Nucleation efficacy and flexural strength of novel leucite glass-ceramics

ObjectivesTo optimize the nucleation mechanism in leucite glass-ceramics to allow more efficacious glass-ceramic manufacture and improvements in microstructure and mechanical reliability.Materials and methodsAn alumino-silicate glass was designed and synthesized using melt quench methods. The glass was crushed and milled using various milling times (48–93 h) and spray drying. Nucleation and growth heat treatment schedules were applied to synthesize glass-ceramics. Glass/glass-ceramic powders and frit specimens were characterized using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), magic angle spinning nuclear magnetic resonance spectroscopy (MAS-NMR) and X-ray diffraction analyses (XRD). Glass-ceramic specimens were tested using the biaxial flexural strength test (BFS).ResultsApplication of defined nucleation heat treatments resulted in the synthesis of Na/Ca titanates. NMR indicated changes to the ²³Na glass spectra in the nucleated glass and TEM/EDX the presence of Na/Ca/Ti domains (<200 nm) within the leucite crystals and associated with the nucleation of the leucite phase. XRD confirmed the presence of a bulk leucite phase in the glass-ceramics. SEM/TEM confirmed the crystallization of the leucite phase (65.5–69.3%) in a thermally matched glass, in conjunction with the nano Na/Ca titanate phase. The leucite glass-ceramics resulted in a high BFS (255–268 MPa), with reduction in powder milling time prior to heat treatments having no significant effect on flexural strength and reliability (p > 0.05).SignificanceNa/Ca titanates were synthesized in leucite glass-ceramics for the first time and associated with its nucleation and efficacious growth. This nucleation optimization provides opportunities for more efficient manufacturing and microstructural/mechanical reliability improvements. Improved synthesis of high strength/reliable leucite glass-ceramics is useful for construction of esthetic minimally invasive restorations.     

Crystallization of high-strength nano-scale leucite glass-ceramics

Objectives

Fine-grained, high strength, translucent leucite dental glass-ceramics are synthesized via controlled crystallization of finely milled glass powders. The objectives of this study were to utilize high speed planetary milling of an aluminosilicate glass for controlled surface crystallization of nano-scale leucite glass-ceramics and to test the biaxial flexural strength.

Methods

An aluminosilicate glass was synthesized, attritor or planetary milled and heat-treated. Glasses and glass-ceramics were characterized using particle size analysis, X-ray diffraction and scanning electron microscopy. Experimental (fine and nanoscale) and commercial (Ceramco-3, IPS Empress Esthetic) leucite glass-ceramics were tested using the biaxial flexural strength (BFS) test. Gaussian and Weibull statistics were applied.

Results

Experimental planetary milled glass-ceramics showed an increased leucite crystal number and nano-scale median crystal sizes (0.048–0.055 μm²) as a result of glass particle size reduction and heat treatments. Experimental materials had significantly (p < 0.05) higher mean BFS and characteristic strength values than the commercial materials. Attritor milled and planetary milled (2 h) materials showed no significant (p > 0.05) strength difference. All other groups’ mean BFS and characteristic strengths were found to be significantly different (p < 0.05) to each other. The mean (SD) MPa strengths measured were: Attritor milled: 252.4 (38.7), Planetary milled: 225.4 (41.8) [4 h milling] 255.0 (35.0) [2 h milling], Ceramco-3: 75.7 (6.8) and IPS Empress: 165.5 (30.6).

Significance

Planetary milling enabled synthesis of nano-scale leucite glass-ceramics with high flexural strength. These materials may help to reduce problems associated with brittle fracture of all-ceramic restorations and give reduced enamel wear.     

IPS-Empress2玻璃陶瓷弯曲强度的测试及意义

目的：研究IPS-Empress2玻璃陶瓷弯曲强度的统计意义。方法：采用三点弯曲强度测量方法测量40个IPS-Empress2玻璃陶瓷的弯曲强度并与Weibull分析方法相结合,求该陶瓷的Weibull模数（m）及其强度与生存概率的对应关系。结果：IPS-Empress2玻璃陶瓷Weibull模数为7．7。其1％、5％、63．21％破坏概率的弯曲强度分别为301．5MPa、319．2MPa、421．1MPa。结论：IPS-Empress2玻璃陶瓷具有低的Weibull模数以及欠佳的材料结构可靠性,所以其在高应力受力区破坏的概率大。采用弯曲强度测试法并结合使用Weibull分析方法能加深对口腔陶瓷修复失败机制的理解。     

Effect of sandblasting,etching and resin bonding on the flexural strength/bonding of novel glass-ceramics

Objectives

To process novel leucite glass-ceramics and test the effects of surface treatment and resin bonding on the biaxial flexural strength (BFS) and shear bond strength (SBS).

