Effect of support structures on the trueness and precision of 3D printing dentures: An <i>in vitro</i> study

Abstract

Additive manufacturing has revolutionized the fabrication of complete dentures. However, this process involves support structure, which is a construction part that holds the specimen during printing, and may prove to be disadvantageous. Therefore, this in vitro study compared the effect of support structure reduction on various volume and area distributions of a 3D-printed denture base to determine optimal parameters based on accuracy. Methods: A complete maxillary denture base construction file was used as reference. Twenty denture bases were 3D printed under four conditions (total n=80): no support structure reduction (control), palatal support structure reduction (Condition P), border support structure reduction (Condition B), and palatal and border support structure reduction (Condition PB). Printing time and resin consumption were also recorded. The intaglio surface trueness and precision of all acquired data were exported to a 3D analysis software, and the dimensional changes to the denture base were analyzed using the root-mean-square estimate (RMSE) to assess geometric accuracy and generate color map patterns. Nonparametric Kruskal-Wallis and Steel-Dwass tests (α=0.05) analyzed the accumulated data. Results: Control had the lowest RMSE values for trueness and precision. Nevertheless, it demonstrated a significantly lower RMSE than that of Condition B (P=0.02) in precision. Owing to negative deviation at the palatal region, Conditions P and PB had higher retention than Control and Condition B regarding the color map pattern. Conclusions: Within the limitations of this study, the reduction of palatal and border support structures showed optimal accuracy with resource and cost savings.

Effect of Support on Tensile Strength of Stereolithography Products

“…The importance of the three samples does not have large deviations, so the support design has little effect on the tensile strength of this material. Namano S. et al [5] showed that with the same printing angle, the number of support structures and their distribution have little effect on the printed part result. Reducing support has a relatively small impact on accuracy.…”

“…The SLA operation procedure is carried out as follows: In a photopolymer liquid tank, the print tray is submerged in a bath of liquid resin solution a fragile distance from the liquid surface (the tray is covered with a layer of liquid resin). The UV rays shine directly through the UV reflectors on the support tray, curing the liquid layer into a solid forming a precise cross-section of the part [2][3][4][5][6][7][8][9]. After each print layer is solidified, the print tray moves by one step, equal to the thickness of the print layer in the liquid, and the re-sweeping blade distributes the resin upwards in preparation for the formation of a new print layer.…”

Digital transformation of removable dentures

“…However, recent studies have revealed that 3D-printed dentures have no significant difference either in fitting onto mucosal surfaces compared to conventional dentures, or in wear resistance of artificial teeth compared to conventional hard resin teeth, thereby indicating that they can be applied clinically. Furthermore, it is possible to decrease the costs by reducing the support structure unique to 3D-printed denture modeling, without compromising accuracy [5]. In a super-aged society such as Japan, the demand for 3D-printed dentures that can be produced inexpensively and efficiently is expected to increase.…”