【作者】 古林娟；

【导师】 赵信义； 李石保；

【作者基本信息】 第四军医大学 ， 口腔医学， 2010， 硕士

【摘要】 随着牙齿修复粘接技术的发展以及树脂材料美学性能、机械性能的极大改善,复合树脂粘接修复技术在临床应用日益广泛。该技术修复效果与其粘接性能密切相关,粘接性能主要包括粘接强度及边缘密合性。近年来,历经七代发展的牙齿粘接剂与牙齿硬组织的粘接强度已有显著的提高,达到前所未有的水平,然而由于复合树脂及粘接剂的聚合收缩等因素所导致的粘接修复体边缘密合性不良的问题,至今尚未得到解决。因此,如何客观全面地对修复材料粘接性能作出评价,以及进一步提高与牙体组织的粘接性能,尤其是减少牙本质粘接界面微渗漏问题,一直是人们研究的热点。本研究分三个实验:实验一:微拉伸测试法是目前常用的一种牙齿粘接强度测试方法,该法能较真实地反映粘接剂与牙齿的粘接强度。但是,在以往的实验中,牙齿微拉伸粘接强度的测试均是在干燥环境下进行的。为此本实验目的是:比较微拉伸试样在干、湿两种测试环境下所测得的粘接强度,探讨测试环境的湿度对测定的粘接强度的影响,为规范实验操作提供实验依据。方法:常规制备6组微拉伸粘接试样(iBond、Adper Prompt、Clearfil SE Bond、Clearfil S3 Bond、Prime&Bond NT、Contax),再将每组粘接试样随机均分为4组(湿润组,干燥2h组、5h组、24h组)并测试其微拉伸粘接强度,扫描电镜下观察试样断裂模式,并对实验结果进行统计分析。结果:所测粘接剂(iBond除外)湿润组的粘接强度均显著低于干燥组(P<0.05),断裂破坏模式与试样干湿状态无关,均以界面破坏为主。结论:牙本质微拉伸试样在干燥状态下测得的粘接强度值明显高于湿状态下测得的粘接强度值,为能真实地反映在体牙本质的粘接强度,在体外测定牙本质的微拉伸粘接强度时,测试过程中应当确保试样处于润湿状态。实验二:染料渗漏法是评价牙齿充填物边缘密合性最常用的方法,但是,该法观测的只是试样剖开面上的渗漏情况。Micro-CT是一种能够三维成像的仪器。本实验的目的是:(1)探讨应用Micro-CT离体观测牙齿充填物边缘微渗漏的可行性;(2)探讨Micro-CT观测充填物边缘微渗漏时的评价指标,为进一步的应用奠定一定的基础。方法:常规制备离体牙V类洞并用复合树脂粘接修复,用硝酸银染液浸泡牙齿后,纵向剖开牙齿及充填修复体,分别在光镜下和Micro-CT下测量剖开面银渗漏的深度,配对比较两种方法测量银渗漏深度的一致性。然后用Micro-CT对修复体边缘的银渗漏进行三维观测,内容包括银渗漏的形态、深度、面积及体积。结果:(1)两种方法对试样开剖面银渗漏深度检测结果高度相关且一致,无统计学差异(P>0.05);(2)常规染色法的剖开位置对测定的渗漏深度有影响,对同一窝洞而言,剖开位置不同,所观测到的渗漏深度亦会不同。结论:Micro-CT是一种较理想的微渗漏检测方法,不仅能精确定位、准确反映出微渗漏二维情况,还能对微渗漏进行定性及定量地三维检测。实验三:为了提高复合树脂修复体边缘密合性,许多学者在修复材料性能及临床操作上作了很多改进,但仍不能消除微渗漏现象。本实验目的是:利用重粘接表面封闭技术(rebonding technique),探讨应用牙齿粘接剂封闭复合树脂修复体边缘表面,并对即刻封闭效果及远期(冷热循环5000次)封闭效果进行评价。方法:常规制备V类洞复合树脂粘接修复试样,再将试样作空白对照与不同封闭(i Bond、Clearfil SE Bond、Clearfil S3 Bond、Prime&Bond NT、Contax)的对比处理,然后对试样封闭效果进行即刻及冷热循环5000次后微渗漏检测。结果:(1)即刻封闭效果显示,各组封闭处理试样均未发生微渗漏,与空白对照试样结果有统计学差异(P<0.05);(2)冷热循环后,封闭处理试样与空白对照试样微渗漏检测结果无显著差异(P>0.05),渗漏均较严重。结论:牙齿粘接剂可用作表面封闭剂,能有效降低微渗漏,但其远期(冷热循环5000次)封闭效果欠佳,还有待进一步改进。更多还原

