电热聚合法对两种树脂基托挠曲强度的影响

目的研究电热聚合方法对义齿基托挠曲强度的影响。方法选择两种常用热凝义齿基托树脂材料,分别采用传统水浴法和电热聚合法制作样本。样本分组为日进水浴组、贺利氏水浴组、日进电热组、贺利氏电热组,每组10个样本。测量各样本的挠曲强度,并用环境扫描电镜进行断面观察。实验数值采用方差分析,α=0.05。结果各组样本的挠曲强度均符合相关要求,日进电热组的挠曲强度值最大为(93.28±4.80)MPa,与其他3组间差别有统计学意义(P<0.05);而其余3组间的比较均无统计学意义。各组样本断面形态存在明显差别。结论电热聚合方法对义齿挠曲强度并无显著影响,所制作样本均符合国家标准。     

不同聚合方法对基托树脂挠曲强度影响的实验研究

目的在实验室条件下比较2种义齿基托树脂经过4种聚合方法处理后基托树脂的挠曲强度,为临床选择适宜的聚合方法提供依据。方法用金属模具制备相同尺寸的蜡型96个,失蜡后使用2种品牌的义齿基托树脂填胶,用4种方法进行热处理使其固化,用万能力学实验机检测基托树脂的挠曲强度．用双因素方差分析和多重比较进行统计学处理。结果两种基托树脂的挠曲强度具有显著差异（P〈0.01）,不同聚合方法间基托树脂的挠曲强度除电热法与一组水浴方法存在显著差异外．其余组间无显著差异。结论基托树脂的挠曲强度和材料的性能有关,不同聚合方法对基托树脂的挠曲强度没有显著影响。     

不同类型义齿清洁剂对热凝基托树脂物理机械性能的影响

目的：观察不同类型义齿清洁剂对热凝基托树脂物理机械性能的影响。方法：将同样规格的热凝基托树脂试件,按使用说明分别浸泡在 Polident 清洁片或 Steradent 清洁片或0．5％次氯酸钠溶液和蒸馏水中60 h,处理后的试件在万能材料试验机和表面粗糙度测试仪上分别测其弯曲强度、弹性模量（n ＝10）和表面粗糙度（n ＝10）。结果：Polident、Steradent 对热凝基托树脂的弯曲强度和弹性模量的影响与蒸馏水组相比差异无统计学意义（P ＞0．05）,0．5％次氯酸钠组的弯曲强度和弹性模量小于其他组（P ＜0．05）;热凝基托树脂粗糙度4组之间差异无统计学意义（P ＞0．05）。结论：Polident、Steradent 均不影响热凝基托树脂的物理机械性能,0．5％次氯酸钠对热凝基托树脂的粗糙度无影响,而使其弯曲强度及弹性模量有所降低。     

纳米义齿基托树脂的制备及挠曲性能的研究

目的在聚甲基丙烯酸甲酯粉（PMMA）中添加有机改性的蒙脱土制备纳米义齿基托树脂,以增强义齿基托树脂的挠曲性能。方法将蒙脱土经十六烷基三甲基溴化铵改性,形成有机化改性的蒙脱土,将其加入牙托粉中形成混和粉,混和粉与热凝牙托水调和后经加热固化形成纳米义齿基托树脂。用X射-线衍射（XRD）和透射电子显微镜（TEM）表征了固化后材料的结构,用三点挠曲试验测量固化后材料的挠曲强度和挠曲弹性模量。用一维方差分析法评价有机化蒙脱土的量对挠曲强度的挠曲弹性模量的影响。结果 XRD、TEM证实当蒙脱土在混合粉中的量为3%和5%时,蒙脱土在PMMA基质中形成部份剥离和插层结构;当蒙脱土在混合粉中的量为3%时,挠曲强度达最大,进一步增加蒙脱土的量,材料的挠曲强度降低。当混和粉中有机蒙脱土的量在1%~10%时,挠曲弹性模量随有机蒙脱土的量增加而增加。一维方差分析表明当混和粉中有机蒙脱土的量为3%时,实验组的挠曲强度与挠曲弹性模量均存在显著性差异（n=5,P〈0.05）。结论牙托粉中蒙脱土的量对义齿基托树脂的挠曲性能有显著性影响。     

