Durability of resin bonding to zirconia ceramic after contamination and the use of various cleaning methods

ObjectivesThe aim of the study was to evaluate the influence of contamination and different cleaning methods on the tensile bond strength with a phosphate monomer containing luting resin to zirconia ceramic.MethodsAfter the contamination with saliva or silicone disclosing agent, 228 polished and airborne-particle abraded zirconia discs were ultrasonically cleaned with 99% isopropanol. In a second step, the specimens were either treated with argon-oxygen plasma, air plasma, enzymatic cleaning agent or did not undergo an additional cleaning process. Uncontaminated zirconia specimens were used as the control group. X-ray photoelectron spectroscopy (XPS) was used for chemical analysis of the bonding surfaces of specimens. Plexiglas tubes filled with composite resin were bonded to zirconia specimens with a phosphate monomer containing luting resin. Tensile bond strength (TBS) was tested after 3 days or 150 days water storage with 37,500 thermal cycles.ResultsXPS revealed a decrease of the carbon/oxygen ratio after plasma treatment and an increase after treatment with an enzymatic cleaning agent in all groups. All contaminated specimens showed high and durable TBS after cleaning with a combination of isopropanol and a non-thermal atmospheric plasma. After the cleaning with enzymatic cleaning agent the TBS was significantly reduced in all groups after 150 days thermal cycling.SignificanceThe combination of isopropanol and plasma cleaning was effective in removing salvia and disclosing agent contamination. Enzymatic clearing agent was not able to remove contamination effectively and had a negative impact on the TBS of non-contaminated specimens.     

Influence of saliva contamination on zirconia ceramic bonding.

OBJECTIVES: The purpose of this study was to investigate the influence of saliva contamination and cleaning methods on adhesive bonding to dental zirconia ceramic with a phosphate-monomer-containing luting resin. METHODS: After saliva immersion, airborne-particle abraded ceramic specimens were cleaned with water rinsing, with isopropanol, with phosphoric acid gel, or with additional airborne-particle abrasion. Airborne-particle abraded specimens without contamination were used as the control group. Chemical analysis of the ceramic surfaces of all groups was done using X-ray photoelectron spectroscopy (XPS). The influence of contamination and cleaning methods on ceramic bond durability was examined by tensile bond strength (TBS) testing after 3 days or 150 days water storage with 37,500 thermal cycles. RESULTS: After saliva contamination XPS revealed an organic coating which was not removed completely with water rinsing, with isopropanol, or with phosphoric acid. Using TBS testing a strong influence of contamination and cleaning methods on resin bond strength and its durability was found. SIGNIFICANCE: Saliva contamination significantly affected resin bonds to zirconia ceramic and its durability. Airborne-particle abrasion was the most effective cleaning method.     

Influence of contamination on zirconia ceramic bonding

The removal of contaminants prior to the bonding of ceramics is critical for the clinical success of a long-term durable resin bond. This study tested the null hypotheses that there are no contaminants on the zirconia ceramic surface left after try-in simulation, and there are no influences of contamination and cleaning methods on zirconia ceramic bonding durability with 10-methacryloyloxy-decyl dihydrogenphosphate-containing composite resins. After saliva immersion and the use of a silicone disclosing agent, airborne-particle-abraded ceramic specimens were cleaned with acetone, 36% phosphoric acid, additional airborne-particle abrasion, or only water spray. Chemical analyses of specimen surfaces were performed by x-ray photoelectron spectroscopy. The influences of contamination and cleaning methods on ceramic bond durability were examined by tensile testing after 3 or 150 days' water storage with 37,500 thermal cycles. Contamination, existing after try-in simulation as confirmed by chemical analysis, significantly reduced zirconia ceramic-resin bonds. Airborne-particle abrasion may be the most effective cleaning method.     

