Application of CO2-Laser Micro-Perforation Technology to Freeze-Drying Whole Strawberry (Fragaria ananassa Duch.): Effect on Primary Drying Time and Fruit Quality.

Freeze-drying (FD) processing preserves foods by combining the most effective traditional technologies. FD conserves the structure, shape, freshness, nutritional/bioactive value, color, and aroma at levels similar to or better than those of refrigerated and frozen foods while delivering the shelf-stable convenience of canned/hot-air-dehydrated foods. The mass transfer rate is the essential factor that can slow down the FD process, resulting in an excessive primary drying time and high energy consumption. The objective of this study was to reduce the FD processing time using CO2 laser technology to improve product competitiveness in the preservation of whole strawberries. The research process consisted of the selection and characterization of fresh strawberries, followed by preparation, pre-treatment, freeze-drying, a primary drying time assessment, and a quality comparison. Experiments were carried out using strawberries without micro-perforation and with five and eight micro-perforations. Quality parameters were determined for fresh, frozen/thawed, and freeze-dried/rehydrated strawberries. It was found that the primary drying time can be significantly reduced by 20% (95% CI) from 26.7 h for non-perforated fruits to 22.3 h when five micro-perforations are made on each strawberry. The quality parameters used to evaluate the strawberries did not show significant differences when comparing frozen/thawed fruits with freeze-dried/rehydrated fruits. The experiments conducted in this study showed that freeze-drying may efficiently compete with freezing technology when processing whole strawberries.

Influence of Different Surface Treatments on the Bond Strength of Yttria-Stabilized Tetragonal Zirconia Ceramic.

Objective: This in vitro study evaluates the shear bond strength (SBS) of yttria-stabilized tetragonal zirconia (Y-TZP) and resin cement after different surface treatments. Materials and methods: Forty-eight ceramic cubes were divided into four groups (n = 12): G1 (control) sandblasting with Al2O3; G2-sandblasting with silica-coated Al2O3 (Rocatec); G3-Rocatec + CO2 laser; and G4-CO2 laser + Rocatec. A metallic primer was applied to the pretreated ceramic. A rubber ring was adapted on the central area, and then, the resin cement was inserted into the matrix and photoactivated. The samples were evaluated regarding surface roughness (Ra), SBS, failure type, and qualitatively with scanning electron microscopy (SEM). The data were analyzed by one-way analysis of variance followed by Tukey's test (p < 0.05). Results: The mean values of Ra (µm) were as follows: G1-4.52a, G2-4.24a,b, G3-4.10a,b, and G4-2.90b and the mean values of SBS (MPa) were as follows: G1-7.84a , G2-4.41b , G3-4.61b and G4-6.14a,b. SEM analyses showed superficial irregularities for all groups, being more prominent for G1. The presence of silica deposits was observed for G2, G3, and G4, but in the last two groups there were some linear areas, promoted by the fusion of silica, due to the thermomechanical action of the CO2 laser. Conclusions: The surface treatment with CO2 laser + Rocatec, using one MDP-based cement, can be an alternative protocol for the adhesion cementation of Y-TZP ceramic since it was as effective as the conventional pretreatment with aluminum oxide sandblasting.

Microneedling in the Treatment of Post-burn Hypertrophic Scars.

INTRODUCTION: Post-burn hypertrophic scars are an important cause of physical discomfort, limitation of movements, psychological disorders, low self-esteem and reduced quality of life. Treatment for this condition is complex and involves several options. Microneedling, also known as minimally invasive percutaneous collagen induction, is an affordable minimally invasive option that can be combined with other treatments, including ablative ones. OBJECTIVE: The goal of this study was to present our microneedling approach for the treatment of hypertrophic scars after burns. METHOD: A prospective study of 15 patients with post-burn hypertrophic scars was conducted between October 2016 and June 2022. All patients were treated with microneedling and drug delivery of triamcinolone. Scars were evaluated using Vancouver Scar Scale (VSS), Burn Scar Assessment Scale (BSAS) and angle measurement for amplitude of movement evaluation of joints. RESULTS: A significant improvement in the VSS score was obtained after microneedling (8.8 ± 0.44 to 4.1 ± 0.98; p = 0.012), especially in the acute group (less than 1 year after burns): 9.3 ± 0.49 to 3.5 ± 1.36; p = 0.041. There was a significant and progressive improvement of the scars throughout the treatment sessions in all criteria evaluated and in the ranges of joint movement (p = 0.012). CONCLUSION: Our microneedling protocol promoted a significant improvement of post-burn scars, especially in acute hypertrophic scars, and in the amplitude of joint motion. Sequential treatments provided progressive improvement. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Women with Genitourinary Syndrome of Menopause Treated with Vaginal Estriol, Microablative Fractional CO2 Laser and Microablative Fractional Radiofrequency: A Randomized Pilot Study.

