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.

Surgical Management of Bilateral Abductor Paralysis: Diode Laser Versus Coblation; A Prospective Study

OBJECTIVES

We aimed to compare the results of both diode laser and coblation in the treatment of bilateral vocal fold immobility (BVFI).

MATERIALS AND METHODS

This prospective clinical study was performed on 80 non-tracheostomised patients with bilateral vocal fold paralysis divided into two groups; Group A: diode laser, Group B: coblation. Medical Research Council "mMRC" Dyspnea scale, maximal phonatory time (MPT), Voice handicap index (VHI), and functional outcome swallowing scale (FOSS) were assessed preoperatively and postoperatively. Also, the VAS pain scale and operative time of both groups are recorded.

RESULTS

Within each group, there was a statistically significant decrease in the mMRC dyspnea scale and maximum phonation time and a significant increase in VHI (P < 0.001). There was a statistically significant difference between the studied groups postoperative and regarding the percent change of the MPT ( more decrease in the coblation group). Concerning the operative time and the VAS pain score, there was a statistically significant difference between the studied groups regarding operating time and the VAS pain scale (significantly lower in the coblation group) (P < 0.001).

CONCLUSION

Both Coblation and diode laser are effective tools in the treatment of BVFI with similar minimal voice quality affection. The maximum phonation time decreased more in the coblation group, while the voice handicap index did not significantly differ between both groups. However, Coblation may be superior to diode laser in terms of less operative pain and shorter intraoperative time. Coblation may be more favorable for patients at risk of prolonged general anesthesia duration.

Adjuvant therapy with a 980-nm diode laser in root canal retreatment: randomized clinical trial with 1-year follow-up

The purpose of this study is to assess the laser effect in root canal disinfection and periapical healing of endodontically treated teeth from patients with asymptomatic apical periodontitis. This study was performed as a randomized clinical trial. Thirty patients were selected according to the inclusion/exclusion criteria. Fifteen patients received the root canal retreatment (RCR) combined with 980-nm diode laser irradiation (LI). The canals were irrigated with saline solution and gently dried with paper points, keeping the dentin partially moist. The irradiation was performed using a 320-µm-diameter fiber in helicoidal movements (pulsed mode, power output of 1.5 W, 100 Hz for 20 s). The other 15 patients received the RCR with placebo irradiation (PI). Microbiological samples were taken in three periods: S1, after the filling material removal (baseline); S2, after laser or placebo irradiation (LI or PI); and S3, after the RCR followed by laser or placebo. The samples were submitted to the total microbial and E. faecalis counting. The periapical radiographic healing was analyzed after 3, 6, 9, and 12 months. Microbiological data (CFU/mg) were analyzed by ANOVA and Tukey's test (P < 0.05), and the repair by Mann-Whitney test (P < 0.05). In S2, the laser provided 42.44% microbial reduction and 53.14% of E. faecalis, different from the placebo that had no reduction, and 4.85% for Enterococcus (P < 0.05). In S3, the bacterial counts decreased without differences between groups. No differences in healing were found at 3 months. However, diode laser facilitated the repair from 3- to 12-month follow-up (P < 0.05) and had 45% more healed cases than placebo. Diode laser provided an antimicrobial effect before the biomechanical preparation but was not synergistic in RCR. It improved the periapical healing during follow-up.

Diode laser on excision of giant peripheral odontogenic myxoma: a rare case report and literature review

It was to report a rare case of peripheral odontogenic myxoma removed with high-power diode laser and to do an extensive review of studies of odontogenic cysts and tumors treated with high-power laser (HPL). This is a rare case of a 63-year-old male patient with a peripheral odontogenic myxoma measuring approximately 10 cm in the attached gingiva region of tooth 16 removed with a high-power diode laser (808 nm, 3 W, in continuous mode, under constant suction, with 400-µm optical fiber). A literature review was also carried out looking for articles that involved the use of HPL in the treatment of odontogenic cysts and tumors, without restriction of year or language. In the present case, there was no need for suturing, no postoperative discomfort, and minimal bleeding during the procedure. In a 12-month follow-up period, there were no signs of recurrence. Only two cases of intra-osseous odontogenic myxomas treated with HPL and 10 cases involving other odontogenic cysts and tumors were found. All studies showing HPL to be effective in treating these lesions. Despite the different types of lasers used and different parameters, it is observed that lasers are effective in the treatment of odontogenic lesions.

