光固化复合树脂修补活髓牙缺损几种垫底材料的比较

为了选择良好的垫底材料用于活髓前牙缺损的光固化复合树脂的修复，本研究采用高级牙用羧聚陶瓷，丁香油粘固粉，磷酸锌粘固粉，氢氧化钙糊剂作为垫底材料，用于前牙牙本质浅层及牙本质深层损坏的光固化树脂修复。比较以上４种材料在保护牙髓，以及充填体牢固程度和颜色等单方面的差异，结果证明高级牙用羧聚陶瓷明显优于其他材料，是目前较为到时候的前牙光固化树脂修复的垫底材料。     

4种光固化复合树脂治疗楔形缺损的临床疗效比较

４种光固化复合树脂治疗楔形缺损的临床疗效比较高娟，张成飞，林琼光北京医科大学口腔医学院（１００Ｏ８１）光固化复合树脂是目前口腔科常用的充填、修复材料。由于它的色泽美观，具有一定的抗压强度，因此在临床工作中起着越来越重要的作用，为了进一步提高修复的成功...     

四种光固化复合树脂修复物边缘微渗漏的体外试验研究

目的:比较4种光固化充填材料修复体边缘微渗漏.方法:在新鲜拔除的40个人前磨牙的颊侧牙颈部制洞,将牙齿分为4组,每组10个.分别充填4种修复材料Restorative Z-350、Z-100(3M),Chafisma(Dentsply),Durafill(Kulzer)经冷热交替试验(4～60℃,循环600次),采用10 g/L碱性品红染料渗入法,在体视显微镜下观察修复体与牙体洞壁间边缘微渗漏.结果:4种材料中3M-Z350微渗漏最小,Durafill最大,DurafiU与其他3组相比有显著性差异(P＜0.05);3M-Z100和Chrisma无显著性差异(P＞0.05);3MZ350与其他3组相比有显著性差异(P＜0.01).结论:3M-Z350可能是临床修复牙体缺损的较好材料.     

3种光固化灯照射不同颜色复合树脂的固化深度比较

目的探讨LED光固化灯与传统卤素灯对不同颜色复合树脂的固化深度的影响。方法选取FiltekTMZ350和Premisa两种树脂,FiltekTMZ350组选取A1B,A2B,A3B 3种颜色,Premisa组选取A1E,A2E,A3E 3种颜色,自制实验模具,将树脂填入模具。每种颜色树脂制作60例试件,分为3组,每组20例,分别用2种新型LED光固化灯Demi LED和Bluephase20i与传统卤素灯ALC-50在标准条件下照射试件,检测固化深度。结果 Demi LED光照10 s、Bluephase20i光照10 s树脂的固化深度均达到3 mm,与传统的卤素光固化灯ALC-50光照40 s有显著差异,但前两者之间无显著差异。Premisa树脂中2种LED照射组A1E,A2E和A3E 3种颜色之间固化深度有统计学差异。结论在相同条件下,Demi LED和Bluephase20i照射10 s树脂固化深度大于传统卤素灯ALC-50照射同一树脂40 s,适合临床应用。树脂颜色的加深对树脂固化深度有影响。     

Comparing the effectiveness of self-curing and light curing in polymerization of dual-cured core buildup materials

BackgroundThe authors conducted an in vitro study to investigate the influence of various curing protocols on subsurface microhardness of dual-cured resin-based composites.MethodsThe authors filled molds with four dual-cured resin-based composite core buildup materials: Clearfil DC Core Automix (Kuraray, Tokyo), Core?X flow (Dentsply DeTrey, Konstanz, Germany), LuxaCore Z-Dual (DMG, Hamburg, Germany) and MultiCore Flow (Ivoclar Vivadent, Schaan, Liechtenstein). They light cured the specimens for 20 or 60 seconds immediately after the filling procedure (time delay, 0 seconds) or after a 90-or 300-second delay. Self-cured specimens served as controls. The authors tested 15 specimens in each group. They measured the Knoop hardness number (KHN) at depths of 0.25, 2.00 and 5.50 millimeters two weeks after the initiation of polymerization.ResultsLight curing with Core?X flow, LuxaCore Z-Dual and MultiCore Flow did not result in significantly higher KHNs at any depth compared with those for the self-cured control specimens. For Clearfil DC Core Automix, immediate light curing for 60 seconds resulted in significantly higher KHNs than those for self-cured specimens only at a depth of 5.50 mm (P = .0171). The study results showed no significant differences in KHN at different depths for Core?X flow specimens, independent of the curing protocol. All other materials exhibited a significant decrease in KHN at increased depths in only one of the six light-cured groups.ConclusionThe results of this study show that photoactivation of the tested dual-cured materials provided no clinically relevant benefit compared with self-curing with regard to the degree of microhardness.Clinical ImplicationsThe dominant self-curing mode allows placement of the tested buildup materials in areas inaccessible to a curing light.     