Objective: This pilot study intended to assess the feasibility of a large-scale randomized clinical trial designed to analyze the effectiveness of microablative fractional CO2 laser (CO2L) and microablative fractional radiofrequency (RF) compared with vaginal estriol (VE) as treatments for women with moderate-to-severe Genitourinary Syndrome of Menopause (GSM). Methods: Participants were randomized into VE, CO2L, or RF groups. In the VE group, women were required to use vaginal estriol cream for 14 days and then twice a week for 4 months. In the CO2L and RF groups, three energy therapies were administered at monthly intervals. Visual Analog Scale (VAS) for GSM symptoms, Female Sexual Function Index (FSF-I), Vaginal Health Index (VHI), and Nugent Score (NS) were analyzed before and 120 days after the beginning of the treatments. Pain scores were verified after each CO2L and RF session. Results: Thirty-four participants completed the study: 11 in the VE group, 11 in the CO2L group, and 12 in the RF group. No unexpected or serious adverse events were observed. We also verified that GSM symptoms, sexual function, and VHI significantly improved (p < 0.05) with no difference among the groups. NS did not show statistically significant difference before and after the treatments. Pain during RF application was associated with higher scores. Conclusions: The study is feasible and does not seem to have safety implications. Preliminary results suggest that CO2L and RF are good alternatives to VE for ameliorating clinical symptoms, FSF-I, and VHI in patients with GSM. Clinical Trial Registration number: NCT04045379.

Combined clinical and radiological remission of rectovaginal fistulas using fractional CO2 vaginal laser: a case series and medium-term follow-up.

INTRODUCTION: Despite the advances in surgical and clinical approaches, there is no consensus regarding the best line of treatment from rectovaginal fistula (RVF). Faced with a challenging scenario in the approach of RVF, the fractional CO2 laser receives attention as a possible form of treatment. OBJECTIVES: A single-center, prospective, open-label study evaluating the effectiveness and safety of laser therapy for RVF treatment. SUBJECTS AND METHODS: The total of 15 patients was recruited at the Juiz de Fora University Hospital between August 2018 and July 2022. Inclusion criteria were presence of clinically suspects RVF of any etiology confirmed by pelvic magnetic resonance image (MRI) and gynecological examination. Five fractional CO2 laser sessions with monthly interval followed by complete evaluation through clinical examination and pelvic MRI were performed for all patients after the completion of treatment. Analysis of sexual function before and after the treatment was performed using Female Sexual Quotient (FSQ). RESULTS: The evaluation through physical examination showed no persistent inflammatory signs in the vagina for all patients. Additionally, 10 of out 15 (67.7%) patients achieved clinical remission of RVF symptoms, while 33.3% patients reported significant improvement. Of note, five patients who did not have previous sexual activity returned to regular sexual activity while seven patients who have baseline sexual activity had improvement in their sexual function as assessed by the FSQ. Three out of four ostomized patients had their ostomy reversed and remained without complains. All six patients with RVF secondary to Crohn's disease reported a marked improvement in symptoms and sexual function. In seven (47%) patients radiological remission was confirmed by pelvic MRI. CONCLUSION: CO2 fractional laser can be considered a promising and safe therapeutic alternative for the management of RVF.

Sulfanilamide Electrochemical Sensor Using Phenolic Substrates and CO2 Laser Pyrolysis.

The concentration of environmental pollutants needs to be monitored constantly by reliable analytical methods since they pose a public health risk. Developing simple and affordable sensors for such pollutants can allow for large-scale monitoring economically. Here, we develop a simple electrochemical sensor for sulfanilamide (SFD) quantification using a phenolic resin substrate and a CO2 laser to pyrolyze the sensor geometry over the substrate. The sensors are modified with carbon nanotubes via a simple drop-casting procedure. The carbon nanotube loading effect the electrochemical performance toward a redox probe and analytical performance for SFD detection is investigated, showing no net benefit beyond 1 mg L-1 of carbon nanotubes. The effects of the modification on the SFD oxidation are shown to be more than just an electrode area effect and possibly attributed to the fast electron transfer kinetics of the carbon nanotubes. SFD detection is performed at small solution volumes under static (800 µL) and hydrodynamic conditions (3 mL) in a fully integrated, miniaturized batch-injection analyses cell. Both methods have a similar linear range from 10.0 to 115.0 µmol L-1 and high selectivity for SFD determination. Both systems are used to quantify SFD in real samples as a proof of concept, showcasing the proposed device's applicability as a sensor for environmental and public health monitoring of SFD.

