Deep subsurface cavities in skin utilizing mechanical optical clearing and femtosecond laser ablation.

Background And Objectives: High precision subsurface ablation can be produced in transparent materials using femtosecond laser pulses and multiphoton absorption. Light scattering limits application of the same technique to most biological tissues. Previously, subsurface ablation was demonstrated at superficial depths (50-250 µm) in highly scattering tissues including murine skin and human sclera.

Femtosecond laser lithotripsy: feasibility and ablation mechanism.

Light emitted from a femtosecond laser is capable of plasma-induced ablation of various materials. We tested the feasibility of utilizing femtosecond-pulsed laser radiation (lambda=800 nm, 140 fs, 0.9 mJ/pulse) for ablation of urinary calculi.

Plasma-mediated ablation: an optical tool for submicrometer surgery on neuronal and vascular systems.

Plasma-mediated ablation makes use of high energy laser pulses to ionize molecules within the first few femtoseconds of the pulse. This process leads to a submicrometer-sized bubble of plasma that can ablate tissue with negligible heat transfer and collateral damage to neighboring tissue. We review the physics of plasma-mediated ablation and its use as a tool to generate targeted insults at the subcellular level to neurons and blood vessels deep within nervous tissue.

Time and frequency resolved XeCl laser-induced mechanical transients in otic capsule bone.

Objective: This study identifies the presence of photoacoustic waves during excimer laser treatment of porcine otic capsule bone.

Background Data: Pulsed ultraviolet lasers have been suggested for use in middle ear surgery due to their potential for fiberoptic delivery, decreased thermal trauma, and precise ablation characteristics. However, the short pulse width of excimer lasers (typically 10-150 ns) can create large thermoelastic stresses in the ablation specimen.

Enhancement of transepidermal skin clearing agent delivery using a 980 nm diode laser.

Background And Objectives: Patient compliant optical skin clearing requires non-invasive topical delivery of clearing agents such as glycerol. This requires reducing the skin barrier function by disrupting stratum corneum integrity, which was achieved using a 980 nm diode laser with artificial absorption substrates on the skin surface. Reduction of light scattering has the potential to improve many current and novel diagnostic and therapeutic applications of lasers in medicine.

Ultrashort pulse laser ossicular ablation and stapedotomy in cadaveric bone.

Background And Objective: The purpose of this study was to evaluate the ablation of ossicular tissue using a 1,053 nm Ti:Sapphire chirped pulse amplifier laser system configured to deliver ultrashort pulses of 350 femtoseconds (fs) (3.5x10(-13) seconds) in cadaver temporal bone.

Study Design/materials And Methods: Ablation of the formalin-fixed incus and stapes was performed using an ultrashort pulse laser (USPL) (0.

Measurement of Acoustic Transients During Pulsed Holmium:YAG Laser Ablation of Cadaveric Human Temporal Bone.

Pulsed infrared (IR) and ultraviolet (UV) lasers have been suggested for use in middle ear surgery due to potential fiberoptic delivery, decreased thermal trauma and precise ablation characteristics. Although attention has been focused on the thermal and photoacoustic events that occur during pulsed laser ablation of hard tissue, there are few studies which evaluate the acoustic energy generated from these devices from an audiological standpoint. In this study, the mastoid cavities of cadaveric human temporal bones were irradiated with a holmium: yttrium aluminium garnet (Ho:YAG) laser (λ=2.

Effect of XeCl-308nm excimer laser on the mineral content of human dentin.

The effect of the XeCl-308nm excimer laser on the mineral content and surface morphology of cut dentin was examined in ten extracted human teeth. Each dentin specimen was lased for 4 s at a fluence of 1 J/cm2 and a frequency of 25 Hz. Non-lased area of the same specimen served as control.

XeCl laser surgery of the vocal cords: a histologic comparison with CO2 laser in a porcine model.

Fresh cadaveric pig larynxes were ablated with a CO2 (lambda = 10.6 microm) and a XeCl excimer (lambda = 308 nm) laser. Histologic comparison of the ablation craters created by the two lasers was performed, and ablation crater depth and marginal tissue damage were measured.

Thermal imaging of the temporal bone in CO2 laser surgery: an experimental model.

The unique properties of lasers create an enormous potential for specific treatment of chronic ear disease. Despite the widespread acceptance and use of the laser, however, a complete understanding of the time- and space-dependent temperature distribution in otic capsule bone immediately after pulsed laser exposure has not been elucidated. Using a liquid nitrogen-cooled mercury-cadmium telluride infrared detector, the temperature distribution in human cadaveric otic capsule bone was determined immediately after pulsed (100 msec) carbon dioxide laser exposure (0.

Surface temperature distributions in carbon dioxide, argon, and KTP (Nd:YAG) laser ablated otic capsule and calvarial bone.

Hypothesis: The spatial and temporal surface temperature distribution was measured after laser irradiation in fresh porcine otic capsule and calvarial bone tissue using an HgCdTe (mercury-cadmium-tellurium) infrared camera.

