Combined Nd:YAG and Er:YAG lasers for real-time closed-loop tissue-specific laser osteotomy.
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ABSTRACT:
SUBMITTER: Abbasi H
PROVIDER: S-EPMC7173907 | biostudies-literature | 2020 Apr
REPOSITORIES: biostudies-literature
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Combined Nd:YAG and Er:YAG lasers for real-time closed-loop tissue-specific laser osteotomy.
Abbasi Hamed H Beltrán Bernal Lina M LM Hamidi Arsham A Droneau Antoine A Canbaz Ferda F Guzman Raphael R Jacques Steven L SL Cattin Philippe C PC Zam Azhar A
Biomedical optics express 20200304 4
A novel real-time and non-destructive method for differentiating soft from hard tissue in laser osteotomy has been introduced and tested in a closed-loop fashion. Two laser beams were combined: a low energy frequency-doubled nanosecond Nd:YAG for detecting the type of tissue, and a high energy microsecond Er:YAG for ablating bone. The working principle is based on adjusting the energy of the Nd:YAG laser until it is low enough to create a microplasma in the hard tissue only (different energies a ...[more]
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| S-EPMC5820842 | biostudies-literature
Project description:SignificanceAn increasing number of optometrists are performing Nd:YAG laser capsulotomy procedures; however, there is limited published information on the outcomes of these procedures.PurposeThis study aimed to assess the efficacy and safety of capsulotomy procedures performed by optometrists.MethodsSubjects diagnosed with posterior capsule opacification causing reduced vision and subjective visual complaints were recruited for this study. A baseline examination was performed to ensure that the subjects met all the necessary criteria. The procedure was performed by a licensed doctor of optometry at six different clinics, and each subject was monitored for visual outcome and any potential complications.ResultsSubjects' Snellen visual acuity improved from an average of 20/40 to 20/23 ( P < .001) with no complications of increased intraocular pressure, inflammation, visually significant lens pitting, macular edema, or retinal detachment. Of 78 subjects who responded to a post-procedure survey, 77 (99%) reported subjective improvement in vision after capsulotomy.ConclusionsBased on the outcomes of this study, YAG laser capsulotomies are effective treatments to improve patient vision that can be safely and effectively performed by optometrists.
| S-EPMC10662619 | biostudies-literature
Project description:This work explores the room temperature random stimulated emission at 1.064 μm of a Nd:YAG crystal powder (Neodymium-doped yttrium aluminum garnet) in a very simple pump configuration with no assistance from an internal mirror. The laser threshold energy as a function of pump beam area and pump wavelength has been measured, as well as the temporal dynamics of emission pulses. The absolute energy of stimulated emission and the absolute laser slope efficiency have been measured by using a method proposed by the authors. The results show a surprising high efficiency that takes the low Nd3+ ion concentration of the crystal powder into account.