Biaxial flexural strength of bilayered zirconia using various veneering ceramics

PURPOSE

The aim of this study was to evaluate the biaxial flexural strength (BFS) of one zirconia-based ceramic used with various veneering ceramics.

MATERIALS AND METHODS

Zirconia core material (Katana) and five veneering ceramics (Cerabien ZR; CZR, Lava Ceram; LV, Cercon Ceram Kiss; CC, IPS e.max Ceram; EM and VITA VM9; VT) were selected. Using the powder/liquid layering technique, bilayered disk specimens (diameter: 12.50 mm, thickness: 1.50 mm) were prepared to follow ISO standard 6872:2008 into five groups according to veneering ceramics as follows; Katana zirconia veneering with CZR (K/CZR), Katana zirconia veneering with LV (K/LV), Katana zirconia veneering with CC (K/CC), Katana zirconia veneering with EM (K/EM) and Katana zirconia veneering with VT (K/VT). After 20,000 thermocycling, load tests were conducted using a universal testing machine (Instron). The BFS were calculated and analyzed with one-way ANOVA and Tukey HSD (α=0.05). The Weibull analysis was performed for reliability of strength. The mode of fracture and fractured surface were observed by SEM.

RESULTS

It showed that K/CC had significantly the highest BFS, followed by K/LV. BFS of K/CZR, K/EM and K/VT were not significantly different from each other, but were significantly lower than the other two groups. Weibull distribution reported the same trend of reliability as the BFS results.

CONCLUSION

From the result of this study, the BFS of the bilayered zirconia/veneer composite did not only depend on the Young''s modulus value of the materials. Further studies regarding interfacial strength and sintering factors are necessary to achieve the optimal strength.     

Polymerization efficiency and flexural strength of low-stress restorative composites

Objectives

To assess depth of cure (DOC), degree of conversion (DC), and flexural strength (FS) of several resin composites with low-stress behavior.

Methods

SonicFill (Kerr), SureFil^® SDR™ (Dentsply), everX Posterior (GC), Kalore (GC), and Filtek Silorane (3M ESPE) were tested. DOC was measured with the Acetone Shake test. DC was assessed with Fourier Transform Infra-Red spectroscopy on top and at the bottom of 4 mm-thick disk-shaped specimens. Bottom to top ratios of DC percentages were calculated. FS was evaluated with the Three-Point Bending test. DOC, DC, and FS data were statistically analyzed.

Results

SureFil^® SDR™ and everX Posterior achieved significantly greater DOC than Kalore and Filtek Silorane. Also, SonicFill had significantly greater DOC than Filtek Silorane. Mean top DCs ranged between 71.46% and 52.44%. Kalore and everX Posterior had significantly lower top DCs than the other materials. Mean DC values at 4 mm ranged largely from 57.95% to 6.82%. Kalore and Filtek Silorane had the lowest values of bottom DC and the difference was statistically significant. EverX Posterior and SonicFill recorded significantly higher FSs than the other materials.

Significance

SureFil^® SDR™ and everX Posterior exhibited DOC over 4 mm, the maximum thickness recommended for bulk placement, while SonicFill recorded DOC values very close to the 4 mm threshold. SonicFill achieved the highest DC at the irradiated surface, as well as at 4 mm depth. SureFil^® SDR™ demonstrated similarly uniform curing through the bulk increment. All the tested composites complied with the requirements of FS established by ISO 4049/2009.     

Evaluation of machinability and flexural strength of a novel dental machinable glass-ceramic

Objectives

To evaluate the machinability and flexural strength of a novel dental machinable glass-ceramic (named PMC), and to compare the machinability property with that of Vita Mark II and human enamel.

Methods

The raw batch materials were selected and mixed. Four groups of novel glass-ceramics were formed at different nucleation temperatures, and were assigned to Group 1, Group 2, Group 3 and Group 4. The machinability of the four groups of novel glass-ceramics, Vita Mark II ceramic and freshly extracted human premolars were compared by means of drilling depth measurement. A three-point bending test was used to measure the flexural strength of the novel glass-ceramics. The crystalline phases of the group with the best machinability were identified by X-ray diffraction.

