prosthodontic and (or) aesthetic requirements. Considering the various advantages of oral laser, such as safe, precise, minimally invasive and comfort, laser has become a promising technology which can be used to improve the traditional crown lengthening. In this review, the principles and characteristics of laser application in crown lengthening, especially in the minimally invasive or flapless crown lengthening will be reviewed. Its pros and cons will also be discussed.

How we improve the transoral resection for oral and oropharyngeal cancer: the CO2 waveguide laser

PURPOSE

The main aim of this study was to evaluate the CO₂ waveguide laser (CO₂ WGL) with flexible fiber (Lumenis, Santa Clara, CA) in the treatment of oral and oropharyngeal cancers specifically focusing on the lateral thermal damage (LTD) induced by this instrument and therefore on the reliability of the analysis of frozen sections collected during margin mapping.

METHODS

A total of 48 patients with oral and oropharyngeal cancers from T1 to T4a were prospectively enrolled in the study. We collected data about LTD, pathologic tumor and node stage (pTNM), surgical intervention, kind of reconstruction (no flap, local vs free flap), need for tracheotomy and time of removal, postoperative complications (such as bleeding, mucosal dehiscence, and fistula), need for feeding tube and time of removal.

RESULTS

Mean LTD was 164.7 ± 92.4 μm. Comparing frozen section histology before and after formalin embedding we found 5 true positives, 170 true negatives, 4 false positives and 4 false negatives, with a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 55.6%, 98%, 55.6%, 98%, and 96.1%, respectively.

CONCLUSION

CO₂ WGL is a very manageable tool, which allows a precise cut. However, its high costs, the inability to re-use the fibers and its low coagulation capability must be considered.

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

Background

We aim to evaluate the presence of histological artefacts in the surgical margins of human oral fibro-epithelial hyperplasias excised with lasers of different wavelengths, and also electrosurgical scalpel and cold scalpel. Moreover, we aim to determine if some of these instruments could impair the normal histological diagnosis of these lesions.

Material and Methods

We included 130 consecutive surgical samples of 80 females and 50 males (mean age of 53.82±16.55) with a histological diagnosis of an oral benign fibrous-epithelial hyperplasias. The samples were categorized into 6 groups according to the type of instrument used: CO2 laser group, diode laser group, Er:YAG laser group, Nd:YAG laser group, electrosurgical scalpel group and cold scalpel group. Histological instrument-induced changes were microscopic evaluated and related with clinical and pathological variables.

Results

The instrument with highest tissue damage extension (TDE) was the electrosurgical scalpel (1002.2µm±434.92), followed by diode laser (913.73 µm±322.45), Nd:YAG (899.83µm±327.75), CO2 laser (538.37µm±170.50), Er:YAG laser (166.47µm±123.85), and at last with fewer alterations the cold scalpel group (2.36µm±7.27) (P< 0.001). The most regular incision was observed in CO2 laser group, followed by Er:YAG laser, Nd:YAG laser, electrosurgical scalpel and diode laser group with the less regular incision using cold scalpel as comparison (P< 0.001). A correlation was found between the incision score and TDE (P< 0.001). Regarding histological diagnosis, no case showed any limitation of diagnosis related with the use of any instrument evaluated.

Conclusions

Our results suggest that lasers can be used for the excision of oral benign fibrous-epithelial hyperplasias, without hispathological diagnosis limitations, as long as the physical properties of each laser are known and respected. Er:YAG laser have shown to be a laser with few tissue damage extension and with good incision regularity, been a possible instrument of choice for the surgical removal of these lesions.

Key words:CO2 laser, diode laser, Er:YAG laser, Nd:YAG laser, oral mucosa.

