桩核对根管治疗牙修复后强度的影响

目的　比较不同修复方法对根管治疗牙修复后强度的影响。方法　 6 0个完整拔除的人上中切牙 ,根管治疗后随机分为 5组 ,每组 12个。A组 :完整的根管治疗牙 ;B组 :根管治疗后烤瓷熔附金属 (PFM)全冠修复 ;C组 :牙体预备保留 2 0mm高的牙本质套圈 ,铸造金属桩核及PFM全冠修复 ;D组 :牙体预备无牙本质套圈 ,铸造金属桩核及PFM全冠修复 ;E组 :牙体预备保留 2 0mm高的牙本质套圈 ,Parapost预成桩、复合树脂核及PFM全冠修复。在MTS 810材料试验机上沿与牙长轴成 135度方向加载 ,测试折裂强度。结果采用方差分析。结果　牙体预备保留 2 0mm高的牙本质套圈 ,铸造金属桩核及PFM全冠修复者折裂强度最高 ,为 (1793 5 9± 387 93)N ;完整的根管治疗牙次之 ,为(146 6 6 8± 2 40 11)N ;其余 3组的折裂强度 (95 8 49± 2 86 0 2 )N、(992 98± 2 91 0 0 )N、(994 94± 2 85 0 4)N之间 ,差异无显著性。修复牙有无牙本质套圈 ,其折裂强度间差异有高度显著性 (P <0 0 1)。结论　桩核能否增强根管治疗牙的抗折裂强度与其修复设计有关 ,牙本质套圈可明显增强根管治疗牙的抗折裂能力。     

根管治疗牙的桩核修复治疗

桩核修复是固定修复中一个基本的前期修复技术 ,是许多修复治疗的基础。近年来 ,有关桩核修复的研究发现根管治疗牙的传统修复方法不仅是过时的 ,而且在部分病例中促进了牙齿的折裂[1] ,即许多的桩核修复是有害的。一、根管治疗牙的强度临床上常观察到根管治疗牙折裂的可能性增加。基于Helfer等[1] 牙齿中含有不到 10 %胶原结合水的研究报道 ,多数牙医认为根管治疗牙脆弱易折裂是由于牙髓组织的丧失、牙齿干燥造成。牙本质的理化特性提示 :不但根管壁牙本质的湿度含量较冠部牙本质少 ,而且其含量随着根管治疗过程而逐渐减少 ,即使在口腔这…     

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。     

前磨牙楔状缺损修复后的抗折裂强度研究

目的研究楔状缺损深及牙齿颊舌径的1/4或1/2的前磨牙采用不同材料充填后牙体的抗折裂强度及牙齿折裂模式。方法收集正畸拔除的新鲜前磨牙60颗,颊侧颈部设计颊舌径1/2和1/4楔状缺损,对1/2深度根管治疗后分别选择复合树脂、复合体或玻璃离子水门汀三种材料充填,运用万能材料试验机对前磨牙颊尖垂直向载力直至牙体断裂。记录牙断裂时的受力数值,并观察断裂模式。结果不同深度的楔状缺损其抗折裂强度不同,但各组间差异无统计学意义(P>0.05)。充填后前磨牙抗折裂强度显著增加(P<0.01),而不同充填材料对牙齿抗折裂强度无显著差异(P>0.05)。结论楔状缺损深及前磨牙颊舌径的1/4以上时容易导致前磨牙折裂。材料充填后可以提高前磨牙的抗折裂能力且与充填材料的种类无关。     

双洞形离体双尖牙的抗折裂性能研究

目的 研究双洞形离体双尖牙的抗折裂性能.方法 120颗完整的离体双尖牙,随机分成A、B、C、D共4组.A组为对照组,不制备洞形;B组制备(牙合)面洞;C组制备邻颊(舌)面洞加(牙合)面洞(以下简称双洞形);D组制备邻(牙合)洞;B、C、D组模拟根管治疗后行银汞充填,用微机控制电子式万能试验机对离体牙实验模型进行抗折裂负荷测试,绘制各组牙折裂过程的压力变形曲线,分析比较各组的差异.结果 C组的抗折裂性能高于D组,D组牙齿开裂后立即破碎,而C组牙齿在开裂后并不立即破碎,仍然具有承压能力,一般要2～3次开裂后才完全破碎;B组牙齿开裂后也立即破碎,但抗折裂性能略高于C组;A组的抗折裂性能明显大于B、C、D组.结论 制备双洞形的离体双尖牙抗折裂性能优于制备邻(牙合)洞的离体双尖牙.     