CO2 laser irradiation combined with fluoridated dentifrice improved its protective effect on caries lesion progression regardless of the acidulated phosphate fluoride gel application: An in situ study.

OBJECTIVE: This in situ study aimed to investigate the efficacy of CO2 laser at a 10.6-µm wavelength combined with 1.23% acidulated phosphate fluoride (APF) and fluoridated dentifrice with 1100 µg F/g (FD) to control enamel caries progression. MATERIALS AND METHODS: Sixteen volunteers wore palatal appliances containing eight demineralized enamel specimens for four 14-day phases under sucrose exposure. These specimens were submitted to CO2 laser irradiation and APF alone or combined with FD. Treatment groups were non-fluoridated dentifrice-NFD, NFD + CO2 laser, NFD + APF, NFD + CO2 laser + APF, FD, FD + CO2 laser, FD + APF, and FD + CO2 laser + APF. Mineral loss, calcium fluoride (CaF2), fluorapatite (FAp), and fluoride in the biofilm were analyzed by analysis of variance followed by the Student-Newman-Keuls test, p < 0.05. RESULTS: The highest mineral loss inhibition was noted when FD and CO2 laser irradiation were combined, which did not significantly differ from the FD + CO2 laser + APF group. The CaF2, FAp, and F in the biofilm were more pronounced when the FD and APF were combined. The CO2 laser irradiation promoted a slightly higher concentration of CaF2 in the enamel and F in the biofilm. CONCLUSION: Although APF promotes the high formation of CaF2 and FAp, the combined use of FD with CO2 laser overcomes the APF effect in inhibiting the progression of artificial caries-like lesions in situ. CLINICAL SIGNIFICANCE: Under the in situ design of this study, remineralization of white spot lesions was achieved through CO2 laser irradiation and daily use of fluoridated dentifrice. Future clinical trials are encouraged to substantiate this finding.

Effect of CO2 Laser Microperforation Pretreatment on the Dehydration of Apple Slices during Refractive Window Drying.

This research studied the use of CO2 LASER microperforation as a pretreatment for the refractive window (RW) drying of apple slices with respect to total polyphenol content (TPC), antioxidant capacity, color ΔE, and product stability under accelerated storage. For this purpose, the processing variables assessed were pore size (200-600 µm), pore density (9-25 pores/cm2), and drying temperature (70-90 °C). As baseline criteria, a comparison with respect to the control without microperforations and samples subjected to conventional tunnel and lyophilization were also considered. The increase in the pore size from 200 to 600 µm resulted in shorter drying times (≤40 min), minimal change in color (ΔE) and loss of TPC, while DPPH was negatively affected by the combined effect of the pore density and the drying temperature. In general, the use of RW with CO2 resulted in apples of higher quality than those obtained in conventional drying and comparable to those obtained through the use of freeze-drying. Finally, during accelerated storage, quality attributes decreased significantly for samples dried at 90 °C regardless of whether microperforations were used, suggesting that a compromise between drying temperature and pore size must be weighed to reduce processing time and to avoid further quality losses during storage.

Fractional CO2 Laser, Radiofrequency and Topical Estrogen for Treating Genitourinary Syndrome of Menopause: A Pilot Study Evaluating the Vulvar Vestibule.