Temperature and depth evaluation of the in vitro effects of femtosecond laser on oral soft tissue, with or without air-cooling

Femtosecond laser is an effective and safe tool in many surgeries, but the studies of its effect on oral soft tissue ablation are insufficient. This study aimed to investigate the effect of soft tissue ablation with a 1030-nm femtosecond laser on temperature and depth. Twenty Sprague-Dawley rat tongue specimens were obtained and flat-mounted. The 1030-nm femtosecond laser was controlled by a computer system, with a set distance of 4.7 mm between the laser aperture and soft tissue surfaces. Ten specimens were ablated for > 1 min with or without air-cooling for temperature measurement, while the other 10 specimens were ablated for depth measurements, using the following parameters: (i) 3 W, 2000 mm/s; (ii) 3 W, 4000 mm/s; (iii) 5 W, 2000 mm/s; (iv) 5 W, 4000 mm/s; (v) 8 W, 2000 mm/s; (vi) 8 W, 4000 mm/s. Temperature changes were measured using a type-K thermocouple. The depth attained using different power and scanning speed settings was measured by a three-dimensional morphology measurement laser microscope. Laser power, scanning speed, and air-cooling effects were determined. Higher energy and lower speed induced higher temperatures (p < 0.05), which were significantly decreased by air-cooling (p < 0.05). The lowest ablation depth was obtained at 3 W and 4000 mm/s (72.63 ± 6.47 μm) (p < 0.05). The greatest incision depth was achieved at 8 W and 2000 mm/s (696.19 ± 35.37 μm), or 4000 mm/s (681.16 ± 55.65 μm) (p < 0.05). The 1030-nm femtosecond laser application demonstrates clinically acceptable ablation efficiency, without marked temperature damage, in a controlled manner.

Patient perceptions and clinical efficacy of labial frenectomies using diode laser versus conventional techniques

INTRODUCTION

The aim of present study was to compare the keratinized gingival tissue measurements, degree of subjective complaints and functional complications of using an 980nm diode laser versus a scalpel for labial frenectomies.

MATERIAL AND METHODS

Thirty-six patients requiring labial frenectomies, between 14 and 51 years old, were randomly assigned to either scalpel or diode laser treatments. The soft tissue measurements, including the keratinized gingiva width (KGW), attached gingiva width (AGW) and attached gingiva thickness (AGT), were recorded before surgery, immediately after, one week later and one, three and six months after surgery. In addition, the functional complications and the morbidity (level of pain, swelling and redness) were evaluated during the first postoperative week using a visual analog scale (VAS).

RESULTS

We determined statistically significant gains in the KGW, AGW and AGT after surgery in both groups; however, there was no significant difference between the study groups. The VAS scores indicated that the patients treated with a diode laser had less discomfort and functional complications compare with scalpel surgery.

DISCUSSION

The results described above show that diode laser surgery offers a safe, impressive alternative for labial frenectomies that are comfortable for the patients.

High-power diode laser on management of drug-induced gingival overgrowth: Report of two cases and long-term follow-up

BACKGROUND

Drug-induced gingival overgrowth (DIGO) is attributed mainly to the prolonged use of calcium channel blocking agents, anticonvulsants, and anti-calcineurin inhibitors . The management of DIGO depends on the severity of the disease and includes surgical intervention and plaque control. Compared to conventional surgical treatment, the recent literature data have shown that gingivectomy using a high-power laser (HPL) is a short and easy procedure, which results in minimal postoperative discomfort and greater patient accep- tance.

OBJECTIVE AND METHODS

The purpose of this study was to report two cases of recurrent DIGO treated surgically using HPL (λ 808nm, 1.5W).

RESULTS

Minimal bleeding and discomfort were observed during surgery, and patients reported no pain or bleeding after the procedure. After 1 year of follow-up, patients presented a minimal increase of gingival volume, indicating that laser technology can improve the efficiency and prognosis of DIGO.

CONCLUSIONS

The HPL was able to preventing hemorrhage and improving the patient's collaboration with the treatment and quality of life.