前磨牙根管治疗后牙体抗折强度的实验研究

目的研究前磨牙根管治疗后不同洞型、不同材料充填后牙体抗折强度的改变。方法选用因正畸拔除的无龋、无损伤、完整的前磨牙，左右同名牙配对，共48对，分为6组。每对配对牙中，一个做试验，另一个完整牙做对照。实验牙根管治疗后分别制备MO／DO洞，MOD洞，O洞，再分别用银汞、光固化复合树脂充填。置于万能实验机上测试每对牙的最大载荷。用t检验比较各实验组与对照组的抗折强度的差别。结果银汞充填MO／DO洞的抗折强度明显低于对照牙（P〈0．01）。光固化复合树脂充填各类洞的抗折强度与对照牙无显著性差别（P〉0．05）。结论根管治疗后用光固化树脂充填前磨牙的各类洞，牙体的抗折强度优于用银汞充填者。     

不同黏结材料对纤维桩修复牙根发育不完全牙抗折性能的影响

目的:观察比较不同黏结材料对牙根发育不完全牙修复后抗折强度的差异,以期为临床使用桩核系统修复根尖诱导成形术后的牙提供依据.方法:收集符合纳入标准的因正畸需要拔除的第一、二前磨牙75颗,随机分为5组,实验组2组(纤维桩+黏结材料充填)、阳性对照组2组(黏结材料桩道充填)、阴性对照组1组(根管充填后不作处理),每组15颗牙,将桩核系统修复后的样本牙进行包埋,采用TY-8000型电子万能测试机分别测量牙根颈1/3和中1/3的抗折强度,比较不同黏结材料修复对牙根抗折强度的影响.采用SAS6.0软件包对数据进行分析.结果:实验1组牙根颈、中部的抗折强度分别为(999±75.40)N、(799±21.77)N,实验2组牙根颈、中部的抗折强度分别为(896±15.73)N、(739±20.14)N.经统计学分析,2组间根颈1/3和中1/3抗折强度差异有显著性(P<0.01);各实验组与阳性对照、阴性对照组之间差异均有显著性.结论:不同黏结材料对纤维桩修复后的牙根发育不完全的牙各部位的抗折强度有影响.在牙根发育不完全牙玻璃纤维桩的修复中,建议用复合树脂水门汀作为黏结材料.     

根管重塑对薄弱根管抗折性能影响的实验室研究

目的探讨根管重塑对薄弱根管抗折能力的影响。方法收集成人离体牙30例作为样本,分为三组:实验组A、B和对照组每组各10例,实验组A、B组制备成喇叭口状根管,其中实验组B以复合树脂材料对薄弱根管进行重塑,三组样本分别铸造桩核冠修复,在电子万能力学试验机上沿与牙长轴135°方向静态加载,至牙体折裂,记录此时样本所承受的最大负荷,并对实验结果进行单因素方差分析两两比较。结果用复合树脂加强薄弱根管后修复组抗折裂强度与薄弱根管直接修复组差异有显著性,与对照组之间差异无显著性,薄弱根管直接桩核冠修复组与对照组之间的差异有显著性。结论利用复合树脂材料对薄弱根管进行根管重塑后修复,可提高其抗折能力。     

Cortisomol一次性根充治疗折裂牙的临床观察

目的 :观察Cortisomol在折裂牙一次性根充的临床疗效。方法 :对 5 6个折裂牙在治疗前调牙合并用不锈钢丝环形结扎 ,Cortisomol一次性根管充填治疗 ,观察其术后反应。结果 :疗效优良率为 96.4% ,绝大部分患者可进行全冠修复。结论 :使用Cortisomol根充材料可以一次性根管充填治疗隐裂牙     

洞型制备和充填材料对牙齿抗折强度影响的离体牙实验研究

目的　比较不同洞型及充填材料对牙齿抗折强度的影响。方法　将离体上颌第一前磨牙制备不同洞型并用不同材料进行充填 ,电子力学测试机加压测试牙体抗折强度及折裂方式 ,结果进行统计学分析。结果　不同洞型及充填材料对牙齿折裂有显著影响。结论　牙体缺损程度及充填材料类型是影响牙折的主要因素之一。     

