摘要：
目的 探讨经天然交联剂表没食子儿茶素没食子酸酯(epigallocatechin-3-gallate,EGCG)改性后脱矿牙本质粘接面的渗透率、亲水性、耐酶解能力及粘接耐久性的变化,寻找可用于牙本质粘接面预处理的理想天然交联剂.方法 2％牛血清白蛋白溶液模拟髓压,测定在模拟龋病条件下0.02％、0.1％EGCG对牙本质表面渗透率的影响,空白对照组牛血清白蛋白溶液中不含EGCG,阳性对照组为脱敏剂处理组(每组15个试件).检测近髓和远髓牙本质经0.1％EGCG预处理60和120 s、0.5和1h后表面接触角的变化,空白对照组不经EGCG预处理(每组10个试件).扫描电镜观察空白对照组,0.02％、0.1％及0.5％EGCG预处理组(均预处理120 s)经100 mg/L Ⅰ型胶原酶处理后牙本质粘接界面形态的改变;检测4组牙本质粘接试件冷热循环前后微拉伸强度(即粘接强度,每组每种处理方式30个试件).结果 与空白对照组相对渗透率[(151.3±22.3)％]相比;0.1％EGCG牙本质表面相对渗透率[(23.7±6.3)％]显著减少(P＜0.05).与空白对照组相比,0.1％EGCG预处理120 s、0.5和1h后,近髓牙本质表面接触角分别提高31.0％、53.5％、57.8％;远髓牙本质表面接触角分别提高37.4％、59.3％、62.4％.0.1％和0.5％EGCG预处理120 s后牙本质粘接试件冷热循环前粘接强度分别为(29.4±4.8)和(19.8±4.9) MPa,冷热循环后粘接强度分别为(19.9±5.1)和(15.3±6.3) MPa.结论 模拟龋病条件下,0.1％EGCG可使牙本质表面渗透性降低;0.1％EGCG预处理使牙本质粘接基底疏水性提高,耐酶解能力增强,从而提高粘接耐久性.%Objective To investigate the effect of epigallocatechin-3-gallate(EGCG) on biomodification of demineralized dentine substrate,in its permeability,hydrophobicity,and inhibition ability to collagen enzymatic degradation.Methods The dentine substrates were treated with simulated pulpal pressure created by mixtures of 0.02％,0.1％ EGCG/bovine serum albumin(BSA) in acidic environment (pH4.4) for 48 h.A fluid-transport model was used to measure the fluid permeability through demineralized dentine substrate.Positive replicas of dentine substrate were fabricated before and after being subjected to acidic environment for scanning electron microscope(SEM) examination.The blank group contained no EGCG and the positive group were treated with Gluma desensitizer.Static contact angle measurements on demineralized dentin and 0.1％ EGCG primed dentin were performed by contact angle analyzer.The priming time were 60 s,120 s,0.5 h,1 h.Dentine specimens bonded with Adper single bond 2 were subjected to 100 mg/L collagenase and observed under SEM.Resin-bonded specimens(with 0.02％,0.1％,0.5％ EGCG priming,or without EGCG priming) were created for micro-tensile bond strength evaluation(MTBS).Resinbonded specimens after thermolcycling were created for MTBS evaluation.Results The fluid permeability in the blank control group increased([151.3±22.3]％),the fluid permeability in 0.1％ EGCG/BSA group decreased([23.7±6.3]％).Compared to the blank control group,the contact angle of 120 s,0.5 h,1 h groups increased by 31.0％,53.5％,57.8％ in deep dentin and 37.4％,59.3％,62.4％ in shallow dentin.The SEM examination showed that 0.1％ and 0.5％ EGCG priming for 120 s significantly increased dentin collagen's resistance to collagenase.The immediate MTBS of 0.1％ and 0.5％ EGCG groups were (29.4±4.8) and (19.8± 4.9) MPa.After thermol cycling,the MTBS of 0.1％ and 0.5％ EGCG groups were (19.9±5.1) and (15.3± 6.3) MPa.Conclusions Under acidic environment(pH4.4),the 0.1％ EGCG can reduce dentine permeability under acidic environment.The 0.1％ EGCG can increase hydrophobicity of dentin substrate,and strengthen dentin substrate's resistance to collagenase hydrolysis,thus increased the resin-dentin bonding durability.