Type of surgical treatment and recurrence of oral leukoplakia: A retrospective clinical study

BACKGROUND

Oral leukoplakia (OL) is the most typical potentially malignant disorder of the oral mucosa. We aimed to evaluate the clinical outcome of oral leukoplakia treated with several types of lasers and with the use of quantic molecular resonance (QMR) lancet, in terms of recurrence rate.

MATERIAL AND METHODS

Eighty-seven previously untreated OL (52 occurring in females and 35 in males, mean age of 59.4 ± 13.9 years) were consecutively submitted to surgical treatment at University Hospital of Parma, Italy, and Hospital de Valongo, Portugal, (1999 to 2012). Interventions were subclassified into 5 groups according to the instrument used for the surgical removal of OL (cold blade - 17; Nd:YAG 1064nm laser - 14; Er:YAG 2940nm laser - 33; CO2 10600nm laser - 15; and QMR scalpel - 8). The mean follow-up period after treatment was 21.6 months (range 1-151 months). The outcome of treatment was scored through the same clinical protocol in the two participating units. Statistical analysis were carried by univariate analysis using chi-square test (or Pearson's test when appropriate).

RESULTS

Recurrences were observed in 24 cases of OL (27.6%). Malignant transformation occurred in one patient (1.1%) after a period of 35 months. Statistical comparison of the 5 surgical treatment modalities showed no differences in clinical outcomes nor in the recurrence rate of OL. However, when Er:YAG laser group was compared with traditional scalpel, a significantly better outcome in cases treated with Er:YAG laser (P = 0.015) was highlighted.

CONCLUSIONS

Our results suggests that Er:YAG laser could be a promising option for the treatment of OL.

Laser Surgery of Soft Tissue in Orthodontics: Review of the Clinical Trials

Introduction: Recently, a wide variety of procedures have been done by laser application in orthodontics. Apart from the mentioned range of various treatments, laser has become a tool for many soft tissue surgeries as an alternative to conventional scalpel-based technique during orthodontic treatments in the management of soft tissue. Due to scarce information in the latter subject, this study was designed in order to include clinical trials that included soft tissue ablation by laser in orthodontics. Methods: Literature was searched based on PubMed and Google Scholar databases in 5 years (2010-2015) with English language restriction and clinical trial design. Studies that performed soft tissue application of laser during orthodontic treatment were extracted by the authors. Results: Only eight studies met the inclusion criteria. No significant difference was found between laser ablation and conventional scalpel technique in the matter of treatment outcome. However, few issues remained to clarify the differences in the mentioned procedures. Conclusion: Laser performance can be recommended in case of preceding less bleeding and discomfort during surgical procedure. There are still quandaries among clinical application of scalpel-based surgery in aesthetic region with bracket-bonded teeth. Precaution and knowledge regarding the characteristics of laser beam such as wavelength, frequency, power and timing is extremely needed.

In vitro histological evaluation of the surgical margins made by different laser wavelengths in tongue tissues

BACKGROUND

Lasers have become standard tools for the surgical treatment of oral lesions. The purpose of this study is to determine the surgical margins and histologically evaluate the tissue thermal effects induced by different types of surgical instruments.

MATERIAL AND METHODS

Cuts were made in pork tongues' mucosa with different lasers (Er:YAG at 2W with and without air / water spray and at 4W with and without air / water spray; CO2 at 3.5W and 7W in pulsed mode and at 7W in continuous mode; the diode laser at 3.5W and boost 3.5W in pulsed mode; Nd:YAG at 6W, 40Hz and electroscalpel at 5W and conventional scalpel as control. Macroscopic and microscopic morphological changes were evaluated.