23例27个粗大根管的根管治疗及修复临床观察

目的 :观察 2 3例 2 7个粗大根管的根管治疗及修复效果并总结治疗经验。方法 :对 2 7个根管未完全发育成形的残根、残冠进行根管治疗及修复 ,随访 2年观察治疗效果。结果 :2 7个粗大根管在根管治疗过程中 ,2 3个牙经化学根管预备后即产生良好的根充效果 ,3个牙仅作机械根管预备而未作化学预备的患牙首次根管治疗失败 ,采用化学预备重新根充效果良好 ,1个牙反复出现瘘管而拔除。自制牙胶尖未发生超充情况。修复后有 7个牙出现根折 ,其余均修复效果良好。结论 :利用化学方法对粗大根管进行预备是必须的 ,采用自制牙胶尖进行根管充填能形成良好的根尖封闭。修复的关键在于尽量保留牙体组织。牙颈部需形成“颈箍” ,肩台必须位于正常牙体组织上。     

Effect of bonded restorations on the fracture resistance of root filled teeth

AIM: To evaluate the fracture resistance of root filled maxillary premolars restored with different techniques. METHODOLOGY: One hundred and twenty single-rooted maxillary premolar teeth were divided randomly into six groups of 20 teeth and subjected to the following procedures: group 1: intact teeth. Group 2: endodontic access cavities prepared. Group 3: MOD cavities were prepared, root canals were filled and no restoration was placed. Group 4: teeth were prepared as group 3 and restored conventionally with amalgam. Group 5: teeth were prepared as group 3 and restored with amalgam using a bonding material. Group 6: teeth were prepared as group 3 and restored with composite resin using the same bonding material. Teeth were embedded in acrylic resin and the loads for fracture strength were applied vertically with a constant speed of 1 mm min(-1). Data were evaluated statistically with anova and Tukey's tests. RESULTS: The mean force of fracture values were 1191.41, 599.86, 233.03, 494.72, 962.81 and 856.48 N for groups 1, 2, 3, 4, 5 and 6, respectively. The fracture resistance of group 5 was similar to group 1 (P > 0.05). The mean force at fracture of group 5 and group 6 was not significantly different. The fracture resistance of groups 5 and 6 was significantly higher than group 4 (P < 0.001). CONCLUSIONS: The group, restored with conventional amalgam, had the weakest resistance to fracture when compared with the bonded restorations. No statistically significant differences were found between the bonded amalgam and composite resin groups.     

不同桩道预备方法及时机对纤维桩粘结强度的影响

目的:比较根充时是否预留桩道对纤维桩粘结强度的影响。方法:将48颗单根牙根据根管充填时是否预留桩道及纤维桩的粘结时机不同随机分为4组(即A组:预留桩道即刻预备组、B组:常规即刻预备组、C组:预留桩道延期预备组、D组:常规延期预备组),每组12颗,粘结纤维桩后对比各组纤维桩不同部位的粘结强度。结果:实验各组的根尖、根中和根颈部粘结强度组内差异没有显著性。A组与D组的根尖部粘结强度比较差异有显著性(P=0.037)。A、B、C组的根中部粘结强度均显著高于D组P值分别为P=0.026、0.002、0.004。根颈部粘结强度各实验组间没有显著性差异。结论:预留桩道即刻预备不会降低纤维桩的粘结强度。     

The effect of fibre insertion on fracture resistance of root filled molar teeth with MOD preparations restored with composite

AIM: To evaluate the effect of using flowable composite with or without leno woven ultra high modulus polyethylene fibre reinforcement on fracture resistance of root filled mandibular molars with mesio-occlusodistal (MOD) preparations. METHODOLOGY: Sixty sound extracted human mandibular molars were randomly assigned to five groups (n = 12). Group 1 did not receive any preparation. From groups 2 to 5, the teeth were root filled and MOD preparations were created. Group 2 remained unrestored. Group 3 was restored with a dentine bonding system (DBS; SE Bond, Kuraray, Japan) and composite resin (CR) (AP-X; Kuraray). In group 4, flowable composite resin (Protect Liner F; Kuraray) was used before restoring teeth with CR. In group 5, leno woven ultra high modulus polyethylene ribbon fibre (Ribbond, Seattle, WA, USA) was inserted into the cavities in a buccal to lingual direction and the teeth were then restored with DBS and CR. After finishing and polishing, the specimens were stored in 100% humidity at 37 degrees C for 1 day. Compressive loading of the teeth was performed using a universal testing machine at a crosshead speed of 0.5 mm min(-1). The mean load necessary to fracture the samples were recorded in newtons (N) and were subjected to analysis of variance (ANOVA) and Tukey post-hoc test. RESULTS: The mean load necessary to fracture the samples in each group were (in N): group 1: 1676.75 +/-154.63(a), group 2: 376.51 +/- 37.36(b), group 3: 733.23 +/- 133.33(c), group 4: 786.48 +/- 145.34(c), group 5: 943.63 +/- 121.15(d). There were statistically significant differences between the groups annotated with different letters. CONCLUSIONS: (i) Use of flowable composite resin under composite restorations had no effect on fracture resistance of root filled molar teeth with MOD preparations, (ii) use of polyethylene ribbon fibre under composite restorations in root filled teeth with MOD preparations significantly increased fracture strength.     

