填料含量对实验双固化树脂水门汀与纤维桩黏结强度的影响

目的:比较二氧化硅填料含量对EAM树脂材料黏结性能的影响,为研制纤维桩树脂核修复材料奠定基础.方法:根据二氧化硅填料在EAM树脂中添加含量的不同分为4组(A组:40%、B组:50%、C组:60%、D组:70%),E组(对照组)LuxaCore-Dual树脂,将各组树脂水门汀在圆筒形模具内分别与纤维桩黏结后,制备成微拉伸试件.用微拉伸试验机进行拉伸,直至试件破坏,并作统计学处理.结果:4个不同二氧化硅无机填料组的微拉伸强度分别为:A组(10.15±2.72)MPa,B组(11.48±2.81)MPa,C组(12.03±2.78)MPa,D组(10.07±2.06)MPa,E组(10.88±2.85)MPa,B、C两组的黏结强度显著高于A、D、E组(P<0.05).结论:60%左右无机填料含量的复合树脂微拉伸黏结强度较为理想.     

两种充填方式对不同光固化复合树脂充填体内孔隙的影响

目的 探讨光固化复合树脂的稠度及充填方式对充填体内孔隙的影响,以期为复合树脂的临床应用提供参考.方法 6位操作者将3种复合树脂(树脂A:Prodigy;树脂B:Tetric EvoCeram;树脂C:Tetric Ceram HB)以器械充填和注射充填的方式充填入模拟I类洞中,将充填体纵向片切成0.5 mm厚的切片,测定切片内孔隙数量;并测试未进行充填的复合树脂内的固有孔隙数量.结果 未充填的复合树脂内固有孔隙数量极少(≤5个);稠度居中的树脂B的孔隙数量[器械充填和注射充填分别为(1137.1±365.0)和(566.1±206.4)个]远多于稠度最大的树脂C[分别为(193.1±35.8)和(156.3±33.0)个]和稠度最小的树脂A[分别为(241.0±116.1)和(195.8±28.7)个,P<0.05).树脂B器械充填的孔隙数量明显多于注射充填(P<0.05),而树脂A和C两种充填方式的孔隙数量差异均无统计学意义(P>0.05).结论 复合树脂充填体内的孔隙基本是在充填过程中形成的,孔隙数量与复合树脂稠度无线性关系;并非所有复合树脂用注射充填均能显著减少充填体内孔隙数量.     

不同处理剂对氧化锆与正畸托槽间黏结强度的影响

目的:比较不同表面处理剂对氧化锆修复体表面与正畸托槽间黏结强度的影响.方法:将50个氧化锆陶瓷试件随机分为5组(n=10),进行喷砂和磷酸处理,A组为对照组;B组以硅烷偶联剂处理;C组以硅烷偶联剂+SE Bond 处理;D组以Z-PrimeTM Plus氧化锆处理剂处理;E组以Z-PrimeTM Plus+SE Bond处理.所有试件均用3M Transbond 光固化树脂黏结剂与右上中切牙的托槽黏结,经24 h、37℃恒水浴后,进行抗剪切强度测试;去除托槽后,对氧化锆表面黏结剂残留指数进行统计.其中,每组1个氧化锆表面处理后用扫描电镜观察其表面形态变化,并对氧化锆及处理剂进行红外光谱分析.采用SPSS17.0软件包对数据进行统计学分析.结果:各组的抗剪切强度分别为A组(3.12±0.84) MPa、B组(1.92±0.83) MPa、C组(5.26±0.80) MPa、D组(6.54±0.98)MPa和E组(9.47±2.11) MPa,各组间差异均具有显著性(P＜0.05).A组和B组残留指数最低,E组最高.D组和E组达到了有效的黏结强度.结论:单独使用氧化锆处理剂能获得有效的黏结强度,但是略偏低.建议Z-PrimeTM Plus+SE Bond处理联合使用,以达到正畸临床所需的较高的黏结强度.     