RESULTS

The results of this study showed that the surgical instruments that caused greater tissue damage extension were: the Nd:YAG laser (670.68μm), the diode 3.5W and boost PW (626.82μm), the CO2 7W CW (571.18μm), the CO2 at 7W PW (485.45μm), the diode 3.5W PW (456.15μm), the electroscalpel (409.57μm) and lastly the CO2 laser 3.5W PW (306.19μm) and Er:YAG (74.66μm) laser, regardless of power, mode or air / water spray used. An association between the Tissue Damage Extension and the Degree of Carbonization (r = 0.789; P = 0.01), and an association between the Tissue Damage Extension and Regularity of the Incision were found (r = -, 299; P = 0.01).

CONCLUSIONS

The results of this study suggest that lasers can be used in soft tissues biopsies of the oral cavity, enabling a correct histopathological analysis, as long as the biological effects of each laser type are considered. The Er:YAG laser revealed its potential for biopsies of the oral mucosa ensuring a successful histological evaluation and the CO2 laser at 3,5W in pulsed mode presented itself as the best choice for surgeries with hemostasis. Key words:CO2 laser, diode laser, Er:YAG laser, laser surgery, Nd:YAG laser, oral mucosa, thermal effect.

The advantages of carbon dioxide laser applications in paediatric oral surgery. A prospective cohort study

The aim of this study is to evaluate and demonstrate the advantages of the carbon dioxide laser in paediatric oral surgery patients in terms of less post-operative complications, healing without scaring, functional benefits, positive patient perception and acceptance of the treatment. One hundred fit and healthy paediatric patients (aged 4-15 years) were recruited to undergo laser surgery for different soft tissue conditions. The outcome of these laser treatments was examined. The Wong-Baker Faces Pain Rating Scale was employed to evaluate the pain before, immediately after laser treatment in the clinic and 1 day after post-operatively at home. Post-operative complications and patients' perception and satisfaction were self-reported during a review telephone call the day after treatment. The patients were reviewed 2 weeks after surgery. Laser parameter was 1.62 W, measured by power meter, continuous wave mode with 50 % emission cycle. The beam spot size at the target tissue was 0.8 mm. The pain score pre-operative, during and immediately after laser treatment was rated 0. Whilst the pain score 1 day after surgery was rated between 0 and 2, the healing time was measured over 2 weeks. None of the patients reported post-operative complications after surgery. Patients' perception and acceptance were rated very good. Laser dentistry is a promising field in modern minimally invasive dentistry, which enables provision of better care for children and adolescents. In this cohort study, the use of the carbon dioxide laser therapy offers a desirable, acceptable and minimally invasive technique in the surgical management of soft tissues in paediatric oral surgery with minimal post-operative complications.

Selected applications of Er:YAG and CO2 lasers for treatment of benign neoplasms and tumorous lesions in the mouth

INTRODUCTION

Benign neoplasms and hyperplastic tumorous lesions are common oral pathologies. These lesions require to be surgically removed by conventional surgery, laser, or electrosurgery. Surgical treatment aims at complete removal of pathological lesions and ensuring proper healing of the tissues to minimize the risk of lesion recurrence.

AIM

To present possible applications of Er:YAG and CO2 lasers in removal of benign neoplasms and tumorous lesions developing on oral mucosa as well as to specify indications and limitations of these two methods.

MATERIAL AND METHODS

Temperature-induced injuries due to laser light application, possibility of post-operative histopathological evaluation of the removed tissue, efficacy of the cut and coagulation, healing process and completeness of laser surgeries give rise to our special concern.

RESULTS

The main asset of the CO2 laser comparing to Er:YAG laser is an effective coagulation while thermal injury to the tissues is its limitation, especially with multiple passage of the beam and too high power applied. Er:YAG laser application does not exclude histopathological examination of the removed lesion tissue which is its advantage over CO2 laser.

CONCLUSIONS

Still, insufficient coagulation is a limitation ofits use in the case of richly vascularized lesions.

