两种纤维桩表面处理方法对牙根抗折裂性能的影响

目的:对比分析不同纤维状表面处理方式对牙跟修复后抗折裂强度的影响,为临床纤维状表面处理提供参考依据。方法:将60个纤维桩按数字随机分为对照组20个、喷砂组20个和过氧化氢酸蚀组20个,将其固定于经过纤维桩道准备的离体牙内,采用相同树脂成核行全冠修复后,模拟口腔内部环境给予冷热等环境,经相同环境加载后于电子万能实验机上测试其抗折裂强度,并进行记录。结果:3组离体牙的牙齿长度、牙根长度、颈部颊舌径以及颈部近远中径军无显著差异,无论采用那种表面处理方式,离体牙受硬力后的断裂方式均以牙颈1/3处多见,说明断裂的部位和方式与纤维桩表面处理与否关系不大。喷砂组与过氧化氢酸蚀组的抗折裂强度均高于对照组(P＜0.05),但喷砂组与过氧化氢酸蚀组之间的抗折裂强度差异不大。无统计学意义。结论:喷砂与过氧化氢酸蚀的表面处理方式均能增加纤维桩的抗折裂强度,但两者之间抗折裂强度差异不大,表面处理与否与纤维桩的断裂方式无关。     

根管内壁酸蚀处理对桩核冠修复后牙根抗折性能影响的体外实验研究

[摘要] 目的 研究铸造桩表面酸蚀处理对牙根抗折性能的影响。方法 32颗近期拔除的单根第一前磨牙,根管治疗后于釉牙骨质界冠方1.5 mm截冠,铸造桩核及金属全冠修复,随机分为4组。实验组根管内表面酸蚀分别酸蚀10 s、30 s及60 s,对照组不作处理。所有样本处理完成后均以磷酸锌水门汀粘固。试件包埋于丙烯酸树脂块中,在电子万能实验机上进行测试。结果 实验组牙根折裂强度分别为（2.981±0.102） kN、（3.097±0.084） kN、（3.128±0.071） kN,对照组牙根折裂强度为（2.699±0.445） kN,各实验组与对照组间差异均具有统计学意义（P<0.05）。结论 对根管内表面进行酸蚀处理可以提高桩核冠修复后牙根的抗折强度。     

铸造桩表面喷砂处理对牙根抗折性能影响的体外实验研究

目的：研究铸造桩表面喷砂处理对牙根抗折性能的影响。方法：20颗近期拔除的单根第一前磨牙,根管治疗后于釉牙骨质界冠方1.5mm截冠,随机分为2组,铸造桩核及金属全冠修复。实验组铸造桩粘固前表面喷砂处理,对照组不作处理。试件包埋于丙烯酸树脂块中,在电子万能实验机上进行测试。结果：对照组牙根折裂强度为2.773±0.357kN,实验组牙根折裂强度为3.113±0.357kN,2组间差异具有统计学意义（P〈0.05）。结论：对铸造金属桩表面进行喷砂处理,可以提高桩核冠修复后牙根的抗折强度。     

不同方法修复薄弱根管的疲劳抗折性能比较

目的 比较根管重塑后纤维桩核系统及传统铸造桩核修复薄弱根管前磨牙的疲劳抗折性能.方法 将16颗实验牙截冠后制备成薄弱根管,随机分为2组,A组根管重塑+预成纤维桩+树脂核修复;B组传统铸造桩核修复.所有样本全冠修复并进行5000次冷热水循环及30万次循环加载,再以3mm/min的速度静加载至折裂发生,记录2组试件折裂发生时的加载强度、折裂模式.结果 抗折载荷分别为A组1.79±0.26KN和B组2.35±0.22KN,差异有统计学意义.A组多见可再修复性折裂,B组多见破坏性折裂.结论 在本实验条件下,根管重塑后纤维桩核系统修复薄弱根管的疲劳抗折强度不及传统铸造桩核修复,但其折裂模式更有利于牙根的保护.     

