Data Fitting to Study Ablated Hard Dental Tissues by Nanosecond Laser Irradiation.

Y Al-Hadeethi,A Al-Mujtaba,S Al-Jedani,A M Abdel-Daiem,M Shahnawaze Ansari,A Saeed,M A N Razvi,Saeed S Babkair,Numan A Salah

doi:10.1371/journal.pone.0156093

Y Al-Hadeethi, A Al-Mujtaba + Show 7 more

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https://doi.org/10.1371/journal.pone.0156093

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Abstract

Laser ablation of dental hard tissues is one of the most important laser applications in dentistry. Many works have reported the interaction of laser radiations with tooth material to optimize laser parameters such as wavelength, energy density, etc. This work has focused on determining the relationship between energy density and ablation thresholds using pulsed, 5 nanosecond, neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12 (Nd:YAG) laser at 1064 nanometer. For enamel and dentin tissues, the ablations have been performed using laser-induced breakdown spectroscopy (LIBS) technique. The ablation thresholds and relationship between energy densities and peak areas of calcium lines, which appeared in LIBS, were determined using data fitting. Furthermore, the morphological changes were studied using Scanning Electron Microscope (SEM). Moreover, the chemical stability of the tooth material after ablation has been studied using Energy-Dispersive X-Ray Spectroscopy (EDX). The differences between carbon atomic % of non-irradiated and irradiated samples were tested using statistical t-test. Results revealed that the best fitting between energy densities and peak areas of calcium lines were exponential and linear for enamel and dentin, respectively. In addition, the ablation threshold of Nd:YAG lasers in enamel was higher than that of dentin. The morphology of the surrounded ablated region of enamel showed thermal damages. For enamel, the EDX quantitative analysis showed that the atomic % of carbon increased significantly when laser energy density increased.

Highlights

In dentistry, cavity preparation is carried out through either a low-speed high-torque handpiece or a high-speed low-torque handpiece [1]
The ablation threshold is generally defined as the minimum energy density that atom needs to escape from the material [35]
Ablation threshold was defined as appearance of minimal intensity of calcium line by using laser-induced breakdown spectroscopy (LIBS)

Summary

Introduction

Cavity preparation is carried out through either a low-speed high-torque handpiece or a high-speed low-torque handpiece [1]. Despite their efficiency, they are still somewhat painful, irritating, and noisy [2]. It is necessary to use local anesthetic for the majority of dental procedures. A continuous water spray is used in conjunction with the drills. Data Fitting and Ablated Hard Dental Tissues by Laser Irradiation to balance the temperature produced by friction between the drill and the tooth. Dentin contains a large number of nerve endings that are connected with the pulp [3]. The dentin pain mainly arises from a rapid outward flow of fluid in dentinal tubules [4]

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