Results

In terms of the drilling depth, Group 2 of the novel glass-ceramics proves to have the largest drilling depth. There was no statistical difference among Group 1, Group 4 and the natural teeth. The drilling depth of Vita MK II was statistically less than that of Group 1, Group 4 and the natural teeth. Group 3 had the least drilling depth. In respect of the flexural strength, Group 2 exhibited the maximum flexural strength; Group 1 was statistically weaker than Group 2; there was no statistical difference between Group 3 and Group 4, and they were the weakest materials. XRD of Group 2 ceramic showed that a new type of dental machinable glass-ceramic containing calcium-mica had been developed by the present study and was named PMC.

Conclusions

PMC is promising for application as a dental machinable ceramic due to its good machinability and relatively high strength.     

3种大块充填树脂的耐磨耗性能及挠曲强度的比较研究

目的:比较3种大块充填树脂的耐磨耗性能及挠曲强度.方法:选取SDR、SonicFill、Tetric N-Ceram Bulk Fill及传统纳米树脂Herculite Precis,分别制作成直径为10 mm、高度为2 mm的圆柱体耐磨耗实验试件和2 mm×2 mm×25 mm长方体挠曲强度实验试件.将磨耗试件固定在往复滑动球-片式磨耗试验机上,以人工唾液作为磨耗介质,加载力为50 N,磨耗1万次后计算体积磨损值.应用万能实验机以1 mm/min的加载速度,测量并计算试件挠曲强度值.采用SPSS13.0软件包对4种复合树脂体积磨损量及挠曲强度值的差异进行单因素方差分析.结果:4种树脂的体积磨损量从大到小依次为SDR(1.2433±0.11) mm3、SonicFill (0.6331±0.09) mm3、Tetric N-Ceram Bulk Fi11(0.3558±0.05) mm3、Herculite Precis (0.3097±0.04) mm3,挠曲强度值从大到小依次为SonicFill(136.2184±14.61) MPa、HerculitePrecis(124.1468±18.25) MPa、Tetric N-Ceram Bulk Fill(119.2082±16.36) MPa、SDR(103.6246±7.03) MPao Tetric N-Ceram Bulk Fill与对照树脂Herculite Precis的体积磨损量和挠曲强度值均无显著差异(P＞0.05).结论:综合材料的耐磨耗性能和挠曲强度,大块充填树脂Tetric N-Ceram Bulk Fill可能更适合作为后牙直接充填材料.     

Reduced wear of enamel with novel fine and nano-scale leucite glass-ceramics

Objectives

Leucite glass-ceramics used to produce all-ceramic restorations can suffer from brittle fracture and wear the opposing teeth. High strength and fine crystal sized leucite glass-ceramics have recently been reported. The objective of this study is to investigate whether fine and nano-scale leucite glass-ceramics with minimal matrix microcracking are associated with a reduction in in vitro tooth wear.

Methods

Human molar cusps (n = 12) were wear tested using a Bionix-858 testing machine (300,000 simulated masticatory cycles) against experimental fine crystal sized (FS), nano-scale crystal sized (NS) leucite glass-ceramics and a commercial leucite glass-ceramic (Ceramco-3, Dentsply, USA). Wear was imaged using Secondary Electron Imaging (SEI) and quantified using white-light profilometry.

Results

Both experimental groups were found to produce significantly (p < 0.05) less volume and mean-height tooth loss compared to Ceramco-3. The NS group had significantly (p < 0.05) less tooth mean-height loss and less combined (tooth and ceramic) loss than the FS group. Increased waviness and damage was observed on the wear surfaces of the Ceramco-3 glass-ceramic disc/tooth group in comparison to the experimental groups. This was also indicated by higher surface roughness values for the Ceramco-3 glass-ceramic disc/tooth group.

Conclusions

Fine and nano-sized leucite glass-ceramics produced a reduction in in vitro tooth wear. The high strength low wear materials of this study may help address the many problems associated with tooth enamel wear and restoration failure.     

