Impact of erosion and aging simulation on chairside materials

This study investigates the influence of acid exposure and thermocycling simulating erosion tooth wear, on the optical properties and surface roughness of chairside materials. Resin-ceramic, lithium disilicate, premium zirconium oxide and resin composite material comprise the materials tested. To simulate the dental erosion and aging, specimens from each material were immersed in hydrochloric acid, while the thermocycling procedure included 10,000 cycles. The translucency, the color differences and the surface roughness were calculated. The materials phase composition was tested using X-ray diffraction analysis to evaluate T-M phase transformation. The CIEDE₂₀₀₀ color difference and the translucency parameter were tested different significantly among groups. Data were statistically analyzed via independent samples t-test, and paired samples t-test. The thermocycling procedure and the exposure to the acid solution had different effect on the surface roughness of CAD/CAM materials. The present result demonstrated the negative effect the acid exposure has on the zirconia material in terms of color difference. However, no color differences over the threshold of acceptability were recorded after the thermocycling procedure. Both polymer materials exhibit an increase of the surface roughness when they were immersed in acid but they did not display an increase in roughness when they were thermocycled.