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

Abstract

Purpose: 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 disadvan-tageous. 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 (Con-dition 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. Nonparamet-ric 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.