人工老化对全瓷贴面树脂粘结剂颜色稳定性的影响

目的研究人工老化对全瓷贴面树脂粘结剂颜色的影响。方法用VITABLOCS MARK-Ⅱ制作厚度为1 mm的试件40个,随机分为4组(n=10)。分别采用Superbond C&B化学固化粘结剂、VariolinkⅡ双重固化粘结剂、RelyX Veneer光固化粘结剂和Filtek Z350 Flow流动复合树脂进行粘结,4种粘结剂颜色均为A3。在黑暗环境下保持24 h后用色度计测量色度值。再将各组试件置于紫外光老化实验箱中进行老化后再次测量其色度值,比较4种树脂粘结剂的颜色稳定性。选定ΔE<3为临床可接受范围。结果 Superbond C&B、VariolinkⅡ、RelyX Veneer和Filtek Z350 Flow粘结剂的ΔE分别为2.32±0.21,2.50±0.29,0.68±0.24和0.79±0.20。其中Superbond C&B和VariolinkⅡ的ΔE高于其他组(P<0.05)。Superbond C&B和VariolinkⅡ之间,RelyX Veneer和Filtek Z350 Flow之间无显著性差异(P>0.05)。结论 4种树脂粘结剂在人工老化后均出现不同程度的颜色变化,但这种颜色改变程度在临床美学要求范围内。RelyX Veneer和Filtek Z350 Flow树脂具有较好的颜色稳定性。     

粘接间隙对变色牙全瓷贴面颜色效果的影响

目的 比较不同粘接间隙的全瓷贴面与理想色之间的色泽匹配度,为变色牙行全瓷贴面修复提供参考依据.方法 采用三维技术精确设计4种粘接间隙(0.05 mm,0.15 mm,0.30 mm,0.50 mm),制成0.5 mm厚度A2色低透明度铸瓷贴面模型各10片.用ND9牙本质代型材料模拟变色牙,漂白色试色糊剂代替树脂粘接剂,...     

粘接剂与基牙颜色对三种CAD/CAM全瓷贴面颜色的影响

目的 评价全瓷修复体材料、基牙颜色及粘接剂对CAD/CAM椅旁系统修复体色泽的影响.方法 选择三种CAD/CAM椅旁全瓷修复材料：IPS Empress CAD、IPS E.max CAD和Cerec Blocs.每种材料各制备出厚度为（0.8±0.02）mm的试样18片,随机分为3组,以聚四氟乙烯为模板,制作15mm×13mm×2mm的3种颜色的基牙树脂试件,分别采用2种颜色（Transparent与Bleach）的粘接剂粘接瓷片与基牙树脂,每组3片,静压2min,光照20s,使用台式分光亮度仪测量三种全瓷材料的透光度,比较粘接前后修复体的L＊、a＊、b＊值,并计算粘接前后的色差△E.结果 不管基牙颜色或瓷片种类如何,透明色粘接剂组粘接前后的色差△E皆显著大于漂白色粘接剂组.Cerec Blocs组粘接前后的色差最大,E.max组的色差最小,而Empress则介于两者之间.结论 三种全瓷材料中,Empress的透光度最佳,Cerec Blocs陶瓷材料更易受基牙颜色与粘接剂的影响.透明色粘接剂对基牙树脂与瓷贴面复合体的颜色影响大于漂白色粘接剂.     

铸瓷贴面厚度对修复体颜色匹配性的影响

目的:分析瓷材料厚度变化对瓷贴面修复体颜色匹配性的影响。方法:选用36颗树脂人工牙按临床要求进行贴面牙体预备。制作二硅酸锂热压铸陶瓷贴面(HT和LT瓷块),按修复体中1/3的厚度分为0.50 mm、0.75 mm和1.00 mm组(n=6)。使用树脂粘接剂将瓷贴面粘接于预备后的树脂人工牙上。比色仪测量瓷贴面试样颈部、中部和切端区域的色度参数。计算瓷贴面试样与A2色标(Vita Classical比色板)的色差值△E。结果:3种厚度瓷贴面修复体与A2色标的色差值范围2.17~6.60,其中0.75 mm和1.0 mm组HT瓷贴面试样在颈部和中部与A2色标的色差值小于3.3。双因素方差分析表明瓷材料厚度和测色部位显著影响瓷贴面试样与A2色标的色差值(P< 0.001)。结论:瓷材料厚度变化影响瓷贴面修复体的颜色参数。随瓷材料厚度增加,LT瓷贴面亮度降低色彩饱和度增加,而HT瓷贴面亮度增加色彩饱和度降低。     