唾液污染对氧化锆陶瓷粘结影响的研究

目的:研究唾液污染对氧化锆陶瓷粘结的影响,以及有效清除污染的方法。方法:Al2O3颗粒喷砂处理的氧化锆陶瓷盘状标本40个,分成5组,每组8个,1组标本不经唾液浸润作为对照组,其余4组标本进行唾液浸润后,分别用75%乙醇冲洗、37%磷酸冲洗、水冲洗和喷砂的清洁方法处理,用X-射线电子光谱对各组标本进行表面化学分析,然后将复合树脂小柱与各组陶瓷盘状标本用含有磷酸盐单体的树脂类粘结剂粘结,在水中浸泡3d以后,测量其拉伸强度(TBS)。结果:与对照组相比,磷酸组和喷砂组的唾液污染被有效清除,而乙醇和水不能清除陶瓷表面的唾液污染。结论:在氧化锆陶瓷修复体的试戴过程中,唾液污染显著地降低了氧化锆陶瓷与树脂类粘结剂粘结的拉伸强度(TBS),而进行喷砂处理是最有效的去除唾液污染的方法。     

Ten‐years degradation of resin–dentin bonds

Hashimoto M, Fujita S, Nagano F, Ohno H, Endo K. Ten‐years degradation of resin–dentin bonds. Eur J Oral Sci 2010; 118: 404–410. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci The purpose of this study was to evaluate the durability of resin–dentin bonds in 10‐yr water‐storage testing. Resin–dentin bonded bulk specimens were prepared using six commercially available resin adhesives. The resin–dentin bonded specimens were stored in water for 24 h (control group) or for 10 yr (experimental groups). After each storage period, the specimens were sectioned to make specimen beams and then subjected to a microtensile bond test. After the bond test, fractured surfaces were examined by scanning electron microscopy (SEM). In addition, interfacial observation of silver nanoleakage was performed using the backscatter electron mode of SEM. The bond strengths of four of the six adhesive systems tested decreased significantly after 10 yr. However, no significant bond‐strength reduction was recorded for the other two systems. The interfacial observations showed water tree propagation in the bonding resin layer as a typical morphological change after aging for five of the six adhesives tested. Water tree propagation may be a symptom of degradation in the resin bonding layer of resin–dentin bonds.     

Microtensile Bond Strength of a Resin Cement to Silica‐Based and Y‐TZP Ceramics Using Different Surface Treatments

Purpose

To evaluate the effects of different surface treatments on the microtensile bond strength (μTBS) of bonding between resin cement and lithia or zirconia‐based ceramics using an in vitro study.

Materials and Methods

Three zirconia ceramic blocks (IPS e.max ZirCAD) and three lithium disilicate ceramic blocks (IPS e.max CAD) were sintered and duplicated in resin composite. The zirconia specimens underwent various treatments (n = 1): (i) Sandblast + primer (ZiSa); (ii) sandblast + laser irradiation + primer (ZiSaLa); or (iii) laser irradiation + primer (ZiLa). The lithium disilicate specimens also underwent various treatments: (i) sandblast + HF + silane (LiSaE); (ii) sandblast + silane (LiSa); or (iii) sandblast + laser irradiation + silane (LiSaLa). The ceramic–composite blocks were cemented with resin cement and cut to produce bars with approx. 1 mm² bonding areas. The specimens were thermocycled, and bond strength tests were performed in a universal testing machine. The fracture type was determined by observing the fractured surface under a stereomicroscope. The mean bond strengths of the specimens were statistically analyzed using one‐way ANOVA and Duncan's tests (α = 0.05).

Results

Mean comparison of the μTBS showed no significant difference between LiSaE and LiSa (p > 0.05), but significant differences between LiSaE and other groups (p ≤ 0.01). No significant differences were found between the ZiSaLa and ZiSa groups (p > 0.05). The modes of failure in all groups were mostly adhesive (57% to 80%). The mean bond strengths in laser‐irradiated ceramics were significantly lower than those from other surface treatments. All ZiLa specimens debonded before testing (pretest failure).

Conclusions

Lithium disilicate ceramic surface treated with a combination of sandblasting and silane application provided a bond strength comparable to that provided by sandblasting in combination with acid etching and applying silane. Groups treated with laser irradiation had significantly lower bond strengths than other groups.     