Advantages of new technologies in oral mucosal surgery: an intraoperative comparison among Nd:YAG laser, quantic molecular resonance scalpel, and cold blade

The aim of this study is to evaluate the possible intraoperative advantages of Nd:YAG laser and quantic molecular resonance (QMR) scalpel in oral soft tissue surgery. One hundred sixty-three interventions were evaluated. Group 1 (G1) included 77 interventions performed with Nd:YAG laser, group 2 (G2) 45 with QMR scalpel, and group 3 (G3) 41 with cold blade. Parameters analyzed were as follows: speed of incision, time of intervention, intraoperative bleeding, number of stitches, patient compliance, and operator comfort. Data were analyzed using software STATA 12 (StataCorp LP, College Station, TX, USA). Mean speed of incision was 0.54 mm/s in G1, 2.83 mm/s in G2, and 1.58 mm/s in G3, Nd:YAG laser being the slowest. However, no significant differences among times of intervention were found. In particular, interventions in G1 (221.15 ± 220.89 s) have a mean duration lower than G2 (280.56 ± 248.31 s) and G3 (316.10 ± 248.69 s). Intraoperative bleeding occurred in 29.9 % (n = 23/77) of interventions in G1, 97.8 % (n = 44/45) in G2, and 97.6 % (n = 40/41) in G3 (p < 0.0001). Mean number of stitches in G1 was statistically lower (G1, 0.10; G2, 2.07; G3, 2.29; p < 0.0001). No differences with regard to patient compliance were detected. Operator comfort was higher in G1 (p < 0.0003). Nd:YAG laser and QMR scalpel give several advantages in oral mucosal surgery: Nd:YAG laser cuts tissue slowly, but it provides a good visibility and excellent hemostasis. QMR scalpel allows a very rapid cutting with no considerable temperature increase, but there is major risk of bleeding and need for sutures with lower operator comfort.

Aesthetic Depigmentation of Gingival Smoker's Melanosis Using Carbon Dioxide Lasers

Melanic pigmentation results from melanin produced by the melanocytes present in the basal layer of the oral epithelium. One of the most common causes of oral pigmentation is smoker melanosis, a condition associated with the melanocyte stimulation caused by cigarette smoke. This paper aims to illustrate the use of a carbon dioxide laser in the removal of the gingival melanic pigmentation for aesthetic reasons in a 27-year-old female patient with history of a smoking habit. The carbon dioxide laser vaporisation was performed on the gingival mucosa with effective and quick results and without any complications or significant symptoms after the treatment. We conclude that a carbon dioxide laser could be a useful, effective, and safe instrument to treat the aesthetic complications caused by oral smoker melanosis.

Management of a soft tissue tumor in a child with Worster Drought syndrome using 810 nm diode laser - A case report

BACKGROUND AND AIMS

An out-patient surgical procedure in the paediatric age group is a tough task for a surgeon, more so when compounded with mentally challenging conditions like cerebral palsy. Every step involved, either administration of local anaesthesia or handling sharp surgical instruments around the face or achieving haemostasis, can be a challenge, with compromise on patient safety. Neither undue restraint nor general anaesthesia is advisable, considering the magnitude of the procedure. In such cases, a safe, rapid and effective technique that can be comfortably performed under topical anaesthesia without use of sharp instruments or needles would be an ideal option. The purpose of this paper is to highlight one such situation, where an intra-oral soft tissue tumor was safely and effectively ablated using diode laser, under topical anaesthesia in a child with cerebral palsy concurrent with Worster Drought syndrome.

RESULTS

Topical anaesthesia provided adequate conditions to ablate the tumor. A bloodless field was achieved, with no need for sutures. The procedure was completed in less than half the time required for a conventional approach. Postoperative follow-up of 3 months showed complete healing with no recurrence.

CONCLUSIONS

Portable diode lasers are an effective tool for minor oral surgical procedures in paediatric population especially, children who are mentally challenged.