基牙颜色与粘接剂类型对超薄瓷贴面修复体颜色的影响

目的:研究基牙颜色和粘接剂类型对超薄瓷贴面修复体颜色的影响.方法:使用2类6种粘接剂进行研究,酸蚀-冲洗型3种:Ivoclar Syntac?heliobond(SH)、3M AdperTMSingle Bond 2(SB2)、Bisco One-Step Plus(OSP);通用型3种:Ivoclar Tet-ric...     

瓷贴面修复四环素牙后颜色稳定性的随机对照研究

目的 评价不同厚度瓷贴面及不同固化类型的树脂粘接剂修复四环素牙一段时间后的颜色稳定性.方法 临床选择符合贴面修复适应证、需要制作包括2颗上颌中切牙在内的四环素牙患者20名,按照瓷贴面厚度0.5 mm或0.75 mm,采用同一种粘接剂的光固化或双固化的方式随机分为4组,完成相应的上颌中切牙瓷贴面修复.用比色仪测量瓷贴面粘...     

铝瓷核烧结长石质瓷前后贴面颜色的变化

目的：考察Procera铝瓷核表面烧结长石质饰面瓷形成双层瓷贴面前后的颜色变化。方法：应用自凝树脂和着色材料制作模仿变色牙灰色的底质，15个氧化铝圆盘随机分为3个组，每组5个标本，分别 烧A1、A2、B43种颜色的长石质陶瓷，应用美能达CR－321色度仪测量底质上氧化铝圆盘烧结长石质饰面前后 的颜色变化，并以白色背景作为对照。结果：烧结长石质饰面瓷后颜色变化差异存在显著性（P＜0．01），加入A1、A2、B4饰面陶瓷后，△E从A1（2．311）、A2（4．313）到B4（8．778）逐渐增加；△L^*从A1（－1．530）、A2（－3．369）到B4（－3．358）逐渐减小；△b从A1（－1．440）、A2（2．198）到B4（7．955）逐渐增加，颜色变化方向与已往报道一致并受背景颜色的影响。结论：可通过在氧化铝核表面烧结长石质饰面瓷来调整瓷 贴面颜色。     

IPS-Empress Ⅱ铸瓷贴面与Targis树脂贴面的临床疗效比较

目的：比较IPS-Empress Ⅱ铸瓷贴面和Targis树脂贴面修复后3年的临床疗效。方法：选取14名患者制作IPS-Empress Ⅱ铸瓷贴面50个,22名患者制作Targis树脂贴面86个。使用改良CDA/Ryge标准对两种贴面修复后三年的颜色匹配、表面质地、边缘着色和完整性等指标进行评价,比较两者的临床成功率和患者满意度。结果：IPSEmpress II铸瓷贴面3年存留率为94.0%,Targis贴面为90.7%;IPS-Empress Ⅱ铸瓷贴面修复患者主观满意度为92.0%,Targis贴面为88.4%;两者在颜色匹配、边缘着色和边缘完整性方面没有明显差异;在表面质地上IPS-Empress Ⅱ铸瓷贴面优于Targis树脂贴面。结论：IPS-Empress Ⅱ铸瓷贴面和Targis树脂贴面均是良好的修复系统,IPS-Empress Ⅱ铸瓷贴面的表面性能优于Targis树脂贴面。     