The sources of laser Doppler blood-flow signals recorded from vital and root canal treated teeth

OBJECTIVES: The aim was to determine the strength of signals derived from the dental pulp and those from the surrounding tissues in human teeth using the laser Doppler flowmetry (LDF). METHODS: Twenty-six vital teeth (13 experimental and 13 controls) from 12 patients were used. Experimental teeth had root canal treatment in a single visit and their healthy antimeres were controls. Blood flow measurements were made before and after local anaesthesia, after root canal preparation, following root canal filling and coronal restoration. RESULTS: Perfusion unit (PU) values recorded from empty pulp chamber were determined to be only 30% lower than the values recorded before anaesthesia from the experimental intact teeth. When the measurements in the group were compared with each other the values of variation in the both groups were not statistically significant. The variation between the groups when the measurement values before anaesthesia, 10min after anaesthesia and after coronal restoration were compared, it was not statistically significant (P>0.05). The variation between the groups after preparation and root canal filling in their values of measurements was important statistically (P<0.05). The measurement values of the study group were lower than that of the control group. CONCLUSIONS: In pulpal, LDF a major portion of the signal comes from tissues other than pulp. Without taking precautions (such as rubber-dam application) in pulp blood flow measurements, the results may be inconsistent.     

比较不同冲洗液对根管内氢氧化钙的清除效果及根管牙本质显微硬度的影响

目的:比较5种不同根管冲洗液对根管内氢氧化钙(CH)的清除效果及对牙本质显微硬度的影响.方法:在70颗单根管离体牙的根管壁上制备凹沟,10颗牙齿作为阴性对照组不导人CH糊剂,60颗牙齿导入CH糊剂,封药1周.1周后,10颗牙齿作为阳性对照组不去除CH糊剂,其余50颗牙齿根据清除氢氧化钙所使用的冲洗液不同随机分成5组(n...     

ProTaper机动镍钛锉在乳牙根管预备中的应用

目的:比较ProTaper机动镍钛锉与手用不锈钢锉在乳牙根管预备中的效果.方法:选择42名4～7岁的儿童50个患有牙髓炎、根尖周炎的下颌第一乳磨牙.随机分成2组,分别用ProTaper机动镍钛锉(A组)与手用不锈钢锉(B组)进行根管预备,使用注射型根管充填剂(Matapex充填剂)进行根管充填.比较两组病例根管预备的时间,X线片观察两组根管充填效果.结果:A组根管预备的时间明显少于B组,差异有显著性(p＜0.01).根充效果观察,下颌第一乳磨牙近中根的恰填率A组高于B组,差异有显著性(P＜0.01).远中颊舌根恰填率A组与B组差异无显著性(P＞0.05).结论:ProTaper机动镍钛锉进行根管预备及使用注射型乳牙根管充填剂充填根管,能大大提高乳牙根管治疗的效率和效果.     

Bacterial contamination of the fitting surfaces of restorations in teeth with pulp and periapical disease: a scanning electron microscopy study

Background : The aim of this study was to evaluate the fitting surfaces of restorations in teeth with infected root canal systems and apical periodontitis to determine whether the restoration‐tooth interface is a potential pathway for bacterial penetration. Methods : Thirty clinically satisfactory restorations were sectioned and removed from teeth that had infected root canal systems and apical periodontitis. In the control group, three clinically satisfactory restorations were sectioned and removed from extracted teeth with clinically healthy pulps. In order to confirm the clinical diagnosis of a healthy pulp, histological examination was performed. All restorations were placed in 10% formalin immediately and then prepared for examination using scanning electron microscopy. The degree of bacterial contamination on each restoration was recorded as low, moderate or high. The morphotypes observed were classified as cocci, filaments, rods or spirochaetes. Results : The fitting surfaces of all restorations in both experimental and control groups showed signs of bacterial contamination. Conclusions : This study has demonstrated the presence of bacteria on the fitting surfaces of restorations that were judged to be clinically satisfactory in teeth with infected root canal systems. The restoration‐tooth interface is a potential pathway for bacteria to enter teeth and infect the root canal systems.