Effects of laser-assisted cosmetic smile lift gingivectomy on postoperative bleeding and pain in fixed orthodontic patients: a controlled clinical trial

Background and objective

Diode lasers are becoming popular in gingival treatment following orthodontic treatments. Despite their merit and clinical implications, postoperative pain and bleeding after surgery with diode lasers are not assessed except in few controversial studies.

Method

This controlled clinical trial was conducted on 30 healthy orthodontic patients aged 17–29 years, needing esthetic-only gingivectomy in the anterior maxilla. The patients were randomly divided into two groups of 15 each: experimental (laser-assisted surgery) and control (traditional surgery using scalpels). The bleeding rate following the surgery was assessed using the bleeding criteria established by the World Health Organization. The postsurgical pain level was recorded using visual analog scales immediately after the surgery and in patients who consumed analgesics, also 2 h after the analgesic consumption. The data were analyzed using the independent-samples t, Mann-Whitney U, and chi-square tests (α = 0.05).

Results

The average bleeding rates were 1.15 and 0.36 in the conventional and laser groups, respectively (Mann-Whitney U P < 0.05). Experimental patients had no postsurgical pain (VAS1 and VAS2 = 0). In the control group, the average VAS1 pain was 5.2 out of 10. The difference between VAS1 values in the control/experimental groups was significant (Mann-Whitney U P < 0.001).

Conclusion

940-nm diode laser seems promising in reducing postoperative bleeding and pain of patients needing cosmetic smile lift surgeries.

Biopsy of different oral soft tissues lesions by KTP and diode laser: histological evaluation

Introduction. Oral biopsy aims to obtain clear and safe diagnosis; it can be performed by scalpel or laser. The controversy in this latter application is the thermal alteration due to tissue heating. The aim of this study is the histological evaluation of margins of “in vivo” biopsies collected by diode and KTP lasers. Material and Methods. 17 oral benign lesions biopsies were made by diode 808 nm (SOL, DenMatItalia, Italy) and KTP 532 nm (SmartLite, DEKA, Italy). Samples were observed at OM LEICA DM 2000; margin alterations were evaluated through Leica Application Suite 3.4. Results. Epithelial and connective damages were assessed for each pathology with an average of 0.245 mm and a standard deviation of ±0.162 mm in mucoceles, 0.382 mm ± 0.149 mm in fibromas, 0.336 mm ± 0.106 mm in hyperkeratosis, 0.473 mm ± 0.105 mm in squamous hyperplasia, 0.182 mm in giant cell granuloma, and 0.149 mm in melanotic macula. Discussion. The histologic aspect of lesions influenced the response to laser, whereas the greater inflammation and cellularity were linked with the higher thermal signs. Many artifacts were also associated to histologic procedures. Conclusion. Both tested lasers permitted sure histologic diagnosis. However, it is suggested to enlarge biopsies of about 0.5 mm, to avoid thermal alterations, especially in inflammatory lesions like oral lichen planus.

Histological ex vivo evaluation of peri-incisional thermal effect created by a new-generation CO2 superpulsed laser

The purpose of this study is the evaluation of the histological effects of a new-generation superpulsed CO₂ laser through an “ex vivo” study. A CO₂ (λ = 10,600 nm) ultra-speed laser (SmartUS20D, DEKA, Florence, Italy) has been used at different parameters from 2 to 4 watt in Continuous Wave (CW) and Pulsed Wave (PW, 50 Hz) to obtain 30 samples from pig cadaver tongues. All the specimens have been subdivided into 6 groups (from A to F) and each group consisted of 5 samples. A final specimen has been taken by scalpel and used as control group. Histological analysis has been performed using an optical microscope (Leica DM 2000) at a magnification of ×40. Results showed that histological readability was optimal in all the samples. The thermal damage has been negligible in all the groups. Furthermore, the average of thermal damage was 0,095 mm in the epithelial, while it was 0.245 mm in the connective tissue. Statistical analysis using Graphpad Prism 5 software showed no significant differences among the groups. CO₂ laser demonstrated a good surgical effectiveness provoking little peripheral damage onto the cut edges and allowing a safe histological diagnosis.