氧化锆和纳米金刚石比例对核树脂挠曲强度的影响

目的 探讨二氧化锆、纳米金刚石比例对核树脂挠曲强度的影响.方法 采用双酚A-甲基丙烯酸缩水甘油酯(Bis-GMA)和二甲基丙烯酸三甘醇酯(TEGDMA)为树脂基质, 钡玻璃粉(BG)为主填料, 选择不同比例的微米或纳米级二氧化锆,纳米金刚石作为功能填料, 采用原位聚合法生成光固化牙科核树脂,万能材料试验机测定其挠曲强度.结果 含60wt%钡玻璃粉、0.2wt%纳米金刚石的树脂中,加入纳米级或微米级的二氧化锆含量分别为2wt%、3.5wt%、5wt%,3.5wt%相应核树脂挠曲强度最高;含70wt%钡玻璃粉、0.1wt%纳米金刚石的树脂中,加入40 nm的二氧化锆含量为0wt%、2wt%、3.5wt%、5wt%,2wt%质量百分比相应核树脂挠曲强度最高.结论 适当比例填料的核树脂挠曲强度能达到相应的国家标准及ISO标准的规定,能满足临床需要.     

The effect of surface grinding and sandblasting on flexural strength and reliability of Y-TZP zirconia ceramic

OBJECTIVES: This study was conducted to evaluate the effect of grinding and sandblasting on the microstructure, biaxial flexural strength and reliability of two yttria stabilized tetragonal zirconia (Y-TZP) ceramics. METHODS: Two Y-TZP powders were used to produce fine grained and coarse grained microstructures. Sixty discs from each material were randomly divided into six groups of ten. For each group, a different surface treatment was applied: dry grinding, wet grinding, sandblasting, dry grinding + sandblasting, sandblasting + dry grinding and a control group. Biaxial flexural strength was determined and data were analyzed using one-way ANOVA, followed by Tukey's HSD test (p < 0.05). In addition, Weibull statistics was used to analyze the variability of flexural strength. The relative amount of transformed monoclinic zirconia, corresponding transformed zone depth (TZD) and the mean critical defect size Ccr were calculated. RESULTS: There was no difference in mean strength between the as sintered fine and coarse grained Y-TZP. Significant differences (p < 0.05) were found between the control group and ground fine grained material for both wet and dry grinding. Sandblasting significantly increased the strength in fine and coarse grained materials. All surface treatment procedures reduced the Weibull modulus of Y-TZP. For both materials, the highest amount of the monoclinic phase and the largest TZD was found after sandblasting. Lower amounts of the monoclinic phase were obtained after both grinding procedures, where the highest mean critical defect size Ccr was also calculated. SIGNIFICANCE: Our results indicate that sandblasting may provide a powerful technique for strengthening Y-TZP in clinical practice. In contrast, grinding may lead to substantial strength degradation and reduced reliability of prefabricated zirconia elements, therefore, sandblasting of ground surfaces is suggested.     

纳米氧化锆对PMMA挠曲强度和表面硬度的影响

目的:研究纳米ZrO2的添加量对聚甲基丙烯酸甲酯(PMMA)基托树脂机械性能的影响。方法:使用质量分数为1.5%的硅烷偶联剂Z-6030对纳米ZrO2颗粒进行表面处理及FTIR表征分析,未经处理者为对照组。将经过表面处理的纳米ZrO2颗粒按照质量比0.5%、1%、1.5%、2%、2.5%、3%和3.5%的添加量与PMMA混合,合成纳米ZrO2/PMMA复合材料,共7组。制作标准试件,进行表面硬度测试和三点弯曲测试,从每组中随机选取1个试件进行扫描电镜观察。采用SAS 6.12软件包对数据进行ANOVA单因素方差分析。结果:红外光谱图显示,经过表面处理的纳米ZrO2颗粒表面有硅烷偶联剂吸附。纳米ZrO2添加量为1.5%和2%组复合材料的表面硬度最佳(P<0.05)。1.5%组复合材料的挠曲强度最高(P<0.05),SEM观察断裂面为韧性断裂。结论:使用硅烷偶联剂能提高纳米ZrO2与PMMA的结合强度,经过表面处理的纳米ZrO2,能提高复合材料的机械性能,但加入量会影响纳米ZrO2的增强作用。纳米ZrO2以1.5%和2%的添加比例对基托材料的表面硬度增强效果最佳,以1.5%的添加比例对PMMA挠曲强度的增强效果最...     

