不同表面处理方法对氧化锆基底材料与饰面瓷结合强度的影响

目的 比较不同表面处理方法对氧化锆基底与饰面瓷之间的结合强度及结合界面微观结构的影响。方法 将WIELAND氧化锆瓷块胚体烧结制成10 mm×5 mm×5 mm大小试件33个。将试件随机分为3组,每组11个。喷砂组在烧结前进行喷砂处理;处理剂组先喷砂处理,再烧结结合衬底瓷;对照组不做处理。3组基底瓷材料采用粉浆涂塑法烧结5 mm×5 mm×5 mm大小的饰面瓷。每组随机抽取1个基底瓷及双层瓷试件,采用扫描电镜、能谱分析方法,研究氧化锆底瓷与饰面瓷之间的结合情况。其余试件则通过电子拉伸机测试结合界面的剪切强度,并用SPSS 17.0软件对实验数据进行统计学分析。结果 喷砂组、处理剂组、对照组试件的剪切强度分别为（18.06±0.59）、（21.04±1.23）、（13.80±1.54） MPa,各组间差异均有统计学意义（P<0.01）。结论 氧化锆胚体烧结前喷砂处理能提高氧化锆基底冠与饰面瓷的结合强度,结合衬底瓷的应用能提高氧化锆基底冠与饰面瓷的结合强度。     

表面多孔涂层对氧化锆与饰面瓷界面结合强度的影响

目的：以表面抛光、喷砂为对照,研究表面多孔涂层对氧化锆与饰面瓷界面剪切结合强度的影响。方法：按照Schmitz-Schulmeyer法测量氧化锆与饰面瓷的剪切结合强度。制作氧化锆基底样本60个（IO×5×5mm）,分为三组（抛光组：耐水碳化硅砂纸逐级抛光至1200#;喷砂组：1lOμmA1203颗粒在3bars的压力下喷砂10sec,距离10mm;涂层组：质量分数为55wt％的氧化锆粉浆涂塑氧化锆表面,致密烧结）,每组20个。表面烧结饰面瓷（5×3×3mm）。每组取10个样本,5℃／55℃水域中交替循环5000次。万能材料试验机测试剪切结合强度,加载速度0．5mm／min。对测试结果进行双因素方差分析（α=0．05）。SEM观察样本断裂模式。结果：涂层组剪切结合强度与抛光组和喷砂组差异均有统计学意义（P〈0．05）;喷砂组与抛光组间差异无统计学意义（P〉0．05）;各组温度循环后剪切结合强度差异均无统计学意义（P〉0．05）。SEM观察显示,涂层组样本以饰面瓷的内聚断裂为主;抛光组和喷砂组以界面断裂为主。结论：表面多孔涂层可显著提高氧化锆与饰面瓷的剪切结合强度,并能耐受短期的人工老化,而结合强度无明显下降。     

高半透性氧化锆基底的不同处理对锆-瓷结合强度的影响

目的探讨高半透性氧化锆的不同表面处理对其与饰瓷界面结合强度的影响,为临床提高氧化锆全瓷修复体的锆-瓷结合强度提供研究基础。方法制作30个高10 mm、直径为10 mm的圆柱形KATANA氧化锆试件,分为四组,每组7个:(1)C组(对照组)打磨后直接堆塑饰瓷粉;(2)S组(喷砂组)打磨后喷砂,堆塑饰瓷粉;(3)B组(结合层组)打磨后先烧结一薄层饰瓷粉,再堆塑饰瓷粉;(4)SB组(喷砂+结合层组)打磨后喷砂,烧结一薄层饰瓷粉,再堆塑饰瓷粉;剩余2个试件观察喷砂前后氧化锆的表面形貌。烧结后包埋成剪切试件,采用剪切强度测试法测定各组的剪切强度值,并进行统计学分析。体视显微镜观察瓷层断裂模式。结果C组剪切强度值为(21.86±3.18)MPa;S组为(22.12±3.06)MPa;B组为(19.19±1.46)MPa;SB组为(27.76±1.95)MPa。C组、S组和B组剪切强度两两比较无显著差异,各组与SB组比较剪切强度值差异有统计学意义(P<0.05)。体视显微镜下观察各组饰瓷断裂模式以混合破坏为主。结论单独喷砂处理不能显著增加锆-瓷结合强度,薄涂饰瓷作为结合层对锆-瓷结合强度没有明显影响,喷砂与结合层结合可显著提高锆-瓷结合强度。     