填料含量和尺寸对复合树脂透明度的影响

目的: 研究填料大小和含量对复合树脂透明度的影响。方法: 每种颗粒大小的填料均以60%、70%、75%和80%的质量分数与基质混合,固化后制备成直径10 mm、厚度1 mm的试件,测定各组试件在标准白板(W)和金属色底板(B)上的色度值。测色系统使用CIELab系统,透明度（TP）根据公式TP=[(L*B-L*W)2+(a*B-a*W)2+(b*B-b*W)2]1/2计算。方差分析颗粒大小和含量对试件透明度的影响,采用SPSS 20.0软件包对均数进行单因素方差分析和HSD检验。结果: 不同直径填料间透明度无显著差异;当填料含量增加时,树脂试件透明度下降。结论: 当填料直径在0.7~1.5 μm范围内变化时,填料含量越高,复合树脂透明度越低。     

根管封闭剂iRoot SP根尖封闭性能评价

目的:比较iRoot SP与AH plus 2种根管封闭剂的根尖封闭效果。方法:选择50颗近期拔除的单根管牙,随机分为2个实验组A、B(每组20颗),2个对照组C、D,C组为阳性对照组(n=5),D组为阴性对照组(n=5)。使用机用Protaper预备所有根管至F2,分别采用iRoot SP根管封闭剂加连续波充填技术(A组)、AH Plus根管封闭剂加连续波热充填技术(B组)充填根管。采用染料渗透法检测根尖微渗漏,对染料渗透的长度进行测量,采用SPSS13.0软件包对数据进行统计学分析。结果:实验组A、实验组B、阳性对照组C、阴性对照组D的微渗透值分别为(1.46±0.21)mm、(1.52±0.22)mm、(10.75±1.28)mm、0 mm。实验组B的微渗漏值高于实验组A,但2组间无显著差异。结论:根管封闭剂iRoot sp的根尖封闭性能与AH Plus相似。     

新型环氧树脂聚合体积收缩率及聚合收缩应力初探

目的 评价新型环氧树脂的聚合体积收缩率和聚合收缩应力,为其临床应用提供参考.方法 选用3种复合树脂材料:A组:丙烯酸酯树脂(XenoⅢ-TPH);B组:丙烯酸酯树脂(Clearfil SE bond-Clearfil Majesty Posterior);C组:新型环氧树脂(FiltekTM silorane adhesive-P90).3组复合树脂经光照固化后,用显微CT测量聚合体积收缩率,用万能材料实验机测试聚合收缩应力.结果 A、B和C组复合树脂的聚合体积收缩率分别为(3.38±0.17)％、(1.95±0.37)％和(1.05％±0.09)％;C组最小,与A、B组的差异均有统计学意义(P ＜0.001).A、B和C组复合树脂的聚合收缩应力分别为(3.04 ±0.26)、(3.49±0.46)和(1.54±0.15) MPa;C组最小,与A、B组的差异均有统计学意义(P＜0.001).结论 新型环氧树脂具有优良的低聚合收缩性能.     

Nd:YAG激光联合不同黏结系统对非龋性硬化牙本质黏结强度的影响

目的:通过微拉伸黏结强度实验,检测Nd:YAG激光联合3种不同黏结系统处理的硬化牙本质与复合树脂的黏结强度。方法:选择15颗硬化牙本质视觉分级为3级以上的面磨损牙,将面硬化牙本质分为面积近似相等的两部分,随机分为A(A1、A2)、B(B1、B2)、C(C1、C2)3组,以1W、10Hz Nd:YAG激光处理硬化牙本质表面后,按照随机数字表,使每颗牙分割的两部分进入不同的处理组,A2、C1联合ScotchbondTM处理,Z350复合树脂充填;A1、B1联合Adper Prompt L-Pop处理,Z350复合树脂充填;B2、C2联合Clearfil SE Bond处理,Z350复合树脂充填。置于37℃生理盐水中24h后,制作微拉伸试件,测试黏结强度,在体视显微镜下观察断裂模式并分类。采用SPSS13.0软件包对试件微拉伸黏结强度值做单因素方差分析。结果:Nd:YAG激光联合3种黏结剂处理后的微拉伸黏结强度分别为ScotchbondTM(A2、C1)处理组(22.96±4.93)MPa,Adper Prompt L-Pop(A1、B1)处理组(18.73±4.71)MPa,Clearfil SE Bond(...     