7种树脂基充填材料的颜色性能评价

目的探讨紫外线照射对光固化树脂基充填材料颜色及不透光度的影响。方法采用7种光固化树脂基充填材料（Aelite Flo、Filtek Z350 Flowable、Clearfil AP-X、Dyract AP、Z100、Durafill VS、Filtek Z350 Universal）各制作5个树脂试件。用色度计测量颜色参数L*、a*、b*（CIE 1976 L*a*b*系统）及Y刺激值（CIE 1931 XYZ系统）,然后将7种试件经紫外线照射老化8、16、24 h后再次测量颜色参数及Y刺激值,计算7种试件经紫外线照射后的色差及不透光度。结果紫外线照射后试件均发生了一定程度的颜色变化,色差变化范围从8 h的1.85~3.21到24 h时的2.88~4.55;不透光度出现了一定程度的升高,变化范围从照射前的0.75~0.82到照射24 h后的0.80~0.98。其中,Z100和Filtek Z350 Flowable试件的色差值较大,Filtek Z350 Universal试件的不透光度较大。结论紫外线老化能够引起树脂基充填材料发生颜色改变和不透光度升高,不同产品的颜色稳定性有所差异。     

Colour stability and opacity of resin cements and flowable composites for ceramic veneer luting after accelerated ageing

Objectives

Colour changes of the luting material can become clinically visible affecting the aesthetic appearance of thin ceramic laminates. The aim of this in vitro study was to evaluate the colour stability and opacity of light- and dual-cured resin cements and flowable composites after accelerated ageing.

Methods

The luting agents were bonded (0.2 mm thick) to ceramic disks (0.75 mm thick) built with the pressed-ceramic IPS Aesthetic Empress (n = 7). Colour measurements were determined using a FTIR spectrophotometer before and after accelerated ageing in a weathering machine with a total energy of 150 kJ. Changes in colour (ΔE) and opacity (ΔO) were obtained using the CIE L*a*b* system. The results were submitted to one-way ANOVA, Tukey HSD test and Student's t test (α = 5%).

Results

All the materials showed significant changes in colour and opacity. The ΔE of the materials ranged from 0.41 to 2.40. The highest colour changes were attributed to RelyX ARC and AllCem, whilst lower changes were found in Variolink Veneer, Tetric Flow and Filtek Z350 Flow. The opacity of the materials ranged from −0.01 to 1.16 and its variation was not significant only for Opallis Flow and RelyX ARC.

Conclusions

The accelerated ageing led to colour changes in all the evaluated materials, although they were considered clinically acceptable (ΔE < 3). Amongst the dual-cured resin cements, Variolink II demonstrated the highest colour stability. All the flowable composites showed proper colour stability for the luting of ceramic veneers. After ageing, an increase in opacity was observed for most of the materials.     

Color stability of resin cements after accelerated aging

PURPOSE: To study the color stability of different resin cements after accelerated aging. METHODS: The color stability of a self-adhesive resin cement (Unicem), one resin-based composite cement (Variolink II), one compomer cement (Principle) and one hybrid ionomer cement (FujiCEM) was studied. Two curing modes of Unicem (self-cured and dual-cured) and Variolink II (light-cured and dual-cured) were also tested. Specimen disks (n = 5) were prepared with a polytetrafluoroethylene split mold and subjected to accelerated aging for 150, 300 and 450 kJ/m2. Color (CIELAB system) was measured before and after each of the three aging cycles on a reflection spectrophotometer. deltaE*, deltaL*, deltaC* and deltaH* were calculated and analyzed by ANOVA. RESULTS: The largest color change occurred during the first 150 kJ/m2 aging cycle, where deltaE* values ranged from 5.6 to 20.5 with Principle showing the least color change and FujiCEM the most. The color changes of all the tested materials were perceptible. The greatest changes were recorded for deltaL* and/or deltaC*. All specimens became significantly rougher and showed evidence of cracking and degradation after aging except Variolink II.     

