Influence of fiber posts on the fracture resistance of endodontically treated premolars with different dental defects

This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading.Fifty extracted single-rooted mandibular premolars were randomized into five groups.Each group was prepared according to numbers of residual walls ranged from 0 to 4.Then each group was divided into two subgroups with one restored with quartz fiber posts and the other without posts.In no-post groups,gutta percha point 2 mm below cemento-enamel junction was removed.Composite resin was adapted to the well and used to shape the core directly.Each tooth was restored with a complete metal crown.Dynamic loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading cycles.Then a quasi-statically load was applied in a universal testing machine 306 to the long axis with a crosshead speed of 1 mm？min21until fracture.Data were analyzed with one-way analysis of variance and pairwise comparison（P,0.05）.No specimens failed during dynamic loading.The fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant（P,0.05）.Placement of fiber posts had a significant effect when fewer than two walls remained（P,0.05）,but it had no significant influence in groups with two,three or four walls（P.0.05）.Fiber post did not change failure mode,and the fracture pattern was mainly favorable.More dentin walls need to be retained in clinic.When no less than two walls remained,a fiber post is not always necessary.

AN EXPERIMENTAL STUDY ON POST-BUCKLING BEHAVIOR OF SLENDER COLUMN WITH FIBER REINFORCED COMPOSITE MATERIAL

Equilibrium paths of post-buckling are measured for large slenderness column specimensmade of the fiber reinforced composite material. The influence of the initial curvature is investigatedexperimentally and compared with the result of the initial post-buckling theory. Both the theoreticaland experimental results reveal that the column with the initial curvature has stable post-buckling be-haviors and is not sensitive to the imperfection in the form of initial curvature. The experimental re-sults show that when the lateral buckling displacement is less than 20 percent of the column length, theexperimental results agree with the results from the theory of initial post-buckling quite well, whilethey agree with the results from the large deflection theory in a quite large range.

Enhanced gas separation performance of mixed matrix hollow fiber membranes containing post-functionalized S-MIL-53

Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.

DT Light-Post纤维桩修复残根、残冠的疗效分析

目的:评价DTLight-Post纤维桩在残根、残冠修复治疗中的作用。方法:选择临床修复病例193例、287颗前牙及前磨牙,其中残冠195例,残根92例,行完善的根管治疗后,用DT Light-Post纤维桩系统恢复桩核后作全瓷冠修复,采用SAS6.12软件包对残根、残冠修复结果作χ2检验。结果:随访1～3a,195例残冠修复中,6例发生冠连桩核脱落;92例残根修复中,17例发生冠连桩核脱落,脱落病例改用化学固化黏结剂粘固后1a内未再脱落。其余修复体完好,未发生桩折或牙折。总治疗成功率为91.98%,残根脱落率显著高于残冠,Ρ=0.001。结论:纤维桩是一种较为理想的桩核修复方法,其适应证的选择及黏结剂种类和黏结技术对治疗成功率有明显影响。

D.T.Light-Post纤维桩的临床应用观察

目的探讨D.T.Light-post纤维桩在残根残冠修复治疗中的临床效果。方法选择187例患者324颗残根残冠,经完善的根管治疗后,选择D.T.Light-post纤维桩核冠修复,并进行半年～2年半临床疗效观察。结果320颗患牙成功修复,4颗患牙因纤维桩折断失败,修复成功率为98.77%。结论D.T.Light-post纤维桩核冠修复残根残冠效果良好。

