Flexural Strength of Denture Base Acrylic Resins Processed by Conventional and CAD/CAM Methods

Abstract

High flexural strength is a desirable property for denture base resins. Currently there is a lack of published studies evaluating the physical properties of newer denture bases such as the CAD/CAM milled bases. The purpose of this study was to compare the flexural strength of three different denture base resins fabricated by compression molding, injection molding, and pre-polymerized CAD/CAM milling. Three groups of ten PMMA acrylic denture base resins were processed into rectangular plates for total sample size of thirty (n=30). The groups differed in their method of processing and resin composition. The three groups were injection molded (SR-Ivocap High Impact, Ivoclar Vivadent), compression molded (Lucitone 199, Dentsply), and pre-polymerized CAD/CAM milled resins (Avadent Digital Dentures). Following storage in water for one week, flexural strength was measured using a 3-point bend test until failure. Kruskal-Wallis and Mann-Whitney tests were used for statistical comparison between groups.

Significant differences in flexural strength was observed among the groups tested. The flexural strength of the pre-polymerized CAD/CAM milled acrylic resin group was higher than that of conventional method groups of compression molded and injection molded. The compression molded group exhibited higher flexural strength than the injection molded group. The results suggest that pre-polymerized milled denture bases may be a useful alternative to conventionally processed denture bases in situations where increased bending forces are anticipated.