Comparison of clinical outcomes of non-surgical adjunctive use of the 980-nm diode laser to conventional periodontal flap procedure-a randomised controlled split-mouth clinical trial

Lasers have been found to be effective as an adjunctive in periodontal therapy. The objective of the study was to compare the outcomes of non-surgical adjunctive use of 980-nm diode laser to that of conventional flap surgery in terms of clinical outcome measures and radiographic osseous defect depths. This study was designed as a double-blinded split-mouth randomised controlled clinical trial. A total of fifteen patients (30 quadrants) with generalised periodontitis stage III grade B were randomly assigned test group (diode laser) and control group (conventional flap surgery). Both test and control groups had 15 quadrants each. At 3 months, the probing pocket depth (PPD) was 3.46 ± 0.19 mm (test) and 4.20 ± 0.20 mm (control), with a statistically significant difference between the groups (p = 0.01). Similarly, at 6 months re-evaluation, PPD was 1.46 ± 0.12 mm (test) and 2.33 ± 0.13 mm (control) with a highly significant statistical difference (p = 0.001). Plaque index showed a difference between both test and control groups at baseline, 3 months and 6 months (p = 0.001) while gingival index, modified sulcular bleeding index and radiographic osseous defect depth showed a difference at 3 months and 6 months (p = 0.001). Within the study's limitations, 980-nm diode laser can result in significant improvements in the clinical and radiographic parameters and is very well tolerated by the subjects.

Eruption Cyst Treated with Diode Laser: A Case Report

Eruption cyst or eruption hematoma is a soft tissue cyst of odontogenic origin that occurs in mucosa, which forms shortly before the eruption of the primary or permanent tooth. It is usually found in children. In some cases, it has been seen that it disappears on its own. If there are complications like pain, bleeding or infection, surgical exposure and drainage are necessary. This case is associated with erupting permanent tooth, and its surgical crown exposure has been done by using a diode laser. How to cite this article: Bansal MB, Kumari A, Asrani KH, et al. Eruption Cyst Treated with Diode Laser: A Case Report. Int J Clin Pediatr Dent 2022;15(2):215-217.

The effect of photodynamic therapy on head and neck squamous cell carcinoma cell lines using spirulina platensis with different laser energy densities

BACKGROUND

Considering the anti-cancer properties of spirulina platensis (S. platensis), we aimed to investigate the effectiveness of this algae as a novel natural photosensitizer for photodynamic therapy (PDT) against oral and hypopharyngeal cancer cells. The appropriate laser energy density to apply during PDT was also determined.

METHODS AND MATERIALS

CAL-27, FaDu and HGF cell lines were exposed to S. platensis with concentrations of 0.3 g/l and 0.6 g/l and were irradiated with 635 nm diode laser using 2, 4, 12, and 24 J/cm² energy densities with constant power. MTT assay was performed to investigate cell viability and cytotoxicity after 24 h. The results were analyzed using two-way ANOVA and post hoc Tukey tests (P-value<0.05).

RESULTS

survival rate in CAL-27 (P-Value<0.001) and FaDu (P-Value<0.001) cell lines were significantly different following irradiation with various laser energy densities. Different concentrations of S. platensis had no significant effect on the viability of CAL-27 cells (P-Value=0.158) and FaDu cells (P-Value=0.072) and showed no significant cytotoxicity against HGF cells, with or without laser.

CONCLUSION

S. platensis could be considered as a novel safe and effective natural photosensitizer for cancer PDT with no cytotoxic effect on normal cells. When combined with laser using appropriate energy densities, it has the ability to induce death in oral and hypopharyngeal cancer cell lines.