【Abstract】 With the development of dental composite resin and bonding technique, composite resin has been applied more and more widely in clinic. The clinical effectivity of composite resin restoration is closely related to its bonding properties, including bond strength and marginal adaptation. In spite of the great improvement of dental adhesives and the resultant bond strength to dental hard tissue, poor marginal adaptation caused by the polymerization shrinkage of composite resin has not been completely eliminated. Thus, recent studies have focused on the improvement of the bonding properties such as marginal adaptation between restoration and tooth hard tissue and how to evaluate the bonding properties of these materials more objectively and roundly.This study consists of three experiments:In the first experiment: Micro-tensile testing is the most common method of testing bond strength between restoration and tooth hard tissue, which can more truly reflect the bond strength of adhesive to dentin. However, in previous experiments, bonding specimens were tested in dry condition, which has given rise to the question about its s significance. The objective of this experiment was to compare the microtensile bond strength of dentin bonded specimens measured in wet or dry conditions and analysis the possible reasons for the differences, and to provide experimental evidence for the standardization of the testing procedure. Methods: Six groups of conventional micro-tensile specimens (iBond, Adper Prompt, Clearfil SE Bond, Clearfil S3 Bond, Prime & Bond NT, Contax) were prepared, and the specimens of each group were randomly divided into 4 subgroups (moist, dry for 2h, 5h, 24h). All specimens were subjected to tensile bond strength test and the fractured surfaces were observed under SEM and the data were statistically analyzed. Results: The dry subgroups of all adhesives (except for iBond) showed higher bond strengths than moist subgroup (P<0.05), however the failure models of both dry and wet subgroups showed no different, mostly being adhesive failure. Conclusion: microtensile bond strength of moist specimens in vitro was low but more objective and reliable to evaluate the authentic bond effect of adhesive systems in vivo; micro-tensile specimen in the testing process should be keep moist.In the second experiment: Dye penetration detection was widely used to evaluate the marginal adaptation of restorations, but in this method only the leakage on the sectioned surface was observed. Micro-CT is a three-dimensional imaging instrument. So the purpose of this study was to investigate the possibility of using micro-CT to detect the marginal leakage of a restoration and to evaluate its advantages and disadvantages. Methods: Conventional class V composite resin restorations were done in extracted third molars and stained with silver nitrate solution. Then all teeth were sectioned longitudinally through the restoration and the silver penetration depth along the margin of the restoration was measured under microscope and micro-CT respectively. The sameness of the results from the two methods was statistically analysed. Some three-dimensional index of the leakage such as shape, depth, area and volume were detected using micro-CT. Results: (1) The silver penetration depths measured by the two methods were highly correlated and showed no significant difference by paired t test (r=1, P> 0.05); (2) In conventional microleakage method, the position of sectioning showed a significant influence on the results of leakage, presenting different leakage depths in different cut positions. Conclusions: Micro-CT can not only accurately demonstrate the three-dimensional shape of a microleakage, but also provide a qualitative and quantitative detection of the microleakage.In the third experiment: In an attempt to improve the marginal adaptation of restoration, many efforts have been made in the modification of adhesive restorative materials and clinical operations. In spite of this, the microleakage is still a problem in clinic. Objective: Using rebonding surface sealing technique to evaluate the immediate and long-term marginal sealing ability of using dental adhesives as surface sealants of bonding interface. Methods: Conventional class V composite resin restorations were done in extracted third molars and divided into two groups, one group being subjected to sealing with different dental adhesives (iBond, Clearfil SE Bond, Clearfil S3 Bond, Prime & Bond NT, Contax), another no any surface. Then the microleakage was detected immediately or after 5000 thermal cyclings in conventional method. Results: Five dental adhesives showed favorable immediate results in terms of sealing of bonded interface gap compared with the control group. After thermal cycling, the results of sealing treatment and control treatment showed no significant difference, both showing severe microleakage. Conclusions: The marginal leakage of a restoration can be reduced immediately after surface sealing with dental adhesive. However, these sealing showed poor resistance to thermal cycling.更多还原