Three-Dimensional Evaluation on Accuracy of Conventional and Milled Gypsum Models and 3D Printed Photopolymer Models.

Jae-Won Choi,Keunbada Son,Jong-Ju Ahn,Jung-Bo Huh

doi:10.3390/ma12213499

Jae-Won Choi, Keunbada Son + Show 2 more

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https://doi.org/10.3390/ma12213499

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Abstract

The aim of this study was to evaluate the accuracy of dental models fabricated by conventional, milling, and three-dimensional (3D) printing methods. A reference model with inlay, single crown, and three-unit fixed dental prostheses (FDP) preparations was prepared. Conventional gypsum models (CON) were manufactured from the conventional method. Digital impressions were obtained by intraoral scanner, which were converted into physical models such as milled gypsum models (MIL), stereolithography (SLA), and digital light processing (DLP) 3D printed photopolymer models (S3P and D3P). Models were extracted as standard triangulated language (STL) data by reference scanner. All STL data were superimposed by 3D analysis software and quantitative and qualitative analysis was performed using root mean square (RMS) values and color difference map. Statistical analyses were performed using the Kruskal–Wallis test and Mann–Whitney U test with Bonferroni’s correction. For full arch, the RMS value of trueness and precision in CON was significantly smaller than in the other groups (p < 0.05/6 = 0.008), and there was no significant difference between S3P and D3P (p > 0.05/6 = 0.008). On the other hand, the RMS value of trueness in CON was significantly smaller than in the other groups for all prepared teeth (p < 0.05/6 = 0.008), and there was no significant difference between MIL and S3P (p > 0.05/6 = 0.008). In conclusion, conventional gypsum models showed better accuracy than digitally milled and 3D printed models.

Highlights

Accurate impressions and working models are important elements for fabricating precise dental prostheses [1]
The root mean square (RMS) value of trueness and precision in Conventional gypsum models (CON) was significantly smaller than in the other groups (p < 0.05/6 = 0.008), and there was no significant difference between SLA 3D printed photopolymer model (S3P) and DLP 3D printed photopolymer model (D3P) (p > 0.05/6 = 0.008)
On the other of trueness in CON was significantly smaller than in the other groups (p < 0.05/6 = 0.008), and there was hand, the RMS value of MIL was smaller than S3P and D3P (p < 0.05/6 = 0.008), and there was no no significant difference between MIL, S3P, and D3P (p > 0.05/6 = 0.008)

Summary

Introduction

Accurate impressions and working models are important elements for fabricating precise dental prostheses [1]. The traditional method is to obtain an intraoral impression by using an elastomeric impression material and fabricate a gypsum cast [2] This procedure causes patient discomfort such as pain, gagging, and inconvenient taste, and the accuracy of the impression is greatly influenced by the skill of the operator [3]. Disadvantages such as deformation of impression material or model material, contamination by saliva, and blood in the oral cavity have been reported [4,5]. Data can be stored permanently, require little storage space, and can be transferred digitally [8]

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