桩核粘固后不同间隔时间预备对冠方微渗漏的影响

目的 比较铸造桩核粘结后不同间隔时间备牙对冠方微渗漏的影响。方法 66颗离体单根管下颌前磨牙,其中60颗随机分为6组,制作铸造桩核。2、4、6组分别于铸造桩 核用磷酸锌水门汀粘结2、10、30 min后备牙,1、3、5组桩核粘结后不备牙作为对照,其余6颗牙分别作为阴性及阳性对照。所有牙齿经1周染色后,作透明处理,评价冠方微渗漏的情况。结果 间隔时间相同的各备牙组与不备牙组的微渗漏差异有统计学意义（P<0.05）;不备牙组之间的微渗漏差异无统计学意义（P>0.05）;间隔2 min和10 min备牙组与间隔30 min备牙组的微渗漏差异亦有统计学意义（P<0.05）。结论 备牙时高速手机产生的震动会明显增加桩冠的冠方微渗漏,桩核粘结后备牙的间隔时间至少为10～30 min。     

CAD/CAM一体化纤维桩核修复薄弱根管的冠向微渗漏研究

目的：观察计算机辅助设计与制作（CAD／CAM）一体化纤维桩核修复薄弱根管的冠向微渗漏大小。方法：选择单根管前磨牙60颗,完善根管治疗后制备成薄弱根管形态。分组制作粘接 CAD／CAM一体化纤维桩核（A 组）、预成单支纤维桩＋流体树脂核（B 组）和铸造金钯金属桩核（C 组）,每组20颗。印度墨水染色4周后脱矿脱水透明化处理,体视显微镜下观察染料渗入情况并分析统计学差异。再将标本完全脱矿,观察微渗漏产生的界面。结果：3种桩核修复薄弱根管后根管壁与桩核之间均存在微渗漏,A 组与 C 组冠方微渗漏无显著性差异（P ＞0．05）,均明显小于 B 组（P ＜0．05）。A 组、C 组微渗漏多产生在桩核与树脂水门汀之间,B 组则多出现于树脂水门汀与根管壁之间。结论：CAD／CAM一体化纤维桩核修复薄弱根管的冠方微渗漏多产生于桩核与粘接剂界面,大小与金属桩组相似且均明显小于单支纤维桩＋树脂核组。     

不同间隔时间预备不同桩核系统对桩核微渗漏的影响

目的：研究不同间隔时间预备不同桩核系统对微渗漏的影响.方法：收集因正畸需要拔除的132颗下颌单根前磨牙,进行根管治疗、根管预备和桩核制作及粘结.132颗牙随机分为4组,分别在桩核粘固后5 min、15 min、30 min、24 h,阴性对照组进行牙体预备,每组内再随机分为铸造桩核磷酸锌粘固、铸造桩核聚羧酸锌粘固和玻璃纤维桩核树脂粘固亚组.每一标本进行染色法评价微渗漏情况.结果：相同的桩核系统中,渗漏值随着桩核粘固间隔时间的延长而降低;相同的间隔时间下,5 min、15 min和24 h时,纤维桩核系统的渗漏值最小,与其它两组比较均有统计学意义（P＜0.05）,30 min时铸造桩核磷酸锌粘固组与纤维桩核系统组无统计学意义（P＞0.05）.结论：不同间隔时间预备不同桩核系统对桩核微渗漏值有影响,为了桩核的稳固,应尽量在桩核粘固24 h后进行牙体预备.     

不同桩核和粘接系统冠向微渗漏的实验研究

目的:通过染色法测量冠向微渗漏的大小,比较不同桩核及粘接剂的冠向封闭能力.方法:选择50 颗离体下颌单根管前磨牙,使用ProTaper镍钛锉冠向下法进行根管预备.样本随机分为6 组.A组为暂封组、B组为树脂粘接纤维桩核组, C组为树脂粘接铸造金属桩核组, D组为磷酸锌粘固铸造金属桩核组, E组为阳性对照组,F组为阴性对照组.除阳性对照组,所有根管侧向加压法充填.桩道预备和桩核修复后印度墨水染色1 周,透明处理,体视显微镜下观察冠向染料渗入情况.结果:暂封组冠向微渗漏值明显大于各桩核修复组(P<0.05);树脂粘接的纤维桩组与金属桩组之间无统计学差异(P>0.05);树脂粘接的纤维桩组和金属桩组的冠向微渗漏值均明显小于磷酸锌粘固组(P<0.05).结论:桩核修复可以减小冠向微渗漏,树脂粘接材料封闭效果更好.     