Influence of ceramic veneer on the transdentinal cytotoxicity,degree of conversion and bond strength of light-cured resin cements to dentin

ObjectivesTo investigate the transdentinal cytotoxicity (TC), degree of conversion (DC), and micro shear bond strength (μSBS) to dentin of light-cured resin cements (LCRCs) photoactivated directly or through a ceramic veneer( ± CV).Materials and methodsThe TC was assessed using human dentin discs adapted into artificial pulp chambers. Odontoblast-like cells were seeded on the pulp surface of the discs, then three LCRCs( ± CV) were applied on their etched and hybridized occlusal surface (n = 8/group). The adhesive systems of each LCRCs and sterile phosphate-buffered saline were used as positive and negative controls, respectively. After 24 h, the viability and morphology of cells adhered on discs were assessed. The extracts (culture medium + components of the materials diffused through the discs) were applied on the MDPC-23 to evaluate their viability, adhesion/spreading (A/S), alkaline phosphatase activity (ALP), and mineralized nodule formation (MN). LCRCs( ± CV) specimens were evaluated concerning the DC and μSBS to dentin. Data were analyzed by one-, two-, or three-way ANOVA/Dunnett, Sidak, and Games-Howell tests (α = 5%).ResultsAll LCRCs( ± CV) reduced cell viability, A/S, ALP, MN, and DC. Except for μSBS, the intensity of reduction was dependent on the LCRC used. LCRCs+CV resulted in lower DC and μSBS but did not increase the TC.SignificanceBesides the presence of CV between the light source and LCRCs reduces the degree of conversion and bond strength to dentin, these materials cause variable level of transdentinal toxicity to pulp cells. Thus, the composition and curing protocols of LCRCs should be revisited and reinforced to prevent mechanical and biological drawbacks.     

Sealing performance of resin cements before and after thermal cycling: Evaluation by optical coherence tomography

Objectives

Self-adhesive resin cements have been recently introduced; however, there is little data available on their long-term performance. In this in vitro study, swept-source optical coherence tomography (OCT) at 1310 nm center wavelength was used for monitoring adaptation of indirect resin restorations after thermal cycling.

Methods

Resin inlays were luted to class-I cavities of extracted human teeth using three resin cements; Clearfil SA Luting (SA; Kuraray), Bistite II DC or Multibond II (Tokuyama Dental). Each cement was applied with or without pre-coating of dentin by a self-etch adhesive (Clearfil SE Bond) and a low-viscosity microfilled resin. OCT imaging was performed after 24 h, after 2000 and after 10,000 thermocycles (n = 5). Selected samples were sectioned for interfacial observation by confocal laser scanning microscope (CLSM). Floor adaptation (percentage) was analyzed by software on 20 B-scans throughout each specimen, and subjected to statistical analysis by three-way ANOVA test at a significance level of 0.05.

Results

Resin cement type, resin coating and thermal aging all significantly affected adaptation (p < 0.05). Initially, SA showed the highest adaptation; however, thermal aging significantly affected its sealing. The best results for all the cements were consistently achieved when the resin coating technique was applied where no deterioration of interfacial integrity was observed in the coated groups. CLSM closely confirmed OCT findings in all groups.

Significance

OCT could be used for monitoring of composite inlays with several interfacial resin layers. The application of a direct bonding agent in the resin-coating technique improved interfacial sealing and durability of all resin cements.     

Improved bonding of zirconia substructures to resin using a "glaze-on" technique

Objective

To investigate the influence of applying thin intermediary coatings of acid-etchable glasses on the shear bond strength between a methacrylate resin based cement and an yttria-stabilized zirconia dental ceramic substrate.

Methods

The upper and lower surfaces of 110 sintered yttria-stabilised tetragonal zirconia polycrystalline disc-shaped specimens were polished using sequential grades of Silicon Carbide, then air-abraded with 25 μm diameter alumina particles. Specimens were randomly allocated to 11 groups (A–K) (n = 10), group A acting as control. The upper surface of Group A specimens was subjected to a tribochemical coating regime (CoJet, 3M ESPE). Five glazing ceramics were applied and fired according to the manufacturer's recommended firing regime. The glaze was etched with 10% HF acid and all specimens coated with a silane primer. Two differing storage regimes were employed (wet storage vs thermocycling). Shear bond strength testing specimens were created by cementing resin-based composite cylinders to the centre of the prepared ceramic surface using Rely-X Unicem (3M ESPE) resin based cement. Shear bond strength testing was performed and load at failure recorded.