Enzymatic degradation of adhesive–dentin interfaces produced by mild self‐etch adhesives

De Munck J, Mine A, Van den Steen PE, Van Landuyt KL, Poitevin A, Opdenakker G, Van Meerbeek B. Enzymatic degradation of adhesive–dentin interfaces produced by mild self‐etch adhesives.
Eur J Oral Sci 2010; 118: 494–501. © 2010 Eur J Oral Sci Endogenous matrix metalloproteinases (MMPs) released by adhesive procedures may degrade collagen in the hybrid layer and so compromise the bonding effectiveness of etch‐and‐rinse adhesives. In this study, endogenous enzymatic degradation was evaluated for several simplified self‐etch adhesives. In addition, primers were modified by adding two MMP inhibitors: chlorhexidine, a commonly used disinfectant, but also a non‐specific MMP inhibitor; and SB‐3CT, a specific inhibitor of MMP‐2 and MMP‐9. Gelatin zymography of fresh human dentin powder was used to identify the enzymes released by the adhesives. Micro‐tensile bond strength (μTBS) testing was used to assess the mechanical properties of resin–dentin interfaces over time. In none of the experimental groups treated with the mild self‐etch adhesives was MMP‐2 and/or MMP‐9 identified. Also, no difference in the μTBS was measured for the inhibitor‐modified and the control inhibitor‐free adhesives after 6 months of water storage. It is concluded that in contrast to etch‐and‐rinse adhesives, the involvement of endogenous MMP‐2 and MMP‐9 in the bond‐degradation process is minimal for mild self‐etch adhesives.     

底涂剂的化学处理对二氧化锆陶瓷树脂粘接效果的影响

目的 评估专用底涂剂的化学处理对二氧化锆陶瓷与自粘接型树脂水门汀间粘接效果的影响。方法 2.5 mm厚可切削二氧化锆陶瓷片（Vita InceramYZ）经烧结、研磨、清洗后,一半的陶瓷试件表面在0.3 MPa压力下接受50 μm Al2O3颗粒喷砂处理20 s。使用X射线荧光光谱仪对研磨和喷砂组的陶瓷表面成分进行定性定量分析。研磨和喷砂组的陶瓷片各分为2组：一组直接与自粘接型树脂水门汀（Biscem）进行粘接,另一组经底涂剂（Z Primer Plus）处理后与Biscem进行粘接。各实验组试件再分为两个亚组（n=10）经0、10000次冷热循环后接受剪切粘接 强度测量。使用多因素方差分析对数据进行统计。结果 喷砂后的陶瓷表面会有质量比为8.27%的Al2O3颗粒附着。 与喷砂处理相比,底涂剂处理对冷热循环前粘接强度的提高更加显著。冷热循环前后,未经过底涂剂处理的陶瓷与 树脂间粘接强度的差异无统计学意义（P>0.05）,但经过底涂剂处理后陶瓷与树脂间粘接强度的差异有统计学意义（P<0.05）。结论 底涂剂的化学处理能够显著提高二氧化锆陶瓷与自粘接型树脂水门汀的初期粘接强度,但在耐 久实验条件下其粘接界面不稳定,会出现快速老化。     

Bond strength durability of self-adhesive resin cements to zirconia ceramic: An in vitro study

Statement of problem

How contamination, cleaning, and artificial aging affect the bond strength of self-adhesive resin cements to zirconia ceramics is unclear.

Durability of the resin bond strength to zirconia ceramic after using different surface conditioning methods.