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目的探讨根管不同长度充填后，即刻与延迟桩道预备对根尖微渗漏的影响。方法选取2011年9月至2012年7月沈阳市口腔医院颌面外科拔除的直根单根管牙齿120颗，行根管预备后随机分为A、B两组，每组60颗牙齿。A组充填根管的根尖区5mm，B组充填全长根管。A、B两组再各自分为3个亚组，即A1～A3、B1-B3，每个亚组20颗牙齿。其中A1组及B1组根管充填后即刻行桩道预备；A2组及B2组于根管充填1周后行桩道预备；A3组及B3组根管充填后不预备桩道。用印度墨水对各组样本染色，透明处理后在体视显微镜下测定根尖染色长度，评价微渗漏情况。结果A1组与B1组，A2组与B2组，A3组与B3组间染色长度差异无统计学意义（P〉0．05）；A1组与A3组，B1组与B3组间染色长度差异无统计学意义（P〉0．05），但分别与A2组及B2组间差异有统计学意义（P〈0．05）。结论部分根管充填相对全根管充填对根尖微渗漏无影响，延迟桩道预备与即刻桩道预备相比会加重根尖微渗漏。     

比较2种根管充填糊剂对根尖封闭性的作用

目的用染料渗透法测量根管微渗漏的程度,比较2种根管充填糊剂在根管充填后不同时间进行桩腔预备后对根尖部的封闭能力。方法选取90颗成人的上颌中切牙,逐步后退法预备根管,侧向加压技术充填根管,充填剂分别用Cortisomol糊剂（A组）和氧化锌丁香油糊剂（B组）,每组45颗上颌中切牙。根据根管充填后桩腔预备时间将A组上颌中切牙随机分为A1组、A2组和A3组,每组15颗,A1组为根管充填后即刻进行桩腔预备,A2组为根管充填后2周进行桩腔预备,A3组为根管充填后4周进行桩腔预备。根据根管充填后桩腔预备时问将B组上颌中切牙随机分为B1组、B2组和B3组,每组15颗,B1组为即刻进行桩腔预备,B2组为根管充填后2周进行桩腔预备,B3组为根管充填后4周进行桩腔预备。进行桩腔预备后用染料渗透法评价各组根尖渗透能力。结果Cortisomot组（A组）与氧化锌丁香油组（B组）在根管充填后相同时间进行桩腔预备后,根尖微渗漏的差异具有统计学意义（P〈0．01）。A组在根管充填后即刻、2周、4周时进行桩腔预备,其根尖微渗漏的差异具有统计学意义（P〈0．01）。B组在根管充填后即刻、2周、4周时进行桩腔预备,其根尖微渗漏的差异无统计学意义（P〉0．05）。结论Cortisomol根管充填糊剂的封闭作用效果比氧化锌丁香油糊剂好。     

不同桩核修复系统在长期水储存条件下的根管微渗漏表现

目的：长时间水储存后桩核修复体冠外微渗漏情况。方法：选用72颗上颌单根管牙,随机分为6组,其中4组为实验组,2组为对照组。所有组别牙齿置人蒸馏水中储存半年后,用体视显微镜观察修复体冠方染料微渗漏情况。结果：采用纤维桩树脂核系统修复的牙体和传统铸造桩核修复后的牙体冠方微渗漏情况有明显差别,而采用DCBOND的实验组与另外两组树脂粘接剂问有明显差别。结论：DCBOND树脂粘接剂进行纤维桩核修复后在冠方微渗漏方面本实验显示了优越性。     

