The Effect of Argon Inert Gas on the Laser Welding Quality of Co-Cr and Ni-Cr Base Metal Alloys

Efthymia Sklavou,Athanasio H Karampotsos,Nikolas Poulis,Anthony Prombonas

doi:10.4236/jbise.2021.1412038

Efthymia Sklavou, Athanasio H Karampotsos + Show 2 more

Open Access

https://doi.org/10.4236/jbise.2021.1412038

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Abstract

The purpose of this research was to study the effect of Argon inert gas on the laser welding quality of Co-Cr and Ni-Cr base metal alloys, which are widely used as Fixed Prosthodontics alloys in Dental Laboratories. A total of 36 specimens were manufactured (18 of Ni-Cr alloy and 18 of Co-Cr alloy). The specimens were then divided into 3 subgroups (6 specimens each): control; argon-welded; and non-Argon welded. The specimens were cut, laser welded, radiographed and finally tested under tensile strength testing, followed by examination using Scanning Electron Microscopy. The tensile strength of welded specimens was lower than the strength of non-welded specimens, however this difference was not found to be statistically significant. The material factor (Co-Cr alloy or Ni-Cr alloy) has a statistically significant effect on the tensile strength, while the presence or not of the inert gas, as well as the combination of the two factors do not have a statistically significant effect. The laser welding process applied in daily practice (separation of specimen, formation of two cones in contact, aggregation of two cones, filling of the remaining gap by welding) is considered satisfactory in terms of weld strength. The factor of the material, as an independent factor, affects the tensile strength to a statistically significant degree, in contrast to the factor of the presence of inert gas which does not affect to a statistically significant degree.

Highlights

The need for improved and functional prosthetic restorations was the primary reason for the development of dental alloys and appropriate welding materials that increase the strength of dental prostheses
The purpose of this research was to study the effect of Argon inert gas on the laser welding quality of Co-Cr and Ni-Cr base metal alloys, which are widely used as Fixed Prosthodontics alloys in Dental Laboratories
The composition provided by the company for the Co-Cr alloy was Co 61%, Cr 27%, Mo 6%, Si 1%, C(x), W 5%, Mo 6%, Fe(x), Mn(x) while for the Ni-Cr was Ni 61.2%, Cr 25.8%, Mo 11%, Si% 1.5%, Al(x), Mn(x)

Summary

Introduction

The need for improved and functional prosthetic restorations was the primary reason for the development of dental alloys and appropriate welding materials that increase the strength of dental prostheses. These alloys have improved properties such as modulus of elasticity, durability, corrosion resistance and low density. If care is not taken, there is a risk of overheating the alloy which can lead to casting failures, to the extent that these restorations cannot be inserted into the oral cavity [1,2,3]

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