多次热处理对Empress 2热压铸玻璃陶瓷强度及色泽的影响

目的 比较多次热处理对 Empress 2热压铸玻璃陶瓷材料的色泽及抗弯强度的影响和对支架瓷-饰瓷复合体的色泽的影响。方法 本实验有3个大试样组:A组试样为15个由支架瓷原料热压铸而成的直径9mm,厚(0.80±0.01)mm的碟形试样,每3个试样为一处理组;B组试样先依照A组试样的方法制作,再在其一个面上烧结饰瓷层使总厚度为(1.50±0.01)mm,共12个,每3个试样为一处理组;C组试样为20个由Empress 2支架瓷原料热压铸而成的规格为 2.0mm×3.0mm×25mm的试样,每 5个试样为一处理组。上述每个处理组都经过了不同次数的热处理后,A、B两组所有试样的色泽参数(L、a、b)由 ShadeEye NCC牙科色度仪测得;C组试样的三点抗弯强度都由MTS Synergie综合测试仪以及Testwork4软件测出。最后用单因素方差分析和t检验来比较各处理组间数据的差异(P<0.05)。结果A,B两组中各处理组间的色泽参数无显著差异;C组中各处理组间的抗弯强度也无显著差异。结论 一定次数的热处理不会对 Empress 2牙科陶瓷的色泽及抗弯强度产生影响。没有证据表明需要对 Empress 2热压铸玻璃陶瓷饰瓷烧结以及上釉等热处理工序的次数进行过于严格的限制。     

氧化锆的用量对纳米氧化锆/PMMA复合材料挠曲性能的影响

目的：研究氧化锆的添加量对纳米ZrO2/PMMA复合材料挠曲强度的影响。方法：采用球磨仪混合基托树脂（聚甲基丙烯酸甲酯,PMMA）Ⅱ型粉剂和硅烷偶联剂Z-6030修饰过的纳米氧化锆粉体,合成纳米ZrO2/PMMA复合材料,按照氧化锆的用量从0%到7%,制作8组标准试件,测试材料的挠曲强度。结果：氧化锆添加量为3%组的挠曲强度最大,与实验组中的4%组无统计学上的差异,与空白组及实验组中的其他组均有统计学上的差异（P〈0.05）,SEM观察断裂面为韧性断裂,其中3%和4%两组断裂面比较的粗糙。结论：经过硅烷修饰的纳米ZrO2颗粒,在其添加量为3.0%时,可以显著地提高纳米ZrO2/PMMA复合材料的挠曲强度。     

Elastic modulus and flexural strength comparisons of high-impact and traditional denture base acrylic resins

Background

Fractures of acrylic resin dentures are a common occurrence in clinical dentistry. The denture may be fractured accidentally when dropped or while in service in the mouth due to flexural fatigue.

Objectives

The aim of this study was to compare the elastic modulus and the flexural strength between two heat-cured acrylic resins used in denture bases: a high-impact resin (Lucitone 199) and a traditional resin (Rodex).

Materials and methods

Rectangular strips of Lucitone 199 and Rodex (10 samples each) were fabricated and stored in artificial saliva at 37 °C for 2 weeks. The specimens were subjected to a three-point flexural test. The data were statistically analysed with Student’s t-test (p ⩽ .05).

Results

The high-impact acrylic resin had a lower elastic modulus (p = .000) and higher flexural strength (p = .001) compared to the traditional acrylic resin.

Conclusion

Within the limitations of this study, it can be concluded that the high-impact acrylic resin is a suitable denture base material for patients with clinical fracture of the acrylic denture.     

Impact of different pretreatments and aging procedures on the flexural strength and phase structure of zirconia ceramics