OBJECTIVES: The purpose of this in vitro study was the evaluation of the bond strength and its durability of two composite resins to zirconia ceramic after using different surface conditioning methods. METHODS: Plexiglas tubes filled with composite resin were bonded to zirconia ceramic discs (Cercon) which were either in their original state as supplied by the manufacturer only cleaned in isopropanol or were cleaned with an air-powder-water spray with sodium hydrocarbonate solution or were air abraded (50 microm Al(2)O(3)). Groups of 20 specimens each were bonded either with a conventional composite resin (Variolink II) or with a phosphate monomer (MDP)-containing resin (Panavia F) to the ceramic discs. Subgroups of 10 bonded specimens were stored in distilled water (37 degrees C) for either 3 days or for 150 days. Additionally, the 150 days specimens were thermal cycled 37,500 times. Statistical analyses were conducted with the Wilcoxon rank sum test adjusted by Bonferroni-Holm. RESULTS: The initial tensile bond strength (TBS) for Variolink II ranged from 9.0 to 16.6 MPa and were significantly lower (p< or =0.05) than for Panavia F ranging from 18.7 to 45.0 MPa. Air abrasion resulted in significantly higher TBS (p< or =0.01) than the two other surface conditioning methods. After 150 days storage, only the air abraded specimens bonded with Panavia F showed high bond strengths of 39.2 MPa, whereas most other specimens debonded spontaneously or showed very low bond strengths. SIGNIFICANCE: The use of the MDP-containing composite resin Panavia F on air abraded zirconia ceramic can be recommended as promising bonding method.     

不同粘固前处理方法对氧化锆陶瓷粘结性能的影响

目的　探讨不同粘固前处理方法对被唾液污染的氧化锆陶瓷粘结性能的影响。方法　将烧结喷砂后的氧化锆陶瓷片分为4组,每组6片,（1）空白对照,（2）唾液污染+水冲洗,（3）唾液污染+水冲洗＋75％乙醇处理＋水冲洗,（4）唾液污染+水冲洗＋磷酸凝胶（含35％正磷酸）＋水冲洗,进行表面处理,与树脂粘结剂粘结,水浴24 h后测试其黏结剪切强度,数据用SPSS12.0软件进行统计学分析。结果　对照组的氧化锆陶瓷试件的粘结剪切粘结强度最高,水冲洗组的氧化锆陶瓷试件粘结剪切强度最低。与对照组粘结剪切强度相比,水冲洗组及乙醇处理组的差别均有统计学意义(P<0.05);结论　唾液污染影响牙科氧化锆陶瓷粘结强度;单纯水冲洗及75％乙醇处理不能清除唾液污染的影响。     

Bonding quality of contemporary dental cements to sandblasted esthetic crown copings*

Aim: To evaluate the shear bond strength of current luting cements to sandblasted crown‐coping substrates. Methods: Specimens of nickel‐chromium, pressable glass ceramic, and zirconia crown‐coping substrates were sandblasted in three groups (n = 30 each) with 50 (group 1), 110 (group 2), and 250 μm (group 3) alumina particles at a pressure of 250 kPa. Cylinders of glass ionomer, universal resin, and self‐adhesive resin cements were then built up on the sandblasted substrate surfaces of each group (n = 10). All bonded specimens were stressed to evaluate the cement–substrate shear bond strength. Both the mode and incidence of bond failure were also considered. Results: No difference was noticed between all test groups in terms of cement–substrate bond strength. In comparison to self‐adhesive type, the universal resin cement provided lower bond strengths to both metal and glass–ceramic substrates in group 1. The self‐adhesive resin cement provided the highest bond strengths to the zirconia substrates in groups 2 and 3. The adhesive type of bond failure was common in the metal and zirconia substrates in all groups. Conclusions: Cement–substrate bonding quality is not affected by the size of sandblasting particles. Resin cements bond better to different coping substrates. Self‐adhesive resin cement is the best choice to bond zirconia‐based substrates.     

Bond strength of composite resin to glass ceramic after saliva contamination

Objectives

Purpose of this study was to investigate the effect of cleaning methods of glass ceramic specimens contaminated with saliva on tensile bond strength (TBS) to composite resin. Additionally, effect of water storage on bond strength was evaluated.

