Objective

Secondary caries and degradation of hybrid layers are two major challenges in achieving durable resin–dentin bonds. The objectives of the present study were to investigate the effects of a 2% quaternary ammonium silane (QAS) cavity cleanser on bacteria impregnated into dentin blocks and the gelatinolytic activity of the hybrid layers.

Methods

Microtensile bond strength was first performed to evaluate if the 2% QAS cavity cleanser adversely affected bond strength. For antibacterial testing, Streptococcus mutans and Actinomyces naeslundii were impregnated into dentin blocks, respectively, prior to the application of the cavity cleanser. Live/dead bacterial staining and colony-forming unit (CFU) counts were performed to evaluate their antibacterial effects. Gelatinolytic activity within the hybrid layers was directly examined using in-situ zymography. A double-fluorescence technique was used to examine interfacial permeability immediately after bonding.

Results

The cavity cleanser did not adversely affect the bond strength of the adhesives tested (p > 0.05). Antibacterial testing indicated that 2% QAS significantly killed impregnated bacteria within the dentin blocks compared with control group (p < 0.05), which was comparable with the antibacterial activity of 2% chlorhexidine (p > 0.05). Hybrid layers pretreated with 2% QAS showed significant decrease in enzyme activity compared with control group. With the use of 2% QAS, relatively lower interfacial permeability was observed, compared with control group and 2% chlorhexidine (p < 0.05).

Significance

The present study developed a 2% QAS cavity cleanser that possesses combined antimicrobial and anti-proteolytic activities to extend the longevity of resin–dentin bonds.

中文翻译：

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季铵基硅烷型抗菌和抗蛋白水解型洁面乳

客观的

次生龋齿和杂化层的降解是实现持久的树脂-牙本质键的两个主要挑战。本研究的目的是研究2％季铵硅烷（QAS）腔清洁剂对浸渍到牙本质嵌段中的细菌的影响以及杂化层的明胶分解活性。

方法

首先进行微拉伸粘合强度以评估2％QAS腔清洁剂是否对粘合强度产生不利影响。为了进行抗菌测试，在应用型腔清洁剂之前，将变形链球菌和内生放线菌分别浸入牙本质块中。进行活/死细菌染色和菌落形成单位（CFU）计数以评估其抗菌效果。使用原位酶谱法直接检查了杂化层中的明胶分解活性。结合后立即使用双重荧光技术检查界面渗透性。

结果

空腔清洁剂不会对测试的粘合剂的粘合强度产生不利影响（p> 0.05）。抗菌测试表明，与对照组相比，2％QAS可以显着杀死牙本质块内的浸渍细菌（p <0.05），与2％洗必泰的抗菌活性相当（p> 0.05）。与对照组相比，用2％QAS预处理的杂种层显示酶活性显着降低。与对照组和2％洗必泰相比，使用2％QAS可以观察到相对较低的界面渗透性（p <0.05）。

意义

本研究开发了一种2％QAS腔体清洁剂，该组合物具有抗微生物和抗蛋白水解活性，可延长树脂-牙本质键的寿命。