The effect of different surface treatments on bond strength between leucite reinforced feldspathic ceramic and composite resin

Objectives

The aim of this study was to evaluate the effect of different surface treatments on the microtensile bond strength between a leucite reinforced glass–ceramic and composite resin.

Methods

Leucite reinforced ceramic blocks (n = 24) were constructed using the hot pressing technique. The blocks were assigned to 4 groups, which received the following surface treatments: G1: hydrofluoric (HF) acid and silane; G2: silane alone; G3: HF acid and silane then dried with warm air (100 °C); G4: silane alone then dried with warm air (100 °C). Unfilled resin was applied, followed by composite resin. Specimens were prepared and loaded in tension to determine the microtensile bond strength. Failure modes were classified by stereo- and scanning electron microscopy (SEM). Data was analysed using Kruskal–Wallis test followed by the Dunn's multiple range test.

Results

The groups including the warm air step (G3 and G4) achieved a significantly stronger adhesion than G1 and G2. Pre-treatment of the surface with hydrofluoric acid in G1 resulted in significantly higher bond strength than G2. Failures were mostly cohesive in the luting resin for G1, G3 and G4 and mainly adhesive at the ceramic–resin interface in G2.

Conclusions

The method of application of silane to the ceramic surface can have a significant influence on the adhesion between the ceramic restoration and the resin cement. Enhancing the condensation reaction by drying the silane with a 100 ?C warm air stream significantly improved the microtensile bond strength, possibly eliminating the need for the hydrofluoric acid etching step.     

Effect of different surface treatments on In-Ceram Alumina roughness. An AFM study

Objectives

The aim of this study was to evaluate the influence of different treatments on the surface roughness of In-Ceram Alumina (VITA, Säckingen, Germany).

Methods

The ceramic blocks were polished (4000 grit) and sandblasted (SB) with airborne particle abrasion Al₂O₃; 110 μm particle size; 2.8 bar; 20 s. The following treatments were performed: (1) no treatment; (2) Rocatec System (RC): after SB treatment, sandblasting with silica powder; 30 μm particle size; 2.8 bar; 20 s. (3) Neodymium:yttrium–aluminium–garnet (Nd:YAG) laser (ND) application of graphite powder (stain) on the ceramic surface and Nd:YAG laser irradiation (distance: 1 mm, 100 mJ, 20 Hz, 2 W, and 141.54 J/cm²). (4) Nd:YAG laser plus Rocatec System: after ND treatments, RC was applied. Digital images (20 μm × 20 μm) from the surfaces were obtained by means of an AFM microscope in taping mode (Nanoscope IIIa, Digital Instruments). Roughness was measured in 10 μm × 10 μm boxes. Roughness (R_a) data (nm) were analyzed by one-way ANOVA (p < 0.05).

Results

No differences in ceramic surfaces roughness occurred after any of the tested treatments (p = 0.54).

Conclusions

High-alumina ceramic surface roughness was not increased with any of the tested treatments.     

80件CEREC3全瓷修复体的临床效果回顾分析

目的探讨应用数字椅旁全瓷修复系统（CEREC3）进行椅旁即刻全瓷修复的临床效果。方法采用数字椅旁全瓷修复系统（CEREC3）共完成75例患者的全瓷修复体80件。追踪观察1.0～1.5年,询问患者对全瓷修复的主观感受,记录全瓷修复体的变化等。回顾分析80件全瓷修复的临床疗效。结果患者对CEREC3全瓷修复体的主观评价满意率为95.00%（76/80）,崩瓷率为3.75%（3/80）。结论采用CEREC3,能制作出高质量并且具有天然牙色的全瓷修复体,方便快捷,临床效果满意。     

两种底板设计的国产陶瓷托槽拉伸粘接强度的研究

目的评价两种不同底板设计的国产多晶体氧化铝陶瓷托槽拉伸粘接强度是否满足临床使用的需要。方法实验组为国产沟槽底板（3条横沟）和网格底板（3×3网格）陶瓷托槽,对照组为临床常用多晶体氧化铝陶瓷托槽CrystalineIV。30颗离体下颌双尖牙随机分为3组,每组10颗,使用37%液体磷酸和京津釉质粘接剂,分别粘接上述三种托槽,在0.9%生理盐水中室温保存24h。使用WDW3050型微机控制电子万能试验机检测拉伸粘接强度。托槽脱落后记录粘接剂残留指数,陶瓷托槽的折断数目和釉质表面出现肉眼可见缺损的牙齿数目。结果国产沟槽底板陶瓷托槽的拉伸粘接强度显著低于网格底板和CrystalineIV,后两者间的差异无显著性意义。三种陶瓷托槽的主要去除部位均在粘接剂内,所有样本未出现陶瓷托槽折断和肉眼可见的釉质缺损。结论国产沟槽底板陶瓷托槽不能获得临床所需的拉伸粘接强度,网格底板的陶瓷托槽更具开发前景。     

An effect of immediate dentin sealing on the shear bond strength of resin cement to porcelain restoration

PURPOSE

The aim of this study was to determine differences in shear bond strength to human dentin using immediate dentin sealing (IDS) technique compared to delayed dentin sealing (DDS).