Background: Carbon dioxide (CO2) (lambda = 10.6 mm), argon (lambda = 514 nm), and Potassium-Titanyl-Phosphate Neodynium: Yttrium-Aluminum-Garnet (KTP[Nd:YAG]) (lambda = 532 nm) lasers are used for stapes surgery and in the treatment of chronic ear disease.

The influence of laser parameter configurations at 9.3 microns on incisional and collateral effects in soft tissue.

These investigations were performed to determine histologic and incisional consequences of varying pulse duration, duty cycle, and average powers during laser incision at 9.3 microns in soft tissue. In 19 fresh pigs' jaws six standardized incisions 3 cm long were made per parameter with a template and motorized jig.

Ablation of human nail by pulsed lasers.

Background And Objective: The hard and resistant structure of the nail plate forms a natural barrier that limits the penetration of topical drugs. To overcome this barrier, the use of pulsed laser systems has been suggested. The purpose of this study was to evaluate the effect of four laser systems on nail plate ablation rates, ablation efficiencies, and subsequent craters morphology.

Identification of photoacoustic transients during pulsed laser ablation of the human temporal bone: an experimental model.

Laser ablation of hard tissues during neurotologic operations has been accomplished with continuous-wave (CW) lasers in the visible and midinfrared spectrum. The mechanism of ablation at these wavelengths is secondary to photothermal-induced tissue destruction. As a result, significant thermal damage to surrounding tissue may occur.

Two-lasers assisted ablation: a method for enhancing conventional laser ablation of materials.

A new method for enhanced ablation by pulsed laser radiation has been demonstrated. The method utilizes an "impulse" ablation laser in conjunction with cyclical heating of the tissue by an auxiliary source: the "primer." In this study we use an auxiliary laser as the "primer" heat source, which sets up a thermal and stress field modulation in the target material.

Dentin ablation with three infrared lasers.

Background And Objective: Lasers are used for caries removal in enamel and dentin, but are currently limited in their ability to remove sound tooth structure. In this study plasma interaction regimes are investigated as the principal factor determining the ablation characteristics.

Study Design/materials And Methods: Three ablation parameters are considered: ablation rates (AR), surface temperatures (ST), and surface morphological characteristics.

Efficacy of XeCl-308 excimer laser in fusing hydroxyapatite to seal the root apex.

Sealing the root apex during apical surgery is important for a successful outcome. The effect of XeCl-308 nm excimer laser irradiation on the fusion and seal of hydroxyapatite to the root apex was tested in extracted human teeth. Twenty-four roots of intact single-rooted premolars were instrumented to size 30 K-file at the apex leaving a patent apical foramen.

Developmental competence of mouse embryos following zona drilling using a non-contact holmium:yttrium scandian gallium garnet (Ho:YSGG) laser system.

The purpose of this study was to assess the efficacy of the holmium:yttrium scandian gallium garnet (Ho:YSGG) laser, operating in a pipette-free, non-contact mode, to assist hatching and sustain normal embryonic development. Two-cell mouse embryos were recovered and assigned to laser-assisted hatching (LAH) treatment or control human tubal fluid (HTF) culture with or without serum (HTF-s, HTF-o) or with late serum supplementation (HTF-o/s). The basic experimental apparatus for LAH consisted of a stationary 2.

Efficacy of XeCl 308-nm excimer laser in reducing dye penetration through coronal dentinal tubules.

The efficacy of XeCl excimer laser irradiation in reducing dye penetration through human coronal dentinal tubules was studied. The roots of 20 freshly extracted human molars were resected, and the apical aspect of the crowns was ground until the pulp chamber was completely exposed. Following total removal of the pulp chamber and further grinding of the occlusal and apical surfaces up to the intact dentin, the teeth were randomly divided into experimental and control groups of 10 each.

Assisted hatching in mouse embryos using a noncontact Ho:YSGG laser system.

Purpose: A noncontact holmium:yttrium scandium gallium garnet (Ho:YSGG) laser system has been designed and tested for the micromanipulation of mammalian embryos. The purpose of this preliminary investigation was to determine the effectiveness of this laser for assisted hatching and evaluate its impact on embryo viability. The Ho:YSGG system, utilizing 250-microsecond pulses at a wavelength of 2.

Opening of the mouse zona pellucida by laser without a micromanipulator.

A contact-free laser system is described for ablation of the embryonic mouse zona pellucida using a pulsed excimer 308 nm laser. Effects on further embryonic development were evaluated. Zonae of 8- to 16-cell mouse embryos were either lased (n = 189), zona-drilled with acidified Tyrode's solution (n = 183) or left zona-intact (n = 188).

Sealing of human dentinal tubules by XeCl 308-nm excimer laser.

Root hypersensitivity occurs as a result of exposed dentinal tubules. Various methods and materials have been tried in an attempt to occlude these tubules. The purpose of this investigation was to study by scanning electron microscope the effects of XeCl excimer laser on exposed dentinal tubules of human extracted teeth.

Effects of the XeCl excimer laser on Streptococcus mutans.

The effect of XeCl excimer laser irradiation on the growth of Streptococcus mutans in liquid media and on agar plates was studied. Bacterial suspensions of S. mutans were placed in 96 wells of well culture plates.