ObjectiveTo test the impact of zirconia pretreatment and aging on flexural strength and phase structure.MethodsFor flexural strength measurements, 180 3Y-TZP_0.25 specimens were fabricated and pretreated: (i) air-abraded (105-μm alumina, 0.25 MPa), (ii) air-abraded (50-μm alumina, 0.25 MPa), (iii) air-abraded (30-μm silica-coated alumina, 0.28 MPa) (iv) non-pretreated. Each pretreated group (n = 15) was aged: (a) hydrothermal (134 °C, 0.23 MPa, 2 h) (b) in a mastication simulator (1,200,000×, 5/55 °C) and (c) not aged. The fractured specimens were stored dry for 5 years (23 °C) for analysis of phase transformation. Additionally, specimens were fabricated from 3Y-TZP_0.25 (n = 12) and 3Y-TZP_0.05 (n = 8), pretreated (i, ii, iii, iv), and hydrothermally aged. Each air-abrasion method was alternated using 0.05, 0.25 and 0.4 MPa pressure. The phase transformation was examined by Raman spectroscopy and surface topography by scanning electron microscope. Data were analyzed using univariate ANOVA with the Scheffé post hoc test and partial-eta-squared (?_p²) (α = 0.05).ResultsThe highest impact on flexural strength was exerted by the pretreatment (η_P² = 0.261, p < 0.001), followed by interactions between pretreatment and aging (η_P² = 0.077, p = 0.033). Non-pretreated and non-aged specimens showed the lowest monoclinic percentage. Hydrothermal aging and 5 years of storage at room temperature increased the monolithic percentage of 3Y-TZP_0.25. The highest phase transformation was observed in groups air-abraded with 105-μm alumina particles. Increasing pressure during the air-abrading process increased the content of the monoclinic phase in zirconia surfaces.SignificanceAir-abrasion with 30-μm silica-coated alumina powder can be recommended for pretreatment of 3Y-TZP_0.25 and 3Y-TZP_0.05. For air-abrasion using alumina powder lower pressure should be used.     

ZTA和Al2O3正畸托槽的研究

目的 分别评价ZTA(ZrO2增韧Al2O3)和Al2O3陶瓷的性能,探索一种适合制备正畸托槽的陶瓷材料.方法 选用ZrO2(3mol%Y2O3)和α-Al2O3粉体作为原料,利用热压铸成型工艺制备陶瓷托槽,在1600 ℃下烧结.将制得样品进行各方面的性能测试.结果 采用纯Al2O3制备的托槽抗弯强度远远低于ZTA复合陶瓷.结论 牙科正畸托槽可以选用具有较高抗弯强度的ZTA复合陶瓷作为原料.     

Effect of acidic media on flexural strength and fatigue of CAD-CAM dental materials

ObjectiveTo investigate the effect of acidic media, including beverages and gastric fluids on flexural strength and fatigue of CAD-CAM materials.MethodsFour CAD-CAM materials (high-translucency zirconia (Ceramill Zolid HT+), lithium disilicate (IPS e-max CAD), hybrid ceramic (Vita Enamic), and nanohybrid resin composite (Grandio Blocs) were prepared and immersed in one of five media (gastric HCl, white wine, Coca-Cola, orange juice, and artificial saliva) in an incubator (37 ℃, 24 h). Surface topography and roughness were obtained using a scanning electron microscope (SEM) and a stylus contact profilometer, respectively. Initial 3-point flexural strength was measured for half of the bars (n = 20/gp) using a universal testing machine (0.5 mm/min). The other bars underwent 10⁶ cyclic fatigue loadings before measurement of residual 3-point flexural strength. Data were statistically analyzed (two-way and three-way ANOVA, Tukey’s post-hoc, p < 0.05). Weibull distributions were plotted for reliability analysis.ResultsZirconia bars has the highest initial flexural strengths followed by lithium disilicate, while resin composite and hybrid ceramic groups had the lowest strength regardless of the erosive medium. Cyclic fatigue significantly reduced initial flexural strengths for all materials except for hybrid ceramic and resin composite. Weibull moduli were the highest for zirconia, lithium disilicate and resin composite and lowest for hybrid ceramic.SignificanceErosive media significantly changed surface roughness of CAD-CAM materials except for zirconia and resin composite without jeopardizing the flexural strength of the CAD-CAM materials. Despite the higher flexural strengths for zirconia and lithium disilicate, resin composite and hybrid ceramic were more resistant to cyclic fatigue.     

硅藻土基底瓷与饰面瓷厚度比对抗弯强度的影响

目的:探讨不同基底瓷与饰面瓷厚度比对硅藻土基全瓷材料结合强度的影响。方法:硅藻土基底瓷尺寸为16 mm×5. 4 mm×1 mm,随机分为4组,表面堆塑不同厚度的IPS e.max饰面瓷,分别为不烧结（A组）、0.6 mm（B组）、0.8 mm（C组）和1.0 mm（D组）,测定不同分组的抗弯强度并观察陶瓷试件的断裂模式,扫描电镜观察断面显微形貌。采用SPSS 17.0软件包对数据进行单因素方差分析。结果:随着饰面瓷厚度的增加,抗弯强度也随之增强,其中C组抗弯强度最大,达到（277.24±15.47） MPa。结论:基底瓷与饰面瓷厚度比可显著影响硅藻土基底瓷与饰面瓷的抗弯强度。