Efficacy of laser powder bed fusion as a production method of removable partial dentures

Abstract

This study examines the efficacy of manufacturing removable partial dentures through laser powder bed fusion, an innovative additive manufacturing technique. This transformative approach offers alternatives to traditional casting methods by integrating digitization within the engineering and manufacturing workflow, thereby advancing the field of digital dentistry. Removable partial dentures serve as a cost-effective solution to the increasing prevalence of edentulism among an aging population.

This investigation employed a threefold methodology, with the aim of assessing the efficacy of dentures produced by laser powder bed fusion it is necessary to the evaluate the applicability of the materials used, the quality of the parts produced, and the fit accuracy of the parts must be evaluated. Firstly, the characteristics of the feedstock powder were meticulously evaluated to determine the efficacy for production of dentures. Parameters such as chemical composition, powder morphology, true powder density, and particle size distribution were measured to quantify the quality of the input materials for this manufacturing process.

Secondly, to ensure the quality of the dentures produced the part density as a measure of quality has been studied. The importance of porosity in additively manufactured parts cannot be understated as porosity leads to premature failure due to crack initiation locations under complex fatigue loading. Elimination of porosity without post processing heat treatments such as annealing and hot isostatic pressing eliminates unnecessary costs and shortens the turnaround time.

Thirdly, the applicability of the distortion compensation technique was investigated to achieve accurate and representative geometric tolerances in the production of dentures. The inherent strain method was utilized to mitigate the effects of residual stress and subsequent distortion arising from the part's thermal history.

The study found that particle size distribution was the most significant quantifiable factor influencing the packing density of the powder within the manufacturing unit, facilitating improved densification upon laser melting. The Archimedes principle proved to be the most cost effective, accurate and most repeatable manner to efficiently quantify the relative part density. It was also shown that the part density is strongly dependant on the fundamental chemical composition of the biocompatible alloy studied. The distortion compensation numerical modelling method demonstrated its effectiveness on thin structures, such as removable partial dentures, significantly reducing observed distortion to within an acceptable tolerance.

In conclusion, this study indicates that the production of removable partial dentures using laser powder bed fusion presents a viable solution. Additive manufacturing can yield dentures that possess superior properties in comparison to other manufacturing methods. This novel contribution offers numerous possible advancements regarding workflow implementation of technologies such as intra-oral scanning, dental specific computer aided design software and a fully digital workflows in the clinical field of dentistry