Search results for "Nd:YAG laser"
showing 6 items of 26 documents
Characterisation of cw Nd : YAG laser keyhole dynamics
2001
Abstract The paper concerns laser–matter interaction characterisation. In this work, we use a rapid CCD camera located coaxially to the laser beam and we compare recorded images with those obtained by numerical modelling. Because images are difficult to understand, we compute thermal radiation emitted by a keyhole of fixed geometry and we adjust it trying to approach the camera record. The modelling treats radiative heat transfer within the keyhole and determines the sensor illumination map. By adjusting the geometrical characteristics of the hole, we seek to obtain the image that corresponds as well as possible to the realised experiment. Results are compared with other experimental method…
Microstructural and tribological study of Nd:YAG laser treated titanium plates.
2008
Abstract In this work, the fretting behaviour of pure Ti plates laser treated with a Nd:YAG pulsed laser was compared to that of untreated Ti plates. Fretting tests were done at room temperature without lubrication. The contact geometry was a cylinder (bearing steel) on a plane. The evolution of both the ratio, μ = Q / P , between the normal and the tangential forces, and the Fouvry's energy criterion ( A ) were recorded as a function of the number of fretting cycles, N . Energy dispersive spectrometry and micro-Raman spectroscopy were used to analyse the fretting scars. The oxidized layer formed by the laser treatment displayed a mixed slip regime as a function of N , and a smaller frettin…
Grooving by Nd:YAG laser treatment
2000
Abstract The properties of the laser beam have been used to produce deep and thin grooves in metals, melted material being removed with the assistance of a high velocity gas. Preliminary experiments show that the geometry and the location of the gas inlet tube are the main parameters governing the evacuation of the scoria. The influence of the nature of the materials on the depth of the grooves is discussed from examination of the grooves realized on various metals (copper, aluminum, titanium,…). Finally, a statistical study is performed to indicate the parameters that have to be controlled to secure regular grooves. It appears that the groove width is not too much affected by parameter var…
Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study
2012
Objective: Literature reports bactericidal and biostimulant effects for Nd:YAG laser procedures on bone and oral mucosa but the possible overheating can cause damage to anatomical structures. The aim of the study is the evaluation of thermal increase in different levels of oral tissues: mucosa, periosteum and bone during defocused application of Nd:YAG laser at different parameters. Study Design: Superficial thermal evaluation was performed in pig jaws with a thermal camera device; deep thermal evaluation was realized by 4 thermocouples placed at a subperiosteal level and at 1,2 and 4 mm depth in the jaw bone. Laser applications of 1 minute were performed 5 times (with a pause of 1 minute) …
Effectiveness of Nd:YAG Laser on the elimination of debris and Smear Layer : a comparative study with two different irrigation solution: Edta and qmi…
2018
Background The aim of this study was to evaluate the effectiveness in dentin debris and smear layer removal from root canal walls using EDTA and QMix® alone and also activated with Nd:YAG laser. Material and Methods 50 single-rooted teeth were instrumented and divided in 5 groups according to irrigation protocol: 17% EDTA, QMix®, Nd:YAG laser alone, and combination of 17% EDTA - Nd:YAG laser and QMix® - Nd:YAG laser. Samples were evaluated using SEM. Statistical analysis was done using Chi-Square Fisher exact test and McNemar test. Results Dentinal debris analysis showed statistically significant differences when comparing 17% EDTA vs Laser and Laser vs QMix® in combination with Laser at th…
Nd:YAG-Laserung einer retrohyaloidalen Blutung nach Venenastverschluss
2006
Background A retrohyaloidal haemorrhage can be caused by different underlying diseases. Usually dense haemorrhages are treated by early vitrectomy. We want to report the successful treatment of a retrohyaloidal haemorrhage by means of Nd:YAG laser membranotomy. Materials and methods A 47-year-old man noticed two weeks before presentation a sudden visual loss in the left eye. Visual acuity on the first visit was c. c. 20/32 OD and c. c. 20/400 ex. OS. Dilated fundus examination of the left eye showed multiple intraretinal haemorrhages in the superior periphery and a dense retrohyaloidal haemorrhage over the macula. Anamnestic risk factors for ocular bleeding were systemic hypertension in con…