Results

A factorial analysis of variance at a 95% significance level demonstrated that all glazing techniques resulted in a significant increase in the shear bond strength compared with using the resin based cement alone (P < 0.01), with the different glazing ceramics resulting in significant differences in mean shear bond strength (P = 0.008). The differences were a function of the storage state (wet storage vs thermocycling (P = 0.013)).

Conclusion

The glazing techniques used in the current investigation resulted in a significantly enhanced shear bond stress to the resin based cement when compared with the current ‘gold standard’ – tribochemical coating.     

Effect of exposure time and moving the curing light on the degree of conversion and Knoop microhardness of light-cured resin cements

ObjectiveTo evaluate the effect of exposure time and moving the light-curing unit (LCU) on the degree of conversion (DC) and Knoop microhardness (KH) of two resin cements that were light-cured through ceramic.MethodsTwo resin cements: AllCem Veneer APS (FGM) and Variolink Esthetic LC (Ivoclar Vivadent) were placed into a 0.3 mm thick matrix in 6 locations representing the canine to canine. The resins were covered with 0.5 mm thick lithium disilicate glass-ceramic (IPS e.max CAD, Ivoclar Vivadent). A motorized device moved the LCUs over the ceramic when the LCU was on. Two single-peak LCUs: Elipar DeepCure-L (3M Oral Care) and Emitter C (Schuster), and one multi-peak: Bluephase G2 (Ivoclar Vivadent) were used with 3 different exposure protocols: a localized exposure centered over each tooth for 10 or 40 s; moving the tip across the 6 teeth for a total exposure time of 10 or 40 s; and moving the tip across the 6 teeth resins for a total exposure time of 60 or 240 s. After 24 h, the DC and KH were measured on the top surfaces and the data was analyzed using three-way ANOVA and Tukey’s tests (α = 0.05).ResultsInterposition of 0.5 mm of ceramic reduced the irradiance received by the resin by approximately 50%. The 40 s localized exposure over each tooth always produced significantly higher DC and KH values. Moving the LCUs with a total exposure time of 10 s resulted in the lowest DC and KH. There was no beneficial effect on the DC or KH when the multi-peak (violet-blue) LCU (Elipar DeepCure-L or Bluephase G2), but the lower light output from a small tip LCU reduced the DC and KH values (Emitter C).SignificanceMoving the LCUs when photo-curing light-cured resin cements is not recommended. This study showed that a single-peak LCU could activate a resin cement that uses Ivocerin™ as well as the multi-peak LCU.     

Microhardness of resin cements after light activation through various translucencies of monolithic zirconia

PURPOSEThis study aimed to investigate the Vickers Hardness Number (VHN) of light- and dual cured resin cements cured through monolithic zirconia specimens (VITA YZ) of various translucencies: translucent (T); high translucent (HT); super translucent (ST); and extra translucent (XT) at 0, 24, and 48 h after curing.MATERIALS AND METHODSFour zirconia specimens from each translucency were prepared. Two light-cured resin cements (Variolink N LC; VL and RelyX Veneer; RL) and two dual-cured resin cements (Variolink N DC; VD and RelyX U200; RD) were used. The cement was mixed and loaded in a mold and cured for 20 s through the zirconia specimen. The upper surface of cements was tested for VHN using a microhardness tester at 0, 24, and 48 h after curing. The VHN were analyzed using two-way repeated, Brown-Forsythe ANOVA with Games Howell post-hoc analysis and independent t-tests (P < .05).RESULTSAll cements showed significantly higher VHN from 0 h to 24 h (P < .001). At 48 h, the VHN of light-cured cements were significantly lower when cured under the T groups than under XT groups (P = .001 in VL, P = .014 in RL). At each post curing time of each translucency, VD showed higher VHN than VL (P < .05), and RD also showed higher VHN than RL (P < .05).CONCLUSIONThe translucency of zirconia has an effect on the VHN for light-cured resin cements, but has no effect on dual-cured resin cements. Dual-cured resin cement exhibited higher VHN than the light-cured resin cement from the same manufacturer. All resin cements showed significantly higher VHN from 0 h to 24 h.