Abstract
This study attempted to determine the dimensional stability of maxillary and mandibular edentulous denture bases constructed using three-dimensional (3D) printing systems based on stereolithography and digital light processing according to the postcuring treatment time and the removal time of the support structure. Three-dimensional printing of the designed denture base file was performed using two types of 3D printing photocurable resin (standard gray resin (Formlabs) (Somerville, MA, USA) and MAZIC D resin (Vericom) (Anyang, Korea)) and their compatible 3D printers (Form3 (Formlabs) and Phrozen Shuffle (Phrozen) (Hsinchu City, Taiwan)). Different postcuring times (no postcuring, and 15, 30, 45, and 60 min) and times of removal of the support structure were set for each group. Data relating to the denture bases in all groups were obtained using 3D scanning with a tabletop scanner after postcuring. All acquired data were exported to 3D analysis software, and the dimensional changes during postcuring of the denture base were analyzed using RMSE (root-mean-square error) values. It could be confirmed that the dimensional changes increased with postcuring time, and the accuracy was higher in the maxilla than in the mandible. The accuracy was highest for the group in which the postcuring process was performed while the support structure was present.
Highlights
Three-dimensional printing is called additive manufacturing or rapid prototyping, and it has contributed to the popularization of digital dentistry while overcoming the limitations of subtractive machining methods based on milling or grinding [1,2]
The results of the three-way ANOVAs of standard gray resin and MAZIC D resin are presented in Figures 3 and 4
Values between the modeling and scan data after the postcuring process confirmed that the dimensional changes were significantly affected by whether the support structure was removed (F = 17.317, p < 0.001), the arch position (F = 567.555, p < 0.001), and the postcuring time (F = 9.755, p < 0.001) (Figure 3)
Summary
Three-dimensional printing is called additive manufacturing or rapid prototyping, and it has contributed to the popularization of digital dentistry while overcoming the limitations of subtractive machining methods based on milling or grinding [1,2]. The current methods of prosthesis production using 3D printing can overcome the limitations of subtractive manufacturing, such as reducing cutting forces due to the wear of milling tools, limitations associated with tool sizes, difficulty in manufacturing complex shapes, and material wastage. Postcuring is an essential step when using a photopolymer resin with an SLA or DLP printer, as it can cause improvements in mechanical or biological properties through crosslinking of unreacted monomers after processing of 3D printing materials [15,16]
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