Short-time dental resin biostability and kinetics of enzymatic degradation
Xiaohong Wang, Sheng Song, Lei Chen, Christopher M. Stafford, Jirun Sun
Resin biostability is an important concern regarding the durability of methacrylate-based dental resin restorations. Current resin biostability evaluation methods take considerable time, from weeks to months, and provide no short-time kinetics of resin degradation. The objective of this study is to develop a more sensitive method to assess resin biostability over short times (hours to days) that will enhance our understanding of biostability and its resin chemistry, as well as decrease the amount of resin required for quantitative measurements of this type. Ultra-flat resin films of equimolar urethane dimethacrylate (UDMA) and triethylene glycol dimethacrylate (TEGDMA) are produced through photo-curing between two flat surfaces. Next, metal-covered enclaves and bare-resin channels are generated using stencil lithography to create both degradable and protected (internal reference) regions simultaneously in a single specimen. Resins with three levels of degree of vinyl conversion (DC) are compared, and nanoscale changes in morphology in the two regions are monitored by atomic force microscopy (AFM). Specimen biostability is ranked based on the profile changes when viewed in cross- section before and after enzymatic challenges. In addition, kinetics studies of resin degradation from 2 h to 72 h revealed that enzymatic degradation is detected as early as 4 h. A model is proposed to quantify specimen enzymatic degradation. Based on this model, a short-time surge of enzymatic degradation is detected between 4 h to 8 h. The correlation between the DC of resin network and the surge in degradation is discussed. In summary, we describe a new method that is effective in ranking biostability and quantifying enzymatic degradation while also reducing labor, time and cost, which lends itself well to materials development and evaluation of dental resins.
, Song, S.
, Chen, L.
, Stafford, C.
and Sun, J.
Short-time dental resin biostability and kinetics of enzymatic degradation, Journal of Dental Research, [online], https://doi.org/10.1016/j.actbio.2018.05.009
(Accessed December 1, 2021)