Objectives

To evaluate the dentinal tubular occlusion of nano-hydroxyapatite (nHAp) containing desensitizing toothpastes and their influence on the resin-dentin bonding performance of two mild self-etch adhesives.

Materials and methods

Mid-coronal dentin specimens were prepared from obtained intact human third molars. They were immersed in 1% citric acid for 20 s to expose the dentinal tubules to simulate sensitive teeth and then randomly divided into four groups. The control group received no desensitizing treatment. Experimental groups were treated with two commercial nHAp containing desensitizing toothpastes (Biorepair and Dontodent) and an experimental pure nHAp paste respectively. Each group was further divided into two subgroups and bonded with either G-Bond or Clearfil S³ Bond. The micro-tensile bond strength was tested and failure mode distribution was analyzed. Moreover, the effect of desensitizers on dentinal tubular occlusion was observed by the field-emission scanning electron microscope (FESEM). Resin infiltration of the adhesives labeled by fluorescent Rhodamin B was evaluated under confocal laser scanning microscopy (CLSM).

Results

FESEM revealed that all the desensitizers noticeably occluded the dentinal tubules, and the extents were completer after application for 7 days. The majority of the occlusion still preserved even after acid challenge with cola or adhesive. CLSM demonstrated shorter resin tags were produced in the desensitized groups. When bonding with G-Bond, the pure nHAp group showed comparable bond strength to the control group, while Biorepair and Dontodent treatment decreased the bond strength. For groups bonded with Clearfil S³ Bond, all the desensitizers reduced the bond strengths compared to the control and no significant difference was found among the three groups.

Conclusion

Nano-hydroxyapatite containing desensitizing toothpastes could occlude dentinal tubules effectively with a certain degree of acid resistance, which contributes to the relief of dentin hypersensitivity. While, the application of these nHAp desensitizers comprised the resin infiltration of G-Bond and Clearfil S³ Bond, resulting in decreased bond strengths of the resin-dentin bonding.

中文翻译：

---

含纳米羟基磷灰石的脱敏牙膏对牙本质小管的密封能力和自蚀刻胶粘剂粘结性能的影响。

目标

要评估包含脱敏牙膏的纳米羟基磷灰石（nHAp）的牙本质小管阻塞及其对两种温和自蚀刻粘合剂的树脂-牙本质粘结性能的影响。

材料和方法

从获得的完整人类第三磨牙制备中冠状牙本质标本。将它们浸入1％柠檬酸中20 s，露出牙本质小管以模拟敏感牙齿，然后随机分为四组。对照组未接受脱敏治疗。实验组分别用两种含脱敏牙膏的商品化nHAp（生物修复和Dontodent）和纯正实验性nHAp糊剂进行治疗。每组进一步分为两个亚组，并与G-Bond或Clearfil S ^3结合键。测试了微拉伸粘结强度并分析了破坏模式分布。此外，通过场发射扫描电子显微镜（FESEM）观察到脱敏剂对牙本质小管阻塞的作用。在共聚焦激光扫描显微镜（CLSM）下评估荧光若丹明B标记的胶粘剂的树脂渗透性。

结果

FESEM显示，所有脱敏剂均明显阻塞了牙本质小管，使用7天后其范围更完整。即使在用可乐或粘合剂进行酸刺激后，大多数咬合仍得以保留。CLSM证明在脱敏基团中产生的树脂标签更短。当与G-Bond结合时，纯nHAp组显示出与对照组相当的结合强度，而Biorepair和Dontodent处理降低了结合强度。对于与Clearfil S ³键结合的基团，与对照相比，所有脱敏剂均降低了键合强度，并且三组之间没有发现显着差异。

结论

含有纳米羟基磷灰石的脱敏牙膏可以有效地阻塞牙本质小管，并具有一定程度的耐酸性，有助于缓解牙本质过敏。同时，这些nHAp脱敏剂的应用包括树脂渗透的G-Bond和Clearfil S ³键，导致树脂-牙本质键的键强度降低。