Q-switched 1064 nm Nd: YAG laser restores skin photoageing by activating autophagy by TGFß1 and ITGB1.

Excessive ultraviolet B ray (UVB) exposure to sunlight results in skin photoageing. Our previous research showed that a Q-switched 1064 nm Nd: YAG laser can alleviate skin barrier damage through miR-24-3p. However, the role of autophagy in the laser treatment of skin photoageing is still unclear. This study aims to investigate whether autophagy is involved in the mechanism of Q-switched 1064 nm Nd: YAG in the treatment of skin ageing. In vitro, primary human dermal fibroblast (HDF) cells were irradiated with different doses of UVB to establish a cell model of skin photoageing. In vivo, SKH-1 hairless mice were irradiated with UVB to establish a skin photoageing mouse model and irradiated with laser. The oxidative stress and autophagy levels were detected by western blot, immunofluorescence and flow cytometer. String was used to predict the interaction protein of TGF-ß1, and CO-IP and GST-pull down were used to detect the binding relationship between TGFß1 and ITGB1. In vitro, UVB irradiation reduced HDF cell viability, arrested cell cycle, induced cell senescence and oxidative stress compared with the control group. Laser treatment reversed cell viability, senescence and oxidative stress induced by UVB irradiation and activated autophagy. Autophagy agonists or inhibitors can enhance or attenuate the changes induced by laser treatment, respectively. In vivo, UVB irradiation caused hyperkeratosis, dermis destruction, collagen fibres reduction, increased cellular senescence and activation of oxidative stress in hairless mice. Laser treatment thinned the stratum corneum of skin tissue, increased collagen synthesis and autophagy in the dermis, and decreased the level of oxidative stress. Autophagy agonist rapamycin and autophagy inhibitor 3-methyladenine (3-MA) can enhance or attenuate the effects of laser treatment on the skin, respectively. Also, we identified a direct interaction between TGFB1 and ITGB1 and participated in laser irradiation-activated autophagy, thereby inhibiting UVB-mediated oxidative stress further reducing skin ageing. Q-switched 1064 nm Nd: YAG laser treatment inhibited UVB-induced oxidative stress and restored skin photoageing by activating autophagy, and TGFß1 and ITGB1 directly incorporated and participated in this process.

No side effects on rabbit retina or vitreous microenvironment by nd:YAG laser vitreolysis.

BACKGROUND: To explore the safety of Neodymium:Yttrium-aluminum-garnet (Nd:YAG) laser vitreolysis based on the histological examination of the retina and the alteration of vitreous cytokines in the rabbits. METHODS: Nine male New Zealand rabbits underwent Nd:YAG laser vitreolysis of 10 mJ x 500 pulses in the left eyes, while the right eyes were used as controls. Intraocular pressure, color fundus photography, and ultrasound B scan were measured before, as well as 1 day, 4 weeks, and 12 weeks after Nd:YAG laser vitreolysis. Three rabbits were euthanized 1 day, 4 weeks, and 12 weeks after treatment, respectively. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and hematoxylin-eosin (H&E) staining were used to look for pathological changes in the retina. An enzyme-linked immunosorbent assay (ELISA) was utilized to detect the expression of vascular endothelial growth factor (VEGF) and some inflammatory cytokines, including interferon inducible protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP-1) and interlenkin 6 (IL-6) in the vitreous humor. The ascorbic acid (AsA) and total reactive antioxidant potential (TRAP) in the vitreous humor were also measured. RESULTS: Following Nd:YAG laser vitreolysis, the levels of VEGF, IP-10, MCP-1, IL6, AsA, and TRAP in the vitreous humor did not change substantially (P > 0.05). There were no detectable pathological changes in the retinal tissues, and no apoptotic signal was found. CONCLUSIONS: Rabbits tolerate Nd:YAG laser vitreolysis without observable impact on retinal tissue or the microenvironment of the vitreous.

Refractory solar lentigines successfully treated with 532-nm nanosecond Nd:YAG Vasculature Salvage Laser Surgery (VSLS) system: Case series.

