Neutrophils, cells of the innate immune system, enter the mouth and release factors that are hypothesized to contribute to the degradation of tooth dentin, methacrylate resin composites, and adhesives at the restoration-tooth-dentin interface. The objectives were to characterize neutrophils’ degradation towards resin composite, self-etch (SE) and total-etch (TE) adhesives, SE and TE resin-dentin interfaces and to identify proteins that could contribute to the degradation process. Neutrophils’ degradation of cured resin composite, and SE and TE adhesives, was quantified by measuring the specific resin degradation by-product, bishydroxy-propoxy-phenyl-propane (bisHPPP), released after 30 days incubation of the materials with the cells. Neutrophils’ degradative effect on resin-dentin interfaces was examined by recording the interfacial fracture toughness (FT), and surface analysis of the fracture mode following incubation of SE and TE miniature short-rod (mini-SR) specimens with the cells. Neutrophils increased degradation of polymerized resin composite, and TE adhesive, but not SE adhesive over 30 days (p < 0.05). Incubation of SE and TE resin-dentin interfaces with neutrophils led to a reduction in FT over time (p < 0.05). The effect was more pronounced for TE interfaces. Neutrophils also affected the fracture mode of SE and TE resin-dentin interfaces. Several proteins that could contribute to the degradative activity of neutrophils, including Neutrophil collagenase (MMP-8), Matrix metalloproteinase- 9 (MMP-9), Cathepsin G, Neutrophil- gelatinase associated lipocalin (NGAL) and Myeloperoxidase, were isolated. The ability of neutrophils to degrade resin, tooth dentin, and reduce the bond strength of resin-dentin interfaces suggest neutrophils’ potential role in primary and recurrent caries and dental restoration failure.

中性粒细胞是先天免疫系统的细胞，进入口腔并释放出一些因素，据推测这些因素可导致牙齿-牙本质，甲基丙烯酸酯树脂复合物和修复体-牙齿-牙本质界面处的粘合剂降解。目的是表征中性粒细胞对树脂复合材料，自蚀（SE）和全蚀（TE）粘合剂，SE和TE树脂-牙本质界面的降解，并鉴定可能有助于降解过程的蛋白质。固化树脂复合材料以及SE和TE粘合剂的嗜中性粒细胞降解通过测量特定的树脂降解副产物双羟基-丙氧基-苯基丙烷（bisHPPP）进行定量，该副产物在细胞与细胞孵育30天后释放。通过记录界面断裂韧度（FT）以及在将SE和TE微型短杆（mini-SR）样品与细胞一起孵育后，观察中性粒细胞对树脂-牙本质界面的降解作用，并分析断裂模式的表面。中性粒细胞在30天内增加了聚合树脂复合材料和TE粘合剂的降解，但未增加SE粘合剂的降解（p  ＜0.05）。SE和TE树脂-牙本质界面与嗜中性粒细胞的孵育导致FT随时间降低（p  <0.05）。对于TE接口，效果更为明显。中性粒细胞还影响SE和TE树脂-牙本质界面的断裂模式。分离了几种可能有助于嗜中性粒细胞降解活性的蛋白质，包括嗜中性粒细胞胶原酶（MMP-8），基质金属蛋白酶-9（MMP-9），组织蛋白酶G，嗜中性明胶酶相关脂钙蛋白（NGAL）和髓过氧化物酶。中性粒细胞降解树脂，牙本质和降低树脂-牙本质界面的结合强度的能力表明，中性粒细胞在原发性和复发性龋齿以及牙齿修复失败中的潜在作用。