Diode Laser Wavelength Research Articles

Efficacy and Safety of Non-Ablative Dual Wavelength Diode Laser Therapy for Genitourinary Syndrome of Menopause: A Single-Center Prospective Study.

This study evaluates the efficacy and safety of non-ablative diode laser therapy for genitourinary syndrome of menopause (GSM) in post-menopausal women unable to use hormonal therapies. A pilot prospective study was conducted from September 2023 to April 2024, involving 22 post-menopausal women aged 45-73years. Participants underwent three sessions of diode laser treatment with the Leonardo® dual-wavelength Diode laser. Assessments were made at baseline, 3months, and 6months post-treatment. Main outcome measures included Visual Analog Scale (VAS) scores for GSM symptoms, Vaginal Health Index Score (VHIS), and sexual function evaluated using the Female Sexual Function Index (FSFI-6), Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12), and Sexual Quality of Life-Female (SQOL-F) questionnaire. Significant improvements were observed in VHIS, increasing from 12 to 19.27 at 6months (p<0.001). GSM symptoms improved significantly: vaginal dryness scores decreased from 7.72±2.37 to 3.72±2.53, burning sensation scores dropped from 6.00±3.22 to 1.90±1.81, and dyspareunia scores reduced from 8.09±2.11 to 3.90±2.58 (all p<0.016). Sexual function improved, indicated by FSFI-6 scores increasing from 12.27±7.29 to 19.30±6.24 (p<0.016) and SQOL-F scores rising from 63.18±22.93 to 71.45±23.31. No adverse events were reported. Non-ablative diode laser therapy is effective and safe for managing GSM symptoms in post-menopausal women, offering significant symptom relief and enhancing sexual health without serious side effects. Further research with a larger cohort and extended follow-up is needed to confirm these findings. Clinical Trials ID NCT06503003.

Initial experience of 980‐nm diode laser treatment for recurrent non‐muscle‐invasive bladder cancer

IntroductionLaser ablation using a 980‐nm wavelength diode laser, which is a new‐generation laser, for recurrent bladder cancer is known to have a lower incidence of complications and recurrence than conventional transurethral resection of bladder tumor surgery. This is the first study to report the use of 980‐nm diode laser ablation for recurrent non‐muscle‐invasive bladder cancer in Japan.Case presentationA 73‐year‐old man underwent transurethral laser ablation for the treatment of recurrent non‐muscle‐invasive bladder cancer. Laser irradiation was performed using LEONARDO DUAL (diode laser/980‐nm wavelength) and a 400‐μm BARE laser fiber. Pathological evaluation indicated low‐grade urothelial carcinoma, pTa. The patient was discharged on the second postoperative day with no perioperative or postoperative complications.ConclusionThis case suggests the potential of transurethral laser ablation for treating recurrent non‐muscle‐invasive bladder cancer.

Diode Laser Irradiation Effects on Physical Properties of Titanium Dioxide Nano Fillers Doped Polyvinyl Alcohol Films

Study effect of diode laser (wavelength 650 nm) irradiation for different irradiant times (0.25, 0.5, 1.00, 3.00, and 4.00 hrs) on the physical properties of titanium dioxide (TiO2) possess particle size of 15.7 nm doped polyvinyl alcohol (PVA) films were experimentally investigated. The solution casting process has been utilized to create as-prepared TiO2/PVA nanocomposite films. Ultraviolet-Visible (UV-Vis) spectroscopy investigates the samples' optical characteristics by analyzing optical absorption spectra in a wavelength range of (200 - 900 nm) at room temperature (RT) of 300 K. The PVA matrix could be used to describe the influence. All optical constants produced artificially through laser radiation, like absorption, refraction index, extinction coefficient and complex dielectric constants, have decreased with increasing radiation times. On the contrary of optical energy gap they increased with increasing radiation times, according to the study's findings. TiO2 Nanoparticles (NPs) additions significantly impacted the PVA host's optical characteristics. When FTIR-spectrum regarding the TiO2/PVA nanocomposite films was examined in various ratios of irradiation times, the peak positions or bonds did not change; instead, they became smaller or larger as the irradiation time increased.

