饰面瓷厚度对氧化锆全瓷冠抗压缩破坏力的影响

目的：研究饰面瓷厚度对氧化锆全瓷冠抗压缩破坏力的影响。方法：常规 CAD-CAM制作氧化锆筒状基底冠25个,厚度均为0．5 mm,随机分为 A、B、C、D、E 5组,饰面瓷厚度依次为0．5、1．0、1．5、2．0、2．5 mm。万能材料试验机测试各组试件抗压缩破坏力值。采用 SPSS13．0统计软件对测试结果进行统计分析。用扫描电镜（SEM）观察试件断裂面微观结构。结果：A ～E 组试件抗压缩破坏力值依次为：（1279．96±42．85）N、（2235．44±50．14）N、（2216．38±48．97）N、（2169．22±60．40）N、（2028．70±47．37）N。A 组、E 组氧化锆全瓷修复体的抗压缩破坏力值均低于其他3组（P ＜0．01）;其余组间抗压缩破坏力值无统计学差异（P ＞0．05）。扫描电子显微镜观察发现,A 组、E 组氧化锆全瓷修复体基底瓷－饰面瓷结合界面处不平坦,较为疏松;饰瓷层出现气孔及微裂纹增多、增大。结论：饰面瓷厚度低于1．0 mm 及高于2．0 mm 时,修复体的微观结构可能会受到影响,从而氧化锆全瓷冠整体抗压缩破坏力的性能受影响,建议临床应用时严格控制饰面瓷厚度。     

Enhancement of the adhesion between cobalt-base alloys and veneer ceramic by application of an oxide dissolving primer

Objectives

Uncontrolled formation of an oxide layer on base metal alloy surface impairs adhesion between the alloy and veneer ceramic. The aim of this study was to investigate the influence of an oxide dissolving primer on the adhesion between cobalt-base alloys and a veneer ceramic.

Methods

Combinations of two cobalt-base alloys (Bärlight/BL, Cara Process/CP) and one veneering ceramic (HeraCeram) were investigated. 40 rectangular specimens of each alloy were covered with the veneer ceramic; half of the alloy samples were treated with an oxide dissolving primer (NP-Primer) prior to veneering (n = 20). Subsequently, the veneering surface was ground flat and notched using the single-edge V-notched-beam method. Then specimens were loaded in a four-point bending test and the critical load to induce stable crack extension at the adhesion interface was determined, in order to calculate the strain energy release rate (G, J/m²). Finally, fracture surfaces of the specimens were evaluated by scanning electron microscopy (SEM).

Results

Strain energy release rates averaged between 24.1 J/m² and 28.8 J/m². While application of the primer statistically significantly increased adhesion between alloy and ceramic with the BL specimens (p = 0.035), no significant influence was found for the CP specimens (p = 0.785). For both material combinations, SEM analysis revealed enhanced wetting of the alloy surfaces with ceramic after application of the primer.

Significance

Application of an oxide dissolving primer increases the wettability of cobalt-base alloy surfaces and thus improves adhesion to veneering ceramics. This may enhance the long-term stability of bilayer restorations made from these materials.     

Effect of surface treatments on adhesion of low-fusing porcelain to titanium as determined by strain energy release rate

Objective

This study evaluated the effect of different chemical surface treatments on the surface characteristics of commercially pure titanium (cp Ti) and the adhesion of the porcelain–titanium system by means of strain energy release rate (G-value, J/m²). Surface roughness and morphology of treated cp Ti were additionally evaluated.

Methods

Two hundred and thirty specimens of machined cp Ti plates grade II were prepared. The specimens were divided into ten groups in each test according to the surface treatment used; Gr 1 (control; machined), Gr 2 (sandblasted), Gr 3 (CH₂Cl₂ for 5 min), Gr 4 (CH₂Cl₂ for 10 min), Gr 5 (10% H₂O₂ for 5 min), Gr 6 (10% H₂O₂ for 10 min), Gr 7 (30% H₂O₂ for 5 min), Gr 8 (30% H₂O₂ for 10 min), Gr 9 (9% HF for 5 min) and Gr 10 (9% HF for 10 min). Titanium–porcelain (Vita Titankeramik) was applied to each group for testing the adhesion. The G-value (J/m²) was measured with a four-point bending configuration. Following fracture testing specimens were examined with a scanning electron microscope (SEM). Surface roughness and SEM analysis were carried out. Data were analyzed using ANOVA and Tukey's test.

Results

Groups treated with 9% HF or CH₂Cl₂ baths for 10 or 5 min showed the highest adhesion values (J/m²) (34.23 ± 4.31, 30.75 ± 4.91, 28.92 ± 4.33 and 22.54 ± 3.58) respectively among the groups. The machined groups demonstrated the lowest value (8.18 ± 1.95) (J/m²). SEM analysis indicated a combination of cohesive and adhesive fractures for 9% HF, CH₂Cl₂, sandblasted and 30% H₂O₂ (10 min) groups, while mainly adhesive fractures were found with the other groups. There was no direct correlation between surface roughness and adhesion.

Significance

Adhesion between porcelain and cp Ti can be improved by the use of certain chemical surface treatments prior to porcelain firing as alternative techniques to sandblasting treatment.     

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KATA-NA氧化锆试件,分为四组,每组7个:①C组(对照组)打磨后直接堆塑饰瓷粉;②S组(喷砂组)打磨后喷砂,堆塑饰瓷粉;③B组(结合层组)...     

The effect of Goldbonder on the adhesion between porcelain and pure titanium

The present study examines the effect of a Goldbonder on the adhesion between titanium and porcelain as measured by the strain energy release rate (G) associated with the interfacial fracture of porcelain and titanium. The influence of surface treatment of titanium prior to Goldbonder application was also examined. The porcelain side of the specimens was notched to the interface with a thin diamond saw, and then a pre-crack was made at the metal-porcelain interface by a special jig. The samples were subjected to a four-point bending test resulting in stable crack extension from which G was calculated. Both the cracked cross-section of interface and peeled fracture surface were examined with scanning electron microscope (SEM). The mean G values were 81.57 +/- 10.34, 46.01 +/- 14.83, and 15.98 +/- 1.76 J m(-2) for the sandblasted surface with the Goldbonder, polished surface with the Goldbonder, and sandblasted surface with the Pastebonder, respectively. The G values revealed significant differences (P < 0.01) between Goldbonder and Pastebonder, and between the sandblasted and polished surfaces with Goldbonder. The SEM photographs and elemental analysis showed that Goldbonder developed both chemical and mechanical bonding to titanium and porcelain.