Influence of the Nd:YAG laser pulse duration on the temperature of primary enamel.

Rodrigo Alexandre Valério ,Rodrigo Galo ,Valnei S Cunha ,Fabrício Augusto De Lima ,Luciano Bachmann ,Silmara Aparecida Milori Corona ,Maria Cristina Borsatto

doi:10.1155/2015/396962

Rodrigo Alexandre Valério , Rodrigo Galo + Show 5 more

Open Access

https://doi.org/10.1155/2015/396962

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Journal: TheScientificWorldJournal	Publication Date: Jan 1, 2015
Citations: 12	License type: CC BY 3.0

Affiliation: Universidade de São Paulo

Abstract

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.

Highlights

Developed by Johnson in 1961 [1], the Nd:YAG can be employed at continuous or pulsed mode emitting light with a wavelength located in the infrared range of the electromagnetic spectrum
The Nd:YAG laser can be recommended in pediatric dentistry, since its use promotes increasing on the acid resistance of primary enamel [3, 4], sealing of pits and fissures [5] and effectiveness on the prevention of carious lesions [6, 7]
The thermal effect promotes melting, formation of cracks and debris on the surface, and the modification of tubular dentin structure [15]. These alterations on dentin can occur due to the lower thermal conductivity of this substrate when compared to the primary enamel [16,17,18]

Summary

Introduction

The parameters used during irradiation of dental structures must comply with the characteristics of the tissues, since the variation in surface temperature of the irradiated enamel can lead to higher heat conduction and spread to the pulp tissue causing irreversible damage. The thermal effect promotes melting, formation of cracks and debris on the surface, and the modification of tubular dentin structure [15]. These alterations on dentin can occur due to the lower thermal conductivity of this substrate when compared to the primary enamel [16,17,18]

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