Influence of the Nd:YAG Laser Pulse Duration on the Temperature of Primary Enamel

The aim of this study is to evaluate the temperature change on specimens of primary enamel irradiated with different pulse duration of Nd:YAG laser. Fifteen sound primary molars were sectioned mesiodistally, resulting in 30 specimens (3.5 × 3.5 × 2.0 mm). Two small holes were made on the dentin surface in which K-type thermocouples were installed to evaluate thermal changes. Specimens were randomly assigned in 3 groups (n=10): A = EL (extra long pulse, 10.000 μs), B = LP (long pulse, 700 μs), and C = SP (short pulse, 350 μs). Nd:YAG laser (λ= 1.064 μm) was applied at contact mode (10 Hz, 0.8 W, 80 mJ) and energy density of 0.637 mJ/mm2. Analysis of variance (ANOVA) was performed for the statistical analysis (P=0.46). Nd:YAG laser pulse duration provided no difference on the temperature changes on primary enamel, in which the following means were observed: A = EL (23.15°C ± 7.75), B = LP (27.33°C ± 11.32), and C = SP (26.91°C ± 12.85). It can be concluded that the duration of the laser pulse Nd:YAG increased the temperature of the primary enamel but was not influenced by different pulse durations used in the irradiation.

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Q-Switch Nd:YAG Laser-Assisted Decontamination of Implant Surface

Dentistry Journal ◽

10.3390/dj7040099 ◽

2019 ◽

Vol 7 (4) ◽

pp. 99 ◽

Cited By ~ 2

Author(s):

Namour ◽

El Mobadder ◽

Magnin ◽

Peremans ◽

Verspecht ◽

...

Keyword(s):

Pulse Duration ◽

Nd:Yag Laser ◽

Yttrium Aluminum Garnet ◽

Short Pulse ◽

Sem Analysis ◽

P Value ◽

Implant Surface ◽

Contact Mode ◽

Short Pulse Duration ◽

Clean Contaminated

Peri-implantitis (PI) is an inflammatory disease of peri-implant tissues, it represents the most frequent complication of dental implants. Evidence revealed that microorganisms play the chief role in causing PI. The purpose of our study is to evaluate the cleaning of contaminated dental implant surfaces by means of the Q-switch Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser and an increase in temperature at lased implant surfaces during the cleaning process. Seventy-eight implants (titanium grade 4) were used (Euroteknika, Sallanches, France). Thirty-six sterile implants and forty-two contaminated implants were collected from failed clinical implants for different reasons, independent from the study. Thirty-six contaminated implants were partially irradiated by Q-switch Nd:YAG laser (1064 nm). Six other contaminated implants were used for temperature rise evaluation. All laser irradiations were calibrated by means of a powermetter in order to evaluate the effective delivered energy. The irradiation conditions delivered per pulse on the target were effectively: energy density per pulse of 0.597 J/cm2, pick powers density of 56 mW/cm2, 270 mW per pulse with a spot diameter of 2.4 mm, and with repetition rate of 10 Hz for pulse duration of 6 ns. Irradiation was performed during a total time of 2 s in a non-contact mode at a distance of 0.5 mm from implant surfaces. The parameters were chosen according to the results of a theoretical modeling calculation of the Nd:YAG laser fluency on implant surface. Evaluation of contaminants removal showed that the cleaning of the irradiated implant surfaces was statistically similar to those of sterile implants (p-value ≤ 0.05). SEM analysis confirmed that our parameters did not alter the lased surfaces. The increase in temperature generated at lased implant surfaces during cleaning was below 1 °C. According to our findings, Q-switch Nd:YAG laser with short pulse duration in nanoseconds is able to significantly clean contaminated implant surfaces. Irradiation parameters used in our study can be considered safe for periodontal tissue.

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Effects of Pulse Duration on Laser Micro Polishing

Journal of Micro and Nano-Manufacturing ◽

10.1115/1.4023756 ◽

2013 ◽

Vol 1 (1) ◽

Cited By ~ 24

Author(s):

Madhu Vadali ◽

Chao Ma ◽

Neil A. Duffie ◽

Xiaochun Li ◽

Frank E. Pfefferkorn

Keyword(s):

Surface Roughness ◽

Laser Pulse ◽

Pulse Duration ◽

Near Infrared ◽

Short Pulse ◽

Laser Pulses ◽

Laser Pulse Duration ◽

Feature Size ◽

Short Pulse Duration ◽

Metallic Parts

Pulsed laser micro polishing (PLμP) has been shown to be an effective method of polishing micro metallic parts whose surface roughness can approach the feature size. Laser pulse duration in the PLμP process is an important parameter that significantly affects the achievable surface finish. This paper describes the influence of laser pulse duration on surface roughness reduction during PLμP. For this purpose, near-infrared laser pulses have been used to polish Ti6Al4V at three different pulse durations: 0.65 μs, 1.91 μs, and 3.60 μs. PLμP at longer pulse durations resulted in dominating Marangoni convective flows, yet significantly higher reductions in the average surface roughness were observed compared to the short pulse duration regime without convection.

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