Evaluation of the effect of various endodontic irrigants and medicaments on dentine fluorescence

This study examined the effect of various root canal irrigants and medicaments on dentin fluorescence elicited by 655 nm visible red laser light. To replicate clinical use, irrigants were applied onto dentin samples for 2 min, while medicaments were applied for 2 weeks. Fluorescence values tracked from baseline across the following to 24 h, starting 5 min after exposure. Sodium hypochlorite, hydrogen peroxide, and articaine local anaesthetic (4% articaine with 1:1000,000 adrenaline) all significantly quenched fluorescence (p < 0.0001), which then returned to baseline levels after 20 min. Conversely, elevated fluorescence readings were recorded after 3% mepivacaine (p < 0.05), 0.2% chlorhexidine (p < 0.01) and chloroform (p <0.05). A 2 week application of Ledermix™ paste containing 3% demeclocycline caused an irreversible increase in fluorescence (p < 0.0001). Other tested endodontic materials (15% EDTA, eucalyptus oil, calcium hydroxide, Odontopaste™ clindamycin paste, and distilled water) had no impact on dentine fluorescence. The influences of endodontic materials on dentin fluorescence need to considered when using fluorescence endpoints to guide the progress of root canal treatment.

Defocused high-power diode laser accelerates skin repair in a murine model through REDOX state modulation and reepithelization and collagen deposition stimulation

Skin wounds represent a burden in healthcare. Our aim was to investigate for the first time the effects of defocused high-power diode laser (DHPL) on skin healing in an animal experimental model and compare it with gold standard low-level laser therapy. Male Wistar rats were divided into 5 groups: Negative control; Sham; 0.1 W laser (L0.1 W); DHPL Dual 1 W (DHPLD1 W); and DHPL Dual 2 W (DHPLD2 W). Rats were euthanized on days 3, 5, 10, 14 and 21. Clinical, morphological, PicroSirus, oxidative stress (MDA, SOD and GSH) and cytokines (IL-1β, IL-10 and TNF-α) analyses were performed. A faster clinical repair was observed in all laser groups at D10 and D14. DHPLD1 W exhibited lower inflammation and better reepithelization compared to other groups at D10. DHPL protocols modulated oxidative stress by decreasing MDA and increasing SOD and GSH. Collagen maturation was triggered by all protocols tested and L0.1 W modulated cytokines release (IL-1β and TNF-α) at D3. In conclusion, DHPL, especially DHPL1 W protocol, accelerated skin healing by triggering reepithelization and collagen maturation and modulating inflammation and oxidative stress.

A representative dataset of the self-reproducing light ray family between the multiple distributed Bragg reflectors of multiple VCSELs and the inner surface of plane-convex mirror

A system consisting of a plano-convex mirror and reflecting surfaces of Vertical Cavity Surface-Emitting Laser (VCSEL) Strip Array of Diode Lasers has been calculated and proved to have a self-reproducing ray sink in it. The initial positions and slopes of two representative groups of light rays are set, and the position and slope of each light ray at each Distributed Bragg Reflector (DBR) of Diode lasers are obtained by computation. The system is a folded resonator, every VCSEL is connected by the axis of the resonator, and this axis is formed by linking the correspondent reflective points on the inner spherical surface of the mirror and the reflective points on the Bragg mirrors. One approach could be to fabricate the array directly on a plane of a GaAs (or Si) plano-convex mirror. The resonator can contain many VCSELs, and therefore can afford a high quality laser beam and high-power output.

Comparison of clinical efficacy of diode laser and erbium, chromium: Yttrium, scandium, gallium, and garnet for implant stage 2 recovery procedure - A randomized control clinical study

Aim:

The aim is to compare the clinical efficacy of diode laser and erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er, Cr:YSGG) laser for implant stage 2 recovery procedure.

Materials and Methods:

A total of 30 patients who had undergone dental implant placement were included in this study. The subjects were randomly allocated into three groups. Group 1 patients (n = 10) had implant recovery using diode laser, Group 2 (n = 10) implant recovery with Er, Cr:YSGG and conventional scalpel method (n = 10) was the third group. The pain assessment was recorded using visual analog scale (VAS scale), time taken for the procedure, intra-operative bleeding, time taken for healing were recorded for the three groups.

Results:

Data were tabulated and the results were analyzed using SPSS software version 26. Mann–Whitney U-test was used to compare the postoperative analgesic used, postoperative VAS score, the time taken for recovery and time taken for healing between the three study groups. Results were considered to be statistically significant when P < 0.05. Operation duration under Er, Cr:YSGG were much faster than the diode laser, however the results were not statistically significant (P = 0.051). The operation time under Er, Ch: YSGG and laser were faster than the conventional scalpel group (P = 0.000). The time taken for healing was faster in the Er, Cr:YSGG laser group than the diode laser and the scalpel group (P = 0.000). VAS scale at day 0 was higher in the conventional group than the two laser groups (P = 0.000).

