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。     

不同桩核修复根管治疗牙抗疲劳强度的体外研究

目的:探讨不同桩核修复根管治疗牙抗疲劳强度.方法:60颗离体上颌中切牙均分为无肩领和有肩领2个实验组.各实验组再分为3部分,各10颗样牙.每部分分别用铸造金属桩核、预成碳纤维桩联合复合树脂核及预成金属桩联合复合树脂核进行修复后再进行全冠修复.测定各样本牙疲劳强度并对实验结果进行双因素方差检验(α=0.05).结果:2个实验组中,用预成碳纤维桩联合复合树脂核修复组根管治疗牙根的平均疲劳强度显著高于金属桩核修复组(P<0.05).预备牙本质肩领可显著提高3种桩核材料修复牙的疲劳强度(P<0.05).结论:纤维桩联合复合树脂核在提高前牙牙根抗疲劳强度方面优于铸造金属桩核和预成金属桩树脂核.保留牙本质肩领,对提高牙根的抗疲劳强度具有重要意义.     

3种桩核材料修复薄弱残根的抗疲劳强度比较

目的:探讨不同材质桩核修复对前牙薄弱残根抗疲劳强度的影响.方法:48颗离体上颌中切牙均分为无牙本质肩领和有牙本质肩领2个实验组,各实验组再分为3组,各8颗样本牙.每组分别用铸造金属桩核、预成碳纤维桩+复合树脂桩核、预成玻璃纤维桩+复合树脂桩核等3种桩核修复后再进行全冠修复.测定各样本牙疲劳强度,采用SPSS12.0软件包对实验结果进行双因素方差分析.结果:2个实验组中,用纤维桩核修复后薄弱残根的平均疲劳强度显著高于金属桩核修复组(P＜0.05).预备牙本质肩领可显著提高3种桩核材料修复牙的疲劳强度(P＜0.05).结论:纤维桩核在提高前牙薄弱牙根抗疲劳强度方面优于铸造金属桩核.保留牙本质肩领,对提高牙根的抗疲劳强度具有重要意义.     

纤维桩和金属桩修复喇叭状残根抗折性研究

目的：比较纤维桩和铸造金属桩修复重塑后喇叭状残根的抗折性能。方法：选择离体上颌中切牙16个,分为A、B两组,每组各8个,将标本制备成喇叭状根管,并用复合树脂重塑根管。A组用铸造金属桩核修复,B组用纤维桩及复合树脂核修复。两组标本经铸造全冠修复后,放置在电子万能试验机上,与牙长轴135°方向静态加载,直至牙齿折裂,记录加载负荷和折裂模式。结果：铸造桩核组的折裂强度为（0．591±0．094）kN,纤维桩组的折裂强度为0．489±0．081kN,经统计学处理,差异有显著性（P〈0．05）。铸造桩核组8个中6个为破坏性修复;纤维桩组均为可修复性折裂。经统计学处理,两组有显著性差异（p〈0．05）。结论：喇叭状残根经根管重塑后,选择纤维桩联合复合树脂核修复更有利于保护薄弱残根。     

牙本质肩领的应用对不同桩核修复后修复体抗折性能的影响

目的：比较不同桩核系统及不同的牙体预备方法对残根抗折强度的影响。方法：40颗下颌前磨牙在釉牙骨质界处截冠后随机均分为四组。A组：金属桩修复的无肩领组。B组：金属桩修复的有肩领组。C组：纤维桩树脂核修复的无肩领组。D组：纤维桩树脂核修复的有肩领组。每组样本都采用金属全冠修复。实验标本包埋于树脂块中,在电子万能测力机上以1mm/min的速度加载直至断裂。结果：A组的抗折裂载荷最高,为3.0369±0.3388KN;D组的抗折强度最低,为2.0188±0.3864KN,A-C、A-B、C-D组间差异有显著性（P〈0.05）。可修复性断裂多见于纤维桩树脂核修复组,而不可修复性的破坏多见于铸造桩核组（P〈0.05）。结论：当牙体大部分缺损达釉牙骨质界时,通过冠延长术勉强预备牙本质肩领可显著降低桩核修复后牙根的抗折强度。而如不制备牙本质肩领,传统的金属桩核比纤维桩树脂核能承受更大的咀嚼力量。     