自粘结树脂水门汀与全酸蚀粘结系统对POPO和Para Post玻璃纤维桩在不同桩道深度剪切粘结强度的影响

目的: 比较不同粘结系统粘固 2 种玻璃纤维桩后,在不同桩道深度的剪切粘结强度。方法: 选取 36 颗新鲜单根管牙,常规根管治疗后分成 4 组: POPO 玻璃纤维桩和自粘结树脂水门汀( POPO + SA) ; POPO 玻璃纤维桩和全酸蚀粘结系统( POPO + ER) ; Para Post 玻璃纤维桩和自粘结树脂水门汀( PP + SA) ; Para Post 玻璃纤维桩和全酸蚀粘结系统( PP + ER) ,每组9 颗。桩道预备后按分组将纤维桩粘固于根管中,每个牙根切成厚度1 mm 的薄片6个,按桩道深度记为颈 1/3、中 1/3 和根尖 1/3,各 2 片。采用薄片推出试验测量剪切粘结强度。结果: 纤维桩、粘结系统和桩道深度均对剪切粘结强度有影响。纤维桩与粘结系统两因素间有交互作用( F =13. 081,P <0. 001) 。在桩道中 1/3,PP + SA 组剪切粘结强度( 9. 900 ±0. 934) MPa 高于 POPO + SA 组的( 6. 537 ±0. 801) MPa 和 POPO + ER组的( 7. 406 ±0. 758) MPa( P <0. 05) ; 在桩道根尖 1/3,PP + SA 组剪切粘结强度( 5. 350 ±0. 488) MPa 高于 PP + ER组的( 2. 534 ±0. 548) MPa ( P <0. 05) 。各组粘结强度随桩道深度增加而呈下降趋势( F =99. 555,P <0. 001) 。结论: Para Post 玻璃纤维桩与自粘结树脂水门汀联合使用的粘结效果最佳; 树脂粘结系统粘结效果在根颈部更可靠。

聚醚醚酮及其复合材料修复桩核冠:问题与临床应用价值

背景:聚醚醚酮是具有良好机械性能、生物相容性、化学稳定性的特种塑料聚合物,可加入不同的填料形成新型复合材料,在桩核修复中有潜在的临床应用价值。目的:综述聚醚醚酮及其复合材料的性能、在桩核修复中的临床应用进展。方法:以“聚醚醚酮,桩核修复,金属桩,纤维桩,氧化锆桩”为中文检索词检索中国知网数据库,以“PEEK,polyetheretherketone post,post core repair,dental Dowels”为英文检索词检索PubMed数据库,检索时间范围重点为2019年1月至2023年10月。通过阅读文献题目、摘要及全文筛选,根据纳入与排除标准进行筛选,最后纳入71篇文献进行综述。结果与结论:聚醚醚酮是高性能热塑性聚合物,实验研究证明聚醚醚酮及其复合材料在机械性能、生物相容性、抗老化性、化学稳定性、粘接性能等方面具有优越性,在桩核修复领域应用前景喜人。聚醚醚酮及其复合材料作为桩核修复临床应用局限于前牙和前磨牙,但都获得了满意的修复效果。聚醚醚酮及其复合材料在桩核修复中属于新型材料,目前还有诸多问题尚待解决,如:3D打印设备和打印过程是否会影响材料的机械性能;临床修复效果观察时间短,缺乏长期的研究验证;缺乏聚醚醚酮及其复合材料作为桩核材料修复磨牙的病例报道等,后续还需不断完善相关研究。

纤维桩联合不同冠部修复方式修复穿髓型非龋性颈部缺损牙体的力学分析

背景:使用纤维桩修复穿髓型非龋性颈部缺损可以改变牙齿的应力分布,显著降低患牙折裂风险,但关于纤维桩改善牙体抗折性的力学机制及穿髓型非龋性颈部缺损的最佳冠部修复方式尚有争论。目的:综述纤维桩修复穿髓型非龋性颈部缺损后的应力分布模式,在各种受力状态下的抗折能力与断裂模式,以及纤维桩联合不同冠部修复方式的最新研究进展。方法:应用计算机在PubMed和中国知网数据库中检索2008年9月至2023年9月发表的相关文献,英文检索词为“non-carious cervical lesions,endodontically treated teeth restoration,endodontically treated teeth stress distribution”,中文检索词为“非龋性颈部缺损,根管治疗后牙体修复,根管治疗后牙齿应力分布”,最终纳入56篇文献进行分析。结果与结论:穿髓型非龋性颈部缺损根管治疗后,应用纤维桩修复可部分改善牙齿颈部应力,同时不会增加牙根纵裂的风险;使应力分布更加均匀,提高牙齿的抗折性。使用纤维桩修复的非龋性颈部缺损牙齿若折断,其断裂模式显示出有利的、可恢复的或可修复的断裂模式。纤维桩联合瓷贴面或贴面式嵌体可能会成为修复穿髓型非龋性颈部缺损的一种较理想微创修复方法。