Conclusion:

Considering the advantages of both these laser systems such as less anesthesia, less surgical trauma and faster healing, and post-operative comfort, lasers are an effective tool for implant stage two recovery techniques. However, since diode lasers are more cost effective when compared to Er, Cr:YSGG, diode lasers may meet the clinical needs when compared to hard-tissue lasers.

Comparative Evaluation of Mineral Trioxide Aggregate Pulpotomy and Laser-Assisted Mineral Trioxide Aggregate Pulpotomy: An Original Research Article

Context and Aim:

Formocresol has been used as the material of choice (gold standard) for pulpotomy procedures because of the ease of use but was discouraged due to its potential immune sensitization and mutagenic effects. Laser irradiation was first applied for pulpotomy procedure in the year 1985. Recently, diode lasers have been used for pulpotomy in primary teeth and have shown clinical success rates comparable to formocresol. The present in vivo study was carried out to compare the clinical and radiographic success rates of mineral trioxide aggregate (MTA) pulpotomy and diode laser-assisted pulpotomy in human primary molars.

Materials and Methods:

The present study was a randomized clinical trial in design wherein 40 primary teeth requiring pulpotomy treatment which met the selection criteria (clinical and radiographic) were divided into two groups, Group 1 (n = 20) wherein the pulpotomy was performed with MTA alone and Group 2 (n = 20) wherein laser-assisted pulpotomy was performed with MTA (L-MTA). The patients were recalled after 3, 6, and 9 months, respectively and evaluated clinically and radiographically.

Statistical Analysis Used:

The data were analyzed using the Statistical Package for the Social Sciences (SPSS) Version 22 (IBM corporation, Washington DC, United States). Descriptive statistics were used to analyze the data while the Pearson's correlation coefficient test was used to analyze the statistical correlation between the overall success rates observed in the clinical and radiographic findings of both the groups. P < 0.05 was considered statistically significant.

Results:

The clinical success rate in the MTA group was 90%, 84.21%, and 88.23% at 3, 6, and 9 months, respectively, with no clinical signs or, symptoms reported at the said follow-up visits while the radiographic success rate was found to be 85%, 84.21%, and 82.3%, respectively. On the contrary, the clinical success rate in the L-MTA group was found to be 95%, 94.74%, and 94.44% at 3, 6, and 9, months, respectively with the radiographic success rate reported being 90%, 89.47%, and 88.89%, respectively.

Conclusion:

The combination of diode laser and MTA yielded better clinical and radiographic success rates over the pulpotomy procedures done with the help of MTA alone, thereby, concluding that lasers may be considered as adjuvant alternatives for vital pulp therapy on human primary teeth.

Cavity Disinfection With a 445 nm Diode Laser Within the Scope of Restorative Therapy - A Pilot Study

Introduction: Cavity disinfection is necessary to prevent a progressive infection of the crown dentin and pulp. Increasing intolerance and resistance to antiseptics and antibiotics as well as the controversy over the effects of those on the dental hard tissue and composite have prompted the investigation of alternative treatment options. The objective of this pilot study is to evaluate the antibacterial potential of a diode laser with a wavelength of 445 nm in the cavity preparation using the bacterium Streptococcus salivarius associated with caries in conjunction with the characteristics and influences of dentin on light transmission. Methods: The bactericidal effect of the laser irradiation was determined in culture experiments by using caries-free human dentin samples on bacteria-inoculated agar. For this, dentin discs (horizontally cut coronal dentin) of 500 µm and 1000 µm thicknesses were produced and irradiated with the laser with irradiation parameters of 0.7-1 W in a cw-mode and exposure times of between 5-30 s. Based on the different sample thicknesses, the penetration depth effect of the irradiation was ascertained after the subsequent incubation of the bacteria-inoculated agar. Additional influential parameters on the irradiation transmission were investigated, including surface moisture, tooth color as well as the presence of a smear layer on the dentin surface. Results: The optical transmission values of the laser radiation for dentin were significantly dependent on the sample thickness (P = 0.006) as well as its moisture content (P = 0.013) and were independent of the presence of a smear layer. There was a 40% reduction in bacteria after the radiography of the 500-µm-thick dentin samples, which was shown as the lowest laser dose (443 J/cm²). Conclusion: These findings indicate that the diode laser with light emission at a wavelength of 445 nm is interesting for the supportive cavity disinfection within the scope of caries therapy and show potential for clinical applications.

