根管治疗后(牙合)面单面缺损双尖牙修复方式的生物力学研究

目的：从生物力学角度比较不同方法修复根管治疗后双尖牙的效果，并探询最佳方案。方法：实验通过收集对称的双尖牙，对照组为完整离体牙，试验组制备根管治疗及殆面单面缺损模型，试验一采用银汞充填；试验二采用高强度粘结性材料FX-Ⅱ充填；试验三为银汞充填后再加冠修复；1mm／min加载于与牙体长轴成45。烦尖舌斜面巾点测试破坏载荷，用SPSS10．0软件包进行配对分析。结果：试验一、试验二P〈0．05，充填组破坏载荷低于对照组；试验三P〈O．05全冠组破坏载荷高于对照组。结论：可认为从生物力学角度来讲，骀面单面缺损的最佳修复方法是全冠修复。     

1 839颗前磨牙楔状缺损与(牙合)面磨损间的相关分析

目的探讨前磨牙楔状缺损与[牙合]面磨损间的关豕。方法以1839颗离体前磨牙为研究对象,观察记录所有牙的[牙合]面磨损程度,颊侧牙颈部楔状缺损情况。对于有楔状缺损的牙,观察记录楔状缺损的形态,测量楔状缺损的深度和宽度,分析楔状缺损与[牙合]面磨损间的相互关系。结果1839颗离体前磨牙中,楔状缺损患牙有644颗,患病率为35．02％。不同牙位的牙楔状缺损的患病率存在统计学差异（P〈0.05）。[牙合]面有磨损的牙与无磨损牙的楔状缺损患病率也存在统计学差异（P〈0．05）,楔状缺损的深度和宽度与牙齿[牙合]面磨损程度有关（P〈0.01）。[牙合]面有磨损的牙与无磨损牙的楔状缺损形态构成有统计学差异（P〈0.05）。结论前磨牙的[牙合]面磨损与其楔状缺损的发生具有相关关系。     

牙列缺损伴重度(牙合)面磨损(牙合)重建修复的临床研究

目的 通过对不同类型牙列缺损并伴重度(牙合)面磨损的患者进行修复治疗,探讨(牙合)重建的有关问题.方法 选取牙列缺损并伴重度(牙合)面磨损患者69例,制取修复前研究模型,根据不同的缺损类型进行(牙合)垫式可摘局部义齿、固定义齿或固定-可摘义齿联合修复,随访3个月～4年,观察修复治疗效果.结果 患者的咀嚼功能明显改善,有颞下颌关节症状者,症状得到了缓解,无颞下颌关节症状者在咬合升高后未出现新的颞下颌关节症状.结论 对于牙列缺损伴重度(牙合)面磨损患者,(牙合)垫式可摘义齿及固定义齿修复均是(牙合)重建修复的有效方法.     

异常(牙合)力对楔形缺损修复效果的影响

本组收集了我院口腔内科1995-2001年间做过修复的楔形缺损患牙877个.877个患牙曾用三种不同方法修复过,复诊后共有104个牙的修复体发生了脱落.本调查试图从(牙合)关系角度发现一些对楔形缺损修复效果产生影响的因素.     

应用(牙合)垫治疗高龄失牙患者种植义齿修复后的前牙深覆(牙合)

目的:应用(牙合)垫治疗高龄患者前牙深度覆(牙合)持续恶化,减轻种植义齿负荷.方法:制作(牙合)垫,适当升高咬(牙合),维持正常前牙覆(牙合)关系.结果:咬(牙合)关系良好,减轻后牙磨损,保护上前牙舌侧面磨损,并阻止下前牙伸长.结论:(牙合)垫制作简单,防止上、下前牙相互的磨损,并消除牙被磨损后的敏感症状,保持前牙的正常咬合关系,不影响双侧颞颌关节.     

铸造邻(牙合)嵌体治疗牙间食物嵌塞的疗效观察

牙间食物嵌塞是临床上一种常见病和多发病,病因虽较复杂,但以局部因素居多.因此,治疗时多采取去除病因,如牙齿的磨改及调(牙合)、充填修复和修复体修复等方法.自1998年以来,作者采用Ni-Cr合金铸造邻(牙合)嵌体恢复后牙正常邻接关系,治疗牙间食物嵌塞,并进行2～3年的随访观察,效果满意.     

复合树脂充填近中(牙合)面洞颈壁边缘微渗漏的研究

目的:比较不同类型树脂充填近中(牙合)面洞的颈壁牙本质-牙骨质边缘微渗漏.方法:在36个新鲜拔除的人上下颌恒磨牙制备近中(牙合)面洞,随机分为3组,分别用3M后牙树脂P60、前后牙通用树脂Z250和纳米树脂z350充填.标本经温度循环,品红染色后,近中远中向沿长轴连续切3片,体视显微镜下观察染料渗漏情况.结果:3组微渗漏由小到大依次为:Z350<72500.05).结论:此3种树脂类型对近中(牙合)面洞颈壁牙本质-牙骨质边缘微渗漏无明显差异.     