Fracture Resistance and Failure Patterns of Open Apex Root Teeth with Different Posts after Endodontic Treatment

The aim of this study is to investigate the influence of different posts on the fracture mechanics of endodontically-treated teeth with open apex. Forty-eight human maxillary anterior teeth were collected, and the root was transversely sectioned 12 mm under the cementoenamal junction （CEJ）. These samples were then randomly divided into two groups, i.e., minor diameter open apex root （group A） and major diameter open apex root （group B）, with mineral trioxide aggregate （MTA） placed into the apical 4 mm in the root canals. Subsequently, both groups were respectively further divided into three subgroups as follows： fiber-post （subgroup 1）, metal post （subgroup 2） and non-post （subgroup 3） group. Teeth were restored with a composite resin crown and tested by using a universal testing machine at the rate of 1 mm/min cross-head. Values of the maximum fracture resistance and failure patterns were recorded and compared among all subgroups. In addition, the changes of MTA properties were carefully examined via X-ray photography. Our results indicate that （1） In group A, the mean value of fracture resistance for teeth restored with fiber posts were statistically higher than that with either metal post or non-post; （2） In group B, there was no statistically significant difference in the mean value of fracture resistance among three subgroups; （3） No statistical significance in the mean value of fracture resistance was found between group A and group B; （4） The failure modes of most samples （58%） were irreparable; （5） MTA in two teeth developed cracks after loading tests. In conclusion, endodontically-treated teeth restored with fiber posts are more resistant to fracture than those restored with either metal posts or non-post, and most of the fracture modes are catastrophic in nature.

RTD MACRO-LOCK POST固位增强型石英纤维桩与金属桩修复上颌前牙残冠的临床疗效比较

目的观察RTD MACRO-LOCK POST固位增强型石英纤维桩与金属桩修复上颌前牙残冠的临床疗效。方法选取上颌前牙牙体缺损患者200例,随机分为两组,分别采用RTD MACRO-LOCK POST固位增强型石英纤维桩与金属桩进行桩核冠修复,随访观察3年。结果纤维桩组患者修复后6个月临床成功率与金属桩组无明显区别(P>0.05),修复后3年临床成功率高于金属桩组(P<0.05)。结论在正确选择适应证前提下,RTD MACRO-LOCK POST固位增强型石英纤维桩修复效果优于金属桩。

数字化辅助一体化纤维桩核及树脂基陶瓷冠修复冠折年轻恒牙1例

桩核修复是临床常见的牙体缺损修复方式,临床常用桩核主要有玻璃纤维预成桩树脂核和个性化一体式桩核。在个性化桩核的材料选择上,由于金属的美观缺陷及氧化锆的弹性模量限制,兼具个性化、机械性能及美学优势的一体化玻璃纤维桩核作为一种新型桩核形式被临床所应用。本文报告1例CAD/CAM一体化纤维树脂桩核及树脂基陶瓷冠修复年轻恒牙冠折的临床病例。