两种树脂粘接剂对纤维桩核冠方微渗漏影响的对比研究

目的：比较两种树脂粘接剂对纤维桩核冠方微渗漏的影响。方法：将22颗新鲜完整的上颌单根管前牙随机分组：A组（DMG LuxaCore粘结＋堆核）;B组（Rely X Unicem粘结＋Z350堆核）;C组（阳性对照组）;D组（阴性对照组）。 A、B组截冠完成根管预备后使用不同树脂粘接剂将纤维桩粘结至根管并制作树脂核。 C、D组截冠后树脂封闭根管口。所有样本经染色处理后使用体视显微镜观察染料渗入深度。结果：各组标本之间微渗漏程度的差异均具有统计学意义,DMG LuxaCore粘接剂组微渗漏程度显著低于Rely X Unicem粘接剂组。结论：不同树脂粘接剂对纤维桩核冠方微渗漏的影响不同,临床粘接操作应严格按照操作说明进行。     

根管冲洗液和黏结剂对金属桩核黏固后根管微渗漏影响的析因分析

目的 探讨根管冲洗液和黏结剂对金属桩核黏固后根管冠方微渗漏的影响,以及二者对于根管冠方微渗漏的交互作用。方法采用两因素析因设计方法,将90颗完成根管充填的离体下颌前磨牙进行桩道预备,经常规制作钴铬桩核后,分为6组,每组15颗。根管冲洗液（因素A）选取3种：A1为无冲洗液（75%乙醇棉球清洁）,A2为3%H2O2+0.9%NaCl溶液,A3为15%乙二胺四乙酸（EDTA）+5.25%NaClO溶液;黏结剂（因素B）选取2种：B1为聚羧酸锌水门汀,B2为玻璃离子水门汀。按照A1B1、A1B2、A2B1、A2B2、A3B1、A3B2分别对6组进行处理,桩核黏固完成后的所有样本浸泡于印度墨水中3周,然后沿颊舌向中线位置纵行劈开,在体视显微镜下拍照并测量染料渗入根管的最大长度,以此评价微渗漏的大小。采用SPSS 13.0软件对结果进行析因分析。结果 A1B1、A1B2、A2B1、A2B2、A3B1、A3B2组染料渗入长度分别为（1 192.59±417.84）、（1 317.38±527.35）、（1 429.33±482.68）、（1 026.79±459.49）、（1 448.29±561.02）、（1 922.47±678.86）μm,A2B2组微渗漏程度最轻,A3B2组最重;不同冲洗液之间微渗漏的差异有统计学意义（P<0.05）,不同黏结剂之间的差异没有统计学意义（P>0.05）,但根管冲洗液和黏结剂对于微渗漏的发生有交互作用（P<0.05）。结论 黏固金属桩核时,3%H2O2+0.9%NaCl溶液冲洗根管联合玻璃离子水门汀黏结剂在减少微渗漏的发生方面有一定优势;15%EDTA和5.25%NaClO联合玻璃离子水门汀会加重根管微渗漏的发生。     

不同粘结剂与桩核材料微渗漏发生的实验研究

目的：评价不同核材料修复后的牙齿经铸造金属全冠修复后边缘微渗漏的情况。方法：将90个大小相似的完好前磨牙,随机分为9个实验组。对离体牙进行铸造金属全冠及固定尺寸的Ⅱ类洞牙体预备后,分别用3种不同的核材料（树脂、银汞合金、铸造合金）充填窝洞。常规方法铸造镍铬合金全冠,用3种不同的粘结材料（聚羧酸锌、玻璃离子、树脂C＆B）进行粘固。温度循环、染色、包埋后,标本片切,镜下观察冠边缘及核下微漏情况。结果：银汞核与树脂核下微漏小于铸造核（P〈0.05）,树脂粘结剂抗微漏性能优于聚羧酸锌水门汀和玻璃离子粘结剂（P〈0.05）。结论：树脂粘接剂抗微漏性能优于玻璃离子与聚羧酸锌粘结剂。树脂核在预先对粘结面处理后,其抗微漏性能与银汞核近似,优于铸造合金核。     

Influence of timing of coronal preparation on retention of two types of post cores