Outcome of a 980-nm diode laser coagulation in women with radiation-induced hemorrhagic cystitis: a single-center retrospective study

The purpose of this study was to evaluate the efficacy of a 980-nm diode laser coagulation in women with radiation-induced hemorrhagic cystitis (RHC). We conducted a retrospective study of 21 RHC patients treated with a 980-nm diode laser between July 2014 and December 2017 at our institution. Data was collected with regard to age, sex, lower urinary tract symptoms, use of transfusions, a drop in hemoglobin levels, indication of radiotherapy, median time between radiation therapy and presentation, previous treatments, operative time, mean energy used, number of coagulated areas, catheterization time, discharge time after treatment, hospital stay, and surgical outcome. All 21 patients were women with a median age of 52 years (range 36-68 years). Eighteen patients complained of frequency and urgency, four patients had dysuria, and one patient developed urinary retention. Radiation therapy was primarily indicated in the treatment of cervical cancer in 18 patients (85.7%) and endometrial cancer in three patients (14.3%). Nine patients (42.8%) received blood transfusion before surgery and three patients (14.3%) needed blood transfusion after the procedure. The mean decrease in hemoglobin prior to the procedure was 4.08 ± 2.04 g/dL. The median length of time from completion of radiotherapy to the presentation of hematuria was 38 months (range 8-65 months). All patients had failed an adequate trial of conservative treatment which included adequate hydration, hemostatics, continuous bladder irrigation (CBI), and clot evacuation at the bedside. Eleven patients (52.4%) had previously been treated with endoscopic electrocoagulation; the mean number of procedures was 1.73 ± 0.78 (range 1-3 sessions). Six patients (28.6%) underwent HBO, and sodium hyaluronate solution irrigation was administered to 3 patients (14.3%). The mean number of HBO sessions was 26.3 ± 16.8 (range 8-50), and the mean number of sodium hyaluronate solution irrigation procedures was 4.33 ± 1.53 (range 3-6). All operations were successful. The mean operative time was 45.6 ± 12.3 min, the mean number of coagulated areas was 11.7 ± 4.4, the mean energy used was 2.74 ± 1.14 kJ, the mean catheterization time was 6.2 ± 0.9 days, the mean discharge time after treatment was 6.8 ± 1.2 days, and the average length of a hospital stay was 7.4 ± 1.3 days. In 16 patients (76.2%), hematuria was completely resolved after one session of diode laser coagulation. Four patients (19.0%) underwent multiple sessions of laser treatment due to recurrent gross hematuria (three patients required two sessions and one patient required three sessions). Only one patient (4.8%) who had persistent gross hematuria after diode laser treatment (two sessions) underwent a radical cystectomy, which resolved the hematuria. The median hematuria-free interval of patients who had multiple procedures was 9 months (range 1-13 months). In total, 21 patients underwent 27 sessions of diode laser coagulation, and the median hematuria-free interval was 16 months (range 1-45 months) with a median follow-up of 25 months (range 7-48 months). Our study shows promising results for the management of patients with RHC; however, further evaluation with a larger cohort is required to confirm the efficacy of this treatment.

Effect of diode laser application as an adjunct to nonsurgical periodontal therapy on the reduction of red complex microorganisms in type 2 diabetics with chronic periodontitis

Bactericidal and detoxification effects of diode laser (DL) have been reported in periodontal treatment. The objective of this study was investigating the additional effect of DL with nonsurgical periodontal treatment on the red complex bacteria in type 2 diabetes mellitus (DM) patients with chronic periodontitis (CP). Sixty type 2 DM patients with chronic periodontitis (CP) were randomly assigned in two parallel groups to receive scaling root planning (SRP, n = 30) or SRP followed by DL periodontal pocket irradiation (SRP + DL, n = 30). Recording of clinical parameters and subgingival plaque sampling were performed at baseline, and post therapy (1 and 3 months after treatment). Amounts of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia were evaluated with quantitative RT-PCR. Significant reductions for numbers of all three bacterial species were observed at 1 and 3 months compared with baseline for both treatments (p < 0.001), but no significant differences were found between two groups regarding bacterial reductions at these follow-up time points. No additional benefit of DL as an adjunct to nonsurgical periodontal therapy was recognized in the reduction of P. gingivalis, T. denticola, and T. forsythia for type 2 DM patients with CP. Further studies are required to clarify the effects of diode laser on the other periodontopathogens.

