Objectives

To evaluate the effect of experimental dentin pre-treatment solutions formulated with different flavonoids on microtensile bond strength (μTBS), nanohardness (NH) and ultra-morphological characteristics of artificial caries-affected dentin (CAD) bonded using a universal bonding system.

Methods

A microbiological method was used to create an artificial CAD in 91 human molars. Five experimental pre-treatment solutions were created using the following flavonoids: quercetin (QUE); hesperidin (HES); rutin (RUT); naringin (NAR), or proanthocyanidin (PRO). A placebo solution (PLA) with no flavonoids added was also evaluated. The flavonoids or placebo solutions were applied to the CAD prior to the application and photoactivation of a universal adhesive (Scotchbond Universal, 3M Oral Care). A control group (CON), in which only the bonding agent was applied without any flavonoid solution, was also evaluated. A 3-mm-thick block of resin composite (Opallis, FGM) was built up on the flat bonded CAD surfaces and was light-cured following the manufacturer’s instructions. Specimens were sectioned to obtain resin-dentin slices and sticks (cross-sectional area of 0.8 mm²). The μTBS, NH, and confocal ultramorphology analysis of resin-dentin interface was evaluated at 24 h and after thermo-cycling aging (25,000 cycles). The results were analyzed using 2-way ANOVA followed by Bonferroni's post hoc test (pre-set α = 0.05).

Results

The specimens from groups QUE, NAR, and RUT presented greater μTBS values than those from CON group (p<0.05). Specimens from some of these experimental groups presented greater nanomechanical properties (p<0.05), and no morphological degradation at the resin-dentin interface after aging.

Significance

The use of exogenous cross-linkers as dentin pre-treatment before bonding procedures may represent a suitable strategy to improve the longevity of universal adhesive systems applied to caries-affected dentin.

中文翻译：

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黄酮类化合物对龋齿影响的牙本质的长期粘合稳定性的影响。

目标

要评估由不同类黄酮配制的实验性牙本质预处理溶液对使用万能粘合系统粘合的龋齿影响的牙本质（CAD）的微拉伸粘合强度（μTBS），纳米硬度（NH）和超形态特征的影响。

方法

使用微生物学方法在91个人臼齿中创建了人工CAD。使用以下类黄酮创建了五个实验性预处理溶液：槲皮素（QUE）；橙皮苷（HES）; 芦丁（RUT）; 柚皮苷（NAR）或原花青素（PRO）。还评估了未添加类黄酮的安慰剂溶液（PLA）。在施用通用粘合剂（Scotchbond Universal，3M Oral Care）并将其光活化之前，将类黄酮或安慰剂溶液施用于CAD。还评估了对照组（CON），其中仅施用了粘合剂而没有任何类黄酮溶液。在平面粘结的CAD表面上建立一个3毫米厚的树脂复合材料块（Opallis，FGM），并按照制造商的说明进行光固化。²）。在24 h以及热循环老化（25,000个循环）之后，评估了树脂-牙本质界面的μTBS，NH和共聚焦超形态学分析。使用2-way ANOVA和Bonferroni的事后检验（预设α= 0.05）对结果进行了分析。

结果

QUE，NAR和RUT组的样本的μTBS值大于CON组（p < 0.05）。来自这些实验组中的一些的样品表现出更大的纳米机械性能（p < 0.05），并且老化后在树脂-牙本质界面上没有形态学降解。

意义

在粘合程序之前使用外源性交联剂作为牙本质预处理可能代表一种合适的策略，以改善应用于龋齿影响的牙本质的通用粘合剂体系的寿命。