A Comparative Investigation of the Physical and Mechanical Properties of Conventional and Light-Cured Denture Base Materials

Abstract

Objective: The purpose of this in vitro study was to compare the mechanical and physical properties of two denture acrylic resins, by evaluating six of their properties: flexural strength, impact strength, surface hardness, colour stability, water sorption and solubility. Materials and methods: Two types of acrylic resin were evaluated in this study: Lucitone-199TM heat-polymerized resin and EclipseTM light-polymerized resin. Twenty rectangular specimens of 64 x 10 x 3.3 mm for flexural strength and surface hardness, 50 x 6 x 4 mm of thirty-six notched rectangular specimens for impact strength, and sixteen specimen discs of 50 mm diameter and 0.7 mm thickness for colour stability, water sorption and solubility were fabricated from both materials. Specimens were measured using the following approaches: three-point bending for flexural strength, Charpy and Izod for impact strength, Vickers micro-hardness for surface hardness, spectrophotometer for colour stability and electronic laboratory balance for water sorption and water solubility. The mechanical and physical properties were evaluated according to the ISO 1567:1999, 178:2001, 179-1: 2000, 180:2000, and 6507-1:2005 standards. Mean values and standard deviations were analysed by an independent samples t-test, and there was a statistically significant difference between Lucitone-199TM and EclipseTM p≤0.001. Results: The flexural strength values (MPa) were 120.0 ±5.78 and 81.1 ±4.94; the impact strength values (kJ/m2) for the Charpy were 6.1 ±0.85 and 2.77 ±0.51, and for the Izod, they were 5.13 ±0.21 and 2.65 ±0.13; the surface hardness (VHN) values were 24.1 ±0.79 and 17.7 ±0.83; the colour change (ΔE) values were 1.26 ±0.45 and 2.48 ±0.075; the water sorption values (μg/mm3) were 13.13 ±0.52 and 24.37 ±1.43; and the water solubility values (μg/mm3) were 0.19 ±0.047 and 0.31±0.068 for EclipseTM and Lucitone-199TM materials, respectively. The results of the inferential tests revealed that there were significant differences between the two material types with respect to flexural strength, impact strength, surface hardness, colour change, water sorption and solubility (p≤0.001 in all cases). Conclusion: The findings of the current study indicated that the mechanical and physical properties of the visible light-polymerized resin (EclipseTM) were superior to those of the PMMA heat-polymerized resin (Lucitone-199TM).

Date of Award	3 Jan 2018
Original language	English
Awarding Institution	The University of Manchester
Supervisor	David Watts (Supervisor) & Julian Yates (Supervisor)