不同表面处理对两种纤维桩粘结强度的影响

目的比较玻璃纤维桩和石英纤维桩分别经3种表面处理后的粘结强度。方法选取40颗单根管人离体上颌前牙,随机分成8组,随机取4组用于玻璃纤维桩,另外4组用于石英纤维桩。2种纤维桩表面分别经24%过氧化氢处理、喷砂处理、硅烷偶联剂处理,对照组不处理。处理后纤维桩粘固于根管内,将牙根切成2mm厚薄片制成试件,采用万能试验机进行微推出实验测试粘结强度。结果玻璃纤维桩粘结强度:24%过氧化氢组>喷砂组>硅烷偶联剂组>对照组。硅烷偶联剂组和对照组无显著性差异(P>0.05),其余各组间差异均有统计学意义(P<0.05)。石英纤维桩粘结强度:喷砂组>24%过氧化氢组>硅烷偶联剂组>对照组。各组间均有统计学差异(P<0.05)。结论 24%过氧化氢处理后玻璃纤维桩粘结强度最大;喷砂后石英纤维桩粘结强度最大。硅烷偶联剂对璃纤维桩粘结强度影响不大,但可增强石英纤维桩粘结强度。     

不同材料修复喇叭型根管口的实验观察

目的观察不同材料修复喇叭型根管口后的抗折裂强度和破坏模式。方法将15颗离体上颌中切牙截除牙冠后进行常规根管治疗,形成喇叭型根管口,然后随机分为A、B、C组,分别用镍铬合金铸造桩核、预成玻璃纤维树脂桩核和可塑性纤维增强树脂桩核修复。在压力测试机上对试件进行抗折裂强度测试,并记录破坏模式。结果3组试件修复后的抗折裂强度无统计学差异（P＞0.05）,但破坏模式不同,其中A组铸造桩核试件主要表现为根折和粘接剂与牙体分离,B组预成玻璃纤维树脂桩核试件主要表现为桩与粘接剂分离,C组可塑性纤维增强树脂桩核试件主要表现为粘接剂与牙体组织分离。结论纤维树脂类修复材料修复喇叭型根管口有利于残根的保存和再次修复。     

循环加载对不同桩核修复后牙体抗折强度的影响

目的 用循环加载的方式模拟核桩冠修复一段时间后的状况,比较不同桩核修复后牙体的抗折强度,了解其远期修复效果。方法 15颗下颌离体前磨牙随机分为3组,分别为铸造金属桩核组（A组）、玻璃纤维加强复合树脂桩核组（B组）、树脂充填组（C组）,每组5个试件。所有试件在完成桩核修复后均做金属冠修复,经过300 000次循环加载和1 000次5~55 ℃冷热循环后,再在力学测试机上测试试件的抗折强度,记录试件断裂时的力值和试件破坏形式。结果 B组和C组抗折强度显著高于A组（P<0.05）。A组主要为不可修复性折裂,其他两组主要为可修复性折裂。结论 临床修复残根残冠时,可以优先考虑纤维桩加树脂核修复或者树脂充填修复。     

可塑纤维桩修复对根管治疗牙抗折强度的影响

目的比较不同桩修复离体牙对修复体整体抗折强度的影响。方法将32颗上颌前磨牙行根管治疗并从唇侧釉牙骨质界上2 mm处截断后随机分为4组,A组采用镍铬金属铸造桩核加铸造冠修复,B组采用Tenax FiberWhite纤维桩、树脂核加铸造冠修复,C组采用EverStick可塑纤维桩单根（直径1.5 mm）、树脂核加铸造冠修复,D组采用EverStick可塑纤维桩双根（直径1.5 mm和1.2 mm）、树脂核加铸造冠修复。所有离体牙均由自凝树脂包埋,电子万能试验机加载头与牙体长轴成45°,以1 mm/min的加载速度加载直至试件任何部分折裂,记录读数并观察修复体折裂模式。结果A、B、C、D组间修复体的整体抗折强度差异无统计学意义（P>0.05）。各纤维桩组牙体折裂位置较铸造桩更接近牙颈部。结论尽管可塑纤维桩自身的弯曲强度较低,但是修复离体牙后整体抗折强度较高,可以满足临床要求。各纤维桩组折裂模式较铸造桩组更有利于修复体失败后的再修复。     