BACKGROUND: Solar lentigo, a common epidermal hyperpigmented lesion found in sun-exposed areas, results from the proliferation of melanocytes and the accumulation of melanin. Although various treatments for solar lentigo have been explored, they often lead to complications, including prolonged erythema and post-inflammatory hyperpigmentation (PIH), posing significant concerns. OBJECTIVES AND METHODS: This study evaluated the safety and efficacy of the Vasculature Salvage Laser Surgery (VSLS) system. We treated six Korean patients, each with solar lentigo, in a single session using the 532-nm nanosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) VSLS system, with follow-up periods ranging from 3 to 10 weeks. RESULTS: The treatment led to the complete removal of pigmented lesions in all patients without resulting in PIH, even in cases where previous laser treatments had failed. The only side effect observed was mild erythema, which resolved over the long term in most instances. CONCLUSIONS: The VSLS system emerges as a safe and effective treatment for pigmented lesions, including refractory solar lentigines. Nonetheless, additional studies are required to verify its long-term efficacy.

The investigation and comparison of the efficacy and safety of stromal vascular fraction (SVF), platelet rich plasma (PRP), and 1064-nm Q-switched Nd:YAG laser in reducing nanofat treated infraorbital dark circles and wrinkles: A controlled blinded randomized clinical trial.

BACKGROUND: To evaluate the efficacy and safety of stromal vascular fraction (SVF), platelet rich plasma (PRP), and 1064-nm Q-switched Nd:YAG laser in reducing nanofat treated dark circles and wrinkles under the eyes. METHOD: This study was a single-blinded randomized clinical trial conducted on patients with suborbital darkening under the eyes that randomly divided into control and case groups. In the control group, 15 patients were treated with one session of nanofat injection only, and five patients of each intervention groups received one session of nanofat+SVF injection, nanofat+PRP injection, and nanofat injection+Nd:YAG laser, respectively. Assessments methods were (1) evaluation of the degree of darkness and repair under the eyes by a blinded dermatologist based on clinical photographs, (2) investigating patient satisfaction, (3) using biometric variables for color, thickness, and density of the skin (only 3 months after the treatment), and (4) recording the possible adverse effects. CONCLUSION: In terms of the extent of reduction in the intensity of darkness under the eyes, the combined treatment of nanofat injection together with SVF, PRP, and Nd:YAG laser had a much greater therapeutic effect than nanofat injection alone. In all three groups of combined treatments, patients were 100% satisfied. In terms of biometric variables, amount of changes in colorimeter, complete and dermal thickness, complete and dermal density, between the different groups was statistically significant. The use of combined treatments including nanofat with SVF injection, PRP, and 1064 Q-switched Nd:YAG laser may be more effective than nanofat alone, in reducing infraorbital dark circles and wrinkles.

Optical Effects of Focused Fractional Nanosecond 1064-nm Nd:YAG Laser: Techniques of Application on Human Skin.

BACKGROUND AND OBJECTIVES: Considering the pulse widths of picosecond and nanosecond lasers used in cutaneous laser surgery differ by approximately one order of magnitude, can nanosecond lasers produce the optical effect in human skin similar to laser-induced optical breakdown (LIOB) caused by picosecond lasers? METHODS: Cutaneous changes induced by a focused fractional nanosecond 1064-nm Nd:YAG laser were evaluated by VISIA-CR imaging, histological examination, and harmonic generation microscopy (HGM). RESULTS: A focused fractional nanosecond 1064-nm Nd:YAG laser can generate epidermal vacuoles or dermal cavities similar to the phenomenon of LIOB produced by picosecond lasers. The location and extent of photodisruption can be controlled by the laser fluence and focus depth. Moreover, laser-induced shock wave propagation and thermal degeneration of papillary collagen can be observed by HGM imaging. CONCLUSION: Focused fractional nanosecond lasers can produce an optical effect on human skin similar to LIOB caused by picosecond lasers. With techniques of application, the treatment can induce epidermal and dermal repair mechanisms in a tunable fashion to improve skin texture, wrinkles, scars, and dyspigmentation, without disrupting the epidermal surface.

Comparison of 755-nm picosecond alexandrite laser versus 1064-nm Q-switched Nd:YAG laser for melasma: A randomized, split-face controlled, 2-year follow-up study.