High Power Laser and Photobiomodulation in Oral Surgery: Case Report

Introduction: The labial frenum is a fold of mucous membrane that attaches the lip and the cheek to the alveolar mucosa, the gingiva, and the underlying periosteum. In some cases, its presence can cause a midline diastema, periodontal diseases related to food impaction, or retention of biofilm, among others. In such cases, lip frenectomy is indicated as treatment, which can be performed with a scalpel (conventional method), an electric scalpel, or a surgical laser. Objective: To show a clinical case performed at Laser Extension Project in Dentistry, Federal University of Maranhão grounded in a literature review. Case Presentation: A laser frenectomy was performed on a female patient, aged 20, who had a diastema between the upper central incisors and an indication for frenum removal. The high-power diode laser is excellent for procedures in soft tissue because its wavelength is well absorbed by hemoglobin and other pigments; its use also allows a reduction in the amount of anesthetic and medicines used. The parameters used were 2 W, in a continuous mode, 808 nm infrared emission; with delivery of the beam through optical fiber 300 μM; energy of 120 J; 20 pps. Conclusion: the high power diode laser allowed a satisfactory result, the procedure was safe, the technique was a simple one and of reduced clinical time, as mentioned in the literature. It is worth noting that the technique is dependent on the skill of the professional performing it.

Comparison of photobiomodulation using either an intraoral or an extraoral laser on oral mucositis induced by chemotherapy in rats

PURPOSE

The aim of the present study was to compare the effect of intraoral (IO) and extraoral (EO) diode laser irradiation on oral mucositis (OM) induced by 5-fluorouracil (5-FU) in rats.

METHODS

Animals (n = 78) were divided into the following groups: negative control (NC), positive control (PC), IO 6 J/cm², EO with 6 J/cm² (EO 6 J/cm²), and 12 J/cm² (EO 12 J/cm²). OM was induced with an intraperitoneal injection of 5-FU and scarification of the buccal mucosa. Over the following 14 days, animals received photobiomodulation (PBM) daily. Clinical and histological evaluation was done by scores at days 8, 10, and 14. The redox state was evaluated by reactive species levels, antioxidant network, and immunohistochemistry analysis.

RESULTS

Clinically, on day 8, PBM groups showed lower scores of OM with EO 6 J/cm² presenting a significantly lower degree compared to PC (p < 0.05). On days 10 and 14, all PBM groups exhibited improvement of OM compared to PC (p < 0.01). On day 8, all PBM groups exhibited an accelerated healing process compared to PC (p < 0.01) and reduction of reactive species (p < 0.001). Also, all PBM groups demonstrated higher levels of antioxidant GPx compared to PC (p < 0.001). Analysis of nitrotyrosine revealed that on day 14, this protein damage marker was significantly reduced in the EO 6 J/cm² group (p > 0.05).

CONCLUSIONS

An EO diode laser protocol promoted positive effects in the clinical, histopathological, and redox state in OM induced by 5-FU in rats. Among the EO protocols, EO 6 J/cm² showed the most encouraging results.

