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

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.

Accuracy of 3-Dimensionally Printed Full-Arch Dental Models: A Systematic Review

“…The controls included were a dental stone cast ( n = 8), a digital STL image of a dental stone cast ( n = 3), typodont digital STL image ( n = 7), typodont ( n = 1), prefabricated resin model digital STL image ( n = 2), patient intraoral scan image (2) or a dry human skull ( n = 1). In addition, there were four studies [ 4 , 35 , 47 , 54 ] that did not include a reference model as a control, rather compared various printing technologies against each other.…”

“…The majority of studies investigated SLA ( n = 20), MJ ( n = 11), DLP ( n = 9) and, to a lesser extent, FFF ( n = 6), BJ ( n = 2) and CLIP ( n = 1). With regards to printing parameters, one study reported following the manufacturers’ recommendations [ 6 ], while others explicitly detailed the printing parameters used [ 4 , 19 , 36 , 37 , 38 , 42 , 43 , 45 , 46 , 47 , 49 , 50 , 51 , 52 , 55 , 56 , 57 ]. In contrast, the remainder of the studies did not provide clear details regarding the printing parameters used.…”

“…Eleven studies did not specify the material used for the corresponding technology [ 19 , 35 , 36 , 40 , 44 , 45 , 48 , 52 , 53 , 54 , 55 ]. Within the studies assessing stone models, four used Type IV dental stone [ 6 , 35 , 40 , 45 ], one used Type III dental stone [ 4 ] and one did not specify the stone type utilised [ 34 ].…”

“…However, these cast models suffer a number of limitations, including a need for expedited processing of impressions, depending on the impression material; storage space for resultant casts; the cost of human and laboratory resources involved in fabrication; poor structural durability; and a propensity to dimensional changes over time [ 3 ]. In contrast, 3D printed models could offer a more efficient workflow that can be manufactured on demand and are more resilient, less-labour intensive and potentially time-saving [ 4 ]. Nonetheless, 3D printed models also present a unique set of limitations.…”

Ceramic Materials and Technologies Applied to Digital Works in Implant-Supported Restorative Dentistry

“…Intraoral scan data are used for both model manufacturing and restoration design [25]. The working model is manufactured by SM (for example, computer numerical control (CNC) milling) or AM (for example, rapid prototyping).…”