Materials and methods

Glass ceramic discs (IPS Empress, Ivoclar-Vivadent, FL) distributed among five groups (n?=?28) were etched with hydrofluoric acid, silanized, contaminated with human saliva, and in group W rinsed with water, group WS additionally silanized, group E rinsed with water and cleaned with ethanol, and group ES additionally silanized. Group C served as a control without contamination. Plastic screws were bonded to the glass ceramic discs using Variolink II (Ivoclar-Vivadent). TBS was measured after 24 h and after 150 days of storage. Failure modes were examined. ANOVA was applied to explore group effect on TBS. Pair-wise comparisons were calculated.

Results

The mean TBS [in megapascals] were for W 46?±?14, WS 55?±?8, E 48?±?11, ES 52?±?10, and C 50?±?8 after 24 h, and W 39?±?11, WS 53?±?9, E 48?±?8, ES 48?±?11, and C 50?±?8 after 150 days. After 150 days specimens of group W showed significantly lower TBS compared to group C (p?=?0.05). Additional silanization in group WS led to a significant increase of TBS compared to specimens of group W (p?=?0.003). Adhesive fractures were observed only in specimens without second application of silane.

Conclusions

The cleaning of the contaminated glass ceramic surface by rinsing only did not result in a durable bond.

Clinical relevance

Pre-silanized glass ceramic restorations need to be rinsed and treated with a fresh layer of silane after saliva contamination.     

The Effect of Laser Treatment on Bonding Between Zirconia Ceramic Surface and Resin Cement

Abstract

Objective. The purpose of this in-vitro study was to evaluate and compare the effects of different surface treatments and laser irradiation on the shear bond strength of resin cement to zirconia-based ceramic. Material and methods. Forty zirconia core specimens (10-mm diameter, 2-mm thickness) were produced and embedded in the centers of autopolymerizing acrylic resin blocks. Subsequently, specimens were randomly divided into four groups, each containing 10 specimens, for different surface treatment methods. The details of the groups are as follows: Group C, no treatment applied (control); Group SB, bonding surfaces of ceramic disks were airborne particle-abraded with 110-μm alumina oxide particles; Group HF, bonding surfaces of ceramic disks were etched with 9.6% hydrofluoric acid; and Group L, bonding surfaces of ceramic disks were irradiated by a CO₂ laser. A total of 40 composite resin disks were fabricated and cemented with an adhesive resin cement to the specimen surfaces. A universal test machine was used for the shear bond strength test at a crosshead speed of 1 mm/min. Results. The highest shear bond strength values were obtained with Group L (20.99 ± 3.77 MPa) and the lowest values with Group C (13.39 ± 3.10 MPa). Although there was no significant difference between Groups C, HF and SB (P > 0.05), Group L showed a significant difference from all other groups (p < 0.05). Conclusion. All surface treatment methods improved the bond strength between resin cement and the zirconium oxide ceramic surface. CO₂ laser etching may represent an effective method for conditioning zirconia surfaces, enhancing micromechanical retention and improving the bond strength of resin cement on zirconia ceramic.     

Long-term resin bond to densely sintered aluminum oxide ceramic

Background: Densely sintered aluminium oxide ceramic is a popular material for ceramic copings and all‐ceramic restorations. A strong, predictable, and long‐term durable resin bond is key for long‐term clinical success of bonded alumina‐based restorations. Purpose: The purpose of this study was to measure and compare in vitro shear bond strengths of three resin cements with and without their corresponding silane coupling/bonding agent to air particle‐abraded densely sintered aluminum oxide ceramic after long‐term water storage and thermocycling. Materials and Methods: Composite resin cylinders were bonded to air particle‐abraded samples of densely sintered aluminum oxide ceramic with Noribond DC® (Noritake Dental Supply, Inc., Aichi, Japan), Panavia 21® EX (Kuraray, Osaka, Japan), and Variolink II® (Ivoclar Vivadent, Schaan, Liechtenstein), which were used with and without their corresponding silane coupling and bonding agents (n= 15). All specimens (N= 90) were stored for 180 days in water and subjected to repeated thermocycling for a total of 12,000 cycles before shear bond strength was tested. Data were analyzed with the Kruskal‐Wallis test and the Wilcoxon two‐sample rank sum test at the 5% level of significance. Results: Most groups had no or only minimal bond strength to densely sintered alumina after simulated aging. Panavia had the highest bond strength without silane/bonding agent application. Noribond with its silane/bonding agent revealed the highest overall bond strength, which was significantly greater than that of either Variolink or Panavia after silanization. Conclusions: Resin cements revealed significantly different bond strengths, and the use of silane coupling and bonding agents had various effects on the resin bond to pure densely sintered alumina. CLINICAL SIGNIFICANCE Selection of the proper cement/bonding system is fundamental to clinical long‐term success of bonded alumina‐based restorations. Noribond with its bonding agent and ceramic primer seem to fulfill these requirements under clinically relevant testing conditions.     

