Deterioration of Dental Restorative Materials Under Erosive and Mechanical Wear

Objectives: Dental restorative materials are subject to various kinds of wear such as erosion, attrition, and abrasion. Prior to choosing an appropriate material for a patient, particularly for use in the posterior, load-bearing areas, it is crucial to have knowledge about the physical and chemical properties of the materials.
The objective was to evaluate the impact of erosion combined with abrasion and attrition on the mechanical and colour properties of a composite-resin material (Filtek Z250®) and two glass ionomer cements (Fuji IX GP® and Equia Forte®) by evaluating surface roughness, hardness and colour stability.
Methods: The specimens (n=6) of each materials group (n=3) were prepared in metal molds, grinded, polished and left in artificial saliva (370C, 24h). Samples were subjected to abrasive (brushing simulator), erosive (liquid cycler) and attrition (chewing machine) tests. Each test was mimicking six months of wear exposure. Baseline and final measurements of surface roughness, hardness and colour shade were recorded and compared. Data were analysed using GraphPad Prism 9.3.1. Statistical significance was set at p<0.05.
Results: A significant increase in surface roughness was observed in all three materials after the experiment, with the largest roughness difference found for Filtek Z250®. Hardness was significantly reduced in Fuji IX® while Filtek Z250®and Equia Forte® had a similar change in hardness values. Regarding color stability, Filtek 250® and Fuji IX® became one shade darker and lighter, respectively. Equia Forte® became greyish after the experiment (Table 1).
Conclusions: Even though Equia Forte® showed superior results compared to Fuji IX®, its performances are rather limited in comparison to Filtek Z250®. Therefore, composite resin should be given priority when used for posterior, load bearing restorations.