Physical properties of polyamide-12 versus PMMA denture base material.

Mieszko Wieckiewicz,Klaus W Boening,Volker Opitz,Gert Richter

doi:10.1155/2014/150298

Mieszko Wieckiewicz, Klaus W Boening + Show 2 more

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https://doi.org/10.1155/2014/150298

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Abstract

Objectives. Polyamide-12 (PA) is a flexible material suited for denture bases and clasping. This study investigated its potential aging effects with a focus on surface roughness, color stability, and elasticity. Methods. PA specimens (Valplast) of 40 × 10 × 2 mm and equally measuring PMMA specimens (Palapress) as control were fabricated. Color changes after storage in air, water, coffee, and red wine (n = 10) were measured using the CIE L*a*b* color specification. Elasticity after thermocycling (1000, 3000, and 7000 cycles, n = 15) was measured by three-point bending testing. Mean surface roughness (Ra) was determined after storage in the liquids mentioned above and thermocycling (n = 10). Results. Tukey's HSD test (P < 0.05) revealed statistically significant color changes of PA in red wine (ΔE = 4.27 after 12 days, ΔE = 6.90 after 12 days) and coffee (ΔE = 3.93 after 36 days) but no color changes in PMMA. Elastic modulus of PA was 845 MPa and not affected by thermocycling (Tukey's HSD test, P > 0.81). Dry specimens showed significantly decreased elasticity (P < 0.001). Mean surface roughness (PA 0.20 μm, PMMA 0.28 μm) did not change significantly after thermocycling or storage (Mann-Whitney U-test, 0.16 < P < 0.65). Significance. PA exhibited a higher susceptibility to discoloration than PMMA. Neither surface roughness nor elasticity of PA was altered by artificial aging.

Highlights

Despite the progress in dental implant treatment, there is still need for conventional removable partial dentures
This study investigated its potential aging effects with a focus on surface roughness, color stability, and elasticity
The aesthetic appearance of removable partial dentures with Polymethyl methacrylate (PMMA) bases may be compromised by the visibility of metal clasps

Summary

Introduction

Despite the progress in dental implant treatment, there is still need for conventional removable partial dentures. It has to be expected that the need for cost effective removable partial dentures will remain substantial. The aesthetic appearance of removable partial dentures with PMMA bases may be compromised by the visibility of metal clasps. A feasible alternative to PMMA-based removable partial dentures may be the use of polyamide-12 [13]. Partial dentures might be pressed in one piece including clasps, minor and major connectors, and denture bases [14]. These nonrigid denture designs are discussed controversially since flexible bases may cause higher displacement of soft tissue and their influence on ridge resorption is not yet fully understood [15]. A solution could be the integration of a metal framework providing rigid major connectors and occlusal rests (Figures 1, 2, and 3)

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