Influence of elapsed time between airborne-particle abrasion and bonding to zirconia bond strength

ObjectiveThe airborne-particle abrasion of zirconia with alumina particle (APA) has been reported to result in the durable bonding of appropriate adhesive luting systems. However, whether a delay between APA and the application of the adhesive luting material might affect the resulting bond strength and its durability is unknown.MethodsA total of 140 disc-shaped zirconia specimens were divided according to the elapsed time between the APA of zirconia and its bonding into 5 test groups (15 min, 1 h, 4 h, 24 h, and 72 h). The specimens were airborne-particle abraded with 50-μm Al₂O₃, and then stored at room temperature according to the test group (n = 28/group). Surface free energy (SFE) was measured for 12 specimens per group using a goniometer. For each group 16 Plexiglas tubes filled with composite resin were bonded to the zirconia specimens with an adhesive luting resin (Panavia 21). Tensile bond strength (TBS) was tested for subgroups of 8 specimens after water storage for 3 days and for 150 days with 37,500 thermal cycles.ResultsSFE decreased significantly within 24 h after APA. TBS after 3 days of water storage ranged from 38.3 (1 h) to 28.4 MPa (24 h) and after 150 days with thermocycling from 38.3 (15 min) to 24.8 MPa (24 h).SignificanceBased on these results, the time between the APA of zirconia and the application of adhesive materials should be minimized when bonding nonretentive zirconia restorations clinically.     

Influence of ageing on self‐etch adhesives: one‐step vs. two‐step systems

The aim of this study was to evaluate microtensile bond strength (μTBS) to dentine, interfacial nanoleakage expression, and stability after ageing, of two‐step vs. one‐step self‐etch adhesives. Human molars were cut to expose middle/deep dentine, assigned to groups (n = 15), and treated with the following bonding systems: (i) Optibond XTR (a two‐step self‐etch adhesive; Kerr), (ii) Clearfil SE Bond (a two‐step self‐etch adhesive; Kuraray), (iii) Adper Easy Bond (a one‐step self‐etch adhesive; 3M ESPE), and (iv) Bond Force (a one‐step self‐etch adhesive; Tokuyama). Specimens were processed for μTBS testing after 24 h, 6 months, or 1 yr of storage in artificial saliva at 37°C. Nanoleakage expression was examined in similarly processed additional specimens. At baseline the μTBS results ranked in the following order: Adper Easy Bond = Optibond XTR ≥Clearfil SE = Bond Force, and interfacial nanoleakage analysis showed Clearfil SE Bond = Adper Easy Bond = Optibond XTR> Bond Force. After 1 yr of storage, Optibond XTR, Clearfil SE Bond, and Adper Easy Bond showed higher μTBS and lower interfacial nanoleakage expression compared with Bond Force. In conclusion, immediate bond strength, nanoleakage expression, and stability over time were not related to the number of steps of the bonding systems, but to their chemical formulations.     

