Influence of different designs of bulb support structures on the accuracy and weight of 3D printed maxillary obturators. An in vitro study.

STATEMENT OF PROBLEM

Evidence is lacking on the influence of different designs of bulb support structures on the accuracy of 3-dimensional (3D) printed obturators.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of various infill designs (hollow, honeycomb, and gyroid) for the bulb of an obturator on the accuracy and weight of digital light projection (DLP) 3D printed maxillary obturators.

MATERIAL AND METHODS

A maxillary obturator was virtually designed and used to obtain 3 digital reference files which were defined based on the design of the infill support structure within the bulb: hollow, honeycomb, and gyroid. The resultant standard tessellation language (STL) files were used to fabricate the obturators using a DLP 3D-printer in FREEPRINT denture resin material (n=10 per each group design). The fitting surfaces of all printed specimens (n=30) were digitized using a laboratory scanner, and the scan STL files were exported to the Geomagic control X program for dimensional accuracy analysis (trueness and precision) using the digital subtraction technique. One-way analysis of variance (ANOVA) was used for analysis (α=.05) RESULTS: Quantitative analysis revealed no significant difference in root mean square estimate (RMSE) values among the test groups for trueness (P=.326) and precision (P=.140). Hollow bulb design was significantly lighter in weight than both honeycomb and gyroid infill designs (P<.001). Colormaps revealed increased areas of negative deviation around the circumference of the bulb wall in the hollow design compared with both the gyroid and honeycomb groups and the close surface matching of fitting surfaces in the 3 groups.

CONCLUSIONS

The lack of significant difference in accuracy among the tested groups and the significantly lighter hollow design obturator compared with honeycomb and gyroid designs favors the selection of the hollow bulb design in the digital fabrication of maxillary obturators.