Wide-Spectrum Tuning and Narrowing of 780 nm Broad-Area Diode Laser with Littrow-Type Transmission Gratings

Spectrum-narrowed and -locked broad-area diode lasers operating at 780 nm are essential for rubidium laser development. With the help of Littrow-type transmission gratings, we demonstrated a simple scheme with a narrow linewidth and the diode laser’s center wavelength locked without thermal drift, in contrast to volume Bragg gratings. By carefully collimating the diode laser beam, we realized a linewidth narrower than 0.17 nm and a side-mode suppression ratio over 20 dB. Furthermore, broad-spectrum tuning at 9 nm was demonstrated by grating angle tuning. This method could easily be adapted to other wavelength diode lasers.

Efficacy of low-level laser therapy enhances the rate of canine retraction by increasing &amp;beta; glucoronidase and pentraxin – 3 in gingival crevicular fluid: A clinical study

The aim of the study was to evaluate the efficacy of low-level laser therapy in enhancing the rate of orthodontic tooth movement using β glucoronidase and pentraxin-3 (TNF) biomarkers in gingival crevicular fluid.A split-mouth design was used in 16 subjects (8 experimental and 8 controlled) aged 14 to 25 years, who’s maxillary first premolars were extracted. A gallium-aluminium-arsenide semiconductor diode laser (wavelength, 810 nm; energy density, 10 J/cm2; power output, 100 mW) delivered low-level laser therapy to the experimental canine undergoing distalization at 10 points. The control canine was distalized without low-level laser therapy. The experimental and control canines were distalized using a force of 150 g provided by nickel-titanium closed coil springs. Gingival crevicular fluid was collected at 5 time points from the control and experimental sides, and the levels of β glucoronidase and pentraxin-3 were analysed by enzyme-linked immuno-sorbent assay (ELISA). The rate of canine retraction was calculated by using ortho analyser software.Increased levels of β glucoronidase and pentraxin-3 were observed in the experimental canines compared with the control canines (P &amp;#60;0.001). Cumulative tooth movements over an 8-week experimental period were greater for the experimental canines compared with the control canines. A positive correlation existed between the β glucoronidase and pentraxin-3 levels and the amounts of tooth movement across all time intervals.Low level laser therapy in adjunct with continuous and light forces leads to increase in β glucoronidase and pentraxin-3 leading to accelerated orthodontic tooth movement.: Low-level laser therapy fastens the rate of canine retraction thus accelerating the orthodontic tooth movement. The levels of β glucoronidase and Pentraxin 5 are increased significantly after laser irradiation which aids in accelerating orthodontic tooth movement.

The Effect of Two Different Wavelengths of Diode Laser on the Shear Bond Strength of Composite to Dental Enamel after Bleaching Process: An In Vitro Study.

In recent years, tooth whitening has become one of the most popular ways of achieving the original tooth color. The effect of whitening gel can be improved through heat, light or laser. The bond strength between the enamel and the composite can be reduced through bleaching and laser radiation. The purpose of this study is to assess the shear bond strength of resin composite to enamel after a bleaching process using hydrogen peroxide, with and without a laser (970 nm and 445 nm lasers). This study used 51 extracted anterior teeth without caries that were divided into three groups. A 40% hydrogen peroxide gel was used on the enamel of all teeth. The control group received bleaching without a laser. Both the second and third treatment groups received bleaching with a laser, one with 970 nm and the other with 445 nm. After the bleaching process, all groups had etching, bonding and curing of the composite performed. Lastly, the shear bond strength between the enamel and the composite was measured and the failure modes were recorded. The data were compared using a one-way ANOVA test. The mean shear bond strength between the enamel and the composite in the 445 nm group three (445 nanometer) was significantly lower than the other groups (p < 0.05). There was no significant difference between the control and the 970 nm groups (p = 0.2). According to the laser wavelengths and parameters that were used in this study and the results of this study, office bleaching with a 445 nm laser weakened the shear bond strength between the enamel and the composite.