预成纤维桩在口腔修复治疗中的应用效果分析

目的探讨预成纤维桩在口腔修复治疗中的效果。方法78例进行口腔修复治疗的患者,随机分为观察组和对照组,各39例。观察组应用预成纤维桩修复术,对照组应用可塑纤维桩修复术。比较两组不同时间[术前(T0)、术后3个月(T1)、术后6个月(T2)]牙周健康指标[菌斑指数(PLI)、出血指数(BI)、牙周袋探诊深度(PD)]、咬合力、咀嚼效率,修复成功率、修复时间及修复前后炎症因子[白细胞介素-17(IL-17)、白细胞介素-23(IL-23)]水平,并发症发生情况。结果①T1时,观察组PLI(1.90±0.22)分、BI(2.01±0.33)分、PD(1.21±0.45)mm明显低于对照组的(2.11±0.26)分、(2.86±0.32)分、(1.51±0.53)mm(t=3.851、11.548、2.695,P<0.05);T2时,观察组PLI(0.83±0.23)分、BI(0.87±0.34)分、PD(0.55±0.49)mm显著低于对照组的(1.65±0.29)分、(1.55±0.35)分、(1.05±0.30)mm(t=13.835、8.703、5.435,P<0.05)。②观察组并发症发生率2.56%低于对照组的17.95%(P<0.05)。③T1时,观察组咬合力(111.51±7.14)lbs、咀嚼效率(73.35±5.01)%明显高于对照组的(94.01±7.46)lbs、(65.35±4.96)%(t=10.583、7.087,P<0.05);T2时,观察组咬合力(133.35±10.01)lbs、咀嚼效率(88.86±7.53)%显著高于对照组的(114.53±18.46)lbs、(77.01±8.02)%(t=5.597、6.727,P<0.05)。④修复后,观察组IL-17(300.84±13.73)ng/L、IL-23(6.29±2.16)μg/L低于对照组的(353.26±10.47)ng/L、(7.65±2.47)μg/L(t=18.959、2.588,P<0.05);观察组修复时间(65.28±3.51)min/颗短于对照组的(100.24±6.61)min/颗(t=29.172,P<0.05)。观察组修复成功率97.44%高于对照组的79.49%(χ^(2)=6.155,P<0.05)。结论预成纤维桩在口腔修复治疗中具有良好的效果,应用价值较高。

羊肉后熟过程中肌肉纤维结构变化及氧化特性

宰后成熟是肉加工和储存过程中改善口感和品质的一种常用方法。通过对新疆山羊肉进行微观结构观察,测定硫代巴比妥酸反应物(thiobarbituric acid reactive substances,TBARS)含量及溶解度,提取羊肉肌原纤维蛋白并进行羰基含量、巯基含量、表面疏水性及FT-IR测定,探究新疆山羊肉在宰后4℃成熟48 h过程中肌肉纤维结构和氧化特性的变化。结果表明:羊肉后熟48 h过程中,肌肉纤维出现聚合、条块边缘变粗糙、纤维间距增大现象;TBARS值增幅达到47.8%;肌原纤维蛋白的溶解度下降,疏水性增加,其羰基含量显著上升、巯基含量下降。后熟0、12、24 h时,肌原纤维蛋白中α-螺旋、β-折叠、β-转角以及无规则卷曲结构平均所占比例分别为29%、19%、21%、31%;后熟48 h时无规则卷曲结构未被检出。研究结果反映出羊肉后熟过程中肌肉纤维条块在聚合后出现降解,后熟的前12 h含巯基蛋白质更容易被氧化,12 h后脂质氧化加速。研究结果为肉宰后成熟过程中从肌原纤维蛋白结构及氧化角度分析肉品质变化提供了理论依据。

修复方式对不同面积楔状缺损抗折强度的影响

目的 研究不同修复方式对不同面积楔状缺损抗折强度的影响。方法 60颗下颌第一前磨牙随机分成6组,制备两种缺损面积的蝶形缺损,其中A1、B1组充填树脂作为对照,A2、A3和B2、B3按缺损面积在1/3以内、大于1/3小于轴角和桩核、桩核冠修复分组。进行10000次人工老化处理后,采用万能材料试验机垂直加载,记录最大载荷数值并分析折裂模式。结果 当缺损面积<1/3时,A1(935.24±50.21)N与A2(950.53±61.23)N、A3(943.35±23.48)N抗折强度差异无统计学意义,当缺损面积>1/3且小于轴角时,B1(867.38±45.79)N与B2(903.20±43.08)N,B3(920.52±82.98)N间差异有统计学意义,B2与B3间差异无统计学意义。除B2与B1、B3之间折裂模式有差异外,其余无差异。结论 当缺损面积<1/3时,直接树脂充填即可,当缺损面积>1/3小于轴角时,可增加纤维桩来进一步提高抗折强度。全冠修复可能会导致不可修复性折裂的发生,是否制作全冠应慎重决定。