The effect of curing with plasma light on the shrinkage of dental restorative materials

Commercially available light activated dental composites were used in this study to compare the shrinkage following curing with plasma light (Apollo95E, DMDS) and a convention halogen dental curing light (Prismetics Lite II, Dentsply). Polymerization shrinkage was determined by measuring the strain in one dimension by means of a contacting transducer. The percentage linear shrinkage were: Spectrum H = 1.84 + 0.31, P = 1.49 + 0.35*; Ana aesthetic H = 2.04 + 0.38, P = 1.85 + 0.27; Esthet.x H = 1.66 + 0.28, P = 1.69 + 0.25; Dyract AP H = 2.39 + 0.33, P = 2.18 + 0.35*; Apollo Restore H = 1.88 + 0.36, P = 1.42 + 0.33*; Surefil H = 0.88 + 0.28, P = 0.99 + 0.30 where * = significantly different, t-test at P < 0.05. The results suggested that there was less shrinkage when curing some, but not all, materials using the plasma light, although this could be attributed to a reduced level of polymerization.     

Cytotoxicity of composite resins polymerized with different curing methods

AIM: To compare the relative cytotoxicity of resin-based composite materials polymerized with three different curing methods on L 929 cells over a period of 1 week. METHODOLOGY: Ten discs of each material (Flowline, P 60 and Z 250) were cured from one side with either standard cure (Optilux 401), soft-start cure (Elipar Free Light) or fast cure (Hilux Ultra Plus). Then the samples were aged for 1, 2, 3, 5 and 7 days in Dulbecco's Modified Eagle Medium/Ham's F12 (DMEM/F12). After each ageing interval, cytotoxicity of the extracts to cultured fibroblasts (L 929) was measured by MTT assay. The degree of cytotoxicity for each sample was determined according to the reference value represented by the cells with a pure culture medium. Statistical significance was determined by one-way analysis of variance (anova), followed by the Student's Newman-Keuls test. RESULTS: Exposure of L 929 cells to the test materials resulted in a high survival fraction at 1 and 7 days. Flowline specimens, either cured with Optilux 401 or Elipar Free Light, had no toxic effect on the cells, whereas the other groups were moderately toxic on the 2-day interval. All experimental groups presented lower cell viability than the control at the 3- and 5-day intervals. CONCLUSIONS: The composite resins used in this study were cytotoxic after 48 h pre-incubation, but this toxicity disappeared after pre-incubation in a biological medium for 7 days. Curing did not have a significant effect on the cytotoxicity of the composite materials tested.     

Influence of light intensity from different curing units upon composite temperature rise

The unavoidable consequence of composite resin photopolymerization is temperature rise in tooth tissue. The temperature rise depends not only on the illumination time, but also on light intensity, distance of light guide tip from composite resin surface, composition and shade of composite resin and composite thickness. The most commonly used units for polymerization today are halogen curing units, which emit a large spectrum of wavelengths. A proportion of the spectrum has no influence on degree of conversion and therefore causes unnecessary temperature rise. Units based on light source - blue light emitting diodes (LED), as an alternative for halogen curing units, have been introduced in clinical practice. The aim of this study was to show the influence of the light intensity of curing units Elipar Trilight, Astralis 7 and Lux-o-Max unit on temperature rise in composite resin sample of Tetric Ceram. The temperature was measurement with Metex M-3850 D multimeter with the tip of temperature probe put into unpolymerized composite resin sample 1 mm depth. The highest temperature rise was recorded with standard curing mode for Elipar Trilight halogen curing unit (13.3 +/- 1.21 degrees C after 40 s illumination), while the lowest temperature rise was recorded for the Lux-o-Max unit based on LED technology (5.2 +/- 1.92 degrees C after 40 s illumination).     