Shear bond strength between an indirect composite layering material and feldspathic porcelain-coated zirconia ceramics

Objectives

This study aims to evaluate the effect of both feldspathic porcelain coating of zirconia frameworks and priming agents on shear bond strength between an indirect composite material and zirconia frameworks.

Materials and methods

A total of 462 airborne-particle-abraded zirconia disks were divided into three groups: untreated disks (ZR–AB), airborne-particle-abraded zirconia disks coated with feldspathic porcelain, (ZR–PO–AB), and hydrofluoric acid-etched zirconia disks coated with feldspathic porcelain (ZR–PO–HF). Indirect composite (Estenia C&;B) was bonded to zirconia specimens with no (CON) or one of four priming agents—Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB?+?activator), Estenia Opaque primer, or Porcelain Liner M Liquid B (PLB)—with or without an opaque material (Estenia C&;B Opaque). All specimens were tested for shear bond strength before and after 20,000 thermocycles. The Steel–Dwass test and Mann–Whitney U test were used to compare shear bond strength.

Results

In ZR–AB specimens, the initial bond strength of the CPB and CPB?+?Activator groups was significantly higher as compared with the other three groups (P?P?Conclusion Feldspathic porcelain coating of a Katana zirconia framework enhanced the bond strength of Estenia C&;B indirect composite to zirconia independent of surface treatment. The use of a silane coupling agent and opaque material yields durable bond strength between the indirect composite and feldspathic-porcelain-coated zirconia.

Clinical relevance

The results of the present study suggest that feldspathic porcelain coating of zirconia frameworks is an effective method to obtain clinically acceptable bond strengths of a layering indirect composite material to a zirconia framework.     

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目的比较不同基底材料与饰面瓷的结合力,为修复临床选择不同的瓷修复体提出依据。方法 2009年11月至2010年5月在大连市口腔医院应用特制模具制作基底材料标本蜡型(直径6mm,高8mm)共60个。根据各基底材料制作要求分别制作镍铬(Ni-Cr)合金、钴铬(Co-Cr)合金、金钯(Au-Pd)合金、混合Au-Pd合金、压铸瓷及氧化锆基底材料标本(每组10个)。在实验标本的一端堆瓷,瓷层总厚度控制在(2.0±0.01)mm。在万能试验机上以0.5mm/min的加载速度进行加载至剪切断裂。对实验标本的剪切强度进行单因素方差分析。结果 6种瓷修复体的的剪切强度为:Au-Pd合金组(51.56±8.93)MPa,Ni-Cr合金组(45.61±3.11)MPa,Co-Cr合金组(37.12±4.08)MPa,混合金钯合金组(36.07±5.42)MPa,氧化锆组(31.52±7.45)MPa,压铸瓷组(29.62±9.97)MPa。单因素方差分析表明不同金属合金基底材料与饰面瓷间的剪切强度差异有统计学意义(P<0.01)。结论不同基底材料与饰面瓷的剪切强度存在差异。Au-Pd合金和Ni-Cr合金与饰面瓷结合力强。     

