Determination of resin bond strength to zirconia ceramic surface using different primers

Adhesion concepts and techniques for laboratory-processed indirect dental restorations

The purpose of this review was to analyze the existing literature on surface conditioning of the veneering surface of substructure restorative materials in dental laboratories. New technologies are constantly improving the treatment options for fabricating dental restorations, and new materials and adhesion procedures are being offered to clinicians and dental technologists. To establish a reliable adhesion between the veneer and substructure in the dental laboratory, various surface treatment procedures and adhesion promoters are employed. The composition of a material influences the adhesion approach selected, and implementing a reliable adhesion strategy is critical for the predictability of veneered indirect dental restorations. However, surface treatment of a wide range of available material options can be challenging. Therefore, understanding various adhesion processes for different restorative materials may assist dental technologists in selecting the best and appropriate surface conditioning protocol for each dental restorative material category.

Do Chemical-Based Bonding Techniques Affect the Bond Strength Stability to Cubic Zirconia?

This study evaluated the effectiveness of chemical-based adhesive techniques on promoting immediate and aged bond strength between zirconia and luting cement. A total of 128 discs of zirconia were divided into 4 groups (n = 32) according to the adhesive treatment: tribochemical silica-coating followed by silane (Silane Primer, Kerr) and bonding (Optibond FL, Kerr), Signum Zirconia Bond (Hereaus), Z-Prime Plus (Bisco), and All-Bond Universal (Bisco). Composite cylinders were cemented on the zirconia sample with Duo-Link Universal (Bisco). Eight specimens per group were subjected to 10,000 thermocycles and subsequently bond strength was tested with shear-bond strength test. ANOVA test showed that artificial aging significantly affected the bond strength to zirconia. Bonferroni test highlighted a significant influence of adhesive treatment (Signum) on bond strength after thermocycling. It was concluded that 10-MDP-based bonding systems showed no improvement in initial bond strength compared with tribochemical treatment. All chemical bonding techniques tested in this study were influenced by thermocycling.

Evaluation of shear bond strength of zirconia to composite resin using different adhesive systems

Background

To evaluate shear bond strength of zirconia to composite resin using different universal and conventional adhesives and a zirconia primer.

Material and Methods

Forty zirconia blocks were fabricated of zirconium ingots (10×10×5 mm) and sintered at 1530°C for 2 hours. They were then air-abraded with Al2O3 particles. The specimens were divided into 4 groups and subjected to one of the following bonding agents: Futurabond U (group 1), Clearfil Universal Bond, universal adhesives (group 2), Z-Prime Plus, zirconia primer (group 3) and Adper Single Bond 2, conventional adhesive (group 4). Composite resin was then applied in a diameter of 5 mm and in a thickness of 2 mm. All the specimens were stored in distilled water at 37°C for 24 hours and then thermocycled between 5°C and 55°C for 5000 cycles with a 30-second dwell time. The shear bond strength was then evaluated with a universal testing machine at a crosshead speed of 1 mm/min. Data (MPa) were analyzed using ANOVA and LSD test (P≤0.05). The specimens were evaluated under a stereomicroscope to determine the mode of failure.

Results

The mean shear bond strength was 16,874 MPa in group I, 13.4434 MPa in group II, 11.6500 MPa in group III and 6.8700 MPa in group IV. ANOVA revealed that the shear bond strength in group IV was significantly lower than that in other groups (P≤0.05).

Conclusions

The shear bond strength in group I was significantly higher than that in groups III and IV. So Universal adhesives could provide higher shear bond strength of zirconia to composite resin after thermocycling compared to zirconia primers.

Key words:10-MDP, shear bond strength, universal adhesive systems, zirconia primer.

The effect of air-particle abrasion and a zirconia primer application on resin cement bonding strength to zirconia

BACKGROUND

This study aimed to evaluate the influence of surface treatments on the bond strength between a zirconia-based ceramic and two resin cements.

METHODS

Eighty blocks (5.25×3.74×4.5 mm) of a zirconia-based ceramic were divided into eight groups (N.=10) according to the factors "surface treatment" (air-particle abrasion with Al2O3 or Al2O3/SiO2 and zirconia primer) and "cement" (conventional resin cement and self-adhesive resin cement). After the surface treatments, cylinders of each resin cement (Ø=3.5 mm, height: 3 mm) were built up on the zirconia surface and photo-activated (40 s). The samples were stored in water for 30 days at 37 °C, followed by shear bond strength test in a universal testing machine (1 mm/min). Data were analyzed by ANOVA and Tukey test (α=0.05).

