Abstract:
Carbodiimide (EDC)-based dentin primers preserve hybrid layer (HL) integrity. However, aging >1 y has not been investigated. The present study examined whether the cross-linking effect of EDC was reflected in dentin bond strength, endogenous enzymatic activity, and the chemical profile of the HL after 5-y aging in artificial saliva. Noncarious human third molars (N = 42) were cut to expose middle/deep coronal dentin and treated as follows: group 1, dentin etched with 35% H3PO4, pretreated with a 0.3M aqueous EDC primer for 1 min and restored with XP Bond (Dentsply Sirona); group 2, as in group 1 but without EDC pretreatment; group 3, Clearfil SE Bond (Kuraray-Noritake) primer applied to dentin surface, followed by EDC pretreatment as in group 1 and application of bond; group 4, as in group 3 without EDC pretreatment. After composite buildup, the specimens were cut into sticks or slabs, depending on the experiment. All tests were performed at baseline (T0) and after 5 y of aging (T5) in artificial saliva at 37 °C. Microtensile bond strength (µTBS) was tested at a crosshead speed of 1 mm/min until failure. Endogenous enzymatic activity was investigated with in situ zymography. The chemical profile of HL was determined via Raman spectroscopy. Three-way analysis of variance and post hoc Tukey test were used to analyze µTBS and in situ zymography data (α = 0.05). EDC pretreatment and aging significantly influenced µTBS and in situ zymography results (P < 0.05). Higher bond strength and lower gelatinolytic activity were identified in the EDC-treated groups at T5 (P < 0.05), especially in the etch-and-rinse groups. Raman spectra revealed less defined amide III peaks in control specimens at T5. The EDC cross-linking effect persisted in the HL for 5 y in terms of bond strength, collagen structure preservation, and dentinal enzyme silencing.
摘要:
基于碳二亚胺(EDC)的牙本质底漆保持杂化层(HL)完整性。然而,年龄>1y尚未调查。本研究检查了EDC的交联作用是否反映在牙本质粘结强度上,内源酶活性,以及人工唾液中5-y老化后HL的化学特征。切割非龋齿的人类第三磨牙(N=42)以暴露中/深冠状牙本质,并进行以下处理:第1组,用35%H3PO4蚀刻牙本质,用0.3M水性EDC底漆预处理1分钟,并用XPBond(DentsplySirona)修复;第2组,与第1组相同,但未进行EDC预处理;第3组,ClearfilSEBond(Kur随后如第1组进行EDC预处理并应用键;第4组,如第3组,不进行EDC预处理。复合材料堆积后,标本被切成棍棒或厚板,取决于实验。所有测试均在37°C下在人工唾液中在基线(T0)和5y老化(T5)后进行。以1mm/min的十字头速度测试微拉伸粘结强度(μTBS)直至失效。用原位酶谱研究内源酶活性。通过拉曼光谱确定HL的化学特征。三向方差分析和事后Tukey检验用于分析µTBS和原位酶谱数据(α=0.05)。EDC预处理和老化显著影响µTBS和原位酶谱结果(P<0.05)。在T5时,在EDC处理组中鉴定出较高的粘结强度和较低的明胶分解活性(P<0.05),尤其是在蚀刻和冲洗组中。拉曼光谱显示,在T5时,对照样品中的酰胺III峰定义较少。就粘结强度而言,HL中的EDC交联效果持续了5y,胶原蛋白结构保存,和牙本质酶沉默。