改良液式冲蚀对3Y-TZP氧化锆基底与饰面瓷结合强度的影响

目的:探讨采用改良液式冲蚀方式对3Y-TZP氧化锆基底表面进行冲蚀后,对其与饰面瓷间结合强度的影响.方法:制作[8 mm×8 mm×3 mm(±0.02)]氧化锆试件块174个,根据不同尺寸的刚玉磨粒、不同的喷砂压强、不同的喷砂时间,采用传统喷砂方式进行分组处理(实验组),在氧化锆处理面上饰面瓷.表面未做处理的氧化锆试件直接上饰面瓷作为对照组,应用电子万能测力计检测各组试件与饰面瓷间的最大剪切力,计算剪切强度.分别用传统干式喷砂、改良液式冲蚀方式在相同条件下(150 μm,0.6 MPa,30 s)处理氧化锆试件块,用扫描电镜下观察处理面,再上饰面瓷,计算剪切强度,与对照组进行组间比较.采用SPSS17.0软件包对数据进行统计学分析.结果:采用传统干式喷砂方式,在0.4 MPa压强作用下,以110 μm A12O3喷砂粉喷砂20 s时,氧化锆与饰面瓷之间的剪切强度最大,显著大于对照组(P＜0.05);改良液式冲蚀组饰面瓷的结合强度显著大于传统干式喷砂处理组及对照组(P＜0.01).扫描电镜下可见,采用改良液式冲蚀的试件表面呈现均匀的粗糙面:采用传统干式喷砂处理的试件表面呈现不均匀的粗糙面,部分位置可见微裂纹.结论:对3Y-TZP氧化锆表面喷砂,能够增强其与饰面瓷间的结合强度;改良液式冲蚀比传统干式喷砂更适用于3Y-TZP氧化锆的表面处理.     

Shear bond strength of veneering porcelain to zirconia and metal cores

STATEMENT OF PROBLEM

Zirconia-based restorations have the common technical complication of delamination, or porcelain chipping, from the zirconia core. Thus the shear bond strength between the zirconia core and the veneering porcelain requires investigation in order to facilitate the material''s clinical use.

PURPOSE

The purpose of this study was to evaluate the bonding strength of the porcelain veneer to the zirconia core and to other various metal alloys (high noble metal alloy and base metal alloy).

MATERIAL AND METHODS

15 rectangular (4×4×9mm) specimens each of zirconia (Cercon), base metal alloy (Tillite), high noble metal alloy (Degudent H) were fabricated for the shear bond strength test. The veneering porcelain recommended by the manufacturer for each type of material was fired to the core in thickness of 3mm. After firing, the specimens were embedded in the PTFE mold, placed on a mounting jig, and subjected to shear force in a universal testing machine. Load was applied at a crosshead speed of 0.5mm/min until fracture. The average shear strength (MPa) was analyzed with the one-way ANOVA and the Tukey''s test (α= .05). The fractured specimens were examined using SEM and EDX to determine the failure pattern.

RESULTS

The mean shear strength (± SD) in MPa was 25.43 (± 3.12) in the zirconia group, 35.87 (± 4.23) in the base metal group, 38.00 (± 5.23) in the high noble metal group. The ANOVA showed a significant difference among groups, and the Tukey''s test presented a significant difference between the zirconia group and the metal group. Microscopic examination showed that the failure primarily occurred near the interface with the residual veneering porcelain remaining on the core.

CONCLUSION

There was a significant difference between the metal ceramic and zirconia ceramic group in shear bond strength. There was no significant difference between the base metal alloy and the high noble metal alloy.     

Effect of zirconia surface treatments on the shear strength of zirconia/veneering ceramic composites

Aim of the investigation was to assess the effect of different surface treatments on the bond strength of veneering ceramics to zirconia. In a shear test, the influences of polishing, sandblasting, and silica-coating of the zirconia surface on bonding were assessed with five different veneering ceramics. In addition the effect of liner application was examined. With one veneering ceramic, the impact of regeneration firing of zirconia was also evaluated. Statistical analysis was performed with one-way ANOVA and post hoc Scheffé's test. Failure in every case occurred in the veneering ceramic adjacent to the interface with a thin layer of ceramic remaining on the zirconia surface, indicating that bond strength was higher than the cohesive strength of the veneering ceramic. Shear strength ranged from 23.5 +/- 3.4 MPa to 33.0 +/- 6.8 MPa without explicit correlation to the respective surface treatment. Regeneration firing significantly decreased the shear strength of both polished and sandblasted surfaces. Findings of this study revealed that bonding between veneering ceramics and zirconia might be based on chemical bonds. On this note, sandblasting was not a necessary surface pretreatment to enhance bond strength and that regeneration firing was not recommended.     