Comparison between contact diode laser with 980 nm and 1470 nm wavelengths for posterior laryngofissure in pigs

To compare two different wavelengths of the surgical contact diode laser (CDL) for producing a posterior laryngofissure in in-vivo pigs. Anesthetized pigs underwent a tracheostomy and an anterior laryngofissure through a cervicotomy. They were randomly selected for the CDL wavelength and Power, according to the peak of Power set at device (980nm wavelength: Ppeak power of 10 W, 15 W, and 20 W, or 1470 nm wavelength: Ppeak 3 W, 5 W, 7 W, 10 W). At the end of the experiment, the laryngotracheal specimen was extracted and sent for histology and morphometry measurements (incision size, depth, area, and lateral thermal damage). Hemodynamic data and arterial blood gases were recorded during the incisions. Statistical analysis of the comparisons between the parameters and groups had a level of significance of p < 0.05. Twenty-six pigs were divided into CDL 980 nm (n = 11) and 1470 nm (n = 15). There was a greater incision area at the thyroid level in the 980 nm CDL and a wider incision at the trachea level, with a larger distance between mucosa borders. There were no significant differences in the area of lateral thermal damage between the two groups and neither difference among the power levels tested. Both wavelengths tested showed similar results in the various combinations of power levels without significant differences in the lateral thermal damage. The posterior laryngofissure incision can be performed by either of the wavelengths at low and medium power levels without great difference on lateral thermal damage.

Evaluating the effectiveness of two wavelengths of 810 and 980 nm Diode laser with two different beam profiles on tooth discoloration in bleaching: an experimental study

Teeth color has a significant impact on facial aesthetics. Tooth bleaching is the safest way to lighten the color of your teeth. Today, hydrogen peroxide is the most commonly used bleaching agent. The diode laser is one of the light sources that speeds up the bleaching process. One of the laser beam features is the laser beam profile, which depicts the distribution of laser intensity across the beam section. The goal of this study is to look into the effectiveness of Gaussian and Flat top beam profiles on tooth shade using two diode laser wavelengths of 810 and 980 nm in the tooth bleaching process. Fifty human anterior and premolar teeth were extracted and placed in a tea and coffee solution for three weeks before being divided into five groups. The first group did not receive laser radiation because 40% hydrogen peroxide was used; in the second and third groups, the profile of the flat top beam and the wavelength were 810 and 980 nm, respectively; and in the fourth and fifth groups, the wavelength of the Gaussian beam profile was 810 and 980 nm. The shade of the samples before and after bleaching was measured with a CIELab-based spectrophotometer, and the results were analyzed using one-way ANOVA and Tukey’s multiple comparison test. All bleaching methods resulted in a significant change in tooth color (ΔE&gt;3.3). There was a significant difference in average shade changes across groups (P&lt;0.001). The highest degree of shade change was observed in two groups of lasers with a wavelength of 980 nm and profiles of Flat top beam (ΔE=5.35) and Gaussian (ΔE=5.02). There were no differences between the remaining groups. We conclude that the 980 nm wavelength produces a greater shade change than the 810 nm wavelength and chemical method. The diode laser’s 810 nm wavelength has no effect on the shade of teeth.

480 nm InGaN-based cyan laser diode grown on Si by interface engineering of active region

InGaN-based long wavelength laser diodes (LDs) grown on Si are highly desirable for expanding the applications in laser display and lighting. Proper interface engineering of high In-content InGaN multi-quantum wells (MQWs) is urgently required for the epitaxial growth of InGaN-based long wavelength LD on Si, because the deteriorated interfaces and crystalline quality of InGaN MQWs can severely increase the photon scattering and further exacerbate the internal absorption loss of LDs, which prevents the lasing wavelength of InGaN-based LDs from extending. In this work, a significantly improved morphology and sharp interface of the InGaN active region are obtained by using a graded-compositional InGaN lower waveguide (LWG) capped with a 10-nm-thick Al0.1Ga0.9N layer. The V-pits density of the InGaN LWG was one order of magnitude reduction from 4.8 × 108 to 3.6 × 107 cm-2 along with the root-mean-square surface roughness decreasing from 0.3 to 0.1 nm. Therefore, a room-temperature electrically injected 480 nm InGaN-based cyan LD grown on Si under pulsed current operation was successfully achieved with a threshold current density of 18.3 kA/cm2.