高嵌体与纤维桩核冠对邻牙合面缺损上颌第一前磨牙修复后抗折力影响的实验研究

目的 比较IPSe.max CAD高嵌体和纤维桩核冠对邻牙合面缺损上颌第一前磨牙修复后对抗折力的影响。方法 收集2021年9月至2023年7月在郑州大学第一附属医院因正畸而拔除的60颗上颌第一前磨牙,随机将其分为A、B、C 3组(n=20),A组、B组样本牙进行完善的根管治疗后,制备邻牙合面缺损洞型,分别采用不同的修复方法。A组行IPSe.max CAD高嵌体修复;B组行纤维桩核冠修复;C组为对照组,样本牙不作处理。记录各组折断力值、折断模式,并进行比较。结果 A组、B组和C组折裂载荷值分别为(781.25±61.23)N、(712.51±54.36)N和(420.28±41.28)N,3组间比较,差异有统计学意义(F=262.154,P<0.001),A组的折裂荷载值最高;3组折裂模式均以可修复折裂为主,组间比较差异无统计学意义(P>0.05)。结论 邻牙合面缺损上颌第一前磨牙采用IPSe.max CAD高嵌体修复后具有较好的临床效果,抗折力较高,且折裂模式主要为可修复性折裂。

PBT高弹纤维的生产工艺

对聚对苯二甲酸丁二醇酯(PBT)长丝的生产工艺及后加工工艺进行研究,制得一种167 dtex/48 f PBT高弹纤维。试验表明:控制PBT熔体黏度波动范围在0.002 dL/g以内,在纺丝温度263~265℃、风速0.38 m/s、卷绕速度2 500 m/min的工艺条件下可得到质量稳定的PBT预取向丝;在加弹机上对PBT预取向丝进行再加工,采用双喂入的方式,设定拉伸倍数为1.5倍,D/Y为1.8,第一热箱温度为195℃,关闭了第二热箱的加热器,超喂率为3.5%,制得的PBT高弹纤维的断裂强度为3.25 cN/dtex,断裂伸长率为26%,卷曲收缩率为65%。

Stress Distribution in Maxillary Central Incisors without Ferrules: A Finite Element Analysis of Post and Core Systems

Purpose: The purpose of this study was to identify optimal post and core materials for central incisors without ferrules using three-dimensional finite element analysis and three-point bending tests. Methods: Stress analyses were performed with six models: cast metal post and core (MP), composite resin core alone, straight fiber-reinforced post-composite resin core (FSR), tapered fiber-reinforced post-composite resin core, straight titanium post-composite resin core (TSR), and tapered titanium post-composite resin core (TTR). A 100-N load was applied to the lingual surface at a 45° angle to the long axis of the tooth. Maximum von Mises stress distributions were calculated with finite element analysis software. Five samples each of composite resin, straight fiber-reinforced post, straight titanium post, straight fiber-reinforced post and composite resin, and straight titanium post and composite resin were subjected to three-point bending tests, followed by analysis of variance and Tukey’s multiple comparison test. Results: Stress distribution was optimal on TTR. Maximum von Mises stress on the cervical side of the post was greatest in TSR (693 MPa) and TTR (556 MPa). Maximum stress on the apical side of the post was greatest in MP (110 MPa). Maximum stress in surrounding dentin was lowest in MP (203 MPa) and TTR (250 MPa). Gap distance was smallest in MP (0.09 mm) and largest in FSR (0.26 mm). Mean maximum three-point bending force was lowest in composite resin (26.9 N/mm) and highest in titanium post and composite resin (97.1 N/mm). Titanium post bending strength was consistently greater than that of the fiber-reinforced post (p < 0.01). Conclusion: These results revealed optimal stress distribution and high bending strength with the tapered titanium post and resin combination, suggesting that this combination can most effectively prevent root or post fracture in an anterior tooth without a ferrule.