The effect of surface treatment of the interfacial surface on fatigue-related microtensile bond strength of milled zirconia to veneering porcelain

Purpose: The success of zirconia‐reinforced all‐ceramic crowns depends on the formation of a stable bond between the zirconia core and the veneering porcelain. The purpose of this study was to test the effects of liner application and airborne particle abrasion of a postsintered Y‐TZP core on the bond strength between the zirconia core and veneering porcelain with or without cyclic loading. Materials and Methods: Kavo Everest® Y‐TZP blank disks were sintered and divided into three treatment groups: airborne particle abrasion, IPS e.max® Ceram Zirliner application, or no surface treatment. The disks were then veneered with IPS e.max® ZirPress veneering porcelain. Half the veneered disks from each group were cyclically loaded. This created six experimental groups: three surface treatment groups cyclically loaded and three not loaded. The disks were then sectioned into microbars for microtensile bond strength (MTBS) testing (40 specimens per group). Specimens were luted to a fixture mount and loaded to failure using a universal testing machine (MTS Insight). The maximum force was measured and bond strength computed. Data were analyzed with a two‐way ANOVA and Tukey's HSD test (α= 0.05). Results: Airborne particle abrasion significantly decreased MTBS values (p= 0.043), and ZirLiner application did not have a significant effect on MTBS values compared to control. Cyclic loading did not have a significant effect on MTBS values. The predominant failure mode in all groups was mixed. Conclusions: Airborne particle abrasion of the interfacial surface of the Everest® Y‐TZP core significantly decreased the MTBS to ZirPress veneering porcelain when compared to no interfacial surface treatment. Application of ZirLiner to the interfacial surface of the Everest® Y‐TZP core did not significantly increase or decrease the MTBS to ZirPress veneering porcelain, compared to the other surface treatments. Cyclic loading did not affect bond strengths in any of the groups, regardless of surface treatment. Neither cyclic loading nor surface treatment affected the failure mode of the specimens.     

Influence of thickness and cooling rate on development of spontaneous cracks in porcelain/zirconia structures

Background: Clinical studies reporting the outcome of zirconia‐based restorations indicate that the strength of the zirconia frameworks is sufficient to withstand masticatory forces. However, a significant incidence of cohesive fracture of the veneering porcelain has been reported. The aim of this study was to investigate spontaneous crack development (chipping, rupture) in a range of porcelains veneered to a zirconia core as a result of thermal stresses induced by changes in thickness and cooling rate. The hypothesis tested was that crack incidence would increase with increased veneer thickness and faster cooling rates. Methods: Zirconia spheres (diameter 7.8 mm) were veneered with 1.5 gm (thickness ratio 1:2) and 2.5 gm (thickness ratio 1:1) of five nominally compatible commercially available porcelains. The manufacturers’ firing cycles and a rapid cooling firing cycle were followed. Results: Multiple regression analysis showed positive associations between the occurrence of cracks and the three covariates (materials, thickness and cooling rate). The incidence of cracks and rupture of the veneering porcelain increased with a faster cooling rate and increased thickness of the specimens in three porcelain–zirconia combinations. Conclusions: Crack incidence increased with increased porcelain veneer thickness and faster cooling rates in nominally compatible porcelain/zirconia systems in the geometrically configured specimens tested.     