Efficacy of Low-Level Laser Versus Topical Erythromycin 2% in the Treatment of Inflammatory Acne Vulgaris.

Acne vulgaris is a skin problem affecting many people of different ages. Despite many options that are available for treatment of acne vulgaris, many patients still respond inadequately to treatment. Phototherapy is one of the best acne treatment options. It was to compare the efficacy of low-level laser therapy in treatment of inflammatory acne versus topical erythromycin 2% cream. This study included 40 patients (18 males, 22 females) with different clinical severities of acne vulgaris. All the participants underwent split-face treatment: one side with 8 treatments (twice per week) of a low-level continuous infrared diode laser (808 nm) wavelength and (500 Hz) frequency and the other side with topical erythromycin 2% twice daily (aknemycin cream 2%). Evaluation was done at start of sessions, 2 weeks after the end of sessions and 3 months after stoppage of treatment depending on: photographs, global evaluation of acne scale, and Indian acne association grading. There was improvement of acne lesions on laser side and antibiotic side (assessed as non-inflammatory and inflammatory lesion counts). Laser side showed better results than antibiotic side. Patients were more satisfied with laser treatment due to minimal side effects and less relapse. A series of 8 treatments using low level continuous infrared diode laser represents a cheap, safe and effective non-invasive therapeutic option for acne vulgaris.

Study on the efficacy and safety of a high-power triple wavelength diode laser (810, 940, 1060 nm) for removing fine and less pigmented facial hair on Asian skin.

Performing laser hair removal treatments on dark skin is limited by the quantity of melanin within the skin. To minimize side effects, lower values of fluence are selected when using standard 755 or 810 nm diode lasers. However, this approach may limit the effectiveness of the procedure, particularly when treating areas with thin and less pigmented hair, which is often the case in facial regions. To improve results, high-power triple wavelength diode lasers can be used. This study aims to assess the efficacy, safety, and comfort of treatments that remove facial hair with a high-power triple wavelength diode laser (810, 940, and 1060 nm) in static mode on Asian patients with thin and less pigmented hair. A single-center retrospective cohort study was carried out using a high-power triple wavelength diode laser (810, 940, and 1060 nm), with a 2.7 cm2 spot size, on faces with thin and less pigmented hair. The study comprised 23 subjects with Fitzpatrick skin types IV and V. Effectiveness was measured by counting the hairs that appeared in high-resolution photos taken prior to and following the procedure, in addition to the Global Aesthetic Improvement Scale (GAIS). Furthermore, mathematical 3D simulations were created on the COMSOL Multiphysics® software to allow for comparisons to be made with regard to thermal damage sustained by the hair follicles and epidermal heating. Assessments were also made in relation to side effects. An average of 66% hair reduction was observed. Patient satisfaction was between 4 and 5 points on the GAIS scale, indicating that the treatment was very well received and tolerated. Adverse side effects were not observed. It can be concluded that the use of a high-power triple wavelength diode laser (810, 940, and 1060 nm) is safe and effective for the treatment of very fine and less pigmented facial hair on Asian skin. Furthermore, a triple wavelength (810, 940, and 1060 nm) laser is absorbed less by the melanin in the skin, enabling the use of higher fluences in stamping mode, with greater efficacy and safety for darker skin.

Is multiple wavelength diode laser for facial contouring safe?

The multiple wavelength diode laser (MWDL) is a sophisticated device designed to target deeper skin layers by emitting various wavelengths. Its unique feature is the ability to deliver heat to specific depths within the tissue using different wavelengths while simultaneously cooling the skin surface. Recent research by Choi etal. suggests that wavelengths of 755 and 810 nm can induce carbonization in hair follicles, while the 1064 nm wavelength penetrates deeper into tissues. MWDL has been proposed for fat redistribution in aging, but concerns have been raised regarding ocular safety and potential tissue damage, particularly when used near the eyes. Studies have shown ocular injuries during cosmetic laser procedures, emphasizing the need for robust ocular protection and safety protocols. Additionally, there are reports of internal ischemic necrosis and burns, highlighting the importance of precise energy settings and parameter management. While MWDL shows promise, further research and comprehensive guidelines are needed to ensure safe and effective usage in clinical practice.

