Faculty of Dentistry, Department of Biological and Diagnostic Sciences, Biomaterilas Discipline, University of Toronto, Canada.
J Biomed Mater Res B Appl Biomater. 2010 Jul;94(1):230-7. doi: 10.1002/jbm.b.31645.
Human Salivary Derived Esterases (HSDE) are part of the salivary group of enzymes which show strong degradative activity toward the breakdown of one of the most common monomers used in dental composites and adhesives, 2,2-[4(2-hydroxy 3-methacryloxypropoxy)-phenyl] propane (Bis-GMA), to form the degradation product 2,2-bis [4 (2,3-hydroxy-propoxy)phenyl] propane (Bis-HPPP). This study was aimed to evaluate the effects of HSDE on the biodegradation and fracture toughness of the adhesive resin-dentin interface. Adhesive resin (Scotchbond Multi Purposes), resin composite (Z250) and mini short-rod specimens, were either not incubated; or incubated in phosphate-buffered saline (PBS) or HSDE media for up to 180 days (37 degrees C, pH 7.0). The amount of Bis-HPPP was analyzed by high performance liquid chromatography and mini-SR specimens were tested for fracture toughness using universal testing machine following 30, 90, or 180-day incubation periods. Significantly higher amounts of Bis-HPPP were produced in HSDE than in PBS incubated specimens (p < 0.05). Non-incubated mini-SR specimens had the higher fracture-toughness values, while specimens incubated for 180-days in HSDE had the lowest fracture toughness (p < 0.05). This study suggests that biodegradation is an on-going clinically relevant process that progressively compromises the integrity of the critical resin restoration-adhesive interface, as well as the resin-composite component with time.
人唾液衍生酯酶（HSDE）是唾液酶组的一部分，对最常见的用于牙科复合材料和黏合剂的单体之一 2,2-[4(2-羟基-3-丙烯酰氧基丙氧基)-苯基]丙烷（Bis-GMA）的分解具有很强的降解活性，形成降解产物 2,2-双[4(2,3-羟基-丙氧基)苯基]丙烷（Bis-HPPP）。本研究旨在评估 HSDE 对黏附树脂-牙本质界面生物降解和断裂韧性的影响。黏附树脂（Scotchbond Multi Purposes）、树脂复合材料（Z250）和微型短棒试件要么不孵育，要么在磷酸盐缓冲盐水（PBS）或 HSDE 介质中孵育，最长可达 180 天（37°C，pH7.0）。采用高效液相色谱法分析 Bis-HPPP 的含量，采用万能试验机对微型短棒试件进行断裂韧性测试，孵育时间分别为 30、90 或 180 天。HSDE 孵育的试件产生的 Bis-HPPP 明显多于 PBS 孵育的试件（p<0.05）。未孵育的微型短棒试件具有较高的断裂韧性值，而在 HSDE 中孵育 180 天的试件具有最低的断裂韧性（p<0.05）。本研究表明，生物降解是一个持续的、与临床相关的过程，随着时间的推移，它会逐渐破坏关键的树脂修复-黏附界面的完整性，以及树脂复合材料的完整性。