义齿基托树脂的力学性能研究

通过测试４种商品义齿基托树脂的弯曲强度，冲击强度，挠度及弹性模量，评价了采用可见光，热和微波聚合的基托树脂的力学性能，结果显示：热处理效果优于光和自凝处理，在热处理中，水热优于热压，热压优于微波加热。     

甲基丙烯酸偶联二氧化钛/PMMA基托树脂的机械性能

目的研究甲基丙烯酸偶联二氧化钛对树脂基托材料的机械性能的影响。方法按质量比2%、4%、6%及偶联剂有无添加在2种树脂基托材料中,检测各组试件的弯曲强度、弯曲弹性模量、挠度和冲击强度,并用扫描电镜观察表面结构的差异,分析添加量以及偶联剂对树脂基托材料机械性能的影响。采用SPSS12.0软件对数据进行统计学处理。结果弯曲强度和冲击强度随着二氧化钛添加量增加而下降,偶联剂能减缓下降量,偶联剂对弯曲弹性模量和挠度有显著影响(P<0.05)。日进MTi4%的弯曲强度(154.22Mpa)、冲击强度(12.50kJ/m2)和弯曲弹性模量(3643.72Mpa)分别显著大于日进TiO24%(P<0.05)。结论二氧化钛会降低基托树脂的机械性能,甲基丙烯酸能减缓其下降幅度。     

冷热循环对硬衬材料颜色及挠曲强度影响的研究

目的 研究冷热循环对义齿硬衬材料的颜色稳定性及挠曲强度的影响。方法 制作热凝树脂材料(日进自然I型)试件(64 mm×10 mm×2 mm)32块,随机分成4组,每组8块试件。分别为热凝树脂衬垫对照组;热凝树脂衬垫实验组;自凝硬衬材料(德山Rebase Ⅱ Fast)对照组;自凝硬衬材料实验组。所有试件衬垫前先进行5 000次冷热循环,然后分别加衬上述2种衬垫材料,形成基托材料与衬垫材料复合体(64.0 mm×10.0 mm×3.3 mm),实验组再行5 000次冷热循环。通过L*a*b*值及三点加载实验,比较实验组与对照组的颜色和挠曲强度差异。结果 德山硬衬材料实验组与对照组b*值间有统计学差异,但2种衬垫材料颜色变化均在临床可接受范围内。4组基托-衬垫复合体间挠曲强度无统计学差异。结论 德山Re-base Ⅱ Fast是一种方便易用的衬垫材料。     

4种义齿基托树脂力学性能比较

目的 :比较 4种义齿基托树脂的力学性能 ,为临床选择材料提供指导。方法 :按临床制作义齿的步骤制备试样 ,在材料试验机上测定材料的冲击强度、弯曲强度、弹性模量和布氏硬度 ,描绘弯曲试验的应力 应变曲线 ,并对断面进行显微分析。结果 :4种义齿基托树脂 (上海珊瑚、山西长治、Luciton199、Meliodent)的冲击强度分别为 (9.94± 2 .2 5)kJ/m2 、(6.55± 1.85)kJ/m2 、(13 .76± 4.3 1)kJ/m2 、(13 .70± 3 .71)kJ/m2 ,弯曲强度分别为 (75.2 7± 3 .2 4)MPa、(78.88± 7.66)MPa、(80 .47± 3 .2 7)MPa、(76.72± 3 .14 )MPa ,弹性模量分别为 (3 .0 8± 0 .15)GPa、(2 .96± 0 .10 )GPa、(2 .63± 0 .11)GPa、(2 .56± 0 .12 )GPa ,布氏硬度分别为(2 4.15± 1.3 4 )kg/mm2 、(2 3 .43± 1.65)kg/mm2 、(2 0 .86± 1.2 6)kg/mm2 、(18.49± 1.71)kg/mm2 。结论 :4种基托树脂材料相比 ,”上海珊瑚”和”山西长治”基托树脂硬而脆 ,Luciton 199基托树脂硬而强 ,Meliodent基托树脂硬而韧     

金属纤维增强树脂基托材料的研制

义齿基托折断是口腔修复中仍未解决的问题,尤其是上颌总义齿的纵折.研究了一种新型的齿科复合材料——金属纤维增强树脂基托材料的加工工艺,经弯曲强度测试、X射线光电子能谱仪扫描、电镜观察、电子探针扫描证实性能优于普通的树脂基托材料;急性毒性试验和临床应用试验初步证实金属纤维增强树脂基托材料是一种很有应用前途的新颖基托材料.     