OBJECTIVES: Pulsed laser treatment of melasma has shown some promising results. To compare the effectiveness and safety of 755-nm picosecond alexandrite laser (PSAL) fitted with diffractive lens array (DLA) versus 1064-nm Q-switched neodynimum:yttrium aluminum garnet laser (QSNYL) for the treatment of melasma. METHODS: We conducted a randomized, split face controlled, 2-year follow-up study. Each face was divided into two parts, each side receiving three treatments with either PSAL or QSNYL at 1 month intervals. Modified Melasma Area Severity Index scores (mMASI), pain scores, patient satisfaction and adverse events were recorded. In vivo reflectance confocal microscopy (RCM) images were acquired. RESULTS: Twenty subjects were enrolled and three dropped out. At 6 months, mMASI scores were significantly lower than baseline for QSNYL sides (p = 0.022), with no statistically significant difference between PSAL sides before and after treatment, PSAL sides versus QSNYL sides, or patient satisfaction scores. QSNYL treatment was associated with less pain (p = 0.014). No serious adverse events were reported. In the PSAL sides RCM showed a large number of dendritic melanocytes infiltrated in the dermis at 2 weeks and 4 weeks after treatment. Ten patients (58.82%) reported recurrence or exacerbation at 2-year follow-up with no statistically significant difference between the two lasers. CONCLUSIONS: QSNYL demonstrated short term clinical efficacy for melasma, but did not provide any additional benefit compared to PSAL with DLA. QSNYL was associated with less pain. There was a high recurrence rate at 2-year follow-up. RCM allowed the detection of cellular changes in melasma lesions.

Treatment of familial glomangiomatosis with Nd:YAG laser: a case report.

Familial glomangiomatosis is a rare autosomal dominant vascular malformation caused by a mutation in the glomulin GLMN gene. It is characterized by the appearance of multiple glomus tumors composed of dysmature veins surrounded by glomus cells. We present a case of an 11-year-old girl with familial glomangiomatosis successfully treated with Nd:YAG long-pulse laser. Three sessions of laser treatment were performed, resulting in more than 80% reduction of the lesion and complete disappearance of pain, with no adverse effects reported. This case report demonstrates the excellent risk-benefit ratio of Nd:YAG long-pulse laser in the treatment of familial glomangiomatosis.

Safety of using laser for hair removal in patients with skin diseases: a retrospective study.

Laser hair removal is a commonly used method in dermatology which is based on selective thermolysis and utilizes the appropriate wavelength, pulse width, and energy density to damage hair follicles. Given the prevalence of skin diseases such as psoriasis, dermatitis, and vitiligo, and the increasing popularity of laser hair removal, the aim of this study was to investigate the safety of laser hair removal in individuals with skin diseases. This retrospective study was conducted at the laser department of Razi Hospital on 99 patients who underwent laser hair removal. The exacerbation of disease after laser therapy was significantly associated with active skin disease (p = .021) and laser treatment at the site of the disease (p < .001). The incidence of Koebner phenomenon was significantly associated with age (p = .017) and the number of sessions with the ND-YAG device (p = .034). It is crucial to exercise caution when performing laser treatment on individuals with active skin disease and to avoid treating the affected area were possible. If necessary, it is recommended to delay laser treatment until the disease is under control for patients with active skin disease or those who wish to receive laser treatment at the site of the disease.

Angiolymphoid hyperplasia with eosinophilia and Kimura disease: A case report and literature review.

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a benign vascular proliferative condition, typically presenting as subcutaneous nodules in the head and neck region of middle-aged women. Kimura disease (KD) is a benign condition that presents with subcutaneous nodules in a similar distribution with lymphadenopathy and eosinophilia, typically in Asian adult males. These diseases are often discussed together, including whether they exist on a spectrum or if they represent separate disease entities. Both are very rare in the pediatric population; in this report we highlight the case of a 10-year-old Caucasian male presenting with ALHE and KD.

An energy efficiency assessment of Yttrium-aluminum-garnet laser in vitro.

