The hydrolysis and enzymolysis of ester groups in dental resins weaken dental restoration materials and reduce their service lives. Current biostability evaluation methods of dental resins take long time (from weeks to months), let alone expensive labor and enzymes needed. The objective of this study was to develop a new method using nano-surface topography to accelerate the assessment of polymer degradation in a biological relevant environment. Ultra-flat resin films made of copolymers of equimolar urethane dimethacrylate (UDMA) and triethylene glycol dimethacrylate (TEGDMA) were produced through nano-imprint lithograph. Gold-covered and bare-resin areas were generated simultaneously using mask-guided metal evaporation method thus resulting in protected and degradable areas on one sample. The step-height between gold and resin surfaces was 17 nm. These areas were challenged by a salivary enzyme and/or control medium for various time periods. After challenges, step-height changes were determined by atomic force microscopy (AFM; tapping mode) to quantify the degradation. Kinetics of resin degradation were examined from 4 h to 72 h. Significant enzymatic degradation was detected as early as 4 h after challenges (Figures 1A and B). Nano-surface topography method was proven effective in quantifying the degradation of ester-containing dental resins. It significantly saves labor, time and cost. This new method has strong potential as an advanced tool for material evaluation and development.

Accelerating evaluation of resin biostability

254th National Meeting (2017)

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