两种桩核冠修复下颌前磨牙的抗折力研究

目的研究两种桩核修复不同牙本质领圈的下颌前磨牙的抗折性能,为临床应用提供实验依据。方法选取离体下颌恒前磨牙48颗,随机分为6组,A组~F组,每组8颗。所有牙经根管治疗后齐釉牙本质界上2 mm截冠。A、B组保留2 mm完整的牙本质壁;C、D组保留舌侧一半牙本质壁;E、F组则保留颊侧一半牙本质壁。然后A、C、E组行铸造桩核冠修复,B、D、F组行金属螺纹桩树脂核全冠修复。在万能测试机上进行加载,记录断裂时的最大载荷。结果各组平均最大载荷值大小趋势为A>B>C>E>D>F。A、B组之间比较P>0.05。C、E组之间比较P>0.05;D、F组之间比较P>0.05。C、D组之间比较P<0.05,E、F组之间比较P<0.05。试件折裂形式大部分为斜向根折,有利于再修复的折裂只出现在螺纹桩树脂核组中。结论根管治疗后的下颌前磨牙保留2 mm的完整牙本质领圈,桩核材料性能对牙体抗折力没有显著影响;同种桩核冠修复牙体,缺损范围对牙体的平均抗折力无明显影响;不完整领圈组铸造桩核冠修复后牙体的平均抗折力大于金属螺纹桩树脂核全冠组,以接近牙本质弹性模量的的复合树脂做核材料有利于保护牙根。     

模拟正畸牵引术联合肩领设计对残根抗折力的影响

目的 探讨不同高度的牙本质肩领设计对预成碳纤维桩核修复后牙体抗折力的影响.方法 24颗完整、离体、单根管下颌第一前磨牙于颊侧釉牙骨质界上1.0 mm处截冠,经根管治疗后制备残根模型.通过模拟正畸牵引术(牙合)向牵引残根并在残根颈部预备一定高度的牙本质肩领;按预备的牙本质肩领高度不同(0.0、1.0、2.0 mm)依次分为A、B、C三组,预成碳纤维桩核联合铸造全冠修复残根.试件自全冠颈缘完成线下2.0 mm包埋于自凝塑料内,电子万能试验机以与牙长轴成150°、横梁位移速度1.0 mm/min于颊尖顶加载,测定折裂载荷并进行统计分析.结果 三组试件的折裂载荷(kN)均值依次为(1.13±0.15)、( 1.63±0.14)、(1.92±0.19).预备牙本质肩领可显著提高牙体的折裂载荷(F=48.437,P＜0.001);并且随着预备的牙本质肩领高度增加,牙体的折裂载荷显著增大(P＜0.05).结论 在残根颈部设计牙本质肩领,可明显提高牙体的折裂载荷.     

两种桩系统修复对根管治疗牙强度的影响

目的比较两种不同弹性模量的桩系统对根管治疗牙修复后强度的影响。方法20颗近期拔除的完整人上颌中切牙,根管治疗后随机分成两组,每组10颗。组一进行玻璃纤维桩ParaPost Fiber white(Coltene/ whaledent Inc)、复合树脂核及铸造全冠修复。组二进行铸造镍铬桩核及铸造全冠修复。每组牙均保留1.5mm的牙本质肩领(Ferrule)。实验标本包埋于自凝树脂块中,固定在DCS5000材料试验机上。加栽头以1mm/min的速度,与牙长轴成130°进行加载直至标本断裂。断裂强度采用独立样本t检验,断裂方式采用Fisher’s精确概率法(P <0.05)。结果组一断裂强度为43.406±18.959kg,组二33.680±9.675kg,差异无显著性(P>0.05)。可修复性断裂方式见于玻璃纤维桩核,而不可修复性的破坏多见于铸造镍铬桩核组(P<0.001)。结论在牙体预备保留1.5mm牙本质肩领(Ferrule)的情况下,两种不同弹性模量的桩对根管治疗牙桩核加全冠修复后的强度影响无差异,可修复性的破坏见于弹性模量与牙本质近似的玻璃纤维桩组。     