Esthetic treatment of gingival hyperpigmentation with Nd:YAG laser or scalpel technique: a 6-month RCT of patient and professional assessment

This double-masked, randomized controlled trial with a split-mouth design aimed to compare patient- and professional-centered outcomes using different therapeutic approaches-neodymium-yttrium aluminum garnet (Nd:YAG) laser or scalpel technique-for gingival depigmentation. Patients presenting bilateral melanin gingival hyperpigmentation and who requested cosmetic therapy were recruited. Contralateral quadrants were randomly assigned to receive Nd:YAG laser (settings: 6 W, 60 mJ/pulse, and 100 Hz) or scalpel technique. Patient morbidity experienced at intratherapy and during the first postoperative week was evaluated. In addition, after 6 months, the cosmetic results achieved for the different therapeutic approaches were evaluated by patients and professionals. The chair time of each technique was also calculated. Patient-oriented outcomes concerning intratherapy morbidity did not demonstrate any differences between groups (p > 0.05), although a higher extent of discomfort/pain was experienced in the side treated by the scalpel technique compared to the Nd:YAG laser procedure during the first posttherapy week (p < 0.05). Regarding to cosmetic outcomes, no differences between techniques were observed for patient and professionals (p > 0.05). Significantly higher chair time was required for the scalpel technique than for the Nd:YAG laser therapy (p < 0.05). The Nd:YAG laser or the scalpel technique may be successfully used for the treatment of melanin gingival hyperpigmentation. However, the use of the Nd:YAG laser has presented advantages in terms of less discomfort/pain during the posttherapy period and a reduction of treatment chair time.

Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study

Objective: Literature reports bactericidal and biostimulant effects for Nd:YAG laser procedures on bone and oral mucosa but the possible overheating can cause damage to anatomical structures. The aim of the study is the evaluation of thermal increase in different levels of oral tissues: mucosa, periosteum and bone during defocused application of Nd:YAG laser at different parameters. Study Design: Superficial thermal evaluation was performed in pig jaws with a thermal camera device; deep thermal evaluation was realized by 4 thermocouples placed at a subperiosteal level and at 1,2 and 4 mm depth in the jaw bone. Laser applications of 1 minute were performed 5 times (with a pause of 1 minute) on a surface of 4 cm2 with a Nd:YAG laser (VSP mode, 320 micrometer fiber, defocused mode) with different parameters. Temperatures were recorded before and after laser applications and after each pause in order to evaluate also the thermal relaxation of tissues. Results: At submucosal level, mean thermal increase was between 1.1°C and 13.2°C, at 1 mm depth between 1.1°C and 8.5°C, at 2 mm depth between 1.1°C and 6.8°C, at 4 mm depth between 1.0°C and 5.3°C. Temperature decrease during the rest time period was variable between 0°C and 2.5°C. Conclusions: Temperatures reached during clinical procedures with parameters reported in the literature in biostimulation protocols (1.25-2 Watts) for the five minutes of application are not dangerous for biological structures. The decrease in temperature during the rest time period is less considerable in the bone in comparison to oral mucosa.

Key words:Nd:YAG laser, thermal increase, thermocouple, thermal camera, low level laser therapy.

Laser-assisted surgery with different wavelengths: a preliminary ex vivo study on thermal increase and histological evaluation