III/V-on-Si MQW lasers by using a novel photonic integration method of regrowth on a bonding template

Silicon photonics is becoming a mainstream data-transmission solution for next-generation data centers, high-performance computers, and many emerging applications. The inefficiency of light emission in silicon still requires the integration of a III/V laser chip or optical gain materials onto a silicon substrate. A number of integration approaches, including flip-chip bonding, molecule or polymer wafer bonding, and monolithic III/V epitaxy, have been extensively explored in the past decade. Here, we demonstrate a novel photonic integration method of epitaxial regrowth of III/V on a III/V-on-SOI bonding template to realize heterogeneous lasers on silicon. This method decouples the correlated root causes, i.e., lattice, thermal, and domain mismatches, which are all responsible for a large number of detrimental dislocations in the heteroepitaxy process. The grown multi-quantum well vertical p-i-n diode laser structure shows a significantly low dislocation density of 9.5 × 10⁴ cm^-2, two orders of magnitude lower than the state-of-the-art conventional monolithic growth on Si. This low dislocation density would eliminate defect-induced laser lifetime concerns for practical applications. The fabricated lasers show room-temperature pulsed and continuous-wave lasing at 1.31 μm, with a minimal threshold current density of 813 A/cm². This generic concept can be applied to other material systems to provide higher integration density, more functionalities and lower total cost for photonics as well as microelectronics, MEMS, and many other applications.

Laser scanning laser diode photoacoustic microscopy system

The development of low-cost and fast photoacoustic microscopy systems enhances the clinical applicability of photoacoustic imaging systems. To this end, we present a laser scanning laser diode-based photoacoustic microscopy system. In this system, a 905 nm, 325 W maximum output peak power pulsed laser diode with 50 ns pulsewidth is utilized as the light source. A combination of aspheric and cylindrical lenses is used for collimation of the laser diode beam. Two galvanometer scanning mirrors steer the beam across a focusing aspheric lens. The lateral resolution of the system was measured to be ∼21 μm using edge spread function estimation. No averaging was performed during data acquisition. The imaging speed is ∼370 A-lines per second. Photoacoustic microscopy images of human hairs, ex vivo mouse ear, and ex vivo porcine ovary are presented to demonstrate the feasibility and potentials of the proposed system.

Sialolith removal in the submandibular region using surgical diode laser: report of two cases and literature review

PURPOSE

Sialolithiasis is defined as the presence of one or more calcified structures within the duct of a major or minor salivary gland. It occurs as a result of deposition of calcium salts around an accumulation of organic debris in the duct lumen. The main signs and symptoms are edema and bacterial infection with abscess formation.

METHODS

This study aimed to report two cases of submandibular sialolithiasis treated surgically with diode laser and conduct a review of the literature by means of a systematic search. In the two cases, the calculi were located in the distal part of the submandibular duct and could be palpated intraorally. Surgery was performed in an outpatient setting under local anesthesia. A linear incision was made in the floor of the mouth, in the region of the opening of Wharton's duct, to expose and remove the calculi. Laser cutting was performed using a diode laser module coupled to a 400-μm optical fiber emitting at a wavelength of 980 nm (infrared), 2.5 W output power, and in continuous pulse mode.

RESULTS

The use of diode laser is a safe and minimally invasive option for this type of procedure.

CONCLUSION

Offering advantages such as enhanced coagulation properties and high-quality incision, absence of bleeding, low risk of nerve damage, and few comorbidities.

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.

The Effect of Combination of Red, Infrared and Blue Wavelengths of Low-Level Laser on Reduction of Abdominal Girth: A Before-After Case Series

Introduction: The objective of this study was to assess the efficacy of a combination of 3 wavelengths (including red, infra-red, and blue) of low-level laser (LLL) as a non-invasive therapeutic method to reduce abdominal girth. To achieve biochemical activity on adipocytes, a red laser was used in our selective laser combination. Near-infrared laser was used to increase depth of penetration. Nitrosyl complexes of hemoglobin (NO-Hb) are sensitive to blue light, thereby leading to increase in release of biologically active nitric oxide (NO), which can affect tissue perfusion. Thus, a blue LED was added to the laser combination. Methods: Eighteen females participated in the study. Twelve sessions of laser therapy were performed, 2 sessions per week for each subject. Continuous wave diode lasers, including red (630 nm), infra-red (808 nm), and a blue LED (450 nm) were applied and were all designed by the Canadian Optic and Laser Center. Results: Statistical analyses revealed that upper abdomen size significantly decreased from pre- (91.86 ± 11.16) to post- (87.41 ± 10.52) low-level laser therapy (LLLT) (P<0.001). Middle abdomen size showed significant reduction from pre- (97.02 ± 8.82) to post- (91.97 ± 8.49) LLLT (P<0.001). Lower abdomen size significantly decreased from pre- (100.36 ± 9.45) to post- (95.80 ± 8.52) LLLT (P<0.001). Conclusion: Based on this case series pilot investigation, the combination of 3 different wavelengths of LLL was effective for abdominal girth reduction in 100% of our subjects (P<0.001), without any side effects. Future studies will assess the long-term benefits of this laser combination for reduction of subcutaneous fat deposits.