Background and Objectives: Genitourinary syndrome of menopause (GSM) affects more than half of postmenopausal women. This study aimed to evaluate the clinical and histological aspects of microablative fractionated CO2 laser (CO2L), microablative fractionated radiofrequency (RF) and intravaginal estrogen (ET) therapy as GSM treatments for the vulvar vestibule. Materials and Methods: This study included postmenopausal women with at least one moderate-to-severe complaint of GSM. Women in the CO2L and RF groups received three monthly sessions of outpatient vulvovaginal therapy. The procedures were performed 30 min after applying 4% lidocaine gel to the vulva and vaginal introitus. Vulvar vestibular pain was assessed after each application using a 10-point VAS. A follow-up evaluation was performed 120 days after beginning each treatment. Digital images of the vulva were obtained and a 5-point Likert scale (1 = much worse, 2 = worse, 3 = neutral, 4 = better, 5 = much better) was used to assess the global post-treatment women's impression of improvement regarding GSM. Results: A significant change in clinical aspects of the vulva was observed after all treatments with a reduction in the atrophic global vulvar aspect and an enhancement of the trophic aspect. High satisfaction was also reported after treatment according to the Likert scale evaluation: CO2L (4.55 ± 0.97), RF (4.54 ± 0.95), CT (4 ± 1.41), p = 0.066. Histological evaluation revealed enhanced dermal papillae before pre-treatment, significantly reducing post-treatment in all groups (p = 0.002). No unintended effects were reported. Conclusions: CO2L, RF, and ET significantly improved GSM concerning the vulvar vestibule at the 4 months follow-up.

Evaluation of the Combination of CO2 Laser and Bifunctional Bonding Agents for Composite Resin Repairs After 1 Year of Aging.

Objective: to evaluate the bond strength of repairs to composite resin restorations treated with CO2 laser and bifunctional monomers after 1 year of aging. Background: Adequate bond strength between a composite restoration and resin repair agent can be achieved through mechanical and/or chemical treatment. However, the longevity of such repairs is unknown. Methods: Resin blocks (volume: 125 mm3) were created. Failure surfaces were either not treated or were treated before the repair with a universal adhesive, a silane bonding agent and/or CO2 laser. The blocks were distributed into six groups (n = 6 per group): resin+resin group (RRG), universal adhesive+resin group (ARG), silane+universal adhesive group (SAG), laser+silane+universal adhesive group (LSAG), laser+universal adhesive group (LAG), and laser+silane group (LSG). After treatment, repairs were made with another resin composite. "Sticks" (1.0 mm2 in area and 1.0 cm in length) were cut from the specimens in each group and immersed in distilled water at 37°C. Microtensile bond strength was evaluated after 1 year of aging. Bond strength values were compared using the Kruskal-Wallis test and Dunn's test. Results: Bond strength was significantly higher in the LSAG compared with the RRG, adhesive system, LSG, whereas statistically similar results were found for the SAG, LSAG, and LAG. Bond strength was lowest in the RRG. The LSAG and LAG presented predominantly cohesive fractures. Conclusions: The bond strength of composite resin repairs was satisfactory over time. Treatment with CO2 laser contributed to the maintenance of bond strength during the 1-year storage period and bifunctional monomers present in the universal adhesive on the irradiated repair surface were of fundamental importance to the maintenance of bond strength values, as demonstrated by microtensile bond test and fracture pattern analysis.

Blefaroplastia realizada con láser de CO2 versus radiocirugía en pacientes con dermatochalasis / Blepharoplasty performed with CO2 laser versus radiosurgery in patients with dermatochalasis

Objetivo: Describir los resultados de las blefaroplastias con láser de CO2 y radiocirugía realizada a pacientes con dermatochalasis del párpado superior en el Hospital "Hermanos Ameijeiras". Métodos: Se realizó un estudio descriptivo longitudinal en pacientes del servicio de Oftalmología. Después de aplicar los criterios de selección la muestra quedó conformada por los primeros 100 pacientes que asistieron de forma consecutiva y se dividieron al azar en dos grupos de 50 casos cada uno, al grupo A se le realizó blefaroplastia superior transcutánea con radiofrecuencia y al grupo B se le realizó blefaroplastia superior transcutánea con láser de CO2. Resultados: En ambos predominaron los pacientes entre los 60 a 79 años, el sexo femenino y los de color de piel blanca (p>0,05); se logró una reducción completa de la piel redundante en más de un 50 pr ciento. El tiempo quirúrgico promedio con el láser de CO2 fue de 31.5 min y con radiofrecuencia de 35,9 min. El sangrado intraoperatorio fue menor en operados con el láser de CO2. La satisfacción de los pacientes fue buena en ambos grupos. Complicaciones posoperatorias: el 16 del grupo A y el 11% del B, presentaron alguna complicación. Conclusiones: Se observó que con el uso del láser de CO2 el tiempo quirúrgico, el sangrado intraoperatorio y las complicaciones disminuyeron; con lo cual mejoró el aprovechamiento del salón. Ambas técnicas mostraron un elevado grado de satisfacción y mejoría de la estética palpebral por lo que son efectivas y seguras(AU)

