1 Macromolecular Science and Engineering, College of Engineering, University of Michigan, Ann Arbor MI, USA.
2 Department of Biology, Metropolitan State University of Denver, Denver, CO, USA.
J Dent Res. 2019 Jan;98(1):91-97. doi: 10.1177/0022034518795673. Epub 2018 Sep 6.
The breakdown of the polymeric component of contemporary composite dental restorative materials compromises their longevity, while leachable compounds from these materials have cellular consequences. Thus, a new generation of composite materials needed to be designed to have a longer service life and ensure that any leachable compounds are not harmful to appropriate cell lines. To accomplish this, we have developed concurrent thiol-ene-based polymerization and allyl sulfide-based addition-fragmentation chain transfer chemistries to afford cross-linked polymeric resins that demonstrate low shrinkage and low shrinkage stress. In the past, the filler used in dental composites mainly consisted of glass, which is biologically inert. In several of our prototype composites, we introduced fluorapatite (FA) crystals, which resemble enamel crystals and are bioactive. These novel prototype composites were benchmarked against similarly filled methacrylate-based bisphenol A diglycidyl ether dimethacrylate / triethylene glycol dimethacrylate (bisGMA/TEGDMA) composite for their cytotoxicity, mechanical properties, biofilm formation, and fluoride release. The leachables at pH 7 from all the composites were nontoxic to dental pulp stem cells. There was a trend toward an increase in total toughness of the glass-only-filled prototype composites as compared with the similarly filled bisGMA/TEGDMA composite. Other mechanical properties of the glass-only-filled prototype composites were comparable to the similarly filled bisGMA/TEGDMA composite. Incorporation of the FA reduced the mechanical properties of the prototype and bisGMA/TEGDMA composite. Biofilm mass and colony-forming units per milliliter were reduced on the glass-only-filled prototype composites as compared with the glass-only-filled bisGMA/TEGDMA composite and were significantly reduced by the addition of FA to all composites. Fluoride release at pH 7 was greatest after 24 h for the bisGMA/TEGDMA glass + FA composite as compared with the similarly filled prototypes, but overall the F release was marginal and not at a concentration to affect bacterial metabolism.
当代复合牙科修复材料的聚合成分的分解会影响其耐久性，而这些材料中的可浸出化合物会对细胞产生影响。因此，需要设计新一代的复合材料，使其具有更长的使用寿命，并确保任何可浸出的化合物对适当的细胞系都没有危害。为了实现这一目标，我们开发了基于硫醇-烯的聚合反应和基于烯丙基硫醚的加成-断裂链转移化学，以提供具有低收缩率和低收缩应力的交联聚合物树脂。在过去，牙科复合材料中使用的填料主要由玻璃组成，玻璃是生物惰性的。在我们的几个原型复合材料中，我们引入了氟磷灰石 (FA) 晶体，它类似于牙釉质晶体，具有生物活性。这些新型原型复合材料与同样填充有甲基丙烯酸酯双酚 A 二缩水甘油醚二甲基丙烯酸酯/三乙二醇二甲基丙烯酸酯（BisGMA/TEGDMA）复合材料的细胞毒性、机械性能、生物膜形成和氟化物释放进行了基准比较。所有复合材料在 pH7 时浸出物对牙髓干细胞没有毒性。与同样填充的 BisGMA/TEGDMA 复合材料相比，仅填充玻璃的原型复合材料的总韧性呈上升趋势。仅填充玻璃的原型复合材料的其他机械性能与同样填充的 BisGMA/TEGDMA 复合材料相当。FA 的加入降低了原型复合材料和 BisGMA/TEGDMA 复合材料的机械性能。与仅填充玻璃的 BisGMA/TEGDMA 复合材料相比，仅填充玻璃的原型复合材料上的生物膜质量和每毫升菌落形成单位减少，并且 FA 的加入显著降低了所有复合材料的生物膜质量和每毫升菌落形成单位。在 pH7 时，BisGMA/TEGDMA 玻璃+FA 复合材料的氟释放量在 24 小时后最大，与类似填充的原型材料相比，但总体而言，F 释放量微不足道，不会影响细菌代谢。