IL-37 evaluation in chronic periodontitis after periodontal treatment with and without low level laser therapy.

Periodontal disease poses a significant global health challenge. Traditional treatments focus on reducing inflammation and bacterial load, yet novel approaches are continually being investigated. Recent research suggests that IL-37, a potent anti-inflammatory cytokine, may play a crucial role in modulating the inflammatory processes associated with periodontal disease. In conjunction with IL-37, low-level laser therapy (LLLT) has gained attention for its potential in promoting tissue repair, reducing inflammation, and enhancing cellular processes. This study aims to investigate the effects of LLLT on IL-37 in periodontal disease management. Thirty patients were enrolled: the G1 group patients were treated with only scaling and root planning-SRP, the G2 group was treated with SRP and LLLT. Before treatment (T0) all periodontal probing pocket depth and bleeding on probing were obtained. Before (T0) and 10 (T1), 30 (T2) and 60 (T3) days after treatment, was achieved plaque sample and specimens of gingival crevicular fluid. Diode laser wavelength range was used between 600-1000 nm and 0.04-60 J/cm2 energy density for 3-s spotlights. In all patients PPD, BOP and IL-37 have shown healing improved parameters. Although LLLT is widely recommended for its biostimulatory and anti-inflammatory roles, it only showed additional short-term merits in reducing the pocket depth after conventional SRP. Its long-term adjunctive benefits remain unclear. Future RCTs with better study designs, adequate sample power and longer durations of follow-up are required to assess the effectiveness of LLLT as an adjunctive treatment strategy in patients with periodontal disease.

EFFECT OF LOW-LEVEL DIODE LASER ON DENTIN TOPOGRAPHY AND SYMPTOMATIC NONCARIOUS CERVICAL LESIONS PRIOR TO COMPOSITE RESTORATIONS: A SPLIT-MOUTH RANDOMIZED CONTROLLED TRIAL

ObjectivesThis study assessed alterations in sensitivity among symptomatic noncarious cervical lesions (NCCLs) following the application of 3 low-level diode laser wavelengths before composite restoration. It analyzed the changes in dentin topography using a scanning electron microscope (SEM). Materials and methodsNine patients with 36 NCCLs were randomly assigned intra-individually to 4 groups based on the laser wavelength: laser simulation, 445 nm, 660 nm, and 970 nm. Cavity preparation, irradiation, and composite restoration were performed for each lesion. Sensitivity to cold stimuli was recorded using a visual analog scale (VAS) before the intervention (baseline) and at 1 day, 14 days, 1-, 3-, and 6-month. Pulp sensibility was recorded using an electrical pulp tester (EPT) at baseline, before treatment, and at 3- and 6-month. Additionally, an in vitro examination was performed on 12 extracted human molars to yield 12 dentin discs. Each disc was randomly divided into 4 quadrants to receive the same laser wavelengths to determine the diameters of the tubules using SEM. Results were analyzed statistically for clinical studies by the Friedman test, while ANOVA (RM-ANOVA) was conducted in-vitro, followed by the Bonferroni test in the case of significance (P < .05). ResultsVAS readings decreased across all groups, with a significant decrease observed for 660 nm and 970 nm from 14 days to 6-month, while at 445 nm there was a significant decrease at 6-month compared to the control (P < .05). EPT showed a significant decrease in pain threshold levels at 660 nm and 970 nm at 3- and 6-month, while 445 nm showed a significant decrease at 6-month compared to the control (P < .05). The mean tubular diameter at 445 nm decreased, with no significant difference from the control, whereas a significant decrease was found at 660 nm and 970 nm compared to the control (P < .05). ConclusionsPrior to composite restoration in symptomatic NCCLs, diode lasers with a wavelength of 660 nm showed the highest reduction in sensitivity, followed by 970 nm, whereas 445 nm diode lasers showed the least reduction. Additionally, diode lasers with wavelengths of 660 and 970 nm reduced the width of the dentinal tubules (DT) without inducing melting, as viewed under SEM.