Objective: To describe the results of CO2 laser blepharoplasty and radiosurgery performed in patients with upper eyelid dermatochalasis. Methods: A descriptive longitudinal study was carried out in patients of the Ophthalmology Service of the Clinical Surgical Hospital "Hermanos Ameijeiras". After applying the selection criteria, the sample consisted of the first 100 patients who attended consecutively and were randomly divided into two groups of 50 cases each. Group A underwent transcutaneous upper blepharoplasty with radiofrequency and group B underwent transcutaneous upper blepharoplasty with CO2 laser. Results: In both groups, patients between 60 and 79 years of age, female gender and white skin color predominated (p>0.05); a complete reduction of redundant skin was achieved in more than 50 percnt. The average surgical time with CO2 laser was 31.5 min and with radiofrequency 35.9 min. Intraoperative bleeding was lower in those operated with the CO2 laser. Patient satisfaction was good in both groups. Postoperative complications: 16 por ciento of group A and 11 percent of group B presented some complication. Conclusions: It was observed that with the use of CO2 laser the surgical time, intraoperative bleeding and complications decreased; thus improving room utilization. Both techniques showed a high degree of satisfaction and improvement of palpebral aesthetics, so they are effective and safe(AU)

Couple batch-injection analysis and microfluidic paper-based analytical device: A simple and disposable alternative to conventional BIA apparatus.

Under controlled dispersion conditions, sample injection towards a detector opened essential fields for the Analytical Chemistry fast development methods. Flow injection analysis (FIA) and batch injection analysis (BIA) systems are crucial for injecting the sample in these analytical methods. The BIA system eliminated the flow manifold, with samples injected directly onto the detector inside the batch injection cell. Paper was slightly evaluated coupled to FIA, and no reports were found associated with BIA. Still, it can potentially reduce the BIA manifold by removing the batch injection cell based on the capillarity properties to disperse the injected solution over the detection system. Hence, this article reported the first work coupling batch-injection analysis and microfluidic paper-based analytical device (BIA-µPAD) with pencil-drawn electrodes directly attached to the paper using a CO2 laser pre-treated chromatographic paper. The laser pretreatment of the paper (optimized conditions: 6.5% laser power, 12 mm s-1 scan rate, and 12 mm output distance) was essential to enhance the electrochemical response for ferri/ferrocyanide redox couple and paracetamol (PAR), as shown by spectroscopic and electrochemical techniques. The proposed BIA-µPAD was evaluated using pharmaceutical paracetamol samples as proof-of-concept (optimized conditions: 15 µL injected volume and 6.4 µL s-1 dispensing rate), obtaining good linearity (R = 0.9961) and recovery values ranging from 95 to 103%. Repeatability (n = 16) and reproducibility (n = 9) tests with 1 mmol L-1 PAR also presented well relative standard deviation (RSD) results of 5.1% and 6.6%, respectively. A sampling frequency of 76 h-1 was obtained, which is a similar value compared with conventional BIA apparatus. Limits of detection and quantification were estimated in 0.046 and 0.154 mmol L-1, respectively. Additionally, an improvement in the current response and the sample throughput was observed when comparing FIA and BIA-µPADs, attesting the applicability of the proposed device and opening for new possibilities related to paper-based devices coupled with flow techniques.

Tonsillotomy by a Fractional Carbon Dioxide Laser: A New Technique in the Treatment of Chronic Tonsillitis.

Introduction: Chronic tonsillitis has a global prevalence, ranging from 5% to 12%. Its clinical manifestations, like recurrent acute tonsillitis, tonsils hypertrophy, caseum and halitosis, can lead adult patients to be submitted to palatine tonsillectomy, surgery that has morbidity and the potential risk of complications, including severe bleeding. This article proposes a new therapy for chronic tonsillitis in adult patients using a fractional carbon dioxide (CO2) laser, which is a fast, minimally invasive procedure capable of removing the need for the traditional tonsillectomy in many patients. The present research aimed to verify the efficacy of tonsillotomy by fractional ablation using the CO2 laser by comparing the number of bacterial infections, tonsils hypertrophy, halitosis and caseum; it is also aimed at analyzing the benefits, risks and complications of the technique. Methods: In this clinical prospective study, 20 patients were subjected to one session of tonsillotomy by fractional ablation and were followed up for a year. The control group was formed by the same patients in the pre-procedure period (one year) without treatment. Statistical analysis: The Wilcoxon paired test, Friedman tests, and multiple non-parametric comparisons were utilized to analyze the data (significance level of 5%). Results: No complications occurred, and the procedure was fast (30 seconds), safe and tolerated well without general anesthesia. After 1 year, there was a total remission of recurrent acute tonsillitis in 95% of the patients, and after 6 months there was a statistically significant improvement in halitosis and caseum, and tonsils size reduction (P<0.05). The level of satisfaction average was 10 after 3 months and 8 after one year. Conclusion: tonsillotomy by fractional ablation using the CO2 laser is a safe, efficient procedure for chronic tonsillitis in adults, and it can be incorporated into daily clinical practice.