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。     

纤维树脂桩核系统修复牙根发育不完全牙后抗折强度的分析

目的通过对经根管治疗后使用玻璃纤维桩核进行修复的牙根发育不完全牙各部位抗折强度的测量比较,以期为临床使用桩核系统修复根尖诱导成形术后的牙降低根折风险提供依据。方法收集符合纳入标准的因正畸需要拔除的根尖发育不完全,根尖孔未形成的第1、2前磨牙45颗,随机分成3组。分别为纤维桩复合树脂水门汀组(实验组)、复合树脂水门汀组(阳性对照组)、根管充填后不作处理组(阴性对照组),每组样本15颗,常规桩道预备后用复合树脂和桩核系统进行修复,将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区域的抗折强度,比较经纤维桩核系统修复后牙根不同部位的抗折强度。采用SAS软件包对所得数据进行统计学分析。结果实验组的牙根颈部、中部的抗折强度分别为(999±75.40)N和(799±21.77)N,阴性对照组分别为(501±38.4)N和(472±22.98)N,阳性对照组分别为(704±88.39)、(550±20.14)N。实验组的牙根各部位的抗折能力均最强,与阳、阴性对照组均有显著差异(P<0.0001)。结论纤维桩核系统对牙根抗折性能有显著影响,植入纤维树脂桩的牙齿在牙根颈1/3和中1/3区域都显示出比植入复合树脂粘接材料和仅经根管充填后的牙齿具有更大的抗折强度。     

Impact of different surface treatment methods on bond strength between fiber post and composite core material

PurposeTo assess the impact of different surface treatments on the push-out bond strength between fiber post and a composite resin core material.Material and methodsSeventy-two glass-fiber posts were randomly assigned into six groups according to the method of surface treatment: Control (no treatment), silane, sandblasting, hydrofluoric acid, hydrogen peroxide, and hydrogen peroxide with sandblasting. Two posts from each group were inspected under a scanning electron microscope to assess the surface modifications and 10 posts were employed for the push-out test. Each post was placed vertically in the middle of a cylindrical putty matrix and a dual-cure composite resin material was applied for core build-up. Two discs of each specimen were cut using a low-speed diamond saw (total 120 discs). The push-out test was executed using a universal testing machine at a crosshead speed of 0.5 mm/min. Statistical analysis was performed using one-way ANOVA and Tukey’s test (p ≤ 0.05). The mode of failure of each disc was evaluated under SEM.ResultsThe sandblasting and hydrofluoric acid groups presented significantly higher bond strength than control and hydrogen peroxide groups. The hydrogen peroxide groups exhibited significantly the lowest bond strength of all groups. There was no significant difference between the control and silane groups. All groups showed predominantly adhesive failure except the hydrogen peroxide with sandblasting, where the cohesive failure of the post was predominant.ConclusionsSandblasting and hydrofluoric acid surface treatments demonstrated superior results to silane and hydrogen peroxide. The combined method of hydrogen peroxide and sandblasting could weaken the fiber post and lead to clinical fractures.     

Effects of chemical surface treatments of quartz and glass fiber posts on the retention of a composite resin

STATEMENT OF PROBLEM: Failure of a fiber post and composite resin core often occurs at the junction between the 2 materials. This failure process requires better characterization. PURPOSE: The purpose of this study was to evaluate the effect of 2 chemical solvents, hydrogen peroxide and methylene chloride, on the shear bond strength of quartz and glass fiber posts to a composite resin. MATERIAL AND METHODS: Twenty-four posts (3 +/-0.1 mm in length) were prepared for each quartz (LIGHT-POST (LP)) and glass fiber (Cytec blanco (CB)) post. Posts were horizontally embedded in acrylic resin with half of the post diameter exposed. The exposed surfaces were successively ground with 400-, 800-, and 1200-grit silicon carbide papers, to ensure uniform smoothness. The specimens were divided into 3 subgroups (n=8) representing different surface treatment techniques, including application of silane for 60 seconds (S), etching with hydrogen peroxide for 20 minutes (H), and etching with methylene chloride for 5 seconds (M). Silane-treated specimens served as controls. A dual-polymerized composite resin (Tetric EvoCeram) was placed in a polytetrafluoroethylene mold (30 x 2 mm) positioned upon the post specimens and polymerized for 20 seconds with a light-emitting diode (LED) polymerization unit. The specimens were stored in water at 37 degrees C for 24 hours. Shear bond strength values (MPa) of posts and composite resin cores were measured using a universal testing machine with a crosshead speed of 0.5 mm/min. Data were analyzed by 2-way analysis of variance (ANOVA). Post hoc Tukey intervals for comparison among the 2 post materials and 3 surface treatment techniques were calculated (alpha =.05). The effect of the chemical surface treatments on glass and quartz fiber post surfaces were examined with a scanning electron microscope (SEM). RESULTS: There were significant differences between the shear bond strength for LP and CB (P<.001). For all groups, the application of H showed the highest bond strength values. There was no significant difference between the S and M groups (P>.05). The SEM observations demonstrated that the fiber post surfaces were modified after chemical surface treatment techniques. CONCLUSIONS: The surface treatment of quartz and glass fiber posts with hydrogen peroxide significantly enhanced the shear bond strength of the composite resin tested due to its ability to dissolve the epoxy resin matrix used in each post. The lowest bond strength was obtained with M and S groups. Application of methylene chloride to the fiber post surfaces for 5 seconds was not effective in increasing the shear bond strength of the fiber post to composite resin.     