暂时冠桥材料抗压强度的体外实验研究

目的:对比分析5种暂时冠桥材料的抗压强度。方法:参照标准制作直径4 mm,高6 mm的圆柱形试件50个,甲基丙烯酸酯即自凝树脂(A组)、Integrity(B组)、Luxatemp(C组)、Temphase(D组)、Protem 3 Garan(tE组)5种暂时冠桥材料试件各10个,采用万能材料试验机测定其抗压强度,并进行统计分析。结果:A组抗压强度(210.28±20.07)MPa,显著低于其余4组(P<0.05),E组抗压强度最高(304.55±24.50)MPa,B、C、D组间无统计学差异(P>0.05),B、D、E组间也无显著性差异(P>0.05),C组和E组间抗压强度差异有统计学意义(P<0.05)。结论:5种暂时冠桥材料抗压强度间存在较大差异,Bis-acryl类材料较甲基丙烯酸酯类材料抗压强度高。     

三种充填技术根管封闭能力的研究

目的:利用葡萄糖定量法检测根管微渗漏模型,评价侧向加压充填技术、垂直加压充填技术及固核载体充填技术对根管微渗漏的影响.方法:选取71颗直根管上前牙,根管预备后随机分为7组,A组(14颗)用热牙胶垂直加压加AH Plus充填;B组(8颗)仅用热牙胶垂直加压充填;C组(13颗)用侧方加压加AH Plus充填;D组(8颗)仅用侧方加压充填技术;E组(11颗)用Thermafil加AH Plus充填;F组(7颗)仅用Thermafil充填;G组(10颗)为阴性对照组,用粘蜡充填根管.牙根外表面、根管口及根尖孔处涂二层指甲油.于第7 d、14 d、21 d、28 d用葡萄糖氧化酶法检测从冠方向根方漏出的葡萄糖量.结果:采用重复测量方差分析,发现第7 d、14 d、21 d、28 d A、C组及C、E组微渗漏值有显著性差异(P＜0.001),但A、E组无显著性差异(P＞0.05).各时间点C、D组比较有显著性差异(P＜0.001),但A、B组与E、F组比较无显著性差异(P＞0.05).第7 d、14 d及第21 d、28 d各组内比较无显著性差异(P＞0.05),但各组第14 d与第21 d比较有显著性差异(P＜0.05).结论:侧方加压充填技术封闭根管的能力优于垂直加压充填技术及固核载体充填技术,而后两种充填技术封闭根管的能力相当.     

硅涂层溶胶-凝胶法制备过程中碳酸氢钠促凝对氧化锆陶瓷粘接强度的影响

目的 探讨硅涂层溶胶-凝胶法制备过程中碳酸氢钠(NaHCO3)促凝对氧化锆陶瓷粘接强度的影响,为溶胶-凝胶法制备硅涂层的临床应用提供实验依据.方法 对比掺杂质量分数为1％、3％、5％、7％、10％的NaHCO3后氧化硅溶胶的胶凝时间,选取胶凝时间最短者进行后续实验.制作5组氧化锆-复合树脂粘接试件,A组:氧化铝喷砂;B组:氧化铝喷砂+摩擦化学法制备硅涂层+硅烷化;C组:氧化铝喷砂+溶胶-凝胶法制备硅涂层+硅烷化;D组:氧化铝喷砂+溶胶-凝胶法制备硅涂层过程中使用NaHCO3促凝+硅烷化;E组:氧化铝喷砂+氧化锆涂底剂处理.测试5组试件抗剪切强度,即粘接强度.结果 掺杂10％的NaHCO3后氧化硅溶胶的胶凝时间最短.B、C、D、E组粘接强度[分别为(10.24±2.78)、(7.36±1.59)、(9.79±2.07)、(8.39 ±0.49) MPa]均比A组[(4.12±0.52) MPa]显著提高,C和D组间差异无统计学意义(P＞0.01).结论 掺杂NaHCO3后氧化硅溶胶的胶凝时间缩短,涂层制备过程中使用NaHCO3促凝不影响氧化锆陶瓷的粘接强度.     