Nonsurgical periodontal therapy with/without diode laser modulates metabolic control of type 2 diabetics with periodontitis: a randomized clinical trial

In order to evaluate whether nonsurgical periodontal treatment with/without diode laser (DL) decontamination improves clinical parameters, the levels of IL-1β, IL-6, IL-8, intercellular adhesion molecule (ICAM), and vascular cell adhesion molecule (VCAM) in gingival crevicular fluid and metabolic control (HbA1c) in chronic periodontitis (CP) patients with diabetes mellitus type 2 (DM2). Sixty patients with DM2 and CP were randomly assigned into two groups to receive scaling and root planing (SRP, n = 30) or SRP followed by diode laser application (SRP + DL, n = 30). Clinical periodontal and gingival crevicular fluid (GCF) parameters were assessed at baseline, 1, and 3 months after periodontal treatment. HbA1c levels were evaluated at baseline and 3 months post-therapy. Total amounts of cytokines and molecules were analyzed by ELISA. Nonsurgical periodontal treatment with/without DL appeared to improve clinical, biochemical parameters, and glycemic control in DM2 patients (BMI < 25 kg/m(2)) with CP. The SRP + DL group provided better reductions in probing depth (PD) and clinical attachment level (CAL) parameters compared to the SRP group (P < 0.05). Significant reductions were found in the total amounts of GCF levels of IL-1, IL-6, IL-8, ICAM, and VCAM after treatment (P < 0.05). HbA1c levels decreased significantly at 3 months after treatment (P < 0.05). SRP + DL reduced HbA1c levels more significantly compared to SRP alone (0.41 vs. 0.22 %, P < 0.05). SRP, especially in combination with DL, shows improvement of glycemic control for DM2 patients with CP.

Evaluation of patient response and recurrence of pigmentation following gingival depigmentation using laser and scalpel technique: A clinical study

Aim:

The present study was undertaken to evaluate patient response and recurrence of pigmentation following gingival depigmentation carried out with a surgical blade and diode laser.

Materials and Methods:

Twenty patients who were esthetically conscious of their dark gums and requested treatment for the same were selected for this study. Complete phase I therapy was performed for all the patients before performing the gingival depigmentation procedures with laser and scalpel on a split-mouth basis. Patients were evaluated for pain (1 day, 1 week), wound healing and melanin repigmentation (Melanin Pigmentation Index) immediately and at 1 week, 1 month and 3 months, respectively.

Results:

The final results were statistically analyzed and significance was evaluated. The results of this study indicated that both scalpel and laser were efficient for gingival depigmentation. Comparative pain assessment (P = 0.148) and repigmentation scores (P = 0.288) at various time intervals between the two groups did not show any statistical significance.

Conclusion:

Both the procedures did not result in any post-operative complications and the gingiva healed uneventfully. When compared, both the techniques were found to be equally efficacious. Care must be taken to assess the gingival biotype and the degree of pigmentation in deciding which technique is to be used.

Clinical Significance:

Various methods of depigmentation are available with comparable efficacies. Depigmentation is not a clinical indication but a treatment of choice where esthetics is a concern and is desired by the patient.

Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial

BACKGROUND

Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation.

OBJECTIVE

Was to find out the effect of irradiation with energy densities of 3.38 J/cm(2), 8 J/cm(2), and 18 J/cm(2) on animal tissue (albino wistar rats) in an excisional wound model and to assess changes in biochemical (hydroxyproline) and histopathological levels in excisional wound model.

MATERIALS AND METHODS

The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm(2)), L2 Helium-neon (He-Ne, 8 J/cm(2)), L3 diode laser (3.38 J/cm(2)), and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni's multiple comparison tests were done for tissue hydroxyproline levels.

RESULTS

There was no significant increase in the hydroxyproline content (P < 0.005) when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm(2).

CONCLUSION

The experimental observations suggest that low intensity helium-neon laser of 8 J/cm(2) intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.