不同表面处理方式对Kavo氧化锆基底与饰瓷结合强度的影响

目的:研究不同表面处理方法对Kavo氧化锆底层材料与Noritake Cerabien饰面瓷结合强度的影响。方法:选择Kavo氧化锆陶瓷作为底层材料,随机分为4组,每组8个试件。A组为染色液浸泡着色+表面不喷砂;B组为染色液浸泡着色+表面喷砂;C组为不浸泡染色液+表面不喷砂;D组为不浸泡染色液+表面喷砂。4组底层材料采用粉浆涂塑法烧结饰面瓷后,使用材料试验机测试其剪切强度,采用SPSS10.0软件包对数据进行统计学分析。结果:采用喷砂处理的2组(B组和D组)材料,其剪切强度均高于未喷砂的2组(A组和C组),差异具有显著性(P<0.01);浸泡染色处理对剪切强度的无显著影响,A组与C组、B组与D组之间的差异无显著性(P>0.05)。结论:对Kavo氧化锆基底表面进行喷砂处理,可以提高基底冠与饰面瓷的结合强度;而浸泡染色则对两者结合力的强度无显著影响。     

锆瓷基底表面形貌对锆瓷饰瓷间结合强度影响的研究

目的：探讨锆瓷基底表面形貌对其与饰瓷结合强度的影响.方法：切削制备1 1mm×10mm×5mm锆瓷烧结瓷块40块,随机均分至4组即对照组（烤瓷面烤瓷前经过常规打磨、喷砂及抛光处理）,垂直组（与对照组不同处在于剪切加载方向与切削瓷面的刀路方向垂直）,平行组（与对照组不同处在于剪切加载方向与切削瓷面的刀路方向一致）,突起组（与对照组不同处在于烤瓷面制备有2个直径2mm,高0.3mm的圆柱状突起）.各组试件烤瓷面涂布粘接瓷,堆积4mm厚饰瓷后烧结.以万能试验机测试饰瓷与锆瓷基底间的剪切强度.结果：对照组、垂直组、平行组、突起组锆瓷与饰瓷间的剪切强度均数与标准差分别为24.1±2.64 MPa、27.9±4.53MPa、27.5±4.79MPa和37.2±7.03MPa,单因素方差分析显示差异有统计学意义,突起组强度显著高于垂直组、平行组（P＜0.05）及对照组（P＜0.01）.结论：锆瓷烤瓷面切削刀路方向对锆瓷与饰瓷间的烧结剪切强度无显著影响;锆瓷烤瓷面制备出适当的突起可显著增强饰瓷抗剥脱的能力.     

The firing procedure influences properties of a zirconia core ceramic.

OBJECTIVES: High-strength ceramics for dental restoration are used as an understructure (core) that subsequently is covered by veneering ceramic. The veneering process involves a firing procedure at high temperatures at least once, usually two to five times. The aim of this study was to investigate whether these firing procedures affect the mechanical properties of a zirconia ceramic. METHODS: Thirty-three specimens of an industrially sintered yttria-stabilized zirconia ceramic (DC Zircon, DCS Dental AG, Allschwil, Switzerland) were cut into bars (1.2mmx4mmx20mm). One set of specimens (n=13) remained untreated (controls). Another set of specimens (n=10) was heat-treated once, corresponding to the first step of the veneering process. The third set of specimens (n=10) was heat-treated five times to mimic the full veneering process. Flexural strength, microhardness, dimensions and surface roughness were measured. The fracture patterns were assessed by light microscopy. RESULTS: The untreated specimens showed a statistically significant higher flexural strength (20%) and microhardness (9%) than both of the test groups (p< or =0.001). No significant differences were found for fracture patterns, dimensions or surface roughness. SIGNIFICANCE: The heat treatment associated with the veneering procedure on a zirconia core material reduced the flexural strength of the core after the first firing. Subsequent firings were not detrimental to the properties measured.     

The Effect of Multiple Firings on Microtensile Bond Strength of Core‐Veneer Zirconia‐Based All‐Ceramic Restorations

