In vitro long-term degradation of aesthetic restorative materials in food-simulating media

Objective. The aim of this study was to evaluate the effect of long-term food-simulating media storage on degradation of restorative materials through roughness measurements. Materials and methods: Sixty cylindrical specimens of each material (Filtek Z250, Esthet X, Filtek Flow, Dyract AP and Vitremer) were prepared, stored for 24 h, and polished. The surface roughness analysis was conducted using Surfcorder (SE1700) roughness-measuring instrument. Three traces were recorded on each specimen at three different locations. The specimens were randomly distributed into five groups (n = 12) according to the storage media: (water, ethanol, Coca-Cola (R), citric acid and lactic acid). Roughness measurements were recorded after 1 week, 1, 3 and 6 months. The storage solutions were weekly changed. Data were submitted to ANOVA and Tukey test (p < 0.05). Results. There was no significant increase on roughness means for Filtek Z250, Filtek Flow and Vitremer over time, regardless the storage media. Significant increase on surface roughness was observed for Esthet X after 1 month of storage in Coca-Cola (R) and after 3 months of storage in citric acid and for Dyract AP after 6 months in water. There were no significant differences on surface roughness between resin composites and compomer. Resin-modified glass ionomer showed a significantly higher surface roughness mean than the other materials. Conclusions. Food-simulating media affects the surface roughness of the materials. Biodegradation is material-, solution- and time-dependent.