Evaluation of flowable resin composite surfaces eroded by acidic and alcoholic drinks

The purpose of this study was to evaluate the morphological changes of the surfaces of flowable resins eroded by orange juice and alcohol drinks. The tested products were Beautifil Flow BF02 and BF10, Clearfil Majesty LV, Filtek Supreme XT Flowable Restorative, Unifil LoFlo Plus and Filtek Supreme. Filler percentages of flowable resins were calculated after the latter were incinerated at 750 degrees C. Specimens were shaped into a disk form with a diameter of 10 mm and a thickness of 1 mm. Morphological changes were evaluated for the following types of flowable resin surfaces: polished surface, surfaces eroded by 100% orange juice, wine and whisky. Filler percentages of the tested flowable resins ranged between 42 and 78%. Surface degradation was observed for the specimens immersed in acidic and alcoholic drinks, and it was thought that the lower the filler percentage, the greater was the surface degradation. Decomposition of the matrix resin and fallout of the fillers were observed in flowable resins that eroded with acidic and alcoholic drinks.     

Effect of temperature on unpolymerized composite resin film thickness

STATEMENT OF PROBLEM: Room temperature (RT) composite resins are viscous, and this condition may affect the ability of the material to flow and adapt to preparation walls. PURPOSE: The purpose of this study was to compare the film thickness of a variety of commercial composite resins heated prior to light polymerization. The film thickness of these heated materials was also compared to those of flowable products at RT. MATERIAL AND METHODS: Five flowable and 7 conventional composite resins were used: 2 microfills, a nanofill hybrid, 2 submicron hybrids, a trimodal hybrid, and a packable. Composite resin (0.05 mL) was pressed between 2 Mylar-covered glass plates (15 kg) for 180 seconds, light polymerized, and the thickness measured using a micrometer. When comparing conventional composite resin heated to 54 degrees C or 60 degrees C, the RT value was control, while the RT flowable values were control when compared to heated composite resin. (n=5/group). Data were analyzed using 1- and 2-way analysis of variance and the Tukey-Kramer post hoc test (alpha=.05). Correlation of filler content to flow potential was evaluated. Scanning electron microscopic analysis of polymerized specimens was characterized by filler size and shape. RESULTS: Room temperature conventional composite resin values varied in film thickness. Not all preheated products reduced in thickness. Thickness of the nanofill did not reduce, and one of the submicron hybrids reduced the greatest. No correlation existed between composite resin classification, filler content or shape, and film thickness. No difference in thickness existed between composite resins preheated to 54 degrees C and 60 degrees C. Room temperature and preheated conventional composite resin provided film thickness greater than that of flowable materials. CONCLUSIONS: Preheating conventional composite resin yields lower film thickness for some products, but flow cannot be attributed to composite resin classification, filler content, or shape. Preheated composite resin thickness was greater than that of all flowables.     

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目的研究无机填料含量对流动树脂的挠曲强度和压缩强度的影响。方法于2012年4月在北京大学口腔医学院口腔材料研究室测定Clearfil Flow、Filtek Flow、DenFil Flow、Filtek Z250复合树脂无机填料的质量分数、挠曲强度和压缩强度。结果流动树脂中无机填料的质量分数与其挠曲强度的变化顺序相一致,由小到大依次为DenFil Flow、Filtek Flow、Clearfil Flow、Filtek Z250。DenFil Flow与其余3组间挠曲强度差异均有统计学意义（P〈0.05）,Filtek Flow与Clearfil Flow、Filtek Z250间挠曲强度差异亦均有统计学意义（P〈0.05）,但Clearfil Flow与Filtek Z250间挠曲强度差异无统计学意义（P〉0.05）。4种材料压缩强度差异均无统计学意义（P〉0.05）。结论高填料型流动树脂的挠曲强度远高于普通流动树脂,并且可达到我国医药行业标准规定面修复材料的要求;压缩强度与前后牙通用树脂相近,可以满足临床应用的需要。     