纳米SiO2对PMMA基托树脂机械性能的影响

目的:采用纳米SiO2粒子对聚甲基丙烯酸甲酯(PMMA)基托树脂进行增韧、增强,以求达到改变基托树脂的结构组成,降低内应力的损害,提高基托树脂的强度.方法:在基托水MMA中超声分散加入表面处理的纳米SiO2与PMMA聚合进行改性.测试改性后的基托树脂的拉伸强度、断裂伸长率、弹性模量.结果:加入少量的纳米SiO2,能够同时提高基托树脂的的强度和韧性,纳米SiO2含量为0.77％时,改性材料的拉伸强度较PMMA树脂提高22.19％,断裂伸长率较PMMA树脂提高37.29％;弹性模量较PMMA树脂提高54％基托树脂的硬度随着纳米SiO2含量的增加而成线性的提高.结论:基托树脂的硬度随着纳米SiO2含量的增加而成线性提高.     

快速液压热聚合义齿基托材料的实验研究

目的 了解快速液压热聚合义齿基托材料的力学性能。方法 采用自行研制的新型液压自控牙用树脂聚合器和常规水浴两种方法加热固化义齿基托材料，进行挠度、抗弯曲强度、弹性模量、抗冲击强度及硬度的对比分折。结果 快速液压热聚合义齿基托材料的力学性能与水浴法相比无显著性差异，但可以明显缩短热处理时间且全过程自动完成。结论 快速新型液压自控牙用树脂聚合器简化了义齿制作的操作过程，明显缩短了热处理时间，可以准确快速制作出理想的义齿。     

快速水式液压热聚合义齿基托材料力学性能的研究

目的：了解快速液压热聚合义齿基托材料的力学性能。方法：采用自行最新研制的新型水式液压自控牙用树脂聚合器、常规水浴法及气压式多功能牙用树脂聚合器3种方法加热固化义齿基托材料，进行挠度、抗弯曲强度、弹性模量、抗冲击强度及硬度的对比分析。结果：快速液压热聚合义齿基托材料的力学性能与水浴法及气压热聚合者相比无显著性差异，同样可以明显缩短热处理时间且全过程自动完成。结论：快速新型液压自控牙用树脂聚合器简化了义齿制作的操作过程，明显缩短了热处理时间，完全可以准确快速制作出理想的义齿。     

Comparative Evaluation of Impact and Flexural Strength of Four Commercially Available Flexible Denture Base Materials: An In Vitro Study

Poly-methyl methacrylate is a rigid material. It is generally observed that the impact and flexural strength of this material is not satisfactory and that is reflected in the continuous efforts to improve these mechanical properties. Hence there was a serious need to make another material which could overcome the limitations of the existing materials and could have better properties, like thermoplastic materials. The study was aimed to evaluate and compare the impact strength and the flexural strength of four different flexible denture base materials (thermoplastic denture base resins) with the conventional denture base material (high impact polymethyl-methacrylate). Two, machine made master moulds of metal blocks according to the size of sample holder of the equipment were prepared to test the impact and flexural strength. Total 40 samples, 10 for each group of flexible denture base materials namely: De-flex (Deflex, United Kingdom), Lucitone FRS (Densply, Germany), Valplast (Novoblast, USA), and Bre-flex (Bredent, Germany) in specially designed flask by injection molded process. For different flexible materials, the time, temperature and pressure for injecting the materials were followed as per the manufacturer’s instructions. Total 20 samples for control (Trevelon denture base materials) were prepared by compression moulded process, for each test. ANOVA test was applied to calculate p value. Unpaired t test was applied to calculate t-value. Tukey–Kramer multiple test was provided for comparison between the groups for flexural and impact strength. From the statistical analysis, it was found that, the impact strength of Group III (Valplast) was found to be the highest than all other groups and nearer to the control group. Whereas Group IV (Bre-flex) had the maximum flexural strength. The flexural strength of Group I (De-flex) was lowest than all other groups and nearer to control group. The values were found to be statistically significant but clinically non-significant with the control (p < 0.001). The overall results of the study showed that, Group III (Valplast) had the maximum impact strength and Group I (De-flex) had the lowest flexural strength, whereas Group IV (Bre-flex) had the maximum flexural strength and lowest impact strength.     