Since the introduction of laser in clinical practice, different wavelengths have been used for oral surgery on the basis of the different characteristics and affinities of each one. The aim of this study was a comparison of different laser wavelengths in relation to both thermal increase and "histological quality" in a model of soft tissue surgery procedures. Thermal evaluation was realized, during laser-assisted surgery excision performed on a bovine tongue, by a thermal camera device to evaluate thermal increase on the surface of the sample and with four thermocouples to evaluate thermal increase on the depth of the specimen; temperature was recorded before starting surgical procedure and at the peak of every excision. The quality of excision, in terms of tissue damage and regularity, was realized by two blind examiners on the basis of established criteria. The highest superficial thermal increase was recorded for Superpulse 5-W CO2 laser, the lowest one for Er:YAG laser. The highest in depth thermal increase was recorded for 5 W Diode laser, the lowest one for Er:YAG laser. The best quality of incision was obtained with a 3-W CO2 laser and 3-W diode laser; epithelial, stromal, and vascular damages were evaluated with different degrees for all the used wavelengths with the best result, in terms of "tissue respect," for Er:YAG laser. In all the surgical procedures performed, thermal increase was evaluated until the end of the procedure; at remaining tissue level, thermal decrease was evaluable in the few seconds after surgery. The Er:YAG laser was the device with a lower influence on thermal increase; CO2 and diode lasers revealed a good histological quality. Further studies may be necessary to test the reliability of laser devices for the excision of all the types of specimens needing histological evaluation and diagnosis.

Diode laser (808 nm) applied to oral soft tissue lesions: a retrospective study to assess histopathological diagnosis and evaluate physical damage

The diode laser is today widely used in oral pathology to excise lesions; however, some controversy surrounds laser surgery, specifically the accuracy of pathological diagnosis and the control over thermal tissue damage. This study aimed to establish if physical damage induced by the diode laser could affect the histopathological diagnosis and to evaluate the damage caused to the resection margins. Between 2005 and 2010, at S. Gerardo Hospital, Milan, 608 cases of soft tissue lesions localized in the oral cavity (cheek, gingiva, buccal mucosa, tongue, and lips) were examined. Specimens were excised with an 808-nm diode laser, output 1.6-2.7 W, in continuous-wave mode with fibers of 320 μm. Specimens were fixed in 10% buffered formalin solution and examined separately under an optical microscope by two pathologists. In all of the specimens, changes to the epithelium, connective tissue and blood vessels, shape of incision damage, and overall width of modified tissues were evaluated. The data for specimens larger than 3 mm excised with the diode laser were not significant in terms of stromal changes or vascular stasis, while epithelial and stromal changes were significantly more frequent in specimens with a mean size below 3 mm; the diagnosis was not achievable in 46.15%. Our data show that the diode laser is a valid therapeutic instrument for excising oral lesions larger than 3 mm in diameter, but induces serious thermal effects in small lesions (mean size below 3 mm). However, from a clinical standpoint, it is suggested necessary that the specimens taken have in vivo a diameter of at least 5 mm in order to have a reliable reading of the histological sample.

Heat generation caused by ablation of restorative materials with an ultrashort pulse laser (USPL) system

Heat generation during the removal of dental restorative materials may lead to a temperature increase and cause painful sensations or damage dental tissues. The aim of this study was to assess heat generation in dental restoration materials following laser ablation using an ultrashort pulse laser (USPL) system. A total of 225 specimens of phosphate cement (PC), ceramic (CE), and composite (C) were used, evaluating a thickness of 1 to 5 mm each. Ablation was performed with an Nd:YVO(4) laser at 1,064 nm, a pulse length of 8 ps, and a repetition rate of 500 kHz with a power of 6 W. Employing a scanner system, rectangular cavities of 1.5-mm edge length were generated. A temperature sensor was placed at the back of the specimens to record the temperature during the ablation process. All measurements were made employing a heat-conductive paste without any additional cooling or spray. Heat generation during laser ablation depended on the thickness of the restoration material (p < 0.05) with the highest values in the composite group (p < 0.05), showing an increase of up to 17 K. A time delay for temperature increase during the ablation process depending on the material thickness was observed in the PC and C group (p < 0.05) with highest values for cement (p < 0.05). Employing the USPL system for removal of restorative materials, heat generation has to be considered. Especially during laser ablation next to pulpal tissues, painful sensations might occur.