三种桩核系统修复后牙体组织抗疲劳强度体外研究

目的:比较两种纤维根管桩核系统和金属铸造桩核修复后牙体组织的抗疲劳强度和破坏模式。方法:2 4个离体上颌中切牙常规根管治疗术后截除牙冠,随机等分成A、B、C三组,A组用AESTHETI -PLUS石英纤维桩、复合树脂核系统及烤瓷冠修复,B组用C- POST碳纤维桩、复合树脂核系统及烤瓷冠修复,C组用Cr -Co铸造金属桩核进行桩核及烤瓷冠修复,包埋于底座后进行抗疲劳强度的测试,最多测试次数约10 0万次或试件破坏,记录试件破坏时的加载次数以及试件破坏的模式。结果:三种桩核系统修复后的离体牙中均有发生根折,但根折的部位不同,A组另有2个离体牙出现树脂核与牙本质分离,B组另有1例出现树脂核与牙本质分离,而C组除2例根折外,其余6个离体牙未出现明显的牙体组织或修复体的破坏。结论:Cr Co铸造金属桩核系统是一种较为成熟的桩核系统,AESTHETI- PLUS石英纤维桩和C POST碳纤维桩核系统具有一定的临床应用前景,但临床使用纤维桩时仍应考虑其他因素对修复效果的影响。     

不同桩核系统修复对根管治疗牙的影响

目的 比较非金属桩核系统和金属铸造桩核修复后牙体的抗折强度及牙折形式。方法 对24颗离体上颌尖牙行根管治疗并从唇侧釉牙骨质界冠方2．0mm处截冠后随机分为四组，分别用u．m.Aestheti-plus纤维桩系统、C-Post纤维桩系统、Cosmopost瓷桩系统、Ni-Cr合金铸造桩核进行桩核及铸造金属全冠恢复外形，自凝塑料包埋后，固定于生物力学试验机上测试实验牙的抗折强度并观察其折裂类型，应用SPSS分析软件进行统计学分析。结果 Cosmopost瓷桩系统修复后牙体抗折强度与Ni-Cr合金铸造桩核系统无差别，但明显高于u．m．Aestheti-plus纤维桩系统和C-Post纤维桩系统，后两者之间无统计学差异；Fisher’s精确概率法结果显示：三种非金属桩核组牙体的折裂形式与Ni-Cr合金铸造桩核组存在统计学差异。结论 在保留2．0mm牙本质领的情况下，三种非金属桩核系统修复根管治疗牙的抗折强度，均能满足临床要求；三种非金属桩核系统均有利于牙根的保护。     

Effects of post-core design and ferrule on fracture resistance of endodontically treated maxillary central incisors

