Effect of Cleansers on the Colour Stability of Zirconia Impregnated PMMA Bio-Nanocomposite

Saleh Zidan, Nick Silikas, Julfikar Haider, Julian Yates

Research output: Contribution to journalArticlepeer-review


Exposure of denture base acrylic resins to the oral environment and storage media for
extended periods of time results in colour change due to changes in the properties of the material. The purpose of this in vitro study was to assess the colour stability of high-impact heat-polymerized denture base acrylic resin (HI PMMA) impregnated with zirconia nanoparticles after storage in distilled water (DW) and denture cleaners such as Steradent (STD) and Milton (MIL) for 180 days. Ninety specimens of PMMA + Zirconia nanocomposite with varying nanoparticle concentrations (1.5 wt.%, 3.0 wt.%, 5.0 wt.%, 7.0 wt.% and 10 wt.%) were prepared with a diameter and thickness of
25 1.0mm 2 0.1mmand divided into six groups, while each group was further divided into three subgroups: storage in DW (control), STD and MIL. Colour changes were measured with a Minolta Chroma Meter (Minolta, Osaka, Japan), and assessed using the CIE L*a*b* colorimetric system. Data were statistically analysed for colour change with Friedman’s Two-way and Kruskal-Wallis tests at a pre-set alpha value level of 0.05. The colour change (DE) exhibiting significant dierences were found
among all groups immersed in denture cleaners, and all values increased with time. According to the National Bureau of Standards, the control group displayed the lowest colour change value (DE = 1.22), and the highest value was for 10 wt.% ZrO2 while stored in MIL (DE = 6.07). The values of colour change for storage in water ranged from 0.49 (control) to 1.82 (10 wt.% ZrO2). The colour change value for the composite group containing 3 wt.% zirconia was clinically acceptable. However, high
concentrations of denture cleaners should be avoided, and the shortest cleaning time is recommended to improve the clinical life of the nanocomposite denture base.
Original languageEnglish
Pages (from-to)1757
Issue number9
Publication statusPublished - 6 Sept 2020


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