To study the effect range of the Nd:YAG laser through various levels of cloudy medium for targets with varying grayscale values in vitro. The coated paper cards with grayscale values of 0, 50, 100, and 150 were used as the laser's targets, which were struck straightly with varying energies using three burst modes (single pulse, double pulse, and triple pulse). Six filters (transmittances of 40, 50, 60, 70, 80, and 90) were applied to simulate various levels of cloudy refractive medium. Image J software was used to measure the diameters and regions of the laser spots. The ranges of the Nd:YAG laser spots increased with energy in the same burst mode (P < 0.05). Under the same amount of energy, the ranges of the Nd:YAG laser spot increased with the grayscale value of the targets (P < 0.05). The greater the transmittance of the filters employed, the larger the range of the Nd: YAG laser spots produced. Assuming that the total pulse energy is identical, the effect ranges of multi-pulse burst modes were significantly larger than those of single-pulse burst mode (P < 0.05). The effect range of a Nd:YAG laser grows with increasing energy and the target's grayscale value. A cloudy refractive medium has a negative impact on the effect range of the Nd: YAG laser. The single pulse mode has the narrowest and safest efficiency range.

The effect of laser therapy for the treatment of dentin hypersensitivity on surface roughness and bacterial adhesion.

The aim of the study was to measure the degree of dentine surface roughness caused by five distinct lasers used to treat dentine hypersensitivity, as well as to evaluate the subsequent bacterial colonization on these irradiated surfaces. Sixty human maxillary premolar teeth without caries or restoration which were extracted for periodontal reasons were used in this study. Five different types of lasers were applied to the root dentin surface. Tested samples were divided into six groups of 10 samples each; control, diode (810 nm), diode (980 nm), Nd: YAG, Er: YAG, and Er, Cr: YSGG laser groups. The arithmetic mean of the surface roughness values (Ra) and the average roughness over a measurement area (Sa) were measured pre- and post-application using any of the laser types. Swab samples were then collected from the dentin surface. Following a 24-hour incubation period at 37 °C, the colony forming units were counted using a stereoscope. The results demonstrated a statistically significant difference in the surface roughness values pre- and post-application (Ra and Sa, respectively) in the Er, Cr: YSGG laser group (p = 0.037,p = 0.007). No significant difference was observed in the other groups (p > 0.05). There was no statistically significant difference in the number of bacterial colonies observed between the test and control groups. Diode and Nd: YAG lasers showed either a decrease or no change in surface roughness; however, the hard tissue lasers (Er: YAG, Er, Cr: YSGG) showed an increase. The Er: YAG and Nd: YAG laser groups exhibited decreased bacterial adhesion compared to the other groups.

Neodymium-doped yttrium aluminum garnet (Nd: YAG) laser treatment in ophthalmology: a review of the most common procedures Capsulotomy and Iridotomy.

Nowadays, lasers are used in various medical fields. Ophthalmology was the first medical specialty to utilize lasers in patient treatment and still remains the leading medical field that uses laser energy for both therapeutic and diagnostic purposes. The neodymium: yttrium-aluminum-garnet (Nd: YAG) laser is one of the most common lasers used in ophthalmology. It is a solid-state laser with a wavelength of 1064 nm that works on the principle of photodisruption. Since its introduction in ophthalmology over 40 years ago, it has found various applications, mainly for procedures where cutting or disruption of ocular tissue is required. Compared to surgical alternatives, the use of Nd: YAG lasers on ocular tissue is minimally invasive. In this review, we focus on the two most common ophthalmic applications of Nd: YAG laser - laser peripheral iridotomy and posterior capsulotomy. The history of the techniques, current trends, potential complications, and the prognosis for future use is discussed.

Awake endoscopic laser surgery for early glottic carcinoma.