离体前磨牙邻面颈部龋一种新洞型抗折裂性能的实验研究

目的对邻面颈部龋一种新洞型及传统洞型进行抗折裂负荷测试,并对新洞型与传统洞型的抗折裂性能进行比较。方法收集200颗完整的离体前磨牙,随机分成A、B、C、D 4组,A组为对照组,B组制备成牙合面洞,C组制备成邻颊(舌)面洞+牙合面洞(即新洞型,简称“双洞型”),D组制备成邻牙合面洞,模拟根管治疗后行银汞充填,用微机控制电子万能测试机对离体牙进行抗折裂负荷测试,测试各组实验牙折裂时的压力强度值。结果牙体折裂时的压力强度均值分别是:A组4 523.17 N,B组2 357.41 N,C组2 343.25 N,D组1 784.22 N。经统计学分析:C组抗折力明显高于D组,C组与B组抗折力接近,B、C、D抗折力明显低于A组。结论新设计的“双洞型”抗折力优于传统的邻牙合面洞型。     

外伤致上前牙缺损反(牙合)牙槽骨塌陷修复1例

患者，男，55岁，因外伤致上前牙缺损，反[牙合]，牙槽骨塌陷，影响进食与面容，于2005-01-01由兰州来我科就诊。     

Survival Rates from Fracture of Endodontically Treated Premolars Restored with Full-coverage Crowns or Direct Resin Composite Restorations: A Retrospective Study

Introduction

The aim of the present study was to compare the survival rates against fracture of premolar endodontically treated teeth (ETT) restored with resin composite or crowns and to identify risk factors associated with the fracture.

Impact of Conservative Endodontic Cavities on Root Canal Preparation and Biomechanical Behavior of Upper Premolars Restored with Different Materials

IntroductionThe purpose of this study was to evaluate the impact of conservative endodontic cavities (CECs) on root canal preparation, restoration, and biomechanical behavior of teeth prepared using different shaping systems and restorative materials.MethodsNinety upper premolars with a bifurcated root were matched based on morphology and randomly assigned to a control group (n = 10) or 1 of the following experimental groups (n = 40): traditional endodontic cavity and CEC. Teeth were subdivided according to instrumentation (n = 10) as follows: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (VDW GmbH, Munich, Germany), Reciproc Blue (VDW GmbH), and Hyflex EDM (Coltene/Whaledent, Altstätten, Switzerland). After canal obturation, teeth were restored using temporary material, conventional composite, regular bulk fill composite, or bulk fill flow combined with conventional composite. Before and after preparation and after obturation, the teeth were scanned using micro–computed tomographic imaging. Canal transportation (CT), the percentage of untouched canal surfaces (UCSs), voids in restoration (VRs), and residual filling material in the pulp chamber were evaluated. Finite element analysis, fracture resistance, and the failure pattern were recorded. The data were analyzed using analysis of variance and the Tukey and chi-square tests.ResultsCECs had greater CT, percentage of filling material, and VRs compared with traditional endodontic cavities (P < .0001). The highest CT and UCSs were observed in CEC with ProTaper Universal. Bulk fill flow combined with conventional composite showed a lower percentage of VRs compared with other restorative materials (P < .05). Finite element analysis, fracture resistance, and failure pattern revealed similar behaviors in all groups (P > .05) .ConclusionsCECs had a negative impact on root canal centralization, UCSs, cleaning of the pulp chamber, and percentage of VRs. Controlled memory instruments were the most adequate for the root canal preparation of CECs. The endodontic cavity did not influence the biomechanical behavior of restored teeth.     

A Practice-based Study on the Survival of Restored Endodontically Treated Teeth

IntroductionThis retrospective study evaluated the survival of endodontically treated teeth (ETTs) and investigated factors influencing restoration and tooth survival.MethodsData from 795 ETTs were recorded, and success (restoration still intact) and survival (restoration intact or failed/repaired/replaced and tooth still in situ) were analyzed using Kaplan-Meier statistics. A multivariate Cox regression analysis was performed to assess the variables influencing success and survival.ResultsAt the end of the observation period (mean observation time = 4.48 years), 45 teeth had been extracted (annual failure rate for survival = 1.9% at 9.6 years) and 114 restorations had received a restorative follow-up treatment (annual failure rate for success = 4.9% at 9.6 years).ConclusionsETTs showed acceptable survival and success in the long-term. Variables showing significant influence on survival were the number of teeth in the dentition and the presence of decay at the moment the patient entered the practice.     