| S-EPMC5503076 | biostudies-other
Project description:BackgroundThe vitreous is the clear jelly of the eye and contains fine strands of proteins. Throughout life the composition of this vitreous changes, which causes the protein strands in it to bundle together and scatter light before it reaches the retina. Individuals perceive the shadows cast by these protein bundles as 'floaters'. Some people are so bothered by floaters that treatment is required to control their symptoms. Two major interventions for floaters include Nd:YAG laser vitreolysis and vitrectomy. Nd:YAG laser vitreolysis involves using laser energy to fragment the vitreous opacities via a non-invasive approach. Vitrectomy involves the surgical replacement of the patient's vitreous (including the symptomatic vitreous floaters) with an inert and translucent balanced salt solution, through small openings in the pars plana.ObjectivesTo compare the effectiveness and safety of Nd:YAG laser vitreolysis to pars plana vitrectomy for symptomatic vitreous floaters.Search methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 12), MEDLINE Ovid (1946 to 17 January 2017), Embase Ovid (1947 to 17 January 2017), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 17 January 2017), the ISRCTN registry (www.isrctn.com/editAdvancedSearch); searched 17 January 2017, ClinicalTrials.gov (www.clinicaltrials.gov); searched 17 January 2017 and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 17 January 2017. We did not use any date or language restrictions in the electronic searches for trials. We also searched conference proceedings to identify additional studies.Selection criteriaWe included only randomised controlled trials (RCTs) that compared Nd:YAG laser vitreolysis to pars plana vitrectomy for treatment of symptomatic floaters.Data collection and analysisWe planned to use methods recommended by Cochrane. The primary outcome we planned to measure was change in vision-related quality of life from baseline to 12 months, as determined by a vision-related quality of life questionnaire. The secondary outcomes we planned to measure were best corrected logMAR or Snellen visual acuity at 12 months for the treated eye(s) and costs. Adverse outcomes we planned to record were the occurrence of sight-threatening complications by 12 months (asymptomatic retinal tears, symptomatic retinal tears, retinal detachment, cataract formation, and endophthalmitis).Main resultsNo studies met the inclusion criteria of this review.Authors' conclusionsThere are currently no RCTs that compare Nd:YAG laser vitreolysis with pars plana vitrectomy for the treatment of symptomatic floaters. Properly designed RCTs are needed to evaluate the treatment outcomes from the interventions described. We recommend future studies randomise participants to either a Nd:YAG laser vitreolysis group or a vitrectomy group, with participants in each group assigned to either receive treatment or a sham intervention. Future studies should follow participants at six months and 12 months after the intervention. Also they should use best corrected visual acuity (BCVA) using an Early Treatment of Diabetic Retinopathy Study (ETDRS) chart read at 4 metres, vision-related quality of life (VRQOL), and adverse outcomes as the outcome measures of the trial.
| S-EPMC6481890 | biostudies-literature
Project description:Importance:Protective eyewear or corneal shields are recommended during cosmetic facial laser treatment. Objective:To describe the occurrence of corneal inlay damage following treatment to the eyelids and face with an Nd:YAG laser. Design, Setting, and Participants:This observational case report includes a single incident case cared for at a tertiary care center. A 58-year-old man who had undergone bilateral uncomplicated myopic laser in situ keratomileusis surgery in 2003 and corneal inlay implant in the nondominant left eye in 2013 experienced decreased visual acuity (VA) and pain in the left eye after the application of 2 passes of the Nd:YAG laser to his face and both eyelids for facial tightening. At presentation, the uncorrected VA was counting fingers OS and 20/20 OD. Slitlamp biomicroscopy showed a corneal epithelial defect overlying a deformed corneal inlay, peripheral scattered pigmentary deposits, corneal haze, and brown discoloration of the lamellar pocket of the inlay. He underwent explant of the inlay and debridement 48 hours later because of deteriorating VA and increasing corneal haze. Exposure:Application of long-pulsed Nd:YAG laser at 1064 nm to the middle one-third of both upper eyelids and the periorbital region in a man with a corneal inlay implant. Corneal shields were not worn during the procedure. The peak penetration depth of this laser system is approximately 4 mm. The mean (SD) thickness of the upper eyelid in Asian eyes is 1.127 (0.238) mm. Main Outcomes and Measures:Improvement of corneal inlay damage. Results:In this 58-year-old man, 3 months after the inlay explant, the intrastromal discoloration had resolved. There was still residual corneal haze, but the patient was able to achieve a best-corrected VA of 20/25 OS for distance and J3 (Snellen equivalent, 20/30) OS for near. Conclusions and Relevance:Although the exact cause and effect cannot be determined from a single case, our findings suggest that a history of corneal inlay implant should be asked about prior to any long-pulsed Nd:YAG laser treatment to the periorbital skin and eyelids. Furthermore, these findings suggest that laser treatment to the eyelids should be avoided and that protective eyewear or corneal shields are recommended during cosmetic facial laser treatment in all patients.