Fiber post etching with hydrogen peroxide: effect of concentration and application time

Introduction

Etching is necessary to expose the fibers and enable both mechanical and chemical bonding of the resin core to the fiber post. This study evaluated the effect of concentration and application time of hydrogen peroxide on the surface topography and bond strength of glass fiber posts to resin cores.

Methods

Fiber posts were etched with 24% or 50% hydrogen peroxide for 1, 5, or 10 min (n = 10). Posts without any treatment were used as a control. After etching, the posts were silanated and adhesive resin was applied. The posts were positioned into a mold to allow a self-cured resin core to be inserted. The post/resin assembly was serially sectioned into five beams that were subjected to a tensile bond strength test. Data were subjected to two-way ANOVA and Tukey test (α = 0.05). The surface topography was analyzed using scanning electronic microscopy.

Results

Non-etched post presents a relatively smooth surface without fiber exposure. Application of hydrogen peroxide increased the surface roughness and exposed the fibers. All experimental conditions yielded similar bond strength values that were higher than those obtained in the control group.

Conclusion

Both 24% and 50% hydrogen peroxide exposure increased the bond strength of resin to the posts, irrespective of the application time.     

Effects of different surface pre-treatments on the bond strength of adhesive resin cement to quartz fiber post

Abstract Objective. The purpose of this study was to evaluate the effect of mechanical and chemical surface treatment methods on the bond strength of resin cement to fiber post. Materials and methods. The roots of 36 maxillary central incisor teeth were mounted in auto polymerized acrylic resin blocks (10 × 15 mm) and the root canals were enlarged with the drills of post system (2.1 mm width, 12 mm length). Thirty-six fiber posts were randomly assigned to one of the following surface conditioning methods: silane coupling agent, methylene chloride etching, 24% hydrogen peroxide etching, air abrasion with 50 μm Al(2)O(3), 1-3 μm synthetic diamond particles and silica coating with 30 μm SiO(x). Fiber posts were cemented to the root canals with adhesive resin cement (Panavia F 2.0). Three slices of 1.5 mm thick were obtained from each root. Push-out tests were performed with a universal testing machine. The data were analyzed with one-way analysis of variance (ANOVA) and Tukey HSD tests (α = 0.05). The effect of the surface treatments were examined under a scanning electron microscope (SEM) and surface roughness were evaluated with a profilometer. Results. Surface pre-treatment methods affected the bond strength (p < 0.05). The highest bond strengths were obtained by air abrasion with synthetic diamond particles, the lowest bond strength were obtained by etching with methylene chloride (p < 0.05). Conclusion. Mechanical surface pre-treatment methods showed higher bond strength values than chemical methods. Synthetic diamond particles may be an alternative method to increase resin cement bonding on the quartz fiber post surfaces.     