五种光固化复合树脂充填材料的机械强度比较

目的:比较Tetri cRCeram HB、Ceram.XTMduo-牙釉质色、Ceram.XTMduo-牙本质色、Qu ixF ilTM和Esthet.XTM五种光固化复合树脂的挠曲强度、压缩强度、固化深度和显微硬度,为临床操作中材料的选择提供依据。方法:根据ISO 4049:2000,采用电子式万能试验机测试材料的挠曲强度、压缩强度;固化深度测试仪测试材料的固化深度;动态超显微硬度仪测试材料的硬度。测试结果用SPSS软件进行方差分析和posthoc Tukey HSD检验,α=0.05。结果:挠曲强度比较,Esthet.XTM为(121.3250±17.1491)MPa,较其他材料大,其他材料之间无统计学差异。压缩强度比较,Ceram.XTMduo-牙釉质色(313.3800±36.8904)MPa和Esthet.XTM(338.4200±25.0402)MPa较其他3种大,两者之间无统计学差别。固化深度比较,Ceram.XTMduo-牙釉质色(2.9280±0.1158)mm和Qu ix.F ilTM(2.8160±0.2027)mm较其他3种大,两者间无统计学差异。硬度比较,Tetric RCeram HB(73.1408±20.8823)GPa与Qu ix F ilTM(67.9288±17.6141)GPa较其他3种大,两者之间也无统计学差异。综合各方面指标,Esthet.XTM的机械性能较高。结论:所测试各种复合树脂的机械性能不同,各有优缺点,在临床操作中应当根据需要选择具有不同机械性能的材料。     

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光固化复合树脂通过光聚合进行固化,已有多种光固化灯用于口腔材料的光固化。随着发光二极管（LED）技术的迅速发展,LED光固化灯已逐渐成为多数临床应用的标准设备。本文就LED光固化灯的物理学特性、口腔临床应用发展、导光管及其消毒作一综述,分析未来发展趋势,为其在口腔临床应用提供参考依据。     

金属表面处理与冠桥树脂粘结效果的观察

对冠桥树脂及其粘结剂与金属表面的粘结性能分别进行了：①单纯砂纸打磨，②砂纸打磨后喷砂，③喷砂后20％盐酸中150v／250mA阳极化三种不同处理方法分别进行了实验观察。结果显示，在一般情况下喷砂处理即可达到较高的粘结强度。此外经过一年使用本材料的临床观察，色泽稳定、与金属冠面粘结性能良好、对口腔组织无刺激性、无徽漏、硬度高，耐磨性好。     

牙科发光二极管光固化灯和普通卤光灯临床应用效果评价

目的：了解牙科发光二极管光固化灯应用于患牙备洞树脂充填固化后的临床效果.方法：按纳入标准选择门诊就诊患者患牙160颗,龋损和楔状缺损各80颗.随机分为试验组和对照组,使用牙科树脂材料充填后,实验组应用发光二极管光固化灯固化20sec,对照组应用普通卤光灯固化40sec,打磨抛光;12个月后复诊,评价.结果：楔状缺损实验组有1颗充填物脱落,1颗边缘密合度缺陷,1颗边缘着色,成功率92.1%;对照组有1颗充填物脱落,1颗边缘着色,成功率94.4%;无统计学意义上的差异（P＞0.05）.龋损实验组有3例边缘密合度缺陷,2颗边缘着色,成功率87.5%;对照组有2颗边缘密合度缺陷,1颗边缘着色,成功率91.7%;无统计学意义上的差异（P＞0.05）.结论：发光二极管光固化灯与普通卤光灯临床效果没有区别,但操作时间更短,使用更为轻巧.     

Effect of delayed light curing of a resin composite on marginal integrity in cylindrical dentine cavities

The effect of delayed light curing of resin composite on marginal adaptation has been examined by measuring the wall-to-wall polymerization contraction gap when using a commercial resin composite together with experimental dentine bonding systems to restore cylindrical preparations in dentine. Morphological changes in dentine during dentine bonding procedures were observed using a scanning electron microscope. In a previous report, the contraction gap width for a resin composite increased when irradiation of the resin system was delayed, despite the use of a dentine bonding system considered to be ‘contraction’ gap free. Such deterioration in marginal adaptation was minimized by use of an experimental dentine primer, 40% erythritol methacrylate aqueous solution (EM), followed by the use of a commercial dual- or autocured dentine bonding agent. Under scanning electron microscopy, the dentine surface microstructure became unclear after EM priming, and a polymer film was detected after polymerization of the dual-cured dentine bonding agent. The hydrogelled primer and the formation of a polymer network on the dentine surface may prevent the flow of fluid from the pulp through the dentine tubules, and maintain marginal integrity if there is delay in light curing of light-activated resin composite systems.