The objective of this study was to demonstrate the oncologic efficacy of awake endoscopic laryngeal surgery in the treatment of T1-T2 glottic carcinoma. This is a retrospective study. Seventy-one patients with early glottic carcinoma (T1a- 26, T1b- 18, T2- 27) who underwent awake flexible endoscopic laryngeal surgery under local anesthesia and mild intravenous sedation were included in the study. In 64 cases (90.1%) only endoscopic tumor ablation by Nd:YAG laser (in 32.4% of cases being preceded by diathermy snare excision) was performed, and in 7 T2 cases postoperative radiotherapy was also offered. There were no complications during or after the endoscopic surgery. Ultimate control of disease, including salvage treatment, was obtained in 67 patients (94.4%). Cure without recurrence was achieved in 60 cases (84.5%). Local control without salvage radiotherapy or/and open surgery was achieved in 64 (90.1%) patients. Larynx preservation was obtained in 66 (93.0%) cases. At 5 years from the beginning of endoscopic treatment, 74.6% of the patients were alive and free of disease. The best results were obtained in the T1a group of treated patients, all the patients being free of disease with the preserved larynx. Awake endoscopic laryngeal surgery is a safe and oncologically efficient method of treatment of early glottic carcinoma that can be considered as an alternative to the traditional approach, primarily, for patients with risks/contraindications for radiotherapy, general anesthesia, and transoral microsurgery, and also for the patients who prefer to avoid general anesthesia with its related risks and would rather choose office-based laryngeal surgery.

Prospective study of using 1064-nm Q-switched Nd: YAG combined with radiofrequency-imported vitamin C on pigmented infraorbital dark circles.

Infraorbital dark circles are a common manifestation of periorbital melanosis, which is aesthetically defective and bring a negative impact on life quality. However, there is no acknowledged treatment for infraorbital dark circles. The 1064-nm Q-switched Nd: YAG laser (QSNYL) is commonly utilized to treat hyperpigmentation disorders. Radiofrequency (RF) therapy can improve the transdermal absorption rate of drugs. A prospective clinical trial was conducted to investigate the clinical efficacy and safety of 1064-nm QSNYL combined with RF-imported vitamin C for the treatment of infraorbital dark circles. A questionnaire was used to explore the relevant factors affecting the severity of infraorbital dark circles. A total of 30 patients with pigmented infraorbital dark circles were enrolled in this clinical trial. Each participant received 4 treatments and was followed up for at least 12 months after the last treatment.We focused on the overall change in the appearance of the included participants before and after treatment, by using satisfaction evaluation.In order to reduce evaluation bias, the vivo reflectance confocal microscopy images were taken on days 1 and 120 to detect pigmentation. The questionnaire survey before treatment showed that high-frequency makeup was positively and statistically significant with the severity of infraorbital dark circles (p < 0.01). Both participants and independent evaluators found that the hyperpigmentation in the infraorbital region was significantly reduced after combined treatment with high treatment satisfaction. The density of melanin particles in the infraorbital dark circles region showed a decreased trend. No significant side effects were observed. The 1064-nm QSNYL combined with RF-imported vitamin C is a safe and effective treatment for pigmented infraorbital dark circles by reducing melanin particles.

Laser hair removal complications and the associated risk factors at a tertiary dermatology center: a case-control study.

Laser hair removal (LHR) has been established as a safe and efficient method for eliminating unwanted hair. This study aimed to investigate the frequency of LHR complications and assess the contributing factors. During one year, 16,900 patients undergoing LHR therapy were evaluated for complications. For each case, two external controls were selected (matched based on age, sex, Fitzpatrick skin type (FST) III-IV, and the treated anatomical region). To assess the impact of anatomical region on complication occurrence, each patient was used as their internal control if another area was treated during the same session. GEE analysis was used for statistical analysis.The incidence of LHR complications was calculated to be 0.69%. The most common complications were petechia, purpura, and ecchymosis (31.66%) followed by pigmentation changes (20.0%). LHR complications were most commonly observed in the lower limbs (32.0%), face and neck (23.3%), and genitalia and thighs (22.3%), respectively. Possible risk factors were younger age (OR = 0.74, P-value ≤ 0.001), operating LHR in the head and neck (OR = 5.8, P-value = 0.022), utilization of the alexandrite laser (OR = 2.32, P-value = 0.011), and fluence in the Alexandrite laser (OR = 3.47, P-value = 0.003).Overall, the results of this study indicate that LHR is generally a safe method for removing unwanted hair. However, factors such as younger age, treatment of the facial area, and use of the alexandrite laser especially with higher fluence levels in patients with FST III-IV were identified as potential risk factors.

In vitro studies the influence of Nd: YAG laser on dental enamels.