| S-EPMC6802051 | biostudies-literature
Project description:Non-resonant lasers exhibit the potential for stable and consistent narrowband light sources. Furthermore, non-resonant lasers do not require well-defined optics, and thus has considerably diversified the available types of laser gain materials including powders, films, and turbid ceramics. Despite these intrinsic advantages, the practical applications of non-resonant lasers have been limited so far, mainly because of their low power efficiency and omnidirectional emission. To overcome these limitations, here we propose a light trap design for non-resonant lasers based on a spherical scattering cavity with a small entrance. Using a porous Nd3+:YAG ceramic, directional laser emission could be observed with significant enhancements in the slope efficiency and linewidth (down to 32 pm). A theoretical model is also developed to describe and predict the operation characteristics of proposed non-resonant laser.
| S-EPMC7782720 | biostudies-literature
Project description:BACKGROUND:Enamel demineralisation is an initial step of the serious dental problem including dental caries, white spot lesions and dental erosion. AIM:Compare the effect of Er, Cr: YSGG (? = 2780 nm) and nanosecond Nd: YAG (? = 1064 nm) laser on enamel acid resistance. MATERIAL AND METHODS:Thirty non-carious human premolars, extracted for orthodontic reasons, were used. The experimental groups (n = 10 each group) were: Group I, untreated (control); Group II, Er, Cr: YSGG laser irradiation (0.75 W, 20 Hz, 140 ?s, 10 s); Group III, nanosecond pulsed Nd: YAG laser irradiation (0.8 W, 10 Hz, 7 ns, 10 s). Scanning electron microscope and Energy Dispersive X-ray Spectroscopy (EDX) were used to assess acquired enamel resistance to PH cycling. RESULTS:After subjecting the three experimental groups to PH cycling, scanning electron microscopic examination revealed irregular porous dissoluted enamel surface in group I. However, groups II and III demonstrated partially dissoluted enamel surface. EDX analysis demonstrated the lowest mean percentage decrease in calcium and phosphorus content in group II followed by group III, then the highest mean percentage decrease was observed in untreated group I. One-way ANOVA revealed significant differences (p < 0.0001) between the tested groups. CONCLUSIONS:Both Er, Cr: YSSG and nanosecond Nd: YAG laser irradiation were able to improve the acid resistance of enamel. However, enamel surface treated with Er, Cr: YSSG laser showed the lowest mean percentage decrease of calcium and phosphorus (highest acid resistance).
| S-EPMC6614279 | biostudies-literature
Project description:BackgroundGlaucoma is a leading cause of global blindness, especially preventable blindness. The increased prevalence of glaucoma has led to a growing demand for newer, safer, more rapid, and simpler treatments for the reduction of intraocular pressure (IOP). In this study, we evaluated the safety and feasibility of performing filtration glaucoma surgery with an Ab-Interno Er:YAG laser in rabbits.MethodsNine New Zealand White rabbits age 16 weeks were studied. After subconjunctival injection of mitomycin C (MMC), a novel Ab-Interno Er:YAG laser probe was inserted into the anterior chamber (AC) through a clear corneal 1 mm paracentesis and directed at the trabecular meshwork adjacent to the MMC injection area. A pulsed laser beam was applied to create a patent sclerostomy connecting the AC to the subconjuctival space, resulting in a filtering bleb. The laser system used was the Er:YAG laser system - LAS25-FCU, (Pantec Biosolutions AG, Liechtenstein). Parameters used: Wave lengh: 2940 nm, Pulse length: 100-400 μsec,frequency: 250 Hz. Average laser power in accordance to the fiber tip diameter: 0.85 W(range 0.8-0.92 W). Complete ocular exams, including IOP measurements, were performed on 1, 7, 14, and 23 days postoperatively. Three rabbits were sacrificed on days 1, 14, and 23, and histological examinations were performed on all nine eyes.ResultsAll procedures resulted in a functional medium-large superior bleb without significant complications. The bleb was sustained in all rabbits by day 14 and in one of the three rabbits that reached the last follow-up at 23 days. No cases of postoperative hypotony were observed. There was a transient significant reduction in mean IOP on postoperative days 5 and 7 (P = 0.028). Histopathological analysis revealed a patent full-thickness scleral tunnel with only a minor degree of surrounding coagulation necrosis.ConclusionsThe Ab-Interno laser sclerostomy procedure is potentially safe and effective based on initial experience in an in-vivo rabbit animal model.