粘接托槽牙面流动复合树脂封闭层抗磨耗的实验研究

目的 观察流动复合树脂表面封闭层的耐磨性及其在提高粘接托槽牙面抗磨耗性能方面的作用.方法 40颗离体前磨牙随机分为未脱矿组、自酸蚀组、直接脱矿组、表面封闭后脱矿组,每组10颗.恒温水浴及冷热循环后,直接脱矿组、表面封闭后脱矿组置0.1M的乳酸胶脱矿48h,将4组离体前磨牙制成试件,牙刷磨耗31000次,扫描电镜观察颊面牙釉质结构及封闭层改变情况.结果 磨耗后,未脱矿组牙面未见刷痕;自酸蚀组、直接脱矿组牙面刷痕较深;表面封闭后脱矿组表面封闭层仍保留在牙面;流动复合树脂表面封闭层磨耗前、后的平均厚度（μm）是167.58±6.38、140.93±7.88,平均磨耗量（μm）是26.85±4.48,经配对t检验,磨耗前、后流动复合树脂表面封闭层厚度差异有统计学意义.结论 牙刷磨耗可磨去部分流动复合树脂,但不能去除流动复合树脂表面封闭层;表面封闭法能够提高粘接托槽牙面抗磨耗性能.     

Fracture resistance of the buccal cusps of root filled maxillary premolar teeth restored with various techniques

AIM: To compare the cusp fracture resistance of teeth restored with composite resins and two post systems. METHODOLOGY: Eighty extracted single-rooted human maxillary premolars were randomly assigned to eight groups (n = 10). Group 1 (control) did not receive any preparation. From groups 2 to 8, the teeth were root filled and mesio-occluso-distal (MOD) cavities were prepared. Group 2 remained unrestored. Group 3 was restored with packable resin composite using a single-step adhesive. Group 4 was restored with packable resin composite using a single-step adhesive and a thin layer of flowable resin composite. Group 5 was restored with packable resin composite using a total-etch two-step adhesive. Group 6 was restored with ormocer resin composite using a total-etch two-step adhesive. Group 7 was restored with an endodontic glass fibre post and hybrid resin composite using a total-etch two-step adhesive. Group 8 was restored with an endodontic zirconium post and hybrid resin composite using a total-etch two-step adhesive. The teeth were then mounted in a universal testing machine, the buccal cusp loaded (30 degrees ) until fracture, and the data analysed statistically. RESULTS: Group 1 had the greatest fracture resistance, and group 2 the poorest. Groups 5-8 had significantly greater (P < 0.05) fracture resistance than groups 3 and 4. No significant differences were found between groups 3 and 4, or amongst groups 5-8 (P > 0.05). CONCLUSIONS: For root filled maxillary premolars with MOD cavities, adhesive resin composite restorations, with and without glass and zirconium posts, increased the fracture resistance of the buccal cuSPS. A total-etch two-step adhesive increased significantly fracture resistance more than a one-step adhesive. For the one-step adhesive, an additional layer of flowable resin composite did not enhance fracture resistance.     

家庭漂白剂对复合树脂表面粗糙度、显微硬度的影响

目的:评价10%过氧化脲家庭漂白剂对直接和间接复合树脂材料表面粗糙度和显微硬度的影响。方法:实验选用2种直接复合树脂材料(Filtek Z350,Clearfil Majesty Esthetic)和2种间接复合树脂材料(Ceramage,Adoro SR)。每种树脂材料在粗糙度和显微硬度试验中分别制作20个盘形试样(直径10 mm、厚1.0 mm),随机分为10%过氧化脲漂白组和去离子水对照组(n=10)。漂白凝胶处理漂白组试样每天使用8 h,共2周。测量树脂试样漂白处理前、后表面粗糙度和显微硬度值。结果:10%过氧化脲漂白剂处理前后,树脂材料表面粗糙度变化无统计学差异(除外Clearfil Majesty Esthetic)。4种树脂材料漂白前后试样的显微硬度值变化不大,且没有统计学差异。结论:10%过氧化脲漂白剂没有改变树脂材料的显微硬度,但树脂材料表面粗糙度的改变取决于树脂材料的类型。     

