Design, 3D printing, and evaluation of full-contact dental models for denture tests.

Abstract

The full-contact model has been widely used in tooth preparation and prosthesis fabrication. However, it is rarely used in denture tests. The purpose of the present study was to design a suitable full-contact dental model for denture tests. A standard dental model with the complete tooth morphology was raster scanned and 3D reconstructed. Then, the positioning and fixing surfaces of the dental model were reshaped. The dental model was digitally trimmed into two parts: a fundamental part and a replaceable part. The modular design was presented according to dentition defects around the first molar. The prepared tooth replicas were designed through preparation/scanning/registration/separation sequences. The dental model was fabricated by stereolithography (SLA) 3D-printing rapid prototype technology. The static fracture force of the dental model was predicted using the finite element method. The effects of the four design methods on the suitability of the five testing operations (abutment fabrication, prosthesis fabrication, assembling, loading, and observation) were quantitatively analyzed. The static tests of three fixed partial dentures (FPDs), including tooth-supported, implant-supported, and tooth-tooth-supported prostheses, were conducted to investigate the fracture feature. The dynamic test of a removable partial denture (RPD) was undertaken to study the wear characteristic. The dental model could bear the maximum fracture strength of 4268.3 N. Seven positive and two negative effects of the design methods were produced. The maximum fracture strength of the FPDs were 1331.2 N, 1356.7 N, and 1987.7 N. The wear facets of the RPD in the dynamic denture test were distributed in three regions. The force capacity of the full-contact dental model allows the application of static denture tests. The dental model provides improvements in fixture design, removable design, and replica design for the testing operations. The dental model is recommended more in the dynamic test than in the static test.