Collagen thermal damage and collagen synthesis after cutaneous laser resurfacing

Kuo, Timothy C.; Speyer, Matthew T.; Ries, William Russell; Reinisch, Lou

doi:10.1002/(sici)1096-9101(1998)23:2<66::aid-lsm3>3.0.co;2-t

Cited by 52 publications

(22 citation statements)

References 15 publications

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“…6). Thus, the new collagen growth followed the amount of thermally damaged collagen as reported by Kuo et al [11]. We also note that the antire¯ection coating on the zinc selenide window was damaged by the laser and epidermal ablation.…”

Section: Resultsmentioning

confidence: 99%

Carbon dioxide laser skin resurfacing with a cooled handpiece

et al. 2001

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Section: Resultsmentioning

confidence: 99%

Carbon dioxide laser skin resurfacing with a cooled handpiece

et al. 2001

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“…The thermal effects of Er:YAG laser were largely studied. 14, 26-28 After laser ablation of tissue, the residual thermal zone can induce collagen neogenesis, 29 but too much thermal damage may result in unwanted complications. 28 The evaluation of residual thermal zone depends on histologic examination previously, but the procedure is not real-time and invasive in nature, rendering biopsy patients after laser treatment for cosmetic purpose impossible.…”

Section: Discussionmentioning

confidence: 99%

Monitoring laser-tissue interaction by non-linear optics

et al. 2008

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To assess laser therapies in clinical practice, histologic examinations were commonly used. But histologic examinations were invasive and not real-time in nature. In this work, we validate multiphoton microscopy as a useful modality in evaluating laser-tissue reaction in vivo. Multiphoton microscopy based on femtosecond titanium-sapphire laser system were used to evaluate autoflurescence (AF) and second harmonic generation (SHG). Nude mouse skin was irradiated with Erbium:YAG laser at low to high fluence. High resolutional images can be obtained by multiphoton microscopy. At low fluence, Erbium:YAG laser can selectively loosen compact stratum corneum with minimal injury to basal layer. At high fluence, ablated keratinocytes and residual debris can be imaged. The laser thermal effect on dermis could be measured by SHG signals of collagen fibers. SHG decreased as laser fluence increased. Multiphoton microscopy is a useful in-vivo technique in evaluating ablative and thermal effects of Erbium:YAG laser on nude mouse skin.

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“…The usefulness of the continuous-wave CO 2 laser (10,600 nm) was limited by its long pulse duration, which had the potential to produce unwanted adjacent thermal damage and scarring. 7,8,9,10 As laser technology improved, higher energy laser systems…”

Section: Ablative Resurfacing Lasers Carbon Dioxide Laser Resurfacingmentioning

confidence: 99%

20 Ablative Laser Facial Skin Rejuvenation

Papel¹,

Frodel²,

Holt³

et al. 2016

Facial Plastic and Reconstructive Surgery

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The primary chromophore for the CO 2 lasers and Er:YAG lasers is water. Whenever using a laser, consideration should be given to other competitive chromophores that may absorb the wavelength. These competing chromophores may give additional benefit or create additional risks associated with using a particular laser wavelength.For example, at a wavelength of 532 nm, there is absorption of laser energy by both oxyhemoglobin and melanin. Thus, this type of laser can affect both vascular and pigmented lesions. Therefore, in patients with higher Fitzpatrick skin types there is an increased risk of developing hypopigmentation if treated with this laser wavelength.The possibility of competing chromophores should be considered whenever a laser is being selected. This should also be considered whenever using an IPL device, which can produce a spectrum of wavelengths. The spectrum of emitted wavelengths will depend on the light source as well as any associated filters.Examples in which competing chromophores can be advantageous are the current hair reduction lasers, which are designed to exert their effect on melanin, the target chromophore. These lasers may also be absorbed by hemoglobin, which is a competing chromophore. This absorption by hemoglobin, the competing chromophore, can also result in injury to the blood vessels supplying the hair follicle, which is desirable.Ninety percent of the epidermis is water. Consequently, water is the primary chromophore for the current resurfacing lasers, including the Er:YAG and CO 2 . During resurfacing treatments, the intercellular water absorbs laser energy and instantly boils or vaporizes. The amount of energy that a laser delivers to the tissue and the time over which it is delivered determines the amount of tissue vaporized. For skin resurfacing, the objective is to vaporize the primary chromophore, water, while transferring a limited amount of heat to the surrounding collagen and other structures. This is because type I collagen is extremely heat-sensitive and becomes denatured at 60°C to 70°C. These lasers are designed to avoid excessive thermal injury to the collagen as this can produce scarring.The fluence of a laser represents the amount of energy (joules) that is applied to the surface area of tissue (centimeter squared). Therefore, fluence is expressed as J/cm 2 . For CO 2 lasers, 0.04 J/mm 2 is the critical energy needed to overcome the tissue ablation threshold. For skin resurfacing, this is can be accomplished with 250 mJ per laser pulse using a 3-mm spot size. After each pulse, the tissue is allowed to cool before the delivery of the next pulse. The tissue thermal relaxation time is the amount of time necessary between pulses for complete cooling to occur. The pulse duration is the time the tissue is actually lasered.

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Collagen thermal damage and collagen synthesis after cutaneous laser resurfacing

Cited by 52 publications

References 15 publications

Carbon dioxide laser skin resurfacing with a cooled handpiece

Carbon dioxide laser skin resurfacing with a cooled handpiece

Monitoring laser-tissue interaction by non-linear optics

20 Ablative Laser Facial Skin Rejuvenation

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