Fatigue resistance of bovine teeth restored with resin-bonded fiber posts: effect of post surface conditioning

This study evaluated the effect of post surface conditioning on the fatigue resistance of bovine teeth restored with resin-bonded fiber-reinforced composite (FRC). Root canals of 20 single-rooted bovine teeth (16 mm long) were prepared to 12 mm using a preparation drill of a double-tapered fiber post system. Using acrylic resin, each specimen was embedded (up to 3.0 mm from the cervical part of the specimen) in a PVC cylinder and allocated into one of two groups (n = 10) based on the post surface conditioning method: acid etching plus silanization or tribochemical silica coating (30 pm SiO(x) + silanization). The root canal dentin was etched (H2PO3 for 30 seconds), rinsed, and dried. A multi-step adhesive system was applied to the root dentin and the fiber posts were cemented with resin cement. The specimens were submitted to one million fatigue cycles. After fatigue testing, a score was given based on the number of fatigue cycles until fracture. All of the specimens were resistant to fatigue. No fracture of the root or the post and no loss of retention of the post were observed. The methodology and the results of this study indicate that tribochemical silica coating and acid etching performed equally well when dynamic mechanical loading was used.     

玻璃纤维的表面预处理对纤维增韧树脂基桩力学性能的影响

目的 研究不同表面预处理的高强玻璃纤维对纤维增强光固化树脂复合材料（FRC）桩的力学性能的影响。方法 将玻璃纤维分为4组分别进行以下表面处理：不预处理、450 ℃高温处理、450 ℃高温+10%HCl蚀刻1 h、450 ℃高温+10% HCl蚀刻3 h,然后将4组纤维经过硅烷偶联剂处理后按相同体积比浸入自行配制的光固化树脂基质中,用压挤法制成纤维增强树脂基桩。测试试样的弯曲模量、弯曲强度、弯曲载荷,扫描电子显微镜观察FRC截面和断裂面的形态。结果 不同表面预处理后的玻璃纤维对FRC桩的力学性能有显著差异,其中450℃+KH570组制成的FRC桩性能最佳,弯曲模量、弯曲强度、弯曲载荷分别为（37.70±1.46） GPa、（737.00±25.51） MPa、（196.53±6.80） N,与其余组有显著差异（P＜0.05）。结论 450 ℃高温+KH570处理玻璃纤维对FRC桩的增韧效果最佳。     

桩核材料与纤维/树脂复合材料桩钉联合修复无髓牙的抗折性能研究

目的评价3种树脂类桩核材料与高强玻璃纤维/树脂复合材料(FRC)桩钉联合修复无髓牙的抗折性能。方法用FRC桩钉和3种经不同方法处理(热压和未热压)的树脂核(Artglass聚合体、Charisma复合树脂、AB组份复合树脂)联合修复离体无髓牙根,测试1300加载时的破坏载荷。结果Artglass聚合体组的抗折力最高(505.4N),经热压处理后强度明显提高(564.1N) ; Chari~复合树脂组经热压后脆性增加,强度降低(热压前后分别为411.3N和 315.3N); AB组份树脂组经热压后强度明显提高(热压前后分别为358.4N和423.4N)。实验中无1例出现桩钉折断和聚酷冠碎裂。结论不同桩核材料与FRC桩钉联合修复无髓牙的抗折力不同,其中Art乡ass聚合体组的抗折力最高,但是此3组的抗折力均超过了咀嚼过程中前牙的咬合力,树脂核与纤维/树脂复合材料桩钉联合修复无髓前牙残根可以满足临床需要。     

Effect of post type and restorative techniques on the strain and fracture resistance of flared incisor roots

Restoring flared endodontically treated teeth continues to be a challenge for clinicians. This study evaluated the effect of post types and restorative techniques on the strain, fracture resistance, and fracture mode of incisors with weakened roots. One hundred five endodontically treated bovine incisors roots (15 mm) were divided into 7 groups (n=15). The two control groups were (C) intact roots restored with Cpc (cast posts and core) or Gfp (glass fiber posts). The five experimental groups were (F) flared roots restored with GfpAp (Gfp associated with accessory glass fiber posts), GfpRc (anatomic Gfp, relined with composite resin), and GfpRcAp (anatomized Gfp with resin and accessory glass fiber posts). All teeth were restored with metal crowns. Mechanical fatigue was performed with 3x10(5)/50 N. Specimens were loaded at 45o, and the strain values (μS) were obtained on root buccal and proximal surfaces. Following that, the fracture resistance (N) was measured. One-way ANOVA and Tukey's HSD tests (α=0.05) were applied, and failure mode was checked. No significant difference in strain values among the groups was found. Cpc presented lower fracture resistance and more catastrophic failures in flared roots. Gfp associated with composite resin or accessory glass fiber posts seems to be an effective method to improve the biomechanical behavior of flared roots.