MATERIALS AND METHODS

Forty extracted human molars were divided into 4 groups with 10 teeth each. The control group was light-cured after application of dentin bonding agent (Excite® DSC) and cemented with Variolink® II resin cement. IDS/SE (immediate dentin sealing, Clearfil™ SE Bond) and IDS/SB (immediate dentin sealing, AdapterTM Single Bond 2) were light-cured after application of dentin bonding agent (Clearfil™ SE Bond and Adapter™ Sing Bond 2, respectively), whereas DDS specimens were not treated with any dentin bonding agent. Specimens were cemented with Variolink® II resin cement. Dentin bonding agent (Excite® DSC) was left unpolymerized until the application of porcelain restoration. Shear strength was measured using a universal testing machine at a speed of 5 mm/min and evaluated of fracture using an optical microscope.

RESULTS

The mean shear bond strengths of control group and IDS/SE group were not statistically different from another at 14.86 and 11.18 MPa. Bond strength of IDS/SE group had a significantly higher mean than DDS group (3.14 MPa) (P < .05). There were no significance in the mean shear bond strength between IDS/SB (4.11 MPa) and DDS group. Evaluation of failure patterns indicates that most failures in the control group and IDS/SE groups were mixed, whereas failures in the DDS were interfacial.

CONCLUSION

When preparing teeth for indirect ceramic restoration, IDS with Clearfil™ SE Bond results in improved shear bond strength compared with DDS.     

唐山市售陶瓷地砖γ射线水平调查

目的 了解唐山市售陶瓷地砖γ射线水平。方法 采集唐山市售的产自A、B、C3省的普通陶瓷地砖、抛光型地砖、颗粒型地砖测定γ射线水平。结果 产自A、B、C3省的陶瓷地砖的γ射线水平分别为91．1、76．8、75.1nGy／h，颗粒型、抛光型、普通陶瓷地砖γ射线水平分别为92．7、88．9、78．0nGy／h。结论 消费者应尽量选购普通型陶瓷地砖。     

Chairside CAD/CAM materials. Part 1: Measurement of elastic constants and microstructural characterization

Objective

A deeper understanding of the mechanical behavior of dental restorative materials requires an insight into the materials elastic constants and microstructure. Here we aim to use complementary methodologies to thoroughly characterize chairside CAD/CAM materials and discuss the benefits and limitations of different analytical strategies.

Color in Zirconia‐Based Restorations and Related Factors: A Literature Review

Zirconia ceramic is a popular trend in esthetic and restorative dentistry. Computer‐aided design/computer‐aided manufacturing (CAD/CAM) systems have been well developed to fabricate zirconia frameworks and restorations with acceptable mechanical properties. Zirconia ceramics have excellent optical characteristics; however, achieving optimal esthetic outcomes with zirconia‐based restorations is still challenging due to multiple effective factors on the final color. These factors are different layers of a zirconia‐based restoration and its underlying structures including: dental substrate, cement, zirconia coping, veneering ceramic, and glaze. Moreover, the laboratory procedure of these restorations’ fabrication is another effective factor on the resultant color. Unpredictable esthetic results may be obtained without estimation of the role of each factor and its effect on the final color. This review discussed the color aspect of zirconia‐based restorations according to these factors and based on the literature. In the past decade, investigators have been concerned with the shade reproduction with zirconia‐based restorations; however, there are no sufficient clinical guidelines on how to reproduce the appearance of natural teeth with these restorations. Zirconia‐based restorations have presented a new chance for accomplishing optimum esthetics. Nonetheless further investigations are needed on these restorations to establish clinical guidelines on esthetics.     

Approximate relative fatigue life estimation methods for thin-walled monolithic ceramic crowns

Objectives

The objective is to establish an approximate relative fatigue life estimation method under simulated mastication load for thin-walled monolithic restorations.

Restoration integrity,but not material or cementation strategy determined secondary caries lesions next to indirect restorations in vitro

Objective

Secondary caries lesions next to direct restorations are associated with the restoration material and the integrity of the tooth-restoration-interface (presence of interfacial gaps) as well as the application of masticatory forces. It remains unclear if this is true for indirect restorations. We aimed to evaluate secondary lesions next to conventionally-cemented partial gold (PG) and adhesively-cemented partial ceramic (PC) restorations, placed with or without interfacial gaps.