Comparison of the Effects of Gluma Gel, Sensodyne Repair and Protect Toothpaste, and an 810 nm Low Power Diode Laser on the Closure of Dentinal Tubules: An In Vitro Study.

Introduction: One of the common problems among dental patients is tooth hypersensitivity. There are various treatments for hypersensitivity, such as gels, solutions, toothpaste, and laser treatments. This report examined the effect of three treatments, namely 810 nm wavelength diode laser, Gluma gel, and Sensodyne Repair and Protect toothpaste, on tooth hypersensitivity. Methods: This experimental survey selected 40 premolars free of caries, fractures, restorations, root canal therapy, or wear. The enamel of the midline in the cervical part of the buccal surface was removed by a bur (the area was 2*2 mm and the depth was 2 mm), and the samples were then prepared and divided into four groups. Sensodyne Repair and Protect toothpaste, Gluma gel, and an 810 nm diode laser with 0.5 W power were applied to three groups of teeth. The samples were analyzed by using a field emission scanning electron microscope (FE-SEM). The data from the occluded dentinal tubules, partially occluded tubules, and open tubules were analyzed by using the Tamhane test. Results: The amount of occluded dentinal tubules was 83.2±9% in the laser group, 74.4±11.62% in the Gluma group, 67.1±18% in the Sensodyne group, and 15.03±3.39% in the control group. The difference between the treatment groups and the control group was meaningful (P<0.05). However, the difference between the Gluma group, the Sensodyne group, and the 810 nm laser group was not significant (P>0.05). Conclusion: The three treatments (810 nm diode laser, Gluma, and Sensodyne) were all effective in occluding dentinal tubules compared to the control group. However, there was no significant difference between these three treatment methods (P>0.05).

Photobiomodulation Effect of Diode Laser on Differentiation of Osteoprogenitor Cells in Rat Bone Marrow.

Bone marrow cells contain nonhematopoietic cells with the ability to differentiate into osteogenic, chondrogenic, and adipogenic lineages. Mechanical stress influences osteoblast differentiation of bone marrow cells into osteogenic, chondrogenic, and adipogenic lineages, measurable as the abundance of alkaline phosphatase-positive (ALP+) colony-forming unit-fibroblasts (CFU-F); however, the effect of diode laser irradiation on osteoblast differentiation is unknown. The aim of this study was to analyze the effects of photobiomodulation on the osteogenic differentiation of mesenchymal stem cells in the bone marrow, using the CFU-F assay. Bone marrow cells isolated from rat tibiae were cultured and irradiated with a diode laser (wavelength 808 nm) at a total energy of 0 J (control), 50 J, and 150 J. On day 7 after irradiation, ALP+ CFU-F were most abundant in the 50 J group and the least abundant in the 150 J group. Mineralized nodule formation was observed after long-term culture (21 days). Compared with the control group, there were significantly more nodules in the 50 J group and significantly fewer nodules in the 150 J group. Osteocalcin mRNA expression was highest in the 50 J group, and there was no difference between the control and 150 J groups. Irradiation with 50 J was effective in stimulating osteogenesis in bone marrow stem cells. These findings suggest that diode laser irradiation can induce osteogenesis in rat bone marrow cells in an energy-dependent manner, and appears suitable for application in bone regeneration therapy.

Hemolasertherapy - A Novel Approach to Reconstruct the Interdental Papilla: A Case Report

Black triangles are considered a nightmare by Periodontists as their treatments have been associated with high failure rate. There is a continuous quest for novel techniques that could restore the normal interdental papilla lost due to the periodontal disease process. In recent times a novel procedure called hemolasertherapy has been introduced that has led to papilla regeneration. Hence we reported a case of a 20-year-old female with a black triangle between the lower central incisors which was treated with hemolasertherapy. Photobiomodulation therapy was carried out with the help of a Sunny diode laser wavelength 650 nm where each of the nine bleeding points were irradiated for 30 seconds. A total of two sessions were conducted at one-week interval. Complete regeneration of the lost interdental papilla was observed by the end of three months. It can be concluded that hemolasetherapy is a non-invasive convenient modality that can be used for regenerating the interdental papilla.

