Xu Hockin H K, Moreau Jennifer L, Sun Limin, Chow Laurence C
Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201, USA.
Biomaterials. 2008 Nov;29(32):4261-7. doi: 10.1016/j.biomaterials.2008.07.037. Epub 2008 Aug 15.
Secondary caries and restoration fracture remain the two most common problems in restorative dentistry. Release of fluoride ions (F) could be a substantial benefit because F could enrich neighboring enamel or dentin to combat caries. The objective of this study was to incorporate novel CaF(2) nanoparticles into dental resin to develop stress-bearing, F-releasing nanocomposite. CaF(2) nanoparticles, prepared in our laboratories for the first time, were combined with reinforcing whisker fillers in a resin. Flexural strength (mean+/-sd; n=6) was 110+/-11 MPa for the composite containing 30% CaF(2) and 35% whiskers by mass. It matched the 108+/-19 MPa of a stress-bearing, non-releasing commercial composite (Tukey's at 0.05). The composite containing 20% CaF(2) had a cumulative F release of 2.34+/-0.26 mmol/L at 10 weeks. The initial F release rate was 2 microg/(hcm(2)), and the sustained release rate after 10 weeks was 0.29 microg/(hcm(2)). These values exceeded the reported releases of traditional and resin-modified glass ionomer materials. In summary, nanocomposites were developed with relatively high strength as well as sustained release of fluoride ions, a combination not available in current materials. These strong and F-releasing composites may yield restorations that can reduce the occurrence of both secondary caries and restoration fracture.
继发龋和修复体折断仍然是口腔修复学中最常见的两个问题。氟离子（F）的释放可能带来很大益处，因为F可以富集邻近的牙釉质或牙本质以抵御龋齿。本研究的目的是将新型CaF₂纳米颗粒掺入牙科树脂中，以开发具有应力承载能力、能释放F的纳米复合材料。首次在我们实验室制备的CaF₂纳米颗粒与树脂中的增强晶须填料相结合。含30%（质量）CaF₂和35%晶须的复合材料的弯曲强度（平均值±标准差；n = 6）为110±11 MPa。它与一种具有应力承载能力、不释放F的市售复合材料的108±19 MPa相当（Tukey检验，P = 0.05）。含20% CaF₂的复合材料在10周时的累积F释放量为2.34±0.26 mmol/L。初始F释放速率为2 μg/(h·cm²)，10周后的持续释放速率为0.29 μg/(h·cm²)。这些值超过了传统和树脂改性玻璃离子材料的报道释放量。总之，已开发出具有相对较高强度以及氟离子持续释放能力的纳米复合材料，这是目前材料所不具备的组合。这些坚固且能释放F的复合材料可能会产生能减少继发龋和修复体折断发生率的修复体。