STATEMENT OF PROBLEM: Studies concerning the effects of post-core design and ferrule on the fracture resistance of endodontically treated teeth remain controversial. PURPOSE: The purpose of this study was to investigate in vitro the effects of post-core design and ferrule on the fracture resistance of root canal treated human maxillary central incisors restored with metal ceramic crowns. MATERIAL AND METHODS: Forty-eight extracted human maxillary central incisors were endodontically treated and divided into 4 groups of 12. The following treatments were evaluated: group A: restored with metal ceramic (porcelain fused to metal [PFM]) crowns as control; group B: 2-mm ferrule/custom cast post-core/PFM crowns; group C: no ferrule/custom cast post-core/PFM crowns; and group D: 2-mm ferrule/prefabricated post and resin core/PFM crowns. Each specimen was subjected to load (N) on the lingual surface at a 135-degree angle to the long axis with a MTS 810 material testing machine until fracture at a crosshead speed of 0.02 cm/min. One-way analysis of variance and nonparametric chi-square test were used to compare the results. A significant analysis of variance result was followed by Newman-Keuls pairwise multiple comparisons (P<.05). RESULTS: There were significant differences among the 4 groups studied (P<.01). Group B had the highest fracture strength (1793.59 +/- 387.93 N). There was no significant difference among the fracture resistances of the other 3 groups (group A: 958.49 +/- 286.02 N; group C: 992.98 +/- 291.00 N; group D: 994.94 +/- 285.04 N). CONCLUSION: Within the limitations of this study, not all of the post-core structures tested improved the strength of the endodontically treated teeth. Those prepared with a 2-mm dentin ferrule more effectively enhanced the fracture strength of custom cast post-core restored endodontically treated maxillary central incisors.     

不同高度的箍结构与牙根抗力的实验研究

目的研究不同高度的箍结构设计对预成纤维桩核修复后牙体抗力的影响。方法32颗完整离体下颌第一前磨牙于颊侧釉牙骨质界上1mm处截冠,预备残根模型;按箍结构高度不同(0.0mm、1.0mm、2.0mm、3.0mm)分为4组,预成碳纤维桩联合复合树脂核修复残根。试件自铸造全冠颈缘完成线下2mm包埋于自凝塑料内,电子万能试验机以与牙长轴成150°、横梁位移速度1.0mm/min于颊尖顶加载,测定断裂载荷并进行统计学分析(α=0.05)。结果箍结构高度为1.0mm组与箍结构高度为2.0mm和3.0mm组相比,均表现出较高的折裂载荷(P<0.05)。结论采用牙冠延长术设计高度2.0mm以上的箍结构,会降低桩核冠修复后牙体的抗力。     

The effect of post-core and ferrule on the fracture resistance of endodontically treated maxillary central incisors.

AIM: To evaluate the effect of post reinforcement, post type and ferrule on the fracture resistance of endodontically treated maxillary central incisors. MATERIALS AND METHODS: Sixty central incisor teeth were selected and grouped into six groups, viz. A, B, C, D, E, and F, each consisting of 10 specimens. Group A specimens were not subjected to any restorative treatment. Group B specimens were endodontically treated and crowned. Specimens of groups C and D were restored with custom cast post and core. Specimens of groups E and F were treated with prefabricated titanium post and composite core. Specimens of groups C and E were restored with porcelain-fused metal (PFM) crown having 2 mm ferrule. Specimens of groups D and F were restored with PFM crown having no ferrule. All the specimens were subjected to load (newton, N) on the lingual surface at a 135 degree angle to the long axis with a universal testing machine until it fractured. The fracture load and mode of fracture of each specimen were noted. One-way analysis of variance with Tukey honestly significant difference procedure was employed to identify the significant difference among the groups at 5% level (P < 0.05). RESULTS: There were significant differences among the six groups studied (P < 0.0001). The highest fracture strength was recorded with specimen of group C (1376.7 N). There were significant differences between groups A and D versus groups B, E, and F. There were no significant differences between groups B, E, and F. Cervical root fracture was the predominant mode of failure in all the groups except group A. CONCLUSION: The results showed that endodontically treated teeth restored with custom cast post core were as strong as the untreated group. Teeth restored with custom cast post core were better resistant to fracture than teeth restored with prefabricated titanium post and composite core. Ferrule is more important in custom cast post core than in prefabricated post and composite core.     