PURPOSE: To compare the effect of coronal preparation on retention of cemented cast (Cr-Ni) and IPS post core systems. METHODS: Cr-Ni and IPS post and cores were placed in 48 extracted single rooted human teeth with two different cements (dual-cure resin and glass-ionomer cement) and randomly divided into four groups of 12 specimens each. twelve of each post-core system were cemented with dual-cure cement and the other 12 of each system were cemented with glass-ionomer cement. Twelve specimens of each post core system were subjected to an axially directed removal force using a universal testing machine. Four groups of 12 specimens were divided into subgroups and subjected to preparation of their cores at 15 minutes and 24 hours after cementation. The specimens were tested at 24 hours having been stored in water at 37 degrees C for the waiting period. The forces required for dislodgement of the posts from their prepared spaces were recorded. Data were statistically analyzed using ANOVA and the Newman-Keuls multiple comparison test. RESULTS: Retention generally increased with time following cementation for both groups. The specimens cemented with glass-ionomer cement revealed less retention compared with specimens cemented with resin cement. Preparation of cemented post cores using a high speed handpiece had a significantly negative effect on retention when carried out 15 minutes and 24 hours after cementation.     

Er：YAG激光预备及酸蚀处理对复合树脂充填体微渗漏的影响

目的 研究Er∶YAG激光备洞及酸蚀处理对复合树脂充填体微渗漏的影响.方法 将40颗离体前磨牙随机平均分为5组制备洞型：A组,高速牙钻预备加酸蚀;B组,Er∶YAG激光预备;C组,Er∶YAG激光预备加酸蚀;D组,高速牙钻预备加Er∶YAG激光蚀刻;E组,高速牙钻预备加Er∶YAG激光蚀刻后酸蚀.所有样本经复合树脂充填后交替放置于5℃与55℃水中各1 min,间隔45 s,共2000个周期进行冷热循环,然后用0.2％亚甲基蓝染色后颊舌向劈开,体视显微镜下观察剖面,记录其微渗漏情况,并进行统计学分析.另选6颗离体前磨牙,随机分为3组,按上述A、B、C三组方法制备,扫描电镜下观察其牙本质界面的结构.结果 在（牙合）壁与龈壁,B组染料渗入严重,到达洞底,微渗漏最大,与其他各组相比有统计学差异（P＜0.05）,A、C、D、E组染料渗入表浅,微渗漏程度之间没有统计学差异（P＞0.05）.扫描电镜下,A组牙本质表面较平整,无玷污层存在,牙本质小管口开放.B组牙本质表面不平整如鳞片状,无玷污层,牙本质小管口开放,直径小于酸蚀组.C组牙本质小管口开放,无玷污层存在,管周牙本质脱矿明显.结论 单纯Er∶YAG激光预备比传统牙钻制备结合酸蚀处理洞型更易发生微渗漏,若Er∶YAG激光预备结合酸蚀剂处理可以使微渗漏程度减小,Er∶YAG激光蚀刻可以达到和酸蚀剂类似的效果.     

四种双固化树脂粘结剂与根管牙本质间微渗漏的研究

目的评价冷热循环对4种双固化树脂粘结剂与根管牙本质间微渗漏的影响。方法20颗健康上前牙随机分为4组。根管预备后选用4种粘结树脂及其配套粘结剂（Clearfil DC Core Automix,Calibra esthetic resincement,DMG LUXACORE Smartmix Dual,3M ESPE RelyX^TM Unicem）分别粘结直径1．2mm树脂纤维桩,并用此4种材料分别做树脂核。将试件冷热循环处理10000次（温度设定为4℃／60℃,浸泡时间30s,传递时间20s）后,用0．5％碱性品红溶液染色24h。将试件连续纵向剖开为四部分,体视显微镜下观察各剖面的微渗漏情况,并用Kmskal-WaillisH非参数检验进行统计分析。结果各种树脂粘结剂均存在微渗漏现象,各种粘结剂之间的微漏程度有显著性差异（P〈0．05）。结论冷热循环后4种双固化树脂粘结剂粘结纤维桩与根管牙本质之间均存在微渗漏现象,使用Clearfd DC Core Automix作为粘结树脂的试件微渗漏程度最轻。     

Influence of timing of coronal preparation on retention of cemented cast posts and cores