Properties of injection-molded thermoplastic polyester denture base resins

Objective. This study investigated the properties of injection-molded thermoplastic polyester denture base resins. Materials and methods. Two injection-molded thermoplastic polyester denture base resins (polyethylene terephthalate copolymer and polycycloalkylene terephthalate copolymer) were tested. Specimens of each denture base material were fabricated for flexural properties testing, Charpy impact testing and shear bond testing (n = 10). The flexural strength at the proportional limit, elastic modulus, Charpy impact strength and the shear bond strength of the two denture base materials were estimated. Results. The polycycloalkylene terephthalate copolymer denture base resin had significantly lower flexural strength at the proportional limit, lower elastic modulus, higher impact strength and lower shear bond strength compared to the polyethylene terephthalate copolymer denture base resin. Conclusion. The properties of the injection-molded thermoplastic denture base resins composed of polyethylene terephthalate copolymer and polycycloalkylene terephthalate copolymer were different from each other. The polycycloalkylene terephthalate copolymer denture base resin had significantly lower flexural strength at the proportional limit, lower elastic modulus, higher impact strength and lower shear bond strength compared to the polyethylene terephthalate copolymer denture base resin.     

Some mechanical properties of a highly cross-linked, microwave-polymerized, injection-molded denture base polymer

PURPOSE: The impact strength and the flexural properties of denture base materials are of importance in predicting their clinical performance upon sudden loading. This study compares the impact and transverse strengths and the flexural modulus of three denture base polymers. MATERIALS AND METHODS: The investigation included a relatively new microwave-polymerized polyurethane-based denture material processed by an injection-molding technique, a conventional microwave-polymerized denture material, and a heat-polymerized compression-molded poly(methyl methacrylate) (PMMA) denture material. Impact strength was determined using a Charpy-type impact tester. The transverse strength and the flexural modulus were assessed with a three-point bending test. The results were subjected to statistical analysis using a one-way analysis of variance and the Scheffé test for comparison. RESULTS: The impact strength of the microwave-polymerized injection-molded polymer was 6.3 kl/m2, while its flexural strength was 66.2 MPa. These values were lower than those shown by the two compression-molded PMMA-based polymers. The differences were statistically significant. The flexural modulus of the new denture material was 2,832 MPa, which was higher than the conventional heat-polymerized polymer but was comparable to the other microwave-polymerized PMMA-based polymer. The difference in the flexural modulus was statistically significant. CONCLUSION: In terms of the impact and flexural strengths, the new microwave-polymerized, injection-molded, polyurethane-based polymer offered no advantage over the existing heat- and microwave-polymerized PMMA-based denture base polymers. However, it has a rigidity comparable to that of the microwave-polymerized PMMA polymer.     

注塑基托树脂力学性能的检测

目的：对Vertex注塑基托树脂的力学性能进行研究,为临床开展注塑技术提供理论依据。方法：分实验对照两组,实验组为注塑基托树脂,对照组为临床常用热凝基托树脂,按照2种基托树脂的操作步骤要求进行试样制备,对不同基托树脂的试样在材料试验机上测定其冲击强度、弯曲强度、弹性模量和布氏硬度,并对断面进行电子显微分析。结果：注塑基托树脂和热凝基托树脂的冲击强度分别为6.01±0.50KJ/mm^3,7.35±0.93KJ/mm^3,（P〉0.05）,弯曲强度为104.44±3.07MPa,90.19±6.88MPa,（P〈0.05）,弹性模量为2.1±0.2GPa,2.4±0.1Gpa,（P〉0.05）,布氏硬度为12.17±0.93kg/mm^2,19.57±2.89kg/mm^2,（P〈0.05）;两种基托树脂的微观结构有明显不同,注塑基托树脂内部分布着许多粒径颗粒。结论：Vertex注塑基托树脂不仅具有热凝基托树脂的抗冲击能力,还具有良好的抗弯性能,韧性佳,是一种比较好的义齿基托树脂。     