RESULTS

Regarding the surface treatments, all strategies were statistically different from each other. The Cojet achieved the higher bond strength values, followed by Signum Zirconia Bond. The resin cements were also statistically different from each other, since the U200 achieved higher bond strength values. The interaction between the factors was also significant. Most of the failures were adhesive and mixed.

CONCLUSIONS

Regardless of the cement used, the air-particle abrasion with alumina coated by silica particles improved bond strength.

Zirconia Primers Improve the Shear Bond Strength of Dental Zirconia

PURPOSE

Various resin cements and priming agents are available for adhesive luting of zirconia restorations. The purpose of this study was to investigate how cement type and priming protocol affect the shear bond strength on zirconia ceramics.

MATERIALS AND METHODS

Yttria-stabilized tetragonal zirconia polycrystalline ceramic cylinders were bonded to flat zirconia ceramic surfaces using 7 commercially available resin cements. Ten specimens of each cement group were pretreated with a universal primer, and 10 specimens per group were bonded without pretreatment. In addition, 10 specimens per group were pretreated with system-specific zirconia primers, which were available for 3 cements. Altogether, 170 bonded specimens were water-stored, thermal-cycled, and then submitted to shear bond strength tests. The shear bond strength and the fracture types were documented. Differences in shear bond strengths were assessed using 2-way ANOVA with post-hoc test (α = 0.05). A point-biserial correlation was run between the fracture patterns and the shear bond strengths.

RESULTS

The mean shear bond strengths of cements in the unprimed group showed large variations between 2.52 ± 3.01 (mean ± SD) MPa and 33.15 ± 7.35 MPa. Pretreating the specimens with a universal primer improved the shear bond strengths significantly in all groups (p < 0.05) with a range of 21.80 ± 12.51 to 57.20 ± 11.40 MPa. The system-specific primers also improved the shear bond strength significantly, compared to the unprimed group (p < 0.01); however, only one system-specific primer achieved a shear bond strength superior to the universal primer (p < 0.01). There was also a statistical correlation between the fracture type and the shear bond strength (p < 0.0005), with cohesively fractured specimens showing higher shear bond strengths (37.24 ± 19.87 MPa) than adhesively fractured specimens (23.10 ± 17.65 MPa) (p < 0.001).

CONCLUSION

Using universal primer can enhance the maximal shear bond strength of zirconia.

The effect of Z-primer on the shear bond strength of zirconia ceramic to dentin: in vitro

Background

One of the major limitations of zirconia ceramic is the difficulty to adhere to dental. Said adhesion improves the marginal sealing of the restoration, minimizing microleakage. According to the limitation of zirconia ceramic bonding, zirconia primer enhances bond strengths to Zirconia, Alumina and Metal substrates. Purpose: the aim of the current study was to determine effect of Z-primer on the shear bond strength of zirconia ceramic to dentin.

Material and Methods

28 newly extracted intact premolars and divided into 4 groups (n=7). In group 1, resin-based (Duo-link; Bisco, Schaumburg, IL) cement was used without applying Z-primer. In group 2, resin-based (Duo-link; Bisco, Schaumburg, IL) cement was used with applying Z-primer. In group 3, resin-based cement (Panavia F2; Kurary, Japan) was used without Z-primer. In group 4, resin- based cement (Panavia F2) with Z-primer was used. Zirconia ceramic blocks (4×4×2mm) without sandblasting were applied onto the surface of dentin then cured from 3 dimensions for 20S. Shear bond strength test was carried out after 24h. Stereo microscope was used to evaluate the zirconia ceramic and dentin topography and failure mode.

Results

According to the data, significant difference detected on after application of the Z-primer compared to the other groups (p<0.001). No significant difference detected between 2 types of resin cements (p>0.05). However, the highest SBS observed in second group (Duo-link(+)Zprimer) while lowest detected in first group (Duo-link(-)Zprimer).

Conclusions

These results suggested application of the Z-primer increased shear bond strength between zirconia ceramic and dentin.

