Comparison of Marginal Integrity and Surface Roughness of Selective Laser Melting, CAD-CAM and Digital Light Processing Manufactured Co-Cr Alloy Copings

Abdulaziz S. Alqahtani,Samar Al-Saleh,Fahim Vohra,Malek Eldesouky,Tariq Abduljabbar,Mazen K. Alnuwaiser,Abdullah M. AlFadda,Abdullah Alshahrani,Saad Alresayes

doi:10.3390/app11188328

Abstract

The purpose of the present study was to evaluate the influence of fabrication techniques on the surface micro-roughness (Ra) and marginal misfit of cobalt chromium (CoCr) copings. A mandibular first molar was prepared for a metal ceramic crown. Forty metal copings were prepared and divided into groups (n = 10). Group 1, Casting-Lost wax technique (Cast-LWT), Group 2, CAD-CAM, Group 3, Selective laser melting (SLM), and Group 4, Digital light processing-Cast (DLP-Cast). Ra was measured using laser profilometry and marginal misfit was analyzed with Micro-CT. Analysis of variance (ANOVA), Tukey multiple comparison, and correlation coefficient tests were applied (p < 0.05). SLM technique showed the highest Ra (2.251 ± 0.310 μm) and the Cast-LWT group presented the lowest Ra (1.055 ± 0.184 μm). CAD-CAM copings showed statistically lower Ra compared with SLM samples (p = 0.028), but comparable Ra to DLP-Cast (p > 0.05). CoCr copings fabricated from the DLP-Cast technique demonstrated the highest marginal misfit (147.746 ± 30.306 μm) and the lowest misfit was established by SLM copings (27.193 ± 8.519 μm). The SLM technique displayed lower marginal misfit than DLP-Cast and CAD-CAM (p = 0.001), but comparable misfit to Cast-LWT copings. Ra influenced the marginal misfit in CAD-CAM, SLM, and DLP-Cast technique-fabricated copings. (p < 0.01). Marginal misfit and Ra of CoCr copings are contingent on the different fabrication techniques.

Highlights

Porcelain-fused-to-metal (PFM) crowns have been widely used in dentistry as a fixed dental aesthetic replacement for decades [1]
Mean Ra of Cast/LWT copings was lower than CAD-CAM (1.840 ± 0.236 μm) (p = 0.001), Selective laser melting (SLM) (p = 0.001), and digital light processing (DLP) cast (p < 0.05) specimens respectively
The uniform high roughness was observed in SLM samples (2 D) and the DLP-Cast specimen displayed a smoother surface with minimal localized craters (2 C)

Summary

Introduction

Porcelain-fused-to-metal (PFM) crowns have been widely used in dentistry as a fixed dental aesthetic replacement for decades [1]. Advancements in casting techniques, availability of different alloys, and their use in almost all clinical conditions account for the popularity of PFM crowns [2]. Available evidence advocates an acceptable range of marginal misfit of full veneer crowns to be 100 to 120 μm [3]. Multiple studies suggest different ranges of acceptable marginal misfit (10 to 160 μm) [4]. Increased marginal discrepancy accounts for the 10% of prosthetic failures, i.e., exposure of dental cement to the oral environment, bacterial penetration and plaque retention, secondary carious lesions, negative pulp reactions, marginal discoloration, periodontal disturbances, and esthetic and functional compromise [3]

Objectives

Methods

Results

Conclusion