Comparative study of the transverse strength of three denture base materials

OBJECTIVES: Fracture resistance of recently introduced denture base resins has not been compared to traditional denture base materials. This study compared the transverse strength of three denture base materials, namely, Lucitone 199, Triad VLC, and the newly introduced Eclipse. MATERIALS AND METHODS: A total of 30 specimens (50mmx25mmx2.5mm) were fabricated, 10 from each material. The specimens were loaded until failure on an Instron universal testing machine using a three point flexural test. One-way analysis of variance (ANOVA) was used to compare the mean transverse strength between the three materials tested. RESULTS: The transverse strength values showed significant differences between the three denture base materials (P<0.0001). The mean transverse strength and standard deviations (MPa) were as follows: Eclipse 116.13+/-17.7, Lucitone 87.12+/-8.1, and Triad VLC 57.96+/-7.3. CONCLUSIONS: Within the limitations of this study, Eclipse showed the highest transverse strength among the materials tested. Eclipse denture base material may provide a stronger alternative to traditional denture base resins.     

喷砂结合化学处理对软衬材料粘结效果的影响

[摘要]目的：研究喷砂结合化学处理对硅橡胶软衬材料与基托树脂间粘结强度及基托树脂挠曲强度的影响。方法：制备48块30mm×10mm×7．5mm热凝聚甲基丙烯酸甲酯树脂块,每2个树脂块配成一个试件,24个试件随机分为4组,每组6个试件,即：（1）喷砂组：喷嘴与试件轻接触,采用250txm的氧化铝,在0．62MPa压力下喷砂30S;（2）喷砂＋丙酮组：粘结面喷砂处理同前,喷砂后的粘结面浸泡在丙酮溶液中30S;（3）喷砂＋甲基丙烯酸甲酯单体组（后简称单体）：粘结面喷砂处理同上,喷砂后的树脂块粘结面浸泡在甲基丙烯酸甲酯溶液中180S;（4）对照组：表面不处理。每个试件的两树脂块间衬以3mm厚的软衬材料,冷热循环5000次后,置于万能测试机上,以5mm／min的加载速度测试其拉伸粘结强度。另制备24块65mm×10mm×3．3mm长方体树脂块,分组及表面处理同前,涂布软衬材料粘结剂后测试挠曲强度。结果：喷砂组、喷砂＋丙酮组、喷砂＋甲基丙烯酸甲酯组及对照组试件的拉伸粘结强度分别为（1．31±0．45）MPa、（1．75±0．34）MPa、（1．96±0．50）MPa及（0．90±0．17）MPa。喷砂组与对照组间差别无统计学意义（P〉0．05）。喷砂＋丙酮组及喷砂＋单体组的拉伸粘结强度与对照组相比有统计学差异（P〈0．05）;喷砂＋丙酮组与喷砂＋单体组组间比较无统计学差异;四组间挠曲强度均无统计学差异（P〉0．05）。结论：喷砂结合化学处理树脂表面能增强硅橡胶软衬材料与基托树脂间的粘结强度,且对基托树脂挠曲强度没有影响。     

氧化锌晶须填料对义齿基托树脂力学性能的影响

目的：研究添加氧化锌晶须对基托树脂力学性能的影响。方法：将氧化锌晶须按不同的质量百分比加人基托粉中,分为空白对照组、1％、3％、5％、7％等5组。根据ISO标准测试各组的力学性能,并对试样断面进行扫描电镜观察。结果：随着氧化锌晶须用量的增加,复合材料的弯曲强度、弯曲弹性模量、显微维氏硬度呈先升后降的趋势。当氧化锌晶须用量为5％时,以上指标测得值最高,分别为（109．00±2．70）MPa、（3645．30±198．68）MPa、（20．57±0．85）kg／mm^2,树脂基托较对照组弯曲强度提高18．29％、弯曲弹性模量提高16．07％、显微维氏硬度提高29．94％。结论：氧化锌晶须填料显著增强了基托树脂的力学性能。