不同桩核材料及箍结构对前牙抗折强度的影响

目的研究不同桩核材料及箍结构对前牙抗折强度的影响。方法选取28颗完整上颌中切牙随机分为四组:A1组:剩余釉牙骨质界上8mm牙体组织+镍铬合金桩修复;A2组:剩余釉牙骨质界上8mm牙体组织+低金合金桩修复;B1组:剩余釉牙骨质界上2mm牙体组织+镍铬合金桩修复;B2组:剩余釉牙骨质界上2mm牙体组织+低金合金桩修复。自凝包埋后,固定于生物力学试验机上,测试实验牙的抗折强度并观察其折裂类型,应用SPSS分析软件进行统计学分析。结果各组样本的折裂力值依次为:614.79±39.03N,438.73±28.20N,430.13±32.99N,411.94±47.46N。桩核材料对折裂强度有显著影响(P<0.05);箍结构形式对折裂强度有显著影响(P<0.05)。桩核材料和箍结构形式两个因素之间存在交互效应(P<0.05)。结论①不同桩核材料对桩核冠修复后的牙齿抗折强度有影响。②正常情况下,尽量使用弹性模量较低桩核材料,可在一定程度上改善破坏性牙折的发生率。③箍结构的形式对折裂强度有显著影响。④桩核材料的弹性模量和箍结构的形式两个因素之间存在交互效应。     

模拟牙冠延长术联合牙本质肩领设计对斜折残根抗折力的影响

目的研究模拟牙冠延长术联合不同高度牙本质肩领设计,对预成纤维桩核修复后的下颌第一前磨牙斜折残根抗折力的影响。 方法选择24颗完整离体下颌第一前磨牙,先于舌侧釉牙骨质界上2.0 mm处截冠成为水平型冠折残根,再自残根断面舌侧向颊侧斜行切割,制备舌唇向斜折残根模型。查随机数字表,将所有残根样本平均分为3组：A组在残根颈部预备颊侧0 mm、舌侧2.0 mm高的半包绕肩领（对照组）,B组和C组通过模拟牙冠延长术在残根颈部分别预备颊侧1.0、2.0 mm高的肩领,对应舌侧肩领高度分别为3.0和4.0 mm。经玻璃纤维桩核铸造金属全冠修复后,所有试样自铸造全冠颈缘完成线下2.0 mm包埋于自凝塑料块中。将试样以与牙长轴成135°放置于万能力学试验机上加载,直至试样发生折裂。记录试样断裂载荷,行单因素方差分析,对差异有显著性结果再行Tukey HSD Test分析（α= 0.05）。 结果A、B、C各组试样的折裂载荷均值依次为（1.01 ± 0.26）、（0.91 ± 0.29）、（0.73 ± 0.19）kN,牙本质肩领对纤维桩核冠修复后斜折残根抗力影响差异无统计学意义（F= 2.588,P= 0.099）。颊侧无肩领对照组的残根抗力最高,而随着根颈部肩领高度的增加,斜折残根的抗折力呈现逐渐下降的趋势。 结论通过模拟牙冠延长术在下颌第一前磨牙舌唇向斜折残根颈部预备1.0~ 2.0 mm完整肩领时,会降低残根的抗折力。     

Effect of a ferrule and increased clinical crown length on the in vitro fracture resistance of premolars restored using two dowel-and-core systems

This study investigated the effect of a crown-lengthening ferrule on the fracture resistance of endodontically-treated teeth restored with two dowel-core systems. Thirty-two extracted mandibular first premolars were sectioned perpendicular to the long axis at a point 1.0 mm occlusal to the buccal cementoenamel junction. Following endodontic treatment, the teeth were randomly assigned to four groups: cast Ni-Cr alloy dowel-core with no ferrule (Group A1), cast Ni-Cr alloy dowel-core with 2.0 mm ferrule (Group A2), prefabricated carbon fiber-reinforced dowel-resin core with no ferrule (Group B1) and carbon fiber-reinforced dowel-resin core with 2.0 mm ferrule (Group B2). Each specimen was embedded in a self-cured acrylic resin block from 2.0 mm apical to the margins of a cast Ni-Cr alloy crown, then loaded at 150 degrees from the long axis in a universal testing machine at a crosshead speed of 1.0 mm/minute until fracture. The data were recorded and analyzed using ANOVA and Fisher's exact tests, with alpha = 0.05. Mean failure loads (kN) for the A1, A2, B1 and B2 Groups were: 1.46 (S.D. 0.45), 1.07 (0.21), 1.13 (0.30) and 1.02 (0.27). The teeth restored with cast Ni-Cr dowel-cores and 2.0 mm ferrules demonstrated significantly lower fracture strengths, p = 0.04. There were significant differences in the root fracture patterns between the two dowel systems, with the carbon fiber-reinforced dowel-resin core system, being the less severe p < 0.05. Crown lengthening with a 2.0 mm apical extended ferrule resulted in reduced fracture strengths for endodontically-treated teeth restored using two dowel-core systems and cast metal crowns. The carbon fiber-reinforced dowel-resin core system reduced the severity of the root fractures.     