The present work aimed at assessing chemical, topographical, and morphological changes induced by Nd : YAG laser treatment of dental enamels by means of energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Fifteen human enamel specimens were obtained, three of samples were kept untreated as a control while the others twelve samples were equally divided into four groups where each group have a three samples according to treating approach as: G1:(untreated);G2: (treated with Nd:YAG laser, 100 mJ/pulse,10 Hz/1064nm); G3(treated with Nd:YAG laser, 500 mJ/pulse, 10 Hz/1064nm); G4(treated with Nd:YAG laser 1000 mJ/pulse, 10 Hz/1064nm), and finally G5(treated with Nd:YAG laser, 1000 mJ/pulse, 10 Hz/532nm) respectively. Beside many craters and cracks, the AFM results showed fractures with depths of 19.23 nm, 174.7 nm, 216.9 nm, 207.4 nm and 156.5 nm and width of 559.2 nm, 833.4 nm, 1115 nm, 695.0 nm, and 5142 nm for all Groups respectively. The highest surface roughness was found in G5 with 111.4 nm while the lowest surface roughness was found in G1 to be 14.3 nm. The inside surface of the fissures was also rough. The SEM micrographs revealed modifications to the morphology. EDS was used to measure the phosphorous (P), calcium (Ca), oxygen (O), and carbon (C) percentages presented in crater areas and their surroundings, Ca, P, O, and C levels were observed to vary significantly at the crater and its rim, a lower percentage of C wt% were realized corresponding to laser treatment of 1000 mJ/Pulse laser energy. However, it was not feasible to recognize a specific chemical arrangement in the craters. It is also concluded that the higher depth and particular edge of ablated part when teeth were irradiated by laser with 1000 mJ/10Hz/1064nm.

Evaluation and comparison of Q-switched Nd: YAG laser 1064 nm and Er: YAG laser 2940 nm in the treatment of macular amyloidosis.

Macular amyloidosis (MA) is one of the most common types of primary localized cutaneous amyloidosis (PLCA), distributed predominantly over the trunk and extremities. Due to the vast therapeutic options, this study aims to compare the effectiveness of Q-switched Nd: YAG laser 1064 nm and Er: YAG laser 2940 nm in treating MA. This clinical trial was performed in 2020-2021 on 33 women with MA. In each patient, the lesion was randomly divided into two areas, A and B. Area A underwent four treatment sessions with 4-week intervals of Q-switched Nd: YAG laser 1064 nm. Area B underwent four treatment sessions with an Er: YAG laser 2940 nm at 4-week intervals. Degree of basal pigmentation and degree of pigmentation after treatment, pruritus intensity, before and after the treatment, and patient and physicians' satisfaction were measured and compared. The pruritus in patients improved significantly after the study (P < 0.001), but no significant differences could be observed between the two groups regarding the improvements (P > 0.05). We also found no significant differences between the two groups of patients regarding patient and physicians' satisfaction rates (P > 0.05). The use of both Q-switched Nd: YAG laser and Er: YAG laser resulted in improvements in terms of pruritus, patient and physicians' satisfaction, and total improvement in pigmentation of the lesions.

Effects of Nd:YAG laser irradiation at different energy densities on dentin bond durability under simulated pulpal pressure.

OBJECTIVES: To evaluate the effects of Nd:YAG laser irradiation on the microstructures of dentin surfaces and the long-term bond strength of dentin under simulated pulpal pressure. MATERIALS AND METHODS: Under simulated pulp pressure, 30 freshly extracted caries-free third molars were cut into 2-mm-thick dentin samples and then divided into five groups: the control and laser groups (93.3 J/cm2; 124.4 J/cm2; 155.5 J/cm2; 186.6 J/cm2). Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and Vickers hardness were used to analyze the surface morphology, composition, and mechanical properties of the dentin before and after laser irradiation. Another 80 caries-free third molars were removed and treated as described above, and the resin was bonded to the dentin surface with Single Bond Universal (SBU) adhesive in self-etch mode to make stick specimens. Microtensile bond strength (µTBS), confocal laser scanning microscopy (CLSM), and interfacial silver nanoleakage tests before and after 10,000 times thermocycling were then performed to analyze the bonding properties and interfacial durability of each group. RESULTS: SEM observations revealed that the surfaces of all laser group specimens were rough with open dentin tubules. Laser irradiation altered the surface composition of dentin while removing some collagen fibers but did not affect its surface hardness or crystallographic characteristics. Furthermore, laser irradiation with an energy density of 124.4 J/cm2 significantly promoted the immediate and aging bond strengths and reduced nanoleakage compared to those of the control group. CONCLUSIONS: Under simulated pulp pressure, Nd:YAG laser pretreatment altered the chemical composition of dentin and improved the immediate and long-term bond strength. CLINICAL RELEVANCE: This study investigated the optimal parameters for Nd:YAG laser pretreatment of dentin, which has potential as a clinical method to strengthen bonding.