PURPOSE: This study investigated the effect of coronal preparation by high-speed handpiece on the retention of cemented cast posts and cores. MATERIALS AND METHODS: Cast posts and cores were fabricated for 90 extracted single-rooted human teeth cemented with zinc-phosphate cement and randomly divided into six groups of 15 specimens each. The six groups were matched randomly two by two, such that one of each of the matched groups was subjected to a 4-minute period of high-speed preparation of the cores. Castings from the first pair (1 and 2) were subjected to an axially directed removal force using a universal testing machine 15 minutes from the start of cement mixing; castings from the second (3 and 4) and third (5 and 6) pairs were tested at 1 hour and 24 hours, respectively, having been stored in water at 37 degrees C for the waiting periods. The forces required for dislodgment of posts from their prepared spaces were recorded. Data were statistically analyzed using two- and one-way ANOVA and the Student's t test. RESULTS: The results showed increased mean retentive strengths of posts as the time to testing increased for both unprepared and prepared groups. Significantly higher mean retentive strengths of posts were recorded for unprepared compared to prepared groups tested at 15 minutes and 1 hour after cementation. CONCLUSION: High-speed preparation had a significant negative effect on the retentive strengths of posts tested at 15 minutes and 1 hour after cementation, but not on those tested at 24 hours.     

Evaluation of the marginal seal of CEREC 3D restorations using two different luting agents

This in vitro study used two resin cements to evaluate the microleakage of CEREC 3D restorations. An mesio-occluso-distal-lingual (MODL) onlay preparation was placed on an ivorine premolar tooth. Sixty elastomeric impressions of this preparation were used to fabricate resin dies. Imaging propellant was applied to the resin dies. Optical impressions were taken with the CEREC 3 and the CEREC 3D software and used to design and mill 60 onlays. The reliability coefficient was alpha = 0.76 with an examiner agreement rate of 96.4%. Restorations cemented with posterior composite demonstrated a mean microleakage value of 1.46 mm (SD+/- 1.64); by contrast, those restored with dual-cure cement reported a mean microleakage value of 0.21 mm (SD+/-0.57). The difference in microleakage was very highly significant (alpha = 0.001). Posterior composite CEREC 3D restorations cemented with the dual-cure cement showed significantly less microleakage compared to those cemented with posterior composite.     

Fracture resistance of teeth restored with 2 different post-and-core designs fixed with 2 different luting cements: an in vitro study. Part II.

OBJECTIVE: The purpose of this in vitro study was to investigate fracture resistance in teeth restored with cast posts and cores with and without ferrule and using 2 different luting cements. METHOD AND MATERIALS: Forty intact extracted maxillary premolars were endodontically treated after their crowns were removed 2 mm from the cementoenamel junction. Specimens were embedded in acrylic resin blocks, in aluminum cylinders, 2.00 mm apical to the cementoenamel junction. Twenty specimens were ferruled. Within this group, half of the posts and cores were cemented with zinc phosphate cement, while the other half were cemented with resin cement. The same procedures were followed for the nonferruled group. The posts and cores were cast in gold alloy. Specimens were placed in a universal testing machine, and loads were applied at an angle of 45 degrees and a rate of 1 mm/min until the teeth fractured. Analysis of variance and Tukey tests were used for statistical analysis; level of significance was established at 5%. RESULTS: There was no association between type of cement and cervical ferrule; ferruled specimens showed greater resistance than nonferruled ones, regardless of the cement used. CONCLUSION: A 2-mm cervical ferrule improves fracture resistance of restored teeth, but the type of luting cement used does not seem to affect resistance.     

三种方法修复薄弱根管冠方微渗漏的体外评价

目的评价可塑型纤维桩、预成纤维桩及根管重塑后预成纤维桩修复薄弱根管后的冠方微渗漏情况。方法选择正畸拔除上颌第一前磨牙36颗,制备形成薄弱根管。将30颗样本牙随机分为3组,A组可塑型纤维桩核系统修复、B组根管重塑后预成纤维桩核系统修复,C组预成纤维桩核系统修复,另外6颗为对照组。所有样本进行5℃-55℃冷热循环5000次后,置于0．5％碱性品红溶液中24h。将试件纵向剖开为2部分,在体视显微镜下观察各剖面修复材料与根管壁之间的微渗漏情况。用Kruskal—Wallisf法进行统计分析。结果3种方法修复后修复材料与根管牙本质之间均存在微渗漏现象,3组间无统计学差异（P〉0．05）。结论在本实验条件下,3种方法修复薄弱根管对冠方微渗漏的影响相近。