Effect of a crown ferrule on the fracture resistance of endodontically treated teeth restored with prefabricated posts

STATEMENT OF PROBLEM: Root fracture is one of the most serious complications following restoration of endodontically treated teeth. PURPOSE: The purpose of this study was to compare the fracture strengths of endodontically treated teeth using posts and cores and variable quantities of coronal dentin located apical to core foundations with corresponding ferrule designs incorporated into cast restorations. MATERIAL AND METHODS: Fifty freshly extracted canines were endodontically treated. The teeth were randomly divided into groups of 10 and prepared according to 5 experimental protocols. Control group: teeth with custom cast post and core; 0-mm group: teeth without coronal structure (no ferrule); 1-mm, 2-mm, and 3-mm groups: teeth with 1 mm, 2 mm, and 3 mm of remaining coronal tooth structure (1-, 2-, and 3-mm ferrule), respectively. All specimens in 0-mm through 3-mm (noncontrol) groups were restored with a prefabricated post (Screw-Post) and composite resin (Z100) core located superior to the different tooth structure heights. All teeth were restored with complete metal crowns. The fracture resistance (N) was measured in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by 1-way analysis of variance and Tukey test (alpha=.05). RESULTS: Significant differences (P<.001) were found among the mean fracture forces of the test groups (control group: 818.2 N; 0-mm, 1-mm, 2-mm, and 3-mm groups: 561.0 N, 627.6 N, 745.3 N, and 907.1 N, respectively). When the mode of failure was evaluated, all failures in the control group occurred due to root fracture, and all failures in the 0-mm group occurred due to core fracture. The majority of failures in the other groups occurred due to crown cementation failure. CONCLUSION: The results of this study showed that an increased amount of coronal dentin significantly increases the fracture resistance of endodontically treated teeth.     

桩核直径和材料种类对根管治疗后牙齿抗折强度的影响

目的：本研究的目的为评估不同直径的铸造纯钛桩和玻璃纤维桩对根管治疗后牙齿抗折强度的影响。方法：选择50颗新近拔除的上颌中切牙,根管治疗后将样本完全随机分为5组（n=10）：A组：1．35mm铸造纯钛桩;B组：1．5mm铸造纯钛桩;C组：1．375mm预成玻璃纤维桩;D组1．5mm预成玻璃纤维桩;E组：树脂修复。采用万能材料测试机对样本的抗折强度进行测试,对实验结果进行统计分析并进行断裂模式分析。结果：5组样本的抗折强度如下：A组404．22±73．92N,B组488．17±78．68N,C组280．32±45．23N,D组317．53±50．87N,E组222．76±38．67N。其中C组与D组组问两两比较差异无统计学意义∽〉0．05）,其余各组间比较差异均有统计学意义（p〈0．05）。铸造纯钛桩主要表现为不可修复的根中或根尖损伤,而预成玻璃纤维桩主要表现为可修复的根颈部损伤或桩折。结论：铸造纯钛桩核修复上颌中切牙表现为较高的抗折强度,可承受较大载荷,而玻璃纤维桩核修复对牙根的破坏小,有利于患牙的再治疗。