Relative wear of flowable and highly filled composite

STATEMENT OF PROBLEM: By decreasing the proportion of filler, flowable composites are easy to adapt to small cavity preparations. However, the wear resistance of flowable composites is a clinical concern, as improved wear has been related to increased filler percentage. PURPOSE: The purpose of this study was to compare wear for flowable composites and comparable heavily filled materials. MATERIAL AND METHODS: Wear by attrition and abrasion (microm) of microfilled flowable (Heliomolar Flow) and heavily filled microfill (Heliomolar HB) was measured and compared to a microhybrid flowable (Tetric Flow) and a heavily filled microhybrid (Tetric HB). There were 5 specimens, 2 mm thick and 15 mm in diameter, in each group. The Oregon Health Sciences University oral wear simulator was used to produce abrasive wear and attrition for all specimens. Abrasion and attrition of the substrates were measured using a profilometer. Data were subjected to a 3-way analysis of variance for the 3 main factors: composite type, filler load, and wear type (alpha=.05) RESULTS: Composite wear rates were significantly influenced (P <.01) by both the type of wear and the filler amount. Abrasive wear occurred less than wear by attrition, and the heavily filled composites experienced less wear than the flowable composites. CONCLUSIONS: Results of this in vitro study suggest that highly filled microhybrid composites may have greater wear resistance for contact-supporting posterior restorations. However, in small noncontact restorations where longevity may be dictated by abrasion, flowable microfilled resins may be adequate.     

Comparison of the wear and flexural characteristics of flowable resin composites for posterior lesions

Abstract

Objectives. To determine the localized wear and flexural properties of flowable resin composites for posterior lesions compared with universal resin composites produced by the same manufacturers. Methods. Ten specimens of each of three flowable resins, G-ænial Universal Flo, G-ænial Flo and Clearfil Majesty Flow, and the corresponding resin composite materials, Kalore and Clearfil Majesty Esthetics, were prepared in custom fixtures and subjected to 400,000 wear machine cycles to simulate localized wear. The total maximum depth and volume loss of the wear facets was calculated for each specimen using a profilometer. A three-point bending test was performed to determine the flexural strength, modulus of elasticity and resilience. Values were statistically compared using one-way analysis of variance (ANOVA) followed by Tukey's Honestly Significant Difference (HSD) test. Results. The wear depth ranged from 58.3–126.9 m and the volumetric loss ranged from 0.019–0.049 mm³, with significant differences observed between restorative materials. The wear depth of G-ænial Universal Flo was significantly smaller than those of the other resin composites tested. The flexural strengths and elastic modulus ranged from 90.5–135.1 MPa and from 4.7–7.6 GPa, respectively. A significantly greater flexural strength and higher elastic modulus was found for G-ænial Universal Flo than the other composites. Conclusions. The wear and mechanical properties of the flowable resin composites tested suggested improved performance compared with universal resin composites.     

Effect of eccentric load cycling on microleakage of Class V flowable and packable composite resin restorations.

Class V composite restorations are subject to the stresses that induce non-carious cervical lesions. This study evaluated the effect of eccentric oblique load on microleakage of restorations. Class V cavities were randomly prepared on the buccal surfaces of 40 recently extracted premolars and restored with composite resin according to manufacturers' directions. Teeth were randomly assigned to one of four treatment groups with 10 teeth per group: (1) flowable resin (Revolution) without load cycling; (2) packable resin (Prodigy Condensable) without load cycling; (3) flowable resin with load cycling (200,000 cycles) and (4) packable resin with load cycling (200,000 cycles). All teeth were then immersed in 2% methylene blue solution for 24 hours after thermocycling (500 cycles). Dye penetration was measured (scores 0-3). The results indicated that adding load cycling significantly increased microleakage (p < 0.05). No significant differences in microleakage were observed for flowable resin vs packable resin. Gingival margins had significantly more microleakage (p < 0.05) than occlusal margins.     

Surface textures of composite resins after combined wear test simulating both occlusal wear and brushing wear

The purpose of this study was to investigate the relation between the texture of worn surfaces of composite resins and the maximum wear depth. Three types of composite resins were investigated: a hybrid composite resin consisting of irregular-shaped inorganic filler particles (APX); a composite resin which contained small, irregular-shaped, inorganic filler particles and large organic composite filler particles (SRE); and another which contained spherical inorganic filler particles and large organic composite filler (SDX). Surface profile measurement and elemental analysis were carried out on the worn surfaces of these three composite resins using an electron probe microanalyzer (EPMA). For the composite resin which exhibited the largest maximum wear depth, its surface texture was slightly rough with fine pores and grooves. For the composite resin with lowest maximum wear depth, it had a smooth worn surface due to the large organic composite filler being abraded during the combined wear test.