上颌前磨牙根管治疗后MOD洞型不同修复方式对牙体抗力的影响

目的：使用不同方式修复上颌前磨牙牙体缺损后,比较牙体修复方式和材料对牙齿抗力的影响。方法：选择60颗单根上颌前磨牙,随机分为4组：A组,对照组;B组,复合树脂充填组;C组,复合树脂覆盖牙尖充填组;D组,聚合瓷嵌体覆盖牙尖修复组。完成所有的修复后,制备抗折强度检测试件。使用万能试验机进行压力试验,直到样本劈裂。每个样本劈裂时的压力及劈裂的类型,分别进行记录。结果：C组和D组的抗折强度明显高于B组（P〈0．05）,C组和D组抗折强度差别不明显。样本的劈裂形式四组存在差异,劈裂形式为Ⅱ型的比例D组低于C组。结论：覆盖牙尖的修复方式修复根管治疗后牙齿的大面积缺损（MOD洞型）,有利于提高牙齿的抗力;聚合瓷嵌体修复要优于复合树脂充填修复。     

上颌前磨牙桩道预备后剩余根管壁厚度和抗折强度的研究

目的:探讨上颌前磨牙桩道预备后剩余根管壁厚度及对抗折强度的影响。方法:对100颗单、双根管上颌 前磨牙,用1#～5#P型钻进行桩道预备,用光学显微镜分别测量各组牙冠方和根方剩余根管壁厚度,并观察桩道预 备对抗折强度的影响。结果:单根管上颌前磨牙,1#～2#P型钻预备后,各壁剩余厚度均大于1mm;而对于双根管 上颌前磨牙,1#～3#P型钻预备后,各壁剩余厚度均大于1mm。另外,1#～5#P型钻预备后,牙根抗折强度逐渐变小 (P 0.01),且相同直径器械预备后,双根管抗折强度大于单根管(P 0.01)。结论:用P型钻预备桩道时,单根 管牙最大可用2#P型钻预备,双根管牙最大可用3#P型钻预备,且剩余牙质的量与牙齿的抗折强度成正相关。     

根管充填后3种暂时充填材料的冠部封闭性能比较

目的：探讨根管充填后暂时充填材料的冠部封闭性能.方法：取105颗单根离体牙,分为12组,常规根管充填,并分别采用磷酸锌水门汀、玻璃离子水门汀和Dyract AP复合体封闭后,置于次甲基蓝液体和^125I标记的IgG溶液进行从冠方向根方的渗漏,1周、2周和6周后分别运用自显影技术或直接测量渗漏深度,统计分析.结果：各组均有渗漏,^125I标记IgG渗漏实验显示在6周时磷酸锌水门汀组的渗漏深度明显大于玻璃离子水门汀组和Dyract AP复合体组（P=0.008＜0.01）.结论：Dyract AP复合体和玻璃离子水门汀可能是远期效果较好的暂封材料.     

显微CT法研究中国人上颌第一前磨牙分支根管形态

目的:使用显微CT扫描法研究中国人离体上颌第一前磨牙分支根管解剖形态。方法:收集63颗中国人上颌第一前磨牙,使用显微CT扫描并构建根管系统三维可视化模型。观察并记录分支根管、根尖三角区发生情况,分析分支根管发生率、分布和开口特征。结果:共有50颗上颌第一前磨牙含有分支根管,发生率为79.37%。共记录到124个分支根管,其中95.16%发生于根尖1/3。分支根管开口于近中和远中方向的分别为33.06%和23.39%。根尖三角区的发生率为7.94%。结论:上颌第一前磨牙分支根管发生率高,根管系统形态复杂,了解其分支根管发生规律对于提高根管治疗成功率具有重要意义。     

Radicular Grooves and Complex Root Morphologies of Mandibular Premolars Among Israeli Population

IntroductionMandibular premolars usually have one root and one root canal. Different studies found that up to 30% of mandibular premolars have more than one root canal, and up to 24% of mandibular premolars have C-shape canals. The purpose of this study was to investigate the root anatomy and the prevalence of complex root canal morphology in mandibular premolars in Israeli population.MethodsA total of 1020 Israeli patients' cone-beam computed tomography scans were screened and evaluated. A total of 1835 mandibular first premolars and 1678 mandibular second premolars were examined. Irregular root anatomy and different root canal morphologies were recorded and analyzed.ResultsThe overall prevalence of complex root morphology (types II–VIII) in mandibular first and second premolars was 21% and 2.8%, respectively. The bilateral prevalence of complex root morphology in mandibular first and second premolars was 46% and 29%, respectively. The prevalence of radicular grooves in mandibular first and second premolars with complex root morphology was 48% and 36%, respectively. No significant difference was found according to gender or the side of occurrence. However, complex root canal morphology was significantly found in mandibular premolars with radicular grooves.ConclusionsComplex root canal morphology frequently occurs in mandibular first premolars in the population of Israel. Radicular groove existence in mandibular first and second premolars is significantly related to complex root canal morphology.