Dimensional stability of double-processed complete denture bases fabricated with compression molding, injection molding, and CAD-CAM subtraction milling

Erna R Einarsdottir; Alessandro Geminiani; Konstantinos Chochlidakis; Changyong Feng; Alexandra Tsigarida; Carlo Ercoli

doi:10.1016/j.prosdent.2019.09.011

Dimensional stability of double-processed complete denture bases fabricated with compression molding, injection molding, and CAD-CAM subtraction milling

J Prosthet Dent. 2020 Jul;124(1):116-121. doi: 10.1016/j.prosdent.2019.09.011. Epub 2019 Nov 21.

Authors

Erna R Einarsdottir¹, Alessandro Geminiani², Konstantinos Chochlidakis³, Changyong Feng⁴, Alexandra Tsigarida⁵, Carlo Ercoli⁶

Affiliations

¹ Assistant Professor, Department of Prosthodontics, University of Iceland, Reykjavik, Iceland.
² Assistant Professor, Department of Prosthodontics and Periodontology, Eastman Institute for Oral Health, University of Rochester, Rochester, N.Y.
³ Assistant Professor and Program Director, Department of Prosthodontics, Eastman Institute for Oral Health, University of Rochester, Rochester, N.Y. Electronic address: kchochlidakis@urmc.rochester.edu.
⁴ Associate Professor, Department of Biostatistics and Computational Biology, University of Rochester, Rochester, N.Y.
⁵ Assistant Professor, Department of Periodontology, Eastman Institute for Oral Health, University of Rochester, Rochester, N.Y.
⁶ Professor, Departments of Prosthodontics and Periodontology, Eastman Institute for Oral Health, University of Rochester, Rochester, N.Y; Chairman, Department of Prosthodontics, Eastman Institute for Oral Health, University of Rochester, Rochester, N.Y.

PMID: 31761276
DOI: 10.1016/j.prosdent.2019.09.011

Abstract

Statement of problem: Studies evaluating the dimensional stability of denture bases fabricated by the double processing method are lacking.

Purpose: The purpose of this in vitro study was to evaluate the dimensional stability of denture bases fabricated by 3 different techniques: compression molding, injection molding, and computer-aided design and computer-aided manufacturing (CAD-CAM) subtraction milling.

Material and methods: Forty-five mandibular denture bases were fabricated from a master cast by a standardized process. A double processing protocol was used with 3 methods: compression molding (PRESS), injection molding (INJECT), or CAD-CAM (CAD). The bases were compared with the titanium master cast after the first processing. By a digital subtraction process, the dimensional stability of the bases was measured at 22 different locations on the intaglio surface. Denture teeth were then positioned according to a standardized protocol, and the denture was processed a second time and finished. The dimensional discrepancy was reassessed after the second processing and compared with the titanium master cast.

Results: In all groups, most of the dimensional changes occurred during the first processing (P<.05), with no statistically significant deformation occurring during the second processing (P>.05). The CAD group presented significantly smaller dimensional changes than PRESS (P<.05) and INJECT (P<.05) groups. No significant difference was found in the dimensional stability in the PRESS and INJECT groups (P>.05).

Conclusions: Denture bases fabricated by a CAD-CAM methodology exhibit fewer dimensional changes than either compression or injection molding. Distortion occurred during the fabrication of the denture base, and a second processing did not significantly affect the dimensional stability of the denture base.

MeSH terms

Computer-Aided Design
Denture Bases*
Denture Design*
Denture, Complete
Mandible