Key words:Flexural strength, monolithic zirconia, sintering temperature, sintered-holding time.

Incorporation of TiO2 nanotubes in a polycrystalline zirconia: Synthesis of nanotubes, surface characterization, and bond strength

STATEMENT OF PROBLEM

Despite numerous advantages such as high strength, the bond of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) to tooth structure requires improvement.

PURPOSE

The purpose of this in vitro study was to evaluate the incorporation of TiO₂ nanotubes into zirconia surfaces and the bond strength of resin cement to the modified ceramic.

MATERIAL AND METHODS

TiO₂ nanotubes were produced by alkaline synthesis, mixed with isopropyl alcohol (50 wt%) and applied on presintered zirconia disks. The ceramics were sintered, and the surfaces were characterized by confocal laser microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analysis. For bond strength, the following 6 groups (n=16) were evaluated: without TiO₂ and Single Bond Universal; with TiO₂ nanotubes and Single Bond Universal; without TiO₂ nanotubes and Z-prime; with TiO₂ nanotubes and Z-prime; without TiO₂ and Signum Zirconia Bond; with TiO₂ and Signum Zirconia Bond. After sintering, resin cement cylinders, diameter of 1.40 mm and 1 mm in height, were prepared and polymerized for 20 seconds. Specimens were stored in water at 37°C for 30 days and submitted to a shear test. Data were analyzed by 2-way ANOVA and Tukey honest significant difference (α=.05) tests.

RESULTS

EDS analysis confirmed that nanoagglomerates were composed of TiO₂. The shear bond strength showed statistically significant differences among bonding agents (P<.001). No significant differences were found with the application of nanotubes, regardless of the group analyzed (P=.682). The interaction among the bonding agent factors and addition of nanotubes was significant (P=.025).

CONCLUSIONS

Nanotubes can be incorporated into zirconia surfaces. However, this incorporation did not improve bond strength.

Adhesive Bonding to Computer-aided Design/ Computer-aided Manufacturing Esthetic Dental Materials: An Overview

AIM

To review the adhesive bonding to different computer-aided design/computer-aided manufacturing (CAD/CAM) esthetic restorative materials.

BACKGROUND

The use of CAD/CAM esthetic restorative materials has gained popularity in recent years. Several CAD/ CAM esthetic restorative materials are commercially available. Adhesive bonding is a major determinant of success of CAD/ CAM restorations. Review result: An account of the currently available bonding strategies are discussed with their rationale in various CAD/ CAM materials.

CONCLUSION

Different surface treatment methods as well as adhesion promoters can be used to achieve reliable bonding of CAD/CAM restorative materials. Selection of bonding strategy to such material is determined based on its composition. Further evidence is required to evaluate the effect of new surface treatment methods, such as nonthermal atmospheric plasma and self-etching ceramic primer on bonding to different dental ceramics.

CLINICAL SIGNIFICANCE

An understanding of the currently available bonding strategies to CA/CAM materials can help the clinician to select the most indicated system for each category of materials.

Bonding Polycrystalline Zirconia With 10-MDP–containing Adhesives

Objective:

The objective of this study was to evaluate the influence of adhesives with different 10-MDP concentrations on the shear bond strength of a resin cement to zirconia.

Methods and Materials:

Six experimental adhesives were prepared with the following composition: camphorquinone, 1,2-diaminobenzene, butylhydroxytoluene, diphenyliodonium hexafluorophosphate, 2-hydroxyethyl methacrylate triethylene glycol dimethacrylate, ethoxylated bisphenol A glycol dimethacrylate, urethane dimethacrylate, bisphenol A diglycidyl methacrylate, and ethanol. The 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) monomer was added at 0wt%, 3wt%, 6wt%, 9wt%, 12wt%, or 15wt%. Three commercially available adhesives were evaluated: Single Bond Universal, Single Bond 2, and Signum Zirconia Bond. Resin cement cylinders made with RelyX Ultimate were bonded to yttria-stabilized tetragonal zirconia polycrystal with one of the evaluated adhesives and were subjected to the shear bond strength evaluation. Failure modes were analyzed with a stereoscopic loupe. Statistical analyses were performed with one-way analysis of variance and the Tukey's Honestly Significant Difference test (α=0.05). Pearson's was used to correlate the percentage of 10-MDP in the experimental adhesives and shear bond strength.