Low-fluence and low-density CO2 laser: histological analysis of collagen fiber changes in skin and its clinical repercussions in photorejuvenation.

This study refers to clinical and histologic analysis of effects on photorejuvenation after one single treatment of fractional CO2 laser with low fluence and low density. To analyze histologically the quantitative variation of collagen fibers type I and III, elastic fibers, and epidermal thickness on D84, besides clinical evaluation of amount, length, thickness, and depth of periocular wrinkles during the same period. This is an open, prospective, interventional study. There were 40 healthy female with age between 35 and 65 years. Twenty-six participants were randomly selected for D0 and D84 biopsy. A single session of fractional CO2 laser was done in the hole face, using a 800-µm tip, 5% density, and 10 mJ fluence with a single pass. On D0, D42, and D84, a clinical comparative analysis of amount, length, depth, and thickness of periocular wrinkles has been done. On histological analysis, a comparative quantitative evaluation of collagen fibers type I and III, elastic fibers, and epidermal thickness has been done on D0 and D84. The results of this study denoted a significant clinical improvement of amount (- 32.17%; p < 0.0001), thickness (- 33%; p < 0.0001), lenght (- 35.84%; p < 0.0001), and depth of periocular wrinkles (- 32.46%; p < 0.0001). A significant increase in the amount of collagen fibers type III was observed on D84 (+ 60.67%; p = 0.0013). Collagen fibers type I and elastic fibers did not have the same result, with a nonsignificant increase (+ 8.31%; p = 0.3820) and a decrease (- 12.4%; p = 0.0585) respectively. Epidermal thickness has a tendency to significant variation (p = 0.05553). The results demonstrate that fractional CO2 laser with low fluence and low density is a safe and efficient option for photorejuvenation of the face.

CO2 laser irradiation for debonding ceramic orthodontic brackets

Abstract This study evaluated shear bond strength (SBS), adhesive remnant index (ARI) and fracture mode of chemically and mechanically retained ceramic brackets bonded with different composite resins and irradiated with CO2 laser. The null hypothesis was that ceramic brackets bonded with different composite resins and irradiated with CO2 laser would have similar SBS values. Ninety human premolars were divided into four experimental groups according to the combination of type of composite resin (Transbond XT and Z 250) and type of ceramic bracket (Fascination and Mystique), and two control groups (n=15). In the four experimental groups, the brackets were irradiated with CO2 laser at 10 W for 3 seconds before SBS testing. Enamel surface ARI was calculated after debonding under electron microscopy scanning. ANOVA and the Mann-Whitney test were used for statistical analysis. The laser groups had lower SBS values than the non-irradiated groups (control) (p<0.05). The mechanically retained brackets (Mystique) had the higher (p<0.05) and Z250 had the lower SBS values after CO2 laser irradiation. The groups bonded with Z250 had the highest ARI. Adhesive fractures were the most prevalent. The null hypothesis was rejected. CO2 laser decreased SBS efficiently and facilitated debonding of mechanically and chemically retained ceramic brackets.

Resumo O objetivo do estudo foi avaliar a resistência de união ao cisalhamento da colagem (RCC), o índice de remanescente de adesivo (IRA) e o modo de fratura de bráquetes cerâmicos com retenção química e mecânica colados com diferentes compositos e irradiados com laser de CO2. A hipótese nula testada foi que bráquetes colados com diferentes compósitos e irradiados com laser de CO2 apresentam valores semelhantes de RCC. Noventa pré-molares humanos foram divididos em 6 grupos (n=15): 2 controles e 4 experimentais que se diferenciaram pelo tipo de bráquete ceramic (Fascination and Mystique) e pelo compósito de fixação (Transbond XT e Z 250). Nos quatro grupos experimentais, os bráquetes foram irradiados com laser de CO2 com 10W por 3 segundos anteriormente ao teste de RCC. O IRA das superficies de esmalte foram avaliados após a descolagem e submetidos a análise em microscopia electrônica de varredura (MEV). Para análise estatística foram utilizados ANOVA e o teste de mann-Whitney. Os grupos laser mostraram valores de RCC menores que os grupos não irradiados (controles) (p<0.05). Os bráquetes com retenção mecânica (Mystique) mostraram alta RCC (p<0.05) e o compósito Z 250 obteve os mais baixos valores de RCC após irradiação com laser. Os grupos colados com o compósito Z 250 apresentaram os mais altos escores do IRA. O modo de fratura mais prevalente foi a adesiva. A hipótese nula foi rejeitada. O laser de CO2 foi eficaz para diminuir os valores de RCC e facilitou a descolagem dos bráquetes cerâmicos de retenção química e mecânica

Estimation of the autoclave and different surface treatments on microleakage between soft liner and heat-cured acrylic / Estimativa da autoclavagem e diferentes tratamentos de superfície na microinfiltração entre o soft liner e o acrílico termopolimerizável

Objective: The present study was oriented to estimate the effect of different surface treatments on the microleakage between the soft liner and acrylic with and without the use of autoclave as disinfection method. Material and Methods: Sixty samples were split into two groups: the autoclaved groups and non-autoclaved groups. Each one subdivided into three groups: first one without any treatments as a control group; in the second group surface of the samples were treated with CO2 laser (10.6 nm wavelength for 15 seconds), and in the third group the surface was treated with sandblasting (250 µm Al2O3). All the samples exposed to thermocycling, then the microleakage test was evaluated by gauging dye penetration depth between the soft liner and acrylic disc using a digital microscope. Data analyzed statistically by One-way ANOVA and Tukey's post-hoc tests. In addition, t-test was used for comparison between two groups (P-value ≤ 0.05). Results: The maximum mean values for the microleakage were observed in the untreated group (control) followed by the group treated by CO2 laser and the lowest mean value of microleakage was related to the third group for both non-autoclaved and autoclaved groups with significant differences among them. In addition, depending on the use of autoclave, there was non-significant in all studied groups. Conclusions: There was a decrease in the microleakage when the surface treated with CO2laser and sandblast. The use of autoclave did not badly change the microleakage between the soft liner and denture base. (AU)

Objetivo: O presente estudo teve como objetivo estimar o efeito de diferentes tratamentos de superfície na microinfiltração entre o soft liner e o acrílico usando ou não a autoclve como método de desinfecção. Material e Métodos: Sessenta amostras foram divididas em dois grupos: grupo com uso da autoclave e grupo sem uso da autoclave. Cada um subdivide em três grupos: o primeiro sem nenhum tratamento como grupo controle; no segundo grupo, a superfície das amostras foi tratada com laser de CO2 (comprimento de onda de 10,6 nm por 15 segundos) e, no terceiro grupo, a superfície foi tratada com jateamento (250 µm Al2O3). Todas as amostras foram expostas à termociclagem, em seguida o teste de microinfiltração foi realizado medindo-se a profundidade de penetração do corante entre o soft liner e o disco de acrílico em microscópio digital. Os dados foram analisados estatisticamente por One-way ANOVA e testes post-hoc de Tukey. Além disso, o teste t foi usado para comparação entre dois grupos (P-valor ≤ 0,05). Resultados: Os valores médios máximos de microinfiltração foram observados no grupo não tratado (controle) seguido pelo grupo tratado com laser de CO2 e o valor médio mínimo de microinfiltração foi relacionado ao terceiro grupo para ambos os grupos não autoclavado e autoclavado com diferenças significativas entre eles. Além disso, dependendo do uso de autoclave, não houve significância em todos os grupos estudados. Conclusão: Houve diminuição da microinfiltração quando a superfície foi tratada com laser de CO2e jateamento. O uso de autoclave não alterou a microinfiltração entre o soft liner e a base da prótese (AU)

Efficacy of Fractional CO2 Laser, Promestriene, and Vaginal Lubricant in the Treatment of Urinary Symptoms in Postmenopausal Women: A Randomized Clinical Trial.

BACKGROUND AND OBJECTIVES: Evaluating the efficacy of the fractional CO2 laser, promestriene, and vaginal lubricant to treat urinary symptoms in women with genitourinary syndrome of menopause. STUDY DESIGN/MATERIALS AND METHODS: We conducted a randomized clinical trial with 72 postmenopausal women aged 50 years or older. The participants were randomized to one intervention each in three treatment groups fractional CO2 laser, promestriene, and vaginal lubricant. Urinary symptoms were assessed prior to treatment and 2 weeks after treatment completion using validated questionnaires, the International Consultation on Incontinence Questionnaire (ICIQ-UI SF), and the International Consultation on Incontinence Questionnaire Overactive Bladder (ICIQ-OAB). RESULTS: There was a significant reduction in the total ICIQ-UI SF score in the intragroup comparison (baseline vs. week 14) of the CO2 laser group (P = 0.004). This group also showed a statistically significant reduction in nocturia (1.33 ± 0.87 vs. 1.00 ± 0.76, respectively; P = 0.031). In the intergroup comparison after treatment, nocturia in the lubricant group had worsened compared with that of the other two groups (P = 0.002). Regarding the total ICIQ-OAB score, the results of the CO2 laser group were superior to those of the lubricant group in the intergroup comparison (7.76 ± 3.36, P = 0.020; analysis of variance P = 0.038). CONCLUSION: The results were significantly different between the intravaginal fractional CO2 laser and topical estrogen groups for treating urinary symptoms related to the genitourinary syndrome of menopause. Further controlled and randomized studies are needed. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.

Efficacy of CO lasers in preventing dental caries in partially erupted first permanent molars: a randomized 18-month clinical trial.

The aim of this controlled randomized double-blinded clinical trial was to evaluate the use of a CO2 laser with or without topical application of acidulated fluorides in the prevention of dental caries in partially erupted first permanent molars. We selected 61 healthy children at high risk of caries, all between 6 and 8 (7.1 ± 0.8) years of age and with 4 partially erupted first permanent molars. A CO2 laser device emitting at 10.6 µm was used (0.5 W, 0.05 mJ per pulse, 10 kHz). Each first molar in an individual was randomly assigned to one treatment: (L) CO2 laser (0.066 J/cm2); (FL) 1.23% acidulated fluoride gel and CO2 laser (0.066 J/cm2); (V) 5% fluoride varnish, or (S) sealant (control). Patients were followed-up at 3, 6, 12, and 18 months after treatment, through direct visual examination and by an operator blinded to the treatments (kappa ≥ 0.70). The International Caries Detection and Assessment System (ICDAS-II) index was used to assess the soundness of tooth structure or the presence of white spot lesions, cavitated enamel, and/or dentin lesions. The Yildiz Visual Index was used to evaluate sealant retention. Results were evaluated using Kaplan-Meier survival analysis, and the hazard ratio of the treatments was estimated using shared frailty models with a gamma distribution, which considered the patient as a cluster. There were no significant differences among treatments compared to sealants. After 18 months, the use of a CO2 laser with or without acidulated fluorides was shown to be effective in preventing caries on the occlusal surface of partially erupted permanent first molars in children at high risk for caries.

Bioactive glass and high-intensity lasers as a promising treatment for dentin hypersensitivity: An in vitro study.

This in vitro study aimed to analyze the physical and chemical characteristics of the hypersensitive human dentin-like surface after application of a bioactive glass (BG) paste (BG/Ac) irradiated or not with high-power lasers. Dentin specimens were treated with 17% Ethylenediamine tetraacetic acid (EDTA) solution to mimic a hypersensitive dentin and then submitted to neodymium: yttrium-aluminum-garnet (Nd:YAG) laser or CO2 laser irradiation prior and after application of BG/Ac. Characterizations were performed by using X-ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The results suggested that application of BG/Ac by itself caused some obstructions of dentinal tubules. Nd:YAG laser irradiation reduced the opening of the dentinal tubules with no changes in the collagen structure. CO2 laser irradiation caused dentin melting and resolidification along with cracks and chemical changes in collagen fibers. However, when BG/Ac paste was irradiated with lasers, a sequence of surface reactions between glass and dentin interface led to the formation of an amorphous hydroxyapatite layer, similar to that of an inorganic component of the normal dentin. Moreover, BG/Ac was able to prevent the formation of cracks and degradation of collagen fibers caused by CO2 irradiation. Overall, this study supports that application of BG/Ac paste irradiated by high-power laser could represent an effective and long-lasting therapeutic approach for dentin hypersensitivity.