Comparison of the Diode Laser Wavelengths 445 nm and 810 nm in Gingival Depigmentation - A Clinical Evaluation.

Introduction: Nowadays, esthetic appearance plays an important role in the field of dentistry. Discolorations and pigmentations of the gingiva reduce the appearance of a healthy-looking smile. On this occasion, the use of lasers shows a promising approach for a fast and non-aggressive treatment in this field. Different laser wavelengths are being used for gingival depigmentation this clinical study aimed to investigate the effect of the novel laser wavelength (445 nm) in this field and compare it with an 810 nm diode laser. Methods: Two diode laser wavelengths (445 nm and 810 nm) were used for depigmentation. The laser output power chosen was 1 W. An optical fiber with a diameter of 400 µm was used. 21 patients with pigmented gingiva were selected. Depigmentation was carried out in a split-mouth design for a direct comparison of the clinical effect. Outcomes were documented by photograph after one month and six months of follow-up. Results: For each wavelength, 21 volunteers evaluated 21 clinical cases of depigmentation, which means that 441 comparisons were carried out in total regarding the color change from brownish to pinkish. A 100% clarification was achieved for 445 nm. In the 810 nm group, the color change in 44 of 441 cases (10%) could not be clearly identified. No statistically significant difference in pain experience was reported for both laser treatments. Conclusion: The clinical evaluation showed that within the limitations of this study, most of the clinical outcome parameters were highly acceptable by the patients due to mild pain and discomfort for both laser systems.

Self-heating allows athermal laser diode wavelength control using a thermally insulating sub-mount over a 70 °C range.

The wavelength of a single frequency quantum dot distributed feedback (DFB) laser operating in the O-band is athermalised over a 74 °C ambient temperature range. Two techniques are presented, one utilising the laser self-heating for tuning control, the other using a resistive heater. Both techniques show greatly improved power efficiency over conventional wavelength control schemes, and both demonstrate wavelength stability of better than 0.1 nm (17.5 GHz) without mode hops over the entire temperature range. The use of a high operating temperature quantum dot laser together with an innovative submount design to increase the thermal impedance of the device enables the improved use of the laser self-heating for wavelength tuning. The submount design entails the laser being suspended over an air gap with the use of glass supports, preventing heat from escaping from the diode.

Photodynamic therapy as adjunctive treatment of single-rooted teeth in patients with grade C periodontitis: A randomized controlled clinical trial

BackgroundThe present study aimed to evaluate the adjunctive effect of an antimicrobial photodynamic therapy (aPDT) protocol on single-rooted teeth of patients with grade C periodontitis. MethodsSixty-four single-rooted teeth (14 patients) were included in each group of this double-blinded split-mouth randomized clinical trial. The teeth were randomly divided into scaling and root planing + aPDT (test group) and scaling and root planing+sham aPDT (control group). The aPDT protocol consisted of incubation with 1% methylene blue for 5 min, rinsing, and application of a diode laser (wavelength of 660 nm, power of 100 mW) for 10 s. aPDT was repeated after 7 days. Bleeding on probing (BoP), probing depth (PD), gingival recession (GR), and clinical attachment loss (CAL) were recorded before and 3 months after treatment. A 5% significance level was adopted for statistical analysis. ResultsFinal PD was significantly (P = 0.02) lower in the test group (2.87 ± 1.40 mm) compared to control (3.12 ± 1.69 mm). The test group showed a significantly higher percentage of sites with PD≤4 mm and concomitant BoP compared to control (91%x86%;P < 0.001). At sites with baseline PD>4 mm, final PD and CAL were significantly (P = 0.01) lower in the test group (4.11 ± 1.66 and 4.89 ± 2.49 mm, respectively) compared to control (4.88 ± 1.99 and 5.89 ± 2.74 mm, respectively). ConclusionsaPDT combined with scaling and root planning provided slightly better periodontal clinical results than the latter procedure alone, exerting a superior effect at sites with greater baseline PD. aPDT might be used as adjunctive treatment in grade C periodontitis affecting single-rooted teeth since it improves the response to conventional periodontal treatment.