Results:

There were significant differences between adhesives (p&lt;0.00001). The highest shear bond strength values were obtained with the Signum Zirconia Bond and Single Bond Universal. Single Bond 2 showed the lowest values. There were no differences between experimental adhesives. All groups showed adhesives failures. A nonlinear correlation was found between bond strength and percentage of 10-MDP in experimental adhesives (r=0.872).

Conclusions:

The commercially available adhesives indicated for bonding to zirconia showed the highest bonding values.

Self-adhesive resin cements: a new perspective in luting technology

Many materials are available for the fabrication of indirect restorations such as, metal alloys, resin-based composites and ceramics. Resin cements have long been valued as luting agents for indirect restorations because of their high retentive strength, resistance to wear, and low solubility. However, one of the common discouraging factors regarding their chairside use is the need of multiple-steps (etching, drying, priming and luting) for bonding. Thus the current impetus is towards the use of self-adhesive cements that require no etching, priming or bonding agents to bond to the tooth surface. Their increased popularity can be judged by the commercial availability of more than a dozen self-adhesive resin products/brands, in a short span of time. This article reviews the composition, physical and biological properties, adhesion characteristics and clinical performance of self-adhesive (resin) cements.

CLINICAL RELEVANCE

Self-adhesive resin cements are dual-cured and adhere to tooth structure without the requirement of a separate etching step and application of an adhesive/bonding agent.

A Review of Surface Treatment Methods to Improve the Adhesive Cementation of Zirconia-Based Ceramics

In spite of high mechanical strength, zirconia-based ceramics (ZrO2) has poor bond strength after conventional bond cementation procedures, requiring different surface treatment methods (STMs). This review gathered information about the STM for adhesive cementation (AC) to ZrO2 in the PubMed database, considering in vitro studies pertaining to AC for acid-resistant ceramics (ZrO2) limited to peer-reviewed papers published in English between 1965 and 2013 in dental journals. Different STMs have been proposed for ZrO2: air-abrasion (laboratory or chairside) with silica- (Si-) coated aluminum particles, the use of materials containing phosphate monomers, primer or silane application, laser irradiation, Si vapor phase deposition, and selective infiltration etching. In conclusion, STMs improve bond strength of resin luting cement to ZrO2 mainly when tested in short time. STMs must be correlated to the type of ZrO2 and the resin cement.

Effect of various intraoral repair systems on the shear bond strength of composite resin to zirconia

PURPOSE

This study compared the effect of three intraoral repair systems on the bond strength between composite resin and zirconia core.

MATERIALS AND METHODS

Thirty zirconia specimens were divided into three groups according to the repair method: Group I- CoJet™ Repair System (3M ESPE) [chairside silica coating with 30 µm SiO₂ + silanization + adhesive]; Group II- Ceramic Repair System (Ivoclar Vivadent) [etching with 37% phosphoric acid + Zirconia primer + adhesive]; Group III- Signum Zirconia Bond (Heraus) [Signum Zirconia Bond I + Signum Zirconia Bond II]. Composite resin was polymerized on each conditioned specimen. The shear bond strength was tested using a universal testing machine, and fracture sites were examined with FE-SEM. Surface morphology and wettability after surface treatments were examined additionally. The data of bond strengths were statistically analyzed with one-way ANOVA and Tamhane post hoc test (α=.05).

RESULTS

Increased surface roughness and the highest wettability value were observed in the CoJet sand treated specimens. The specimens treated with 37% phosphoric acid and Signum Zirconia Bond I did not show any improvement of surface irregularity, and the lowest wettability value were found in 37% phosphoric acid treated specimens. There was no significant difference in the bond strengths between Group I (7.80 ± 0.76 MPa) and III (8.98 ± 1.39 MPa). Group II (3.21 ± 0.78 MPa) showed a significant difference from other groups (P<.05).

CONCLUSION

The use of Intraoral silica coating system and the application of Signum Zirconia Bond are effective for increasing the bond strength of composite resin to zirconia.

Cements and adhesives for all-ceramic restorations

Dental cements are designed to retain restorations, prefabricated or cast posts and cores, and appliances in a stable, and long-lasting position in the oral environment. Resin-based cements were developed to overcome drawbacks of nