Ex vivo histological characterization of a novel ablative fractional resurfacing device

Uncovering key mechanisms and intervention therapies in aging skin

Advancements in understanding skin aging mechanisms, which encompass both external and internal aging processes, have spurred the development of innovative treatments primarily aimed at improving cosmetic appearance. These findings offer the potential for the development of novel therapeutic strategies aimed at achieving long-term, non-therapy-dependent clinical benefits, including the reversal of aging and the mitigation of associated health conditions. Realizing this goal requires further research to establish the safety and efficacy of targeting aging-related skin changes, such as pigmentation, wrinkling, and collagen loss. Systematic investigation is needed to identify the most effective interventions and determine optimal anti-aging treatment strategies. These reviews highlight the features and possible mechanisms of skin aging, as well as the latest progress and future direction of skin aging research, to provide a theoretical basis for new practical anti-skin aging strategies.

Acne-induced pathological scars: pathophysiology and current treatments

Acne is a common chronic inflammatory dermatosis that can lead to pathological scars (PSs, divided into hypertrophic scars and keloids). These kinds of abnormal scars seriously reduce the quality of life of patients. However, their mechanism is still unclear, resulting in difficult clinical prevention, unstable treatment effects and a high risk of recurrence. Available evidence supports inflammatory changes caused by infection as one of the keys to abnormal proliferation of skin fibroblasts. In acne-induced PSs, increasing knowledge of the immunopathology indicates that inflammatory cells directly secrete growth factors to activate fibroblasts and release pro-inflammatory factors to promote the formation of PSs. T helper cells contribute to PSs via the secretion of interleukin (IL)-4 and IL-13, the pro-inflammatory factors; while regulatory T cells have anti-inflammatory effects, secrete IL-10 and prostaglandin E2, and suppress fibrosis production. Several treatments are available, but there is a lack of combination regimens to target different aspects of acne-induced PSs. Overall, this review indicates that the joint involvement of inflammatory response and fibrosis plays a crucial role in acne-induced PSs, and also analyzes the interaction of current treatments for acne and PS.

Effective keloid management using a combinatorial continuous-wave and repeat fractionated ablative CO2 laser regimen

BACKGROUND

Keloids are benign proliferative scars that form as a result of dysregulated growth and collagen deposition in response to cutaneous injury. Laser therapies have emerged as promising options for the treatment of keloids, with performance varying by laser type and lesion characteristics.

PURPOSE

To assess the combined continuous wave and repetitive fractionated CO2 laser treatment of keloids.

METHODS

A retrospective chart review of 22 cases of keloid scars treated with combined CO2 laser modes. A single session of continuous wave followed by five sessions of fractional delivery. Efficacy was assessed using the Patient and Observer Scar Assessment Scale (POSAS) and the Vancouver Scar Scale. The Numeric Rating Scale was used to assess patient satisfaction and pain.

RESULTS

Most patients were female (77.3%) with skin type IV (72.7%), age was 24.3 ± 9.3 years, most keloids were located on the earlobe (56.5%) or arm or hand (17.4%), size ranged from 5 to 10 cm, and time since injury ranged from 3 months to 35 years. No serious adverse events were reported. At 6 months, significant improvements from baseline occurred in all characteristics, scar color (4.8 ± 2.8 to 1.9 ± 1.1), rigidity (5.0 ± 2.8 vs. 5.4 ± 2.8), thickness (5.4 ± 2.8 vs. 2.0 ± 1.1), and irregularity (5.9 ± 2.4 vs. 1.9 ± 0.9). The Vancouver scores followed a similar trend. Patient-rated overall improvement from 37 ± 17.6 at baseline to 16.1 ± 8.5 at 6 months, and improvement in associated pain and pruritus.

CONCLUSION

Combination of two ablative laser delivery modes within a single laser platform provided for effective and safe keloid management and left patients highly satisfied.

Early postoperative interventions in the prevention and management of thyroidectomy scars

Thyroidectomy scars, located on the exposed site, can cause distress in patients. Owing to the cosmetic importance of thyroidectomy scars, many studies have been conducted on its prevention and treatment. Scar formation factors mainly include inflammatory cell infiltration, angiogenesis, fibroblast proliferation, secretion of cytokines such as transforming growth factor (TGF)-β1, and mechanical tension on the wound edges. Anti-scar methods including topical anti-scar agents, skin tension-bearing devices, and local injections of botulinum toxin, as well as lasers and phototherapies, that target these scar formation factors have been developed. However, current studies remain fragmented, and there is a lack of a comprehensive evaluation of the impacts of these anti-scar methods on treating thyroidectomy scars. Early intervention is a crucial but often neglected key to control hyperplastic thyroidectomy scars. Therefore, we review the currently adopted early postoperative strategies for thyroidectomy scar reduction, aiming to illustrate the mechanism of these anti-scar methods and provide flexible and comprehensive treatment selections for clinical physicians to deal with thyroidectomy scars.

Early intervention of carbon dioxide fractional laser in hypertrophic scar through TGFβ-1/ Smad3 signaling pathway

Hypertrophic scars are usually the result of surgical trauma or burn,and more common in individuals with a darker skin color. They appear as red and raised lesions around the wound that continually expand over a period of weeks or months, causing itching, pain, burning sensation and discomfort. Severe scarring affects interpersonal and social relationships, and decreases the quality of life of the patients.The aim of this study was to evaluate the effect of carbon dioxide fractional laser as an early intervention against hypertrophic scars using a rabbit ear scar model, and explore the role of the TGFβ-1/ Smad3 signaling pathway in scar hyperplasia. Four wounds were made into each ear of rabbits, and divided into the untreated control and three laser-treatment groups. The experimental groups received laser intervention once, twice and thrice respectively. laser treatment significantly inhibited the formation of hypertrophic scars, and maximum benefits were seen in the wounds that received three laser treatments. Immunohistochemical staining showed that the in situ expression of TGFβ-1 and Smad3 in the scars decreased by varying degrees after laser intervention, and was most obvious after three laser interventions. Furthermore, the expression levels were the lowest at the end of 6 months after modeling. Therefore, we can assume that early intervention with carbon dioxide fractional laser can prevent formation of hypertrophic scars by regulating the TGF-β1/Smad3 pathway.

Safety and Effectiveness of Laser or Intense Pulsed Light Treatment for Early Surgical Scar: A Systematic Review and Meta-analysis

OBJECTIVE

We aimed to investigate the safety and efficacy of laser or intense pulsed light therapy for early treatment of surgical scar.

METHODS

A literature search was conducted for relevant prospective, randomized controlled trials published in PubMed, Embase, Web of Science, Cochrane Library, CNKI, WanFang Database, and VTTMS between January 2006 and January 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist was used to extract literature data. The risk of bias was assessed by RevMan. Safety was assessed based on the presence of serious adverse reactions (blisters, infections, burns above the second degree), while effectiveness was assessed using the Vancouver Score Scale.

RESULTS

1512 related articles were preliminarily retrieved, including 1211 English articles and 301 Chinese articles. According to the inclusion criteria and exclusion criteria, 12 articles were selected for this analysis. In total, 475 patients were included (laser group, 238; control group, 236). All studies confirmed that the laser group was superior to the control group. In the subgroup analysis of 7 articles, the standardized mean difference was 1.99 (P = 0.0001).

CONCLUSIONS

This meta-analysis demonstrates that laser or intense pulsed light therapy is a safe and effective approach for early surgical scar treatment, resulting in improved scar appearance and minimal adverse reactions.

LEVEL OF EVIDENCE I

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 .

Ablative Laser Therapy of Skin

Laser skin rejuvenation was introduced in the mid-1990s. Early ablative laser devices relied on scanner technology that provided significant ablation and longer time on tissue treatments. These early treatments provided significant improvement in the appearance of the skin, but because of the longer treatment times and in some cases excessive treatment, complications such as scarring and hypopigmentation were significant. More recent advances in skin resurfacing technology have now minimized these risks providing certain key principles are observed. These parameters are reviewed in detail to improve the reader's ability to propose and execute proper skin resurfacing treatments.

Fractional CO2 laser versus 1064-nm long-pulsed Nd:YAG laser for inflammatory acne vulgaris treatment: a randomized clinical trial

Acne vulgaris is challenging to treat for several individuals. Laser therapy may be a desirable alternative to traditional therapies with limited success. This study aimed to assess efficacy of fractional CO2 laser versus Nd:YAG laser for acne vulgaris therapy. Thirty cases with acne vulgaris underwent both fractional CO2 laser and Nd: YAG laser treatments in a randomized split face design at a 14-day interval for four sessions. The clinical efficacy was evaluated by counting acne lesions and utilizing the Global Acne Severity Scale (GEA Scale). GEAs decreased significantly after both fractional CO2 and Nd:YAG modalities after treatment and at a 3-month follow-up; fractional CO2 demonstrated significant more decrease in GEAs with (P = 0.006, 0.00 (respectively. Moreover, fractional CO2 showed a significantly higher satisfaction level (P = 0.004) and a better clinical improvement percentage regarding inflammatory and noninflammatory acne lesions (P = 0.007 and 0.000, respectively) after 3 months of follow-up. Apart from transient erythema, there were insignificant adverse effects concerning both treated sides. Fractional CO2 and Nd:YAG lasers are efficient physical modalities of acne treatment. However, fractional CO2 laser was more effective and more satisfying to the patients.

Nevus of Ota: Combination Treatment with Q-Switched Neodymium-Doped Yttrium Aluminum Garnet Laser and Fractional CO2 Laser

Background

Nevus of Ota is a facial dermal melanocytic hamartoma occurring more commonly in Asians. The mainstay of treatment is 1064-nm Q-Switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, which has shown variable results in pigmented skin.

Objective

The aim of this study was to determine whether Q-Switched Nd:YAG laser treatment combined with fractional CO2 laser is more efficacious than Q-Switched Nd:YAG laser alone.

Materials and Methods

This was a prospective study with 81 patients. The patients were randomly divided into two groups. Group 1 received 1064-nm Q-Switched Nd:YAG laser alone and group 2 in addition received a fractional CO2 laser as well. Both groups received six sittings at monthly intervals. The treatment response was documented with physician global assessment (PGA) and patient's treatment satisfaction on Wong-Baker Facial Pain Scale (WBFPS). Dermoscopic evaluation was done to see subsurface pigment clearance.

Results

In the combination group, 25% of patients had more than 50% improvement as compared with 5.71% in group 1. To achieve a mean PGA score of 1.4, it took six sessions for group 1 versus only four for group 2. Dermoscopic evaluation showed faster pigment clearance in the combination group.

Conclusion

Combining two lasers shows statistically significant faster and greater degree of improvement as compared with Q-Switched Nd:YAG laser monotherapy in nevus of Ota.

Debonding of LDSVs utilising Er,Cr:YSGG laser irradiation with fractional technique: an in vitro study

BACKGROUND

The removal of porcelain laminate veneers with rotary instruments could be accompanied by microfractures because differentiation of the veneer from the dental structure and resin cement is not a highly selective procedure. This can lead to scratches and overheating of the enamel and patient discomfort. Therefore, this in vitro research aimed to examine the effectiveness of the 2790 nm Er,Cr:YSGG laser utilizing a fractional technique to debond lithium disilicate veneer.

METHODS

Six groups of 30 extracted permanent bovine mandibular incisors were selected. Twenty-five samples, G1-5, (n = 5) laser-irradiated groups, and the last five samples (C) were considered the control group. The tested groups were irradiated with 3-5 W output power of Er,Cr:YSGG laser for time intervals of 50 s. During irradiation, the temperature in the pulp chamber was monitored using a thermocouple connected to a digital multilogger thermometer inside the sample's pulp chamber. Subsequently, the shear bond strength was measured for all groups. Furthermore, the remaining adhesive index was measured using a stereomicroscope, the area was analysed, and then transformed into scores. Finally, one untreated sample and two samples of the highest power value from laser-treated groups were examined using a scanning electron microscope (SEM) for their surface morphology.

RESULTS

All debonding protocols were safe regarding intrapulpal temperature increment. The highest temperature elevation was recorded at 5 W, which increased by 1.7 °C. Considering the shear bond strength measurement, there was a significant reduction after laser irradiation for G1-5 compared with group C.

CONCLUSIONS

Er,Cr:YSGG laser with a fractional technique can be used successfully for veneer removal. Besides safe temperature rising, veneers can be reused because there was neither a fractured specimen during the whole study nor major irregularities or cracks shown in SEM pictures analysis for the veneer surfaces; thus, they can be removed quickly, safely, and comfortably using Er,Cr:YSGG. © 2023 Australian Dental Association.

Transepidermal Delivery of Triamcinolone Acetonide or Platelet Rich Plasma Using Either Fractional Carbon Dioxide Laser or Micro-needling in Treatment of Alopecia Areata

INTRODUCTION

Trans-epidermal drug delivery, using "laser-assisted drug delivery", or micro-needling, are new treatment modalities, that can improve drug penetration into skin in treatment of alopecia areata patients.

OBJECTIVES

To evaluate the use of fractional carbon dioxide laser versus micro-needling in trans-epidermal delivery of triamcinolone acetonide and platelet rich plasma in alopecia areata treatment.

METHODS

Interventional comparative study carried out on 60 patients, randomly divided into four equal groups. Group I: Fractional Carbon dioxide laser and triamcinolone acetonide. Group II: micro-needling with Dermapen and triamcinolone acetonide. Group III: fractional carbon dioxide laser and platelet-rich plasma. Group IV: micro-needling with Dermapen and platelet-rich plasma. Patients were evaluated clinically, using Severity of Alopecia Tool score and hair regrowth scale, and dermoscopically.

RESULTS

In all treatment groups, there was improvement in the Regrowth scale, with statistical significance between the different groups at fourth (P = 0.001) and last (P = 0.008) visits, with highest, most significant changes in Pen-Steroid group. Comparing Regrowth scale at last visit, results were in favor of Dermapen, compared to Carbon dioxide laser for trans-epidermal drug delivery (P = 0.023); and in favor of triamcinolone acetonide, compared to platelet-rich plasma as topical medication (P = 0.015). Dermoscopic signs of improvement included decrease in black dots, and appearance of Upright regrowing hairs (P < 0.001).

CONCLUSIONS

Micro-needling and fractional carbon dioxide laser are effective tools for trans-epidermal drug delivery for Alopecia areata treatment. Micro-needling for delivery of Triamcinolone acetonide showed best treatment outcomes. Dermoscopy is highly beneficial in evaluating treatment response in alopecia areata.

The Use of Lasers and Light Devices in Acne Management: An Update

Acne vulgaris is a disease of the pilosebaceous unit and the most common inflammatory dermatosis worldwide. It is also associated with significant economic burden. Limitations of conventional topical and systemic treatments include long treatment course, intolerable adverse effects, antibiotic resistance, and patient compliance. Therefore, laser and light-based interventions present as alternative options over the past decade and have been used in combination with conventional pharmacological therapies and other physical modalities. An updated overview on the use of lasers and light-based devices in acne management is presented to help clinicians understand the safety and efficacy of these treatment options. The effectiveness of neodymium:yttrium aluminum garnet (Nd:YAG) for treating acne is supported by more high-level studies compared with other laser devices. There is limited evidence to support the use of CO₂ lasers, potassium titanyl phosphate lasers, and 1565-nm non-ablative fractional lasers for treating acne. Among light devices, photodynamic therapy is the most studied, showing higher efficacies than some of the conventional topical and oral acne therapies. Intense-pulsed light and blue light therapies also show favorable outcomes. A limitation is that most studies are non-randomized and lack a control group, and report on a variety of device settings, treatment regimens, and outcome measures, making it challenging to summarize and generalize findings. Although the use of laser and light devices to treat acne is promising, further work with randomized controlled study designs and larger sample sizes will provide improved guidance on the application of these modalities.

Effects of multiple modes of UltraPulse fractional CO2 laser treatment on extensive scarring: a retrospective study

The main therapeutic options for extensive scarring (e.g., > 20% of the total body surface area, or TBSA) after burns and trauma have focused on conservative treatments, such as compression, moisturization, and topical agent application. However, these treatments may not achieve optimal effects due to the large size and complexity of the scars. UltraPulse fractional CO₂ laser treatment is a novel approach that is currently a subject of intense interest; this treatment is most widely used to improve texture, pliability, and pigmentation in all types of scars. However, no studies on the independent use of UltraPulse fractional CO₂ laser treatment for extensive scars have been reported. This retrospective study evaluated a total of 21 patients, whose scars covered 20 to 65% TBSA. Scar thickness was measured by ultrasonography before treatment. Personalized treatment modalities and parameters were set according to the scar type and thickness. Scar formation and treatment effects were evaluated by photography, the Patient and Observer Scar Assessment Scale (POSAS), and patients’ judgment of effectiveness. Where the scars covered joints, joint function was assessed by measuring the maximum range of motion (ROM). With laser therapy, scars became flatter and lighter; furthermore, pruritus, pain, and discomfort decreased significantly. POSAS scores significantly decreased after laser therapy, including the item scores for pain and pruritus. There were no instances of joint contracture, ROM reduction, apparent functional impairment, serious adverse events, or comorbidities. This study demonstrates the safety and efficiency of UltraPulse fractional CO₂ laser treatment for extensive scarring.

Laser Therapy for the Treatment of Morphea: A Systematic Review of Literature

Morphea, also known as localized scleroderma (LoS), comprises a set of autoimmune sclerotic skin diseases. It is characterized by inflammation and limited thickening and induration of the skin; however, in some cases, deeper tissues might also be involved. Although morphea is not considered a life-threatening disease, the apparent cosmetic disfigurement, functional or psychosocial impairment affects multiple fields of patients’ quality of life. Therapy for LoS is often unsatisfactory with numerous treatments that have only limited effectiveness or considerable side effects. Due to the advances in the application of lasers and their possible beneficial effects, the aim of this study is to review the reported usage of laser in morphea. We present a systematic review of available literature, performed with MEDLINE, Cinahl, Central, Scopus, Web of Science, and Google Scholar databases. We identified a total of twenty relevant studies (MEDLINE n = 10, Cinahl n = 1, Central n = 0, Scopus n = 2, Web of Science n = 5, Google Scholar n = 2) using laser therapy for LoS. Eight studies were focused on the use of PDL, six on fractional lasers (CO₂ and Er:YAG), four on excimer, and two on either alexandrite or Nd:YAG.

Effects of the lower energy and pulse stacking in carbon dioxide laser skin treatment: an objective analysis using second harmonic generation

PURPOSE

To evaluate the effect of fractional carbon dioxide (CO2) laser treatment using lower power associated with pulse stacking within collagen fibers, using second harmonic generation microscopy and computerized image analysis.

METHODS

Twenty male Wistar rats aging eight weeks were used. Each treatment area received a single-pass CO2 fractional laser with different parameters. The 20 animals were divided into two groups and euthanized after 30 and 60 days. Second harmonic generation images were obtained and program ImageJ was utilized to evaluate the collagen organization within all areas. Collagen anisotropy, entropy and optical density were quantified.

RESULTS

Increased anisotropy over time was observed in all four areas, but only reached statistical significance (p = 0.0305) when the mildest parameters were used (area four). Entropy decreased over time in all areas, but without significance(p = 0.1779) in area four. Density showed an overtime increase only in area four, but no statistical significance was reached (p = 0.6534).

CONCLUSIONS

When combined, the results obtained in this study regarding anisotropy, entropy and density tend to demonstrate that it is possible to achieve collagen remodeling with the use of lower power levels associated with stacked pulses.

A Comparison of Efficacy and Safety of Fractional Carbon Dioxide Laser and Fractional Er:YAG Laser for the Treatment of Xanthelasma Palpebrarum: A Two-Center Randomized Split-Face Controlled Trial

Background: Xanthelasma palpebrarum (XP) is a form of cutaneous xanthoma that presents as collections of yellowish papules or plaques around the eyelids or canthus, affecting patients cosmetically. Objective: This study aimed to compare the efficacy and safety of fractional carbon dioxide (CO₂) laser to that of fractional Er:YAG laser for the treatment of XP. Methods: Two centers recruited patients diagnosed with XP of bilaterally symmetrical lesions. The lesion on one side was randomly assigned to be treated with fractional CO₂ laser while the lesion on the other side was treated with fractional Er:YAG laser. All subjects received up to five treatments, with a 4-week interval between each treatment. Results: Thirty-nine patients completed the study and a total of 82 lesions were available for final assessment. The percentage of "Excellent Improvement" on third and fourth visit was 60.98% versus 39.02% and 90.24% versus 63.41%, respectively, p < 0.05. In a follow-up for 12 to 25 months, the number of lesions recurred on the side treated with fractional CO₂ laser and fractional Er:YAG laser are 9 (22%) and 10 (24%), respectively. Conclusions: In this study, fractional CO₂ laser therapy appears superior since a fewer treatments are required for patients to show significant clinical improvement.

Combination of ablative fractional carbon dioxide laser and platelet-rich plasma treatment to improve hypertrophic scars: a retrospective clinical observational study

BACKGROUND

Hypertrophic scars are one of the main complications that affect the quality of life of patients after burns. Many methods have been shown to be effective in the treatment of hypertrophic scars, such as ablative fractional CO₂ laser (AFCL) and platelet-rich plasma (PRP). However, there are few studies on the effect of the combined application of these measures. The purpose of this study was to explore the therapeutic effect of AFCL combined with PRP on hypertrophic burn scars.

METHODS

A retrospective clinical observation study was conducted on 50 patients with hypertrophic burn scars. The AFCL+PRP group included 31 patients who received AFCL combined with PRP treatment; the AFCL group included 19 patients who received AFCL treatment only. The University of North Carolina 4P Scar Scale (UNC4P) and the Vancouver Scar Scale (VSS) scores that were collected before each treatment were used as indicators of the effectiveness of the previous treatment. The scores recorded at the second, fourth and seventh months were analysed.

RESULTS

The demographic data of the 2 groups were not significantly different. Before treatment, there was no difference in the UNC4P and VSS scores between the 2 groups. There was a significant decline in the UNC4P and VSS total scores over 6 months in both groups (p < 0.05) and scores in the 2 groups were comparable after 3 and 6 months (p < 0.05). UNC4P scores in the AFCL+PRP group decreased from a mean of 8.26 to 2.61 (p < 0.05) with a concomitant drop in VSS scores from a mean of 11.74 to 6.06 (p < 0.01). In the AFCL group UNC4P and VSS scores decreased from 7.68 to 4.63 (p < 0.05) and from 10.89 to 8.16 (p < 0.05), respectively. The sub-items of these 2 assessments were analysed and the results suggest that AFCL combined with PRP can comprehensively improve scarring.

CONCLUSIONS

This study shows that PRP is an effective adjunct for AFCL in the treatment of hypertrophic burn scars and that the combination of PRP and AFCL proved to be more useful than AFCL alone. This combination may be a new and effective clinical practice for the treatment of scars. However, larger and higher-level clinical studies are still needed to determine its efficacy and possible mechanisms.

Laser Treatment of Traumatic Scars and Contractures: 2020 International Consensus Recommendations

BACKGROUND AND OBJECTIVES

There is currently intense multidisciplinary interest and a maturing body of literature regarding laser treatments for traumatic scars, but international treatment guidelines and reimbursement schemes have not yet caught up with current knowledge and practice in many centers. The authors intend to highlight the tremendous potential of laser techniques, offer recommendations for safe and efficacious treatment, and promote wider patient access guided by future high-quality research.

STUDY DESIGN/MATERIALS AND METHODS

An international panel of 26 dermatologists and plastic and reconstructive surgeons from 13 different countries and a variety of practice backgrounds was self-assembled to develop updated consensus recommendations for the laser treatment of traumatic scars. A three-step modified Delphi method took place between March 2018 and March 2019 consisting of two rounds of emailed questionnaires and supplementary face-to-face meetings. The panel members approved the final manuscript via email correspondence, and the threshold for consensus was at least 80% concurrence among the panel members.

RESULTS

The manuscript includes extensive detailed discussion regarding a variety of laser platforms commonly used for traumatic scar management such as vascular lasers and ablative and non-ablative fractional lasers, special considerations such as coding and laser treatments in skin of color, and 25 summary consensus recommendations.

CONCLUSIONS

Lasers are a first-line therapy in the management of traumatic scars and contractures, and patients without access to these treatments may not be receiving the best available care after injury. Updated international treatment guidelines and reimbursement schemes, additional high-quality research, and patient access should reflect this status. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Ablative fractional laser-assisted treatments for keratinocyte carcinomas and its precursors-Clinical review and future perspectives

Keratinocyte carcinomas (KC) are the most common malignant human neoplasms. Although surgery and destructive approaches are first-line treatments, topical therapies are commonly used. Due to limited uptake of topical agents across the skin barrier, clearance rates are often sub-optimal. In pre-clinical investigations, ablative fractional laser (AFL)-assisted drug delivery has demonstrated improved uptake of topical drugs commonly used to treat KC. In 22 clinical trials, the effect of AFL-assisted treatments has been investigated for actinic keratosis (AK; n = 14), Bowen's disease (BD; n = 5), squamous cell carcinoma (n = 1), and basal cell carcinoma (n = 7). The most substantial evidence currently exists for AFL-assisted photodynamic therapy for the treatment of AK and BD. AFL improved 12-months follow-up clearance rates of photodynamic therapy from 45.0-51.0% to 78.5-84.8% for AK and from 50.0-55.3% to 87.0-87.5% for BD. AFL-assisted pharmacological therapy is a promising tool for optimizing topical treatments of KC and its precursor lesions. Future developments include AFL-assisted immune activation, changing drug administration route of systemic therapies, and utilizing drug chemo-combinations.

Application of reflectance confocal microscopy to investigate the non-ablative, micro-ablative, and ablative effects of CO2 fractional laser irradiation on skin

CO₂ fractional laser, as an ablative fractional laser, is commonly used in cosmetic treatment. We applied CO₂ fractional laser irradiation to skin in vitro and used reflectance confocal microscopy (RCM) to image and detect the presence of any non-ablative, micro-ablative and ablative effects, in order to better understand the features of a CO₂ fractional laser. In vitro irradiation of foreskin was performed using a CO₂ fractional laser. Foreskin specimens were divided into 4 groups that received different amounts of irradiation energy, based on the number of irradiation passes they received: 5, 10, 15, and 20 passes, respectively. This corresponds to fluence energy of 16.3, 32.6, 48.9, 65.3 J/cm². Immediately after irradiation, digital microscopy (DM), RCM, and histopathology were performed to observe whether the non-ablative, micro-ablative, and ablative phenomenon occurred, and the injury features of MTZs. Immediately after CO₂ fractional laser irradiation, RCM and DM showed that when the numbers of passes were 5 and 10, a micro-ablative column (MAC) could not be observed or was very small. We mainly observed a thicker thermal coagulation zone (TCZ), representing non-ablative or micro-ablative effects. When the number of passes were increased to 15 and 20, the MAC was significantly enlarged and surrounded by a TCZ of medium thickness, representing ablative effects. For the first time, this study used RCM and DM to demonstrate that a CO₂ fractional laser could achieve non-ablative, micro-ablative, and ablative effects on irradiated skin via different energy levels.

Fractional laser-assisted topical delivery of bleomycin quantified by LC-MS and visualized by MALDI mass spectrometry imaging

Bleomycin exhibits antiproliferative effects desirable for use in dermato-oncology but topical use is limited by its 1415 Da molar mass. Ablative fractional laser (AFL)-assisted drug delivery has been shown to enhance drug uptake in skin. The aim of this study was with AFL to deliver bleomycin into skin, quantify uptake, and visualize biodistribution with mass spectrometry. In a Franz diffusion cell study, pig skin samples (n = 66) were treated with AFL (λ = 10,600 nm), 5% density, and 0, 5, 20, or 80 mJ/microbeam (mb) pulse energies before exposure to bleomycin for 0.5, 4, or 24 h. Bleomycin was quantified in biopsy cryosections at depths of 100, 500, and 1500 µm using high-performance liquid chromatography-mass spectrometry (LC-MS), and drug biodistribution was visualized for 80 mJ/mb samples by matrix assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). The pulse energies 5, 20, and 80 mJ/mb resulted in microscopic ablation zones (MAZs) reaching superficial, mid, and deep dermis respectively. Bleomycin was successfully delivered into the skin and deeper MAZs and longer exposure time resulted in higher skin concentrations. After 24 h, AFL exposure resulted in significant amounts of bleomycin throughout all skin layers (≥510 µg/cm3, p ≤ .002). In comparison, concentrations in intact skin exposed to bleomycin remained below limit of quantification. MALDI-MSI supported the quantitative LC-MS results by visualizing bleomycin biodistribution and revealing high uptake around MAZs with delivery into surrounding skin tissue. In conclusion, topical drug delivery of the large and hydrophilic molecule bleomycin is feasible, promising, and should be explored in an in vivo setting.

A Meta-analysis of the Evidence for Assisted Therapy with Platelet-Rich Plasma for Atrophic Acne Scars

BACKGROUND

A number of studies have investigated the role of platelet-rich plasma (PRP) as an assisted therapy for atrophic acne scars. However, the results are diverse, and no up-to-date meta-analysis was found that exclusively examined atrophic acne scar treatment.

OBJECTIVES

To perform a meta-analysis to assess improvements in the side effects of PRP and the effect of assisted therapy for atrophic acne scars.

METHODS

This study followed PRISMA guidelines. A comprehensive search of the literature was carried out in September 2018 using the electronic databases of PubMed, EMBASE, MEDLINE, and the Cochrane Library.

RESULTS

Seven articles were included in this review. All of the studies published utilized PRP as additive therapy. The major therapies included fractional carbon laser therapy and microneedling. Five studies (249 participants) reported four degrees of improvement on an improvement scale (degrees 3 and 4 were considered improvement in this analysis). Four studies (200 participants) reported mean improvement scores. A significantly higher degree of improvement was shown in the PRP group compared to the control group (OR = 8.19; 95% CI 4.32-15.52; p < 0.00001), as well as better mean improvement score (WMD = 23.73; 95% CI 18.60-28.87; p < 0.00001). Substantial heterogeneity was seen in the degree of improvement (I² = 54% p = 0.07) and the mean improvement score (I² = 75%; p = 0.008). There were overall fewer monitored side effects, including erythema and edema (in days), in the PRP groups; however, no significance was found.

CONCLUSIONS

This review shows that PRP is a useful assisted therapy for atrophic acne scars, which can achieve better improvement.

LEVEL OF EVIDENCE III

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.

Evaluation of autologous adipose-derived stem cells vs. fractional carbon dioxide laser in the treatment of post acne scars: a split-face study

BACKGROUND

Scarring is a distressing outcome of acne, as it causes cosmetic and psychological problems to the patients. Unfortunately no single treatment is satisfactory; instead, employing multiple modalities may have better outcome. Autologous adipose tissue-derived adult stem cells (AT-ASCs) and their secretory factors can stimulate collagen synthesis; angiogenesis and migration of fibroblasts thus regenerate damaged tissues. Also, conventional treatments for acne scarring, such as lasers and topical regimens, induce new collagen synthesis via activation of dermal fibroblasts or growth factors. The aim of the study was to verify the effectiveness of AT-ASCs for the treatment of acne scarring vs. the fractional carbon dioxide laser (FxCR).

SUBJECTS AND METHODS

Split face comparative study included 10 adult patients with post-acne scars on both sides of the face. One side received AT-ASCs single injection while the other received three sessions of FxCR. Scars were then assessed using the global scoring system Goodman and Baron, scar area percent using NIH ImageJ software and functional assessment by measuring the transepidermal water loss (TEWL) and skin hydration. Both sides were followed for three months.

RESULTS

A significant improvement in the degree of scar severity, scar area percent, skin hydration, and TEWL after 3 months of treatment on both sides of the face with insignificant differences between both treatment modalities, provided that AT-ASCs treatment was employed once vs. three sessions of FxCR.

CONCLUSION

One injection of AT-ASCs is as effective as three sessions of FxCR in the treatment of atrophic acne scars.

Molecular Mechanisms of Dermal Aging and Antiaging Approaches

The dermis is primarily composed of the extracellular matrix (ECM) and fibroblasts. During the aging process, the dermis undergoes significant changes. Collagen, which is a major component of ECM, becomes fragmented and coarsely distributed, and its total amount decreases. This is mainly due to increased activity of matrix metalloproteinases, and impaired transforming growth factor-β signaling induced by reactive oxygen species generated during aging. The reduction in the amount of collagen hinders the mechanical interaction between fibroblasts and the ECM, and consequently leads to the deterioration of fibroblast function and further decrease in the amount of dermal collagen. Other ECM components, including elastic fibers, glycosaminglycans (GAGs), and proteoglycans (PGs), also change during aging, ultimately leading to a reduction in the amount of functional components. Elastic fibers decrease in intrinsically aged skin, but accumulate abnormally in photoaged skin. The changes in the levels of GAGs and PGs are highly diverse, and previous studies have reported conflicting results. A reduction in the levels of functional dermal components results in the emergence of clinical aging features, such as wrinkles and reduced elasticity. Various antiaging approaches, including topicals, energy-based procedures, and dermal fillers, can restore the molecular features of dermal aging with clinical efficacy. This review summarizes the current understanding of skin aging at the molecular level, and associated treatments, to put some of the new antiaging technology that has emerged in this rapidly expanding field into molecular context.

The rise of transcutaneous drug delivery for the management of alopecia: a review of existing literature and an eye towards the future

Introduction: Fractional lasers and microneedling devices are increasingly used with topical drugs to treat various conditions, including alopecia, as they grant access to dermal structures such as hair follicles and cutaneous vasculature. Objective: To perform a comprehensive review on transcutaneous drug delivery for the management of alopecia. Methods: PubMed, Embase, and Ovid Medline databases were searched using terms including: alopecia, microneedling, lasers, androgenetic alopecia (AGA), alopecia areata (AA), drug delivery. Articles were examined for inclusion criteria: diagnosis of alopecia regardless of type, use of fractional laser or microneedling devices, and subsequent administration of topical medication. Results: 8 studies, 6 prospective clinical trials and 2 case series, examining either AA or AGA were identified. For AA, five studies examined microneedling together with topical triamcinolone in three of these, while two studies used photodynamic therapy. Regarding AGA, two studies used topical minoxidil plus microneedling, and one examined topical finasteride with fractional erbium glass laser. Improvement was seen in 6 of the 8 studies. Discussion: Transcutaneous drug delivery via fractional laser and microneedling is a promising modality with preliminary evidence for increased hair regrowth over topical therapy alone. Further studies are needed to elucidate treatment parameters and appropriate device selection for drug delivery.

The comparison of skin rejuvenation effects of vitamin A, fractional laser, and their combination on rat

BACKGROUND

Because of long-term exposure of skin, skin aging is an unavoidable natural law with age. Traditional Vitamin A and novel ablative fractional laser technique both have the effects of skin rejuvenation, and studies have demonstrated both of them have apparent clinical efficacy and histology-improving effects on photo-aging skin.

MATERIALS AND METHODS

45 female healthy Wistar rats were selected and the depilation areas of every rat were divided into four regions: control region(Region A), Vitamin A acid region(Region B), combination treatment region(Region C), and fractional laser region(Region D). 0.025% Vitamin A acid cream was applied to Region B and C every day for 3 weeks; Region C and D were irradiated once with 10600nm CO₂ fractional laser on the first day of the trail. The skin tissue was dissected and placed into liquid nitrogen according to the design. The real-time quantitative PCR and western blotting methods were taken to detect the expression changes of miR-29a, Akt, TGF-β, and mRNA of type III pre-collagen.

RESULTS

It can be seen from the results of the real-time quantitative PCR that the mRNA expression levels of type III pre-collagen, Akt, and TGF-β in the treatment regions are up-regulated and the expression levels of miR-29a mRNA are down-regulated compared to the Region A. The hybridization tests showed that changes of the expression of type III pre-collagen, Akt gene, miR-29a gene, and TGF-β gene across the experiment regions are all significantly different in the third week, and the expression levels of them all achieve the highest value in the third week, the expression level of miR-29a gene achieves the lowest value in the third week, which are consistent with the results of real-time quantitative PCR.

CONCLUSION

It is indicated that the combination region of Vitamin A acid and fractional laser may lead to low expression of miR-29a, thus the inhibition of downstream Akt activation is loss, Akt activation is enhanced, enhancement of the expression of TGF-β is induced, leading to proliferation of fibroblasts, and promotion of the collagen proteins' synthesis in skin. Therefore miR-29a/Akt/TGF-β signal pathway may participate in the skin rejuvenation mechanism of action Vitamin A acid and fractional laser. This may provide a new treatment approach for skin rejuvenation.

Histological findings after argon plasma coagulation: an ex-vivo study revealing a possible role in superficial ablative treatment of the skin

Argon plasma coagulation (APC) is an electrosurgical technique which can be used to ablate skin lesions with limited invasion depth into dermal tissue. Hence, APC might be well suited for the removal of epithelial tumours. However, there are no data on the effects of APC on human skin tissue. Thus, the aim of this study was to determine the extent of epidermal and dermal damage after APC of human skin. We performed APC ex-vivo on 91 freshly resected human skin samples, which were obtained after reconstructive surgical closures in actinically damaged areas. Tissue effects were evaluated histologically and compared across different power settings. Using 15, 30, and 45 W, median (interquartile range; IQR) coagulation depths were 110.0 µm (91.7-130.0), 113.3 µm (85.8-135.0), and 130.0 µm (100.0-153.3.0), respectively. Median (IQR) thickness of necrosis zone was 30.0 µm (23.3-40.0) at 15 W, 26.7 µm (20.0-41.6) at 30 W, and 43.3 µm (30.8-57.5) at 45 W. The Kruskal-Wallis test showed significant differences between 15 and 30 W versus 45 W for coagulation depth (P = 0.0414), necrosis zone (P = 0.0017), and necrosis according to overlaying epidermal thickness (P = 0.0467). In summary, APC is a simple and controllable electrosurgical technique to remove epidermal tissue with limited penetration to the dermis. Thus, APC is particularly suited for the ablation of epithelial skin lesions and, therefore, may serve as possible treatment approach for intraepithelial neoplasms such as actinic keratosis.

Fractional Laser Releases Tumor-Associated Antigens in Poorly Immunogenic Tumor and Induces Systemic Immunity

Currently ablative fractional photothermolysis (aFP) with CO₂ laser is used for a wide variety of dermatological indications. This study presents and discusses the utility of aFP for treating oncological indications. We used a fractional CO₂ laser and anti-PD-1 inhibitor to treat a tumor established unilaterally by the CT26 wild type (CT26WT) colon carcinoma cell line. Inoculated tumors grew significantly slower in aFP-treated groups (aFP and aFP + anti-PD-1 groups) and complete remission was observed in the aFP-treated groups. Flow cytometric analysis showed aFP treatment elicited an increase of CD3+, CD4+, CD8+ vand epitope specific CD8+ T cells. Moreover, the ratio of CD8+ T cells to Treg increased in the aFP-treated groups. Additionally, we established a bilateral CT26WT-inoculated mouse model, treating tumors on one-side and observing both tumors. Interestingly, tumors grew significantly slower in the aFP + anti-PD-1 groups and complete remission was observed for tumors on both aFP-treated and untreated sides. This study has demonstrated a potential role of aFP treatments in oncology.

Fractional laser exposure induces neutrophil infiltration (N1 phenotype) into the tumor and stimulates systemic anti-tumor immune response

BACKGROUND

Ablative fractional photothermolysis (aFP) using a CO2 laser generates multiple small diameter tissue lesions within the irradiation field. aFP is commonly used for a wide variety of dermatological indications, including treatment of photodamaged skin and dyschromia, drug delivery and modification of scars due to acne, surgical procedures and burns. In this study we explore the utility of aFP for treating oncological indications, including induction of local tumor regression and inducing anti-tumor immunity, which is in marked contrast to current indications of aFP.

METHODOLOGY/PRINCIPAL FINDINGS

We used a fractional CO2 laser to treat a tumor established by BALB/c colon carcinoma cell line (CT26.CL25), which expressed a tumor antigen, beta-galactosidase (beta-gal). aFP treated tumors grew significantly slower as compared to untreated controls. Complete remission after a single aFP treatment was observed in 47% of the mice. All survival mice from the tumor inoculation rejected re-inoculation of the CT26.CL25 colon carcinoma cells and moreover 80% of the survival mice rejected CT26 wild type colon carcinoma cells, which are parental cells of CT26.CL25 cells. Histologic section of the FP-treated tumors showed infiltrating neutrophil in the tumor early after aFP treatment. Flow cytometric analysis of tumor-infiltrating lymphocytes showed aFP treatment abrogated the increase in regulatory T lymphocyte (Treg), which suppresses anti-tumor immunity and elicited the expansion of epitope-specific CD8+ T lymphocytes, which were required to mediate the tumor-suppressing effect of aFP.

CONCLUSION

We have demonstrated that aFP is able to induce a systemic anti-tumor adaptive immunity preventing tumor recurrence in a murine colon carcinoma in a mouse model. This study demonstrates a potential role of aFP treatments in oncology and further studies should be performed.

Laser in the management of burn scars

BACKGROUND AND OBJECTIVE

Burn scars are associated with significant morbidity ranging from contractures, pruritus, and disfigurement to psychosocial impairment. Traditional therapies include silicone gel, compression garments, corticosteroid injections, massage therapy, and surgical procedures, however, newer and advanced therapies for the treatment of burn scars have been developed. Lasers, specifically ablative fractional lasers, show potential for the treatment of burn scars.

METHODS

Both MeSH and keyword searches of the PubMed, Medline and Embase databases were performed and relevant articles were read in full for the compilation of this review.

RESULTS

Fifty-one relevant observational studies, clinical trials, and systematic reviews published in English from 2006 to 2016 were reviewed and summarized.

CONCLUSION

Laser therapy is effective for the treatment of burn scar appearance, including measures such as pigmentation, vascularity, pliability, and thickness. Ablative fractional laser therapy, in particular, shows significant potential for the release of contractures allowing for improved range of motion of affected joints. Patients may benefit from the use of lasers in the treatment of burn scars, and the safety profile of lasers allows the benefits of treatment to outweigh the risks. Laser therapy should be included in burn scar treatment protocols as an adjuvant therapy to traditional interventions.

The effect of surface treatment with a fractional carbon dioxide laser on shear bond strength of resin cement to a lithium disilicate-based ceramic

BACKGROUND

This study investigated the impact of different surface treatments, including fractional carbon dioxide (CO₂) laser on shear bond strength (SBS) of resin cement to lithium disilicate ceramic.

MATERIALS AND METHODS

In this in vitro study, 72 blocks of IPS e.max CAD ceramic were randomly divided into six groups in terms of treatment (n = 12). Group 1 underwent etching with 9.6% hydrofluoric (HF) acid, whereas group 2 was subjected to air abrasion with aluminum oxide particles. Groups 3 and 4 were treated with a fractional CO₂ laser for 10 s using 10 W/14 mJ (group 3) or 20 W/10 mJ (group 4). In groups 5 and 6, the CO₂ laser was applied similar to that in groups 3 and 4, respectively; then, the specimens were etched by HF acid. After silane application, luting cement was bonded to the specimens. The SBS was assessed with a universal testing machine, and the type of bond failure was determined. Data were analyzed by ANOVA, Duncan, and Fisher's exact tests.

RESULTS

Surface conditioning with fractional CO₂ laser alone resulted in significantly lower SBS than HF acid treatment (P < 0.05). Bond strengths of the specimens treated with a combination of laser irradiation and acid etching were significantly greater than all the other groups (P < 0.05). No significant difference was found in the distribution of failure modes among the groups (P = 0.337).

CONCLUSION

The combination of fractional CO₂ laser irradiation and HF acid etching could be recommended when extra retention is required for lithium disilicate-based restorations, whereas laser treatment alone cannot produce sufficient SBS.

Application of reflectance confocal microscopy to evaluate skin damage after irradiation with an yttrium-scandium-gallium-garnet (YSGG) laser

The objective of this study was to observe the characteristics of the skin after irradiation with a 2790-nm yttrium-scandium-gallium-garnet (YSGG) laser using reflectance confocal microscopy (RCM). A 2790-nm YSGG laser was used to irradiate fresh foreskin (four doses, at spot density 3) in vitro. The characteristics of microscopic ablative columns (MAC), thermal coagulation zone (TCZ), and microscopic treatment zones (MTZ) were observed immediately after irradiation using digital microscope and RCM. The characteristics of MAC, TCZ, and MTZ with variations in pulse energy were comparatively analyzed. After irradiation, MAC, TCZ, and MTZ characteristics and undamaged skin between MTZs can be observed by RCM. The depth and width of MTZ obviously increased with the increase in pulse energy. At 80, 120, and 160 mJ/microbeam (MB), the MTZ actual area and proportion were about two times that of the theoretical value and three times at 200 mJ/MB. With increases in depth, the single MAC gradually decreased in a fingertip-shaped model, with TCZ slowly increasing, and MTZ slightly decreasing in a columnar shape. RCM was able to determine the characteristics of thermal injury on the skin after the 2790-nm YSGG laser irradiation with different pulse energies. Pulse energy higher than 200 mJ/MB may have much larger thermal injury and side effect. RCM could be used in the clinic in future.

Fractional CO₂ Laser Pretreatment Facilitates Transdermal Delivery of Two Vitamin C Derivatives

BACKGROUND

Topical vitamin C derivatives have been used to treat melasma and used as a skin whitener. The aim of this study was to compare skin histology and permeation of l-ascorbic acid 2-phosphate sesquimagnesium salt (MAP-1) and magnesium l-ascorbic acid-2-phosphate (MAP-2) after fractional CO₂ laser pretreatment.

METHODS

The effect of fractional laser treatment on porcine skin was examined by scanning electron microscopy and confocal laser scanning electron microscopy. The effect of fractional CO₂ laser treatment of different fluencies and pass numbers on transdermal flux of the two vitamin C derivatives through porcine skin was examined in vitro using a Franz diffusion chamber.

RESULTS

Fluxes of MAP-1 and MAP-2 across fractional CO₂ laser-treated (5 W) skin were eight- to 13-fold, and 20- to 22-fold higher, respectively, than the fluxes of these compounds across intact skin. Fluxes of MAP-1 and MAP-2 across fractional CO₂ laser-treated (9 W) skin were 14- to 19-fold, and 30- to 42-fold higher, respectively, than their fluxes across intact skin.

CONCLUSION

Fractional CO₂ laser treatment is an effective way of delivering vitamin C derivatives into the skin.

Dermal Remodeling of Burn Scar by Fractional CO2 Laser

BACKGROUND

Ablative CO2 fractional lasers have recently been introduced for burn scar treatment because of pronounced clinical outcomes with fewer treatment sessions than nonablative fractional laser.

OBJECTIVE

This study was conducted to observe clinical as well as histologic changes of burn scars after treatment with CO2 fractional laser.

MATERIALS AND METHODS

Eleven patients (one female and 10 males, aged 31-59 years) with skin phototypes III to V with burn scars received 10 sessions of fractional CO2 laser treatments (UltraPulse(®) Encore; Lumenis, Santa Clara, CA, USA) over an average 5-week interval. Two passes were performed using the following parameters: deep FX mode, 12.5-30 mJ, with a density setting of 5-10 %. Clinical evaluations by three blinded dermatologists were obtained at baseline and at 6 months after the final treatment via photographs using the Vancouver scar scale (VSS). Skin biopsies were done on four patients before and after treatment.

RESULTS

All patients showed clinical improvement in their scars with significant decrease in VSS. Histologic findings showed the changes in the upper dermis with newly formed dermal papilla. This characteristic upper dermis change was presented as improvement in surface smoothness and skin tension clinically. Postinflammatory hyperpigmentation and itching sensation were the most common adverse effects.

CONCLUSION

Burn scar treatment by fractional CO2 laser is effective by forming new collagen fibers mainly in the upper dermis.

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 .

Lower energy and pulse stacking. A safer alternative for skin tightening using fractional CO2 laser

PURPOSE

To evaluate the effect of different energies and stacking in skin shrinkage.

METHODS

Three decreasing settings of a fractional CO2 laser were applied to the abdomen of Twenty five Wistar rats divided into three groups. Group I (n=5) was histologically evaluated for microthermal zones dimensions. Groups II and III (n=10 each) were macroscopic evaluated with freeware ImageJ for area contraction immediately and after 30 and 60 days.

RESULTS

No statistical significance was found within microthermal zone histological dimensions (Group I) in all settings studied. (Ablation depth: 76.90 to 97.18µm; Coagulation depth: 186.01 to 219.84 µm). In Group II, macroscopic evaluation showed that all settings cause significant immediate skin contraction. The highest setting cause significant more intense tightening effect initially, contracting skin area from 258.65 to 179.09 mm2. The same pattern was observed in Group III. At 30 and 60 days, the lowest setting significantly sustained contraction.

CONCLUSION

Lower fractional CO2 laser energies associated to pulse stacking could cause consistent and long lasting tissue contraction in rats.

Fractional carbon dioxide laser versus low-dose UVA-1 phototherapy for treatment of localized scleroderma: a clinical and immunohistochemical randomized controlled study

Morphea is a rare fibrosing skin disorder that occurs as a result of abnormal homogenized collagen synthesis. Fractional ablative laser resurfacing has been used effectively in scar treatment via abnormal collagen degradation and induction of healthy collagen synthesis. Therefore, fractional ablative laser can provide an effective modality in treatment of morphea. The study aimed at evaluating the efficacy of fractional carbon dioxide laser as a new modality for the treatment of localized scleroderma and to compare its results with the well-established method of UVA-1 phototherapy. Seventeen patients with plaque and linear morphea were included in this parallel intra-individual comparative randomized controlled clinical trial. Each with two comparable morphea lesions that were randomly assigned to either 30 sessions of low-dose (30 J/cm²) UVA-1 phototherapy (340-400 nm) or 3 sessions of fractional CO₂ laser (10,600 nm-power 25 W). The response to therapy was then evaluated clinically and histopathologically via validated scoring systems. Immunohistochemical analysis of TGF-ß1 and MMP1 was done. Patient satisfaction was also assessed. Wilcoxon signed rank test for paired (matched) samples and Spearman rank correlation equation were used as indicated. Comparing the two groups, there was an obvious improvement with fractional CO₂ laser that was superior to that of low-dose UVA-1 phototherapy. Statistically, there was a significant difference in the clinical scores (p = 0.001), collagen homogenization scores (p = 0.012), and patient satisfaction scores (p = 0.001). In conclusion, fractional carbon dioxide laser is a promising treatment modality for cases of localized morphea, with proved efficacy of this treatment on clinical and histopathological levels.

Thermal Response of In Vivo Human Skin to Fractional Radiofrequency Microneedle Device

Background. Fractional radiofrequency microneedle system (FRMS) is a novel fractional skin resurfacing system. Data on thermal response to this fractional resurfacing technique is limited. Objectives. To investigate histologic response of in vivo human skin to varying energy settings and pulse stacking of a FRMS in dark-skinned subjects. Methods. Two female volunteers who were scheduled for abdominoplasty received treatment with a FRMS with varying energy settings at 6 time periods including 3 months, 1 month, 1 week, 3 days, 1 day, and the time immediately before abdominoplasty. Biopsy specimens were analyzed using hematoxylin and eosin (H&E), Verhoeff-Van Gieson (VVG), colloidal iron, and Fontana-Masson stain. Immunohistochemical study was performed by using Heat Shock Protein 70 (HSP70) antibody and collagen III monoclonal antibody. Results. The average depth of radiofrequency thermal zone (RFTZ) ranged from 100 to 300 μm, correlating with energy levels. Columns of cell necrosis and collagen denaturation followed by inflammatory response were initially demonstrated, with subsequent increasing of mucin at 1 and 3 months after treatment. Immunohistochemical study showed positive stain with HSP70. Conclusion. A single treatment with a FRMS using appropriate energy setting induces neocollagenesis. This wound healing response may serve as a mean to improve the appearance of photodamaged skin and atrophic scars.

Surface treatment with a fractional CO2 laser enhances shear bond strength of resin cement to zirconia

AIMS

The present study investigated the effect of different surface treatments on shear bond strength (SBS) of resin cement to zirconia.

MATERIALS AND METHODS

Ninety zirconia blocks were prepared and divided into 6 groups of 15 by treatment. Group 1 served as the control group, whereas groups 2 and 3 were treated with air abrasion and a universal primer (Monobond plus), respectively. The remaining zirconia copings were treated with a fractional CO2 laser for 10 seconds using 10 W/10 mJ (group 4), 10 w/14 mJ (group 5) or 20 W/10 mJ (group 6). A luting cement (Clearfil SA) was bonded to the treated zirconia surfaces and cured for 40 seconds. SBS was measured with a universal testing machine and the type of bond failure was determined.

RESULTS

There was a statistically significant difference in SBS among the study groups (p<0.001). The highest SBS values were observed in the groups treated with the fractional CO2 laser at settings of 20 W/10 mJ (28.1 MPa) or 10 W/14 mJ (27.4 MPa), followed by the specimens treated with the universal primer (22.8 MPa). The control specimens exhibited the lowest SBS (9.4 MPa) among the study groups (p<0.05). There was no significant difference in the distribution of failure modes among the groups (p=0.871).

CONCLUSIONS

The application of fractional CO2 laser can improve bond strength of resin cement to zirconia ceramic, and thus it could be considered as an appropriate alternative to conventional methods of zirconia surface treatment.