Purpose: Differences in core and veneer coefficients of thermal expansion, firing shrinkage, and speed of increasing and decreasing the temperature may generate stress in veneered all‐ceramic restorations. Given the necessity of performing multiple firing cycles to achieve improved contour, color, and esthetics, the purpose of this study was to determine the effect of multiple firing cycles on the microtensile bond strength (MTBS) of zirconia core to the porcelain veneer in zirconia‐based all‐ceramic restorations. Materials and Methods: Thirty blocks (12 × 12 × 4 mm³) of semi‐sintered zirconia were machined and sintered according to manufacturer's instruction. Specimens were placed in three groups based on the number of firing cycles (4, 6, 8) for the veneering process. After veneering, the specimens were sectioned into microbars with 8 mm length and 1 mm cross‐section. Twenty sound microbars in each group were stressed to failure in a microtensile tester machine at 1 mm/min. Fractured specimens were surveyed under a scanning electron microscope and classified as cohesive in core, cohesive in veneer, and mixed. MTBS data were analyzed using one‐way ANOVA and Tukey test (p < 0.05). Results: The mean MTBS (MPa) after 4, 6, and 8 firing cycles were 30.33 ± 2.13, 27.43 ± 1.79, and 25.06 ± 1.76, respectively. There was a statistically significant difference between the bond strengths of each of the three groups (p < 0.001). Conclusion: Increase in firing cycles decreased MTBS. Most of the failures (90–95%) in all three groups were cohesive in the veneering porcelain and did not change as the number of firing cycles increased.     

Promoting porcelain–zirconia bonding using different atmospheric pressure gas plasmas

Objectives

To evaluate the effects of different atmospheric-pressure plasma (APP) on the physicochemical properties of yttria-stabilized zirconia, and promoting the adhesion of veneering porcelain.

Shear strength of core-veneer interface in bi-layered ceramics

STATEMENT OF PROBLEM: Delamination of veneering porcelain from underlying ceramic substrates has been reported for all-ceramic restorations. Whether this phenomenon is an inherent weakness of the veneering porcelain due to a weak interface between the veneering and the core porcelains, or merely a fracture through the veneering porcelain itself, has not been explored. PURPOSE: The purpose of this study was to investigate the strength of the substructure and veneering porcelain interface in all-ceramic systems. METHODS: The all-ceramic systems tested with their respective veneering porcelains were IPS-Empress2 with Eris (IE), Procera AllCeram with AllCeram (PA), Procera AllZircon with CZR (PZ), and DC-Zircon with Vita D (DC). The veneering porcelain recommended by the manufacturer for each material was fired to the ceramic core. A metal ceramic (MC) combination was tested as a control group. Sixty specimens, 12 for each system and control, were made from 1 master die. A cylinder of veneering porcelain 2.4 mm in diameter was applied using a specially designed aluminum split mold. After firing, the specimens were placed in a mounting jig and subjected to shear force in a universal testing machine. Load was applied at a crosshead speed of 0.50 mm/min until failure. Average shear strengths (MPa) were analyzed with a 1-way analysis of variance and the Tukey test (alpha=.05). The failed specimens were examined microscopically at original magnification x20 to classify the mode of failure as cohesive in the core, cohesive in the veneer, or adhesive at the interface. RESULTS: The mean shear strengths (+/-SD) in MPa were MC control 30.16 +/- 5.88; IE bonded to Eris 30.86 +/- 6.47; PZ bonded to CZR 28.03 +/- 5.03; DC bonded to Vita D 27.90 +/- 4.79; and PA bonded to AllCeram 22.40 +/- 2.40. IE, PZ, and DC were not significantly different from the MC control. Microscopic examination showed that adhesive failure, or complete delamination, did not occur between the compatible ceramic core and veneering materials. Failure primarily occurred near the interface with residual veneering porcelain remaining on the core. IE with Eris exhibited cohesive failure in both the core and the veneer. CONCLUSION: The bond strengths of 3 of the tested all-ceramic materials (IE, PZ, and DC) were not significantly different from the control (MC) group.     