| S-EPMC8139072 | biostudies-literature
Project description:Purpose To investigate the effects of capsulotomy shape on the visual acuity and visual quality after neodymium: yttrium aluminum garnet laser capsulotomy. Methods In this study, a total of 42 eyes from 35 patients with posterior capsule opacification were divided into the circular and cruciate groups. The corrected distance visual acuity (CDVA), objective scatter index (OSI), modulation transfer function cutoff (MTF cutoff), Strehl ratio, and Optical Quality Analysis System values at contrasts of 100%, 20%, and 9% (OV-100, OV-20, and OV-9) were measured at precapsulotomy and 1 week and 1 month postcapsulotomy. The pseudophakic dysphotopsia questionnaire (PDQ) was used to evaluate the subjects' satisfaction with treatment. Results OSI values were significantly higher in the cruciate group than in the circular group at 1 week and 1 month after capsulotomy (P=0.013 and P < 0.001). No significant difference was found in the OSI values between the two groups before capsulotomy (t?=?0.52; P=0.61). The decrease in OSI was higher in the circular group than in the cruciate group at 1 week and 1 month after capsulotomy (P=0.036 and P=0.019). No significant differences were found in the Strehl ratio, MTF cutoff, CDVA, OV-100, OV-20, and OV-9 between the two groups at 1 week and 1 month after capsulotomy (P > 0.05). The PDQ results showed that patients with circular-shaped capsulotomy complained less with intolerance of bright lights than those with cruciate-shaped capsulotomy. Conclusions Circular-shaped capsulotomy can induce less intraocular light scattering and increase patient satisfaction.
| S-EPMC7125457 | biostudies-literature
Project description:(1) Background: The relatively high prevalence of peri-implantitis (PI) and the lack of a standard method for decontamination of the dental implant surface have pushed us to conduct further research in the field. Bacterial biofilms were found to play a primordial role in the etiology of PI. Therefore, the aim is to evaluate the efficacy of a laser-assisted elimination of biofilm protocol in the removal of a multi-species biofilm on titanium surfaces. (2) Methods: In total, 52 titanium discs (grade 4) were used. The study group consisted of 13 titanium disks contaminated with multi-species biofilms and subsequently irradiated with the laser (T + BF + L). The control groups consisted of the following types of titanium disks: 13 contaminated with multi-species biofilms (T + BF), 13 sterile and irradiated (T + L), 13 sterile and untreated (T). Q-Switch Nd:YAG laser Irradiation parameters were the following: energy density equal to 0.597 J/cm2 per pulse, power equal to 270 milliwatt per pulse, 2.4 mm of spot diameter, and 10 Hz repetition rate for pulse duration of six nanoseconds (ns). The laser irradiation was made during 2 s of total time in non-contact and at 0.5 mm away from the titanium disc surface. After treatment, presence of biofilms on the disks was evaluated by staining with crystal violet (CV), which was measured as optical density at six hundred thirty nm, and statistical analyses were done. (3) Results: the optical density values were 0.004 ± 0.004 for the study group T + BF + L, 0.120 ± 0.039 for group T + BF, 0.006 ± 0.003 for group T + L, and 0.007 ± 0.007 for group T. For the study group, laser treatment resulted in a total elimination of the biofilm, with mean values statistically significantly lower than those of contaminated titanium surfaces and similar to those of sterile titanium surfaces. (4) Conclusions: Our irradiation protocol provided a significant elimination of the multi-species biofilm on titanium surfaces. Laser treated titanium surfaces were biofilm-free, similar to the sterile ones.
| S-EPMC7177273 | biostudies-literature