Prevention efficacy of dentin tubule sealing with Nd:YAG laser against tooth discoloration induced by vital pulp treatment.

BACKGROUND: The discoloration potential of dental materials and applications such as vital pulp therapy also cause discoloration due to the presence of blood. Dentin tubule sealing methods could be used for the prevention of discoloration. AIM: The purpose of this study was to evaluate the effect of sealing pulp chamber walls with Nd:YAG laser against discoloration caused by tricalcium silicate-based materials in the presence and absence of blood contamination. DESIGN: Eighty-one extracted human maxillary incisors were prepared and randomly divided into nine groups according to the Nd:YAG laser application, the cement to be used (NeoMTA Plus/Biodentine), and the presence or absence of blood. The color measurements were obtained with a spectrophotometer at baseline and then at the sixth (T1) and 12th (T2) months thereafter. RESULTS: Sealing with Nd:YAG laser and placing NeoMTA Plus or Biodentine on human blood significantly increased discoloration at T1 and T2 (p < .05). Similarly, without sealing the cavity and placing NeoMTA Plus or Biodentine on human blood significantly increased discoloration at T1 and T2 (p < .05). CONCLUSION: Regardless of sealing the dentin tubules with Nd:YAG laser, NeoMTA Plus and Biodentine caused more discoloration in the presence of blood contamination.

Different wavelengths of laser: are they significant for treatment of denture stomatitis?: an in-vitro study.

BACKGROUND: Denture stomatitis (DS) is an inflammatory disorder that affects the mucosal surface underneath the dentures and frequently causes oral mucosal irritation, discomfort, and altered taste perception, which prevents people from consuming enough nutrients. One of the main causes of DS is an overgrowth of the fungus Candida albicans (C. albicans). A possible alternative treatment for Candida infections is thought to be laser therapy. The aim of this study was to evaluate how different wavelengths of laser would affect growth and pathogenic properties of Candida albicans. METHODS: A concentration of 106 viable cells/ml of Candida albicans were used in the preparation process. Four groups were created from the specimens. Culturing of the control group was completed with no intervention. The other 3 groups received laser radiation for 60 seconds at a power of 1W. The 2nd and 3rd groups were irradiated with diode laser at a wavelength of 940 nm and 980 nm respectively. The 4th group was irradiated with Nd-YAG laser at a wavelength of 1064 nm. Turbidimetric growth was defined as variations in the optical density of fungal growth. These measures were made at three different times: baseline, 48 hours, and 72 hours. RESULTS: In both groups of diode laser, the growth of Candida albicans showed no remarkable differences at baseline, after 48 and 72 hours using a power of 1 W and duration of 60 seconds. The Nd-YAG group showed significant increase in optical density after 48 hrs then significant decrease after 72 hrs. The optical density values in the control group showed no notable difference between the control and diode study groups at different time periods. However, the Nd:YAG group showed a statistically significant difference compared to the control and the 2 diode laser groups. CONCLUSIONS: Different laser parameters have a different effect on growth and pathogenic properties of Candida albicans. Diode laser therapy with wavelengths 940 and 980 nm used in continuous mode with power of 1 W for duration of 60 seconds can result in proliferation of Candida albicans instead of destroying them. Nd:YAG laser, used in pulsed mode, with power of 1 W for a duration of 60 seconds can be used to destroy Candida albicans and therefore, can be used as an effective treatment for denture stomatitis.