Complication rate of molar crowns: a practice-based clinical evaluation

This practice-based study evaluates the initial clinical performance of conventionally luted metal-ceramic and zirconia molar crowns fabricated with a prolonged cooling period of the veneering porcelain. Forty-nine patients were treated (group A: high precious alloy + low fusing porcelain; group B: zirconia crowns). All zirconia crowns were veneered with a modified porcelain firing cycle including a 6-minute cooling period. Ninety-two restorations (74 vital abutments/18 nonvital abutments) were evaluated after a mean observation period of 18.2 +/- 4.6 months. No complete failures or loss of vitality were recorded in either group. Two events were recorded in group A (1 loss of retention/1 minor ceramic chipping < 2 mm2). The third event occurred in group B (minor ceramic chipping <2 mm2). All ceramic defects could be polished intraorally. Statistical analysis revealed non-significant differences in success rates (p = 0.91) of metal-ceramic and zirconia crowns fabricated with a modified porcelain firing. The modified firing of the zirconia porcelain seems to decrease the risk for early ceramic chipping in the molar area, leading to a technical complication rate comparable to that of metal-ceramic crowns.     

不同喷砂条件对氧化锆/间接修复树脂双层结构剪切强度的影响

目的探究不同喷砂压力、喷砂时间以及喷砂氧化铝颗粒大小对牙科氧化锆与间接修复树脂界面剪切强度的影响。方法 250个氧化锆试件根据不同的喷砂压力、喷砂时间及喷砂氧化铝颗粒大小随机分成25组,对照组氧化锆不接受表面喷砂。使用万用试验机对每一组氧化锆试件与间接修复树脂界面的剪切强度进行测量并比较。并观察断面断裂模式。结果随着喷砂时间、喷砂颗粒尺寸增加,氧化锆与间接修复树脂界面剪切强度随着增加(P<0.001;P<0.001)。喷砂压力由0.1 MPa增加至0.2 MPa时,界面剪切强度增加(P=0.036),当喷砂压力由0.2 MPa增加至0.4 MPa或0.4 MPa增加至0.6 MPa,界面剪切强度未有显著变化(P=0.609;P=0.689)。C型断裂模式随着剪切强度增加出现概率也增加。结论在牙科领域氧化锆与间接修复树脂粘结中采用21 s、0.2 MPa及110μm的喷砂条件最为适合。     

Effect of veneering method on the fracture and bond strength of bilayered zirconia restorations

This study evaluated the fracture strength and microtensile bond strength of a new computer-aided design (CAD) veneering method for zirconia frameworks. A new CAD/computer-assisted manufacture system was used to fabricate a resin replica of the esthetic ceramic required to veneer a zirconia framework. The replicas were processed using press-on technology. Identical manually layered zirconia specimens served as a control (n = 18; alpha = .05). Statistical analysis revealed that the fracture strength (442.8 +/- 25 N) and microtensile bond strength (26.6 +/- 2 MPa) of CAD-veneered zirconia were significantly higher (P < .001) compared to the control (346 +/- 24 N and 15.1 +/- 1 MPa, respectively). CAD veneering is a reliable method for veneering zirconia frameworks.     

Effect of surface treatment on bond strength between an indirect composite material and a zirconia framework

The present study evaluated the effect of various surface treatments for zirconia ceramics on shear bond strength between an indirect composite material and zirconia ceramics. In addition, we investigated the durability of shear bond strength by using artificial aging (20,000 thermocycles). A total of 176 Katana zirconia disks were randomly divided into eight groups according to surface treatment, as follows: group CON (as-milled); group GRD (wet-ground with 600-grit silicon carbide abrasive paper); groups 0.05, 0.1, 0.2, 0.4, and 0.6 MPa (airborne-particle abrasion at 0.05, 0.1, 0.2, 0.4, and 0.6 MPa, respectively); and group HF (9.5% hydrofluoric acid etching). Shear bond strength was measured at 0 thermocycles in half the specimens after 24-h immersion. The remaining specimens were subjected to 20,000 thermocycles before shear bond strength testing. Among the eight groups, the 0.1, 0.2, 0.4, and 0.6 MPa airborne-particle abraded groups had significantly higher bond strengths before and after thermocycling. The Mann-Whitney U-test revealed no significant difference in shear bond strength between 0 and 20,000 thermocycles, except in the 0.2 MPa group (P = 0.013). From the results of this study, use of airborne-particle abrasion at a pressure of 0.1 MPa or higher increases initial and durable bond strength between an indirect composite material and zirconia ceramics.