DT Light-post纤维桩修复前牙残根残冠的疗效分析

目的:评价DT Light-post纤维桩在前牙残根、残冠修复治疗中的作用。方法:选择上前牙牙体缺损病例46例,行完善的根管治疗后,A组采用DT Light-post纤维桩系统恢复桩核后作全瓷冠修复,B组采用金属桩核加金属烤瓷冠修复。采用SPSS12.0软件包对实验结果进行统计学分析。结果:随访2年,两组成功率差异有显著性,两组修复牙的牙周情况无显著性差异。结论:纤维桩是一种较为理想的前牙牙体缺损桩核修复方法。

DT Light-Post纤维桩修复前牙缺损的美学与预后效果探讨

目的:探讨DT Light-Post纤维桩对前牙的美容修复和预后效果。方法:选取2015年1月-2016年10月笔者科室收治的172例前牙缺损患者为研究对象,按照简单随机法将患者分为三组。对照组:54例(70颗患牙),采用铸造金属桩制作桩核;普通纤维桩组:58例(70颗患牙),采用玻璃纤维桩核;DT Light-Post纤维桩组:60例(70颗患牙),采用DT Light-Post纤维桩制作桩核。比较三组患者临床修复效果,以及修复后1周、6个月、12个月、24个月的牙龈指数。结果:三组患者前牙修复成功率为84.29%、92.86%、98.57%,DT Light-Post纤维桩组前牙修复成功率高于对照组(P<0.05);DT Light-Post纤维桩组前牙修复成功率与普通纤维桩组比较,无统计学差异(P>0.05)。三组患者前牙修复后1周、6个月牙龈指数比较无明显差异(P>0.05);DT Light-Post纤维桩组患者前牙修复后12、24个月牙龈指数低于对照组(P<0.05)。结论:DT Light-Post纤维桩应用于前牙美容修复具有较好疗效,能够替代铸造桩核,成为临床前牙修复方法之一。

不同纤维桩表面处理方法对根管壁粘接固位的影响

目的研究不同纤维桩表面处理方法对根管壁粘接固位力的影响。方法收集50颗半年内因正畸拔出的完整离体单根管下颌双尖牙,随机分为5组。A组:空白组;B组:硅烷偶联剂处理组;C组:选择性酸蚀处理组;D组:过氧化氢溶液处理组;E组:喷砂处理组;按统一标准制作力学测试件进行力学测试,扫描电镜观察处理后的纤维桩表面相貌。结果各组样本中拉力值最大值与最小值的比较:A组、B组、C组、D组、E组的最大值分别为13.16 MPa、13.42 MPa、18.31 MPa、22.67 MPa、21.05 MPa,最小值分别为8.9 MPa、8.94 MPa、12.98 MPa、17.69 MPa、14.39 MPa,D组、E组内的样本最大值及最小值均比A组大,且是5组实验样本中最大的。各实验组断裂模式的比较:通过卡方检验分析得出,断裂方式之间的差异具有统计学意义(α<0.05),大多为粘接剂与纤维桩之间的粘接界面破坏,其中D组和E组以混合破坏占主导地位,而A组、B组和C组是I型粘结破坏占主导地位;4种不同的处理方法均不同程度的改变了玻璃纤维桩表面形貌,纤维束保存完整表面覆盖基质发生不同程度溶解。结论综合评价4种纤维桩表面处理方法得出经过氧化氢溶液处理和喷砂处理的纤维桩的粘接强度在这4种方法中是最强的,临床值得推广运用。