两种表面处理方法对氧化锆粘接强度影响的研究

目的探究表面清洁剂Ivoclean和氧化锆预处理剂Z-PRIME PLUS对唾液浸泡后的氧化锆陶瓷与自粘接树脂水门汀之间粘接强度的影响。方法制作50块10 mm×10 mm×2 mm氧化锆瓷块,喷砂后,随机分成5组(n=10),A组不作处理,B、C、D、E组于人工唾液浸泡1 min,分别用包含磷酸酯单体10-甲基丙烯酰氧癸二氢磷酸酯(10-methacryloxydecyl dihydrogen phosphate,MDP)的Z-PRIME PLUS及Ivoclean单独或联合处理后,与树脂水门汀粘接。万能试验机测试5组试件的剪切强度,体式显微镜下观察断裂模式。结果氧化锆陶瓷与树脂水门汀之间的粘接强度由高到低为:E>D>A>C>B,E组混合破坏最多。结论唾液污染会降低氧化锆与树脂水门汀之间的粘接强度。含MDP的预处理剂与Ivoclean表面清洁剂均能提高树脂粘接剂与氧化锆瓷块之间的粘接强度,且二者联合应用效果更好。     

Effect of different cleansing agents and adhesive resins on bond strength of contaminated zirconia

PurposeThis study was observed the effect of cleansing agents and adhesive resins on shear bond strength (SBS), surface morphology and phase transformation of saliva and silicone disclosing medium contaminated zirconia.MethodsThe 110 zirconia specimens size 5 × 5 × 1 mm were fabricated and randomly divided into 5 surface treated groups: Non-contaminated (PC) Saliva and silicone disclosing medium contaminated without cleansing (NC) Surface contaminated and cleansing with Phosphoric acid (PO) Ivoclean (IC) or Hydrofluoric acid (HF). The twenty of each surface treated specimens were selected and bonded with Panavia F2.0 (P) and Superbond C&B (S) for SBS test (n = 10). The data was analyzed by Kruskal–Wallis H and Mann–Whitney U test. The remaining specimens of each surface treated groups were examined by SEM and XRD.ResultsThe saliva and silicone disclosing medium contaminated zirconia without cleansing group (PNC) had the lowest SBS when Panavia F2.0 was used for cementation (p < 0.05). The SBS of surface cleansing groups (PPO, PIC and PHF) were not different from the non-contaminated group (PPC) (p > 0.05). However, there were no difference in SBS among groups when cementation with Superbond C&B (SPC, SNC, SPO, SIC and SHF) (p > 0.05). There was no morphologic changing that could be observed by SEM. The XRD showed little phase transformation when surfaces were contaminated and cleaned.ConclusionsThe saliva and silicone disclosing medium contaminated zirconia should be cleaned with Phosphoric acid, Ivoclean or Hydrofluoric acid for 20 s prior to cementation with Panavia F2.0. However, the surface cleansing was not necessary when cementation with Superbond C&B.     

Promotion of resin bonding to dental zirconia ceramic using plasma deposition of tetramethylsilane and benzene

The aim of this study was to investigate the effects of plasma‐enhanced deposition of an organosilane and benzene on resin bonding to a dental zirconia ceramic. A total of 70 zirconia specimens, which were polished before sintering, were randomly divided into five groups according to surface treatments before applying a dental adhesive (each group, n = 14): group 1, no previous treatment (control); group 2, plasma deposition with tetramethylsilane (TMS); group 3, plasma deposition with benzene; group 4, sequential plasma deposition with TMS and benzene; and group 5, a zirconia primer (Z‐Prime Plus). A dental adhesive (Scotchbond Multi‐Purpose adhesive) was applied to the surface‐treated zirconia, and resin composite rods were built in to enable shear bond‐strength testing. The sequential deposition of TMS and benzene showed the highest bond strength [22.7 ± 3.7 MPa (mean ± SD)], approximately twice that of Z‐Prime Plus (10.3 ± 3.2 MPa). The plasma deposition with either TMS or benzene also significantly improved bond‐strength values compared with the negative‐control group, and their effects were not statistically different from that of Z‐Prime Plus. Following plasma deposition with TMS, the introduction of silicon–oxygen–zirconium (Si–O–Zr) bonds on the zirconia surface was confirmed via X‐ray photoelectron spectroscopy (XPS) analysis. Transmission electron microscopy and energy dispersive X‐ray spectroscopy showed that a silica‐like layer and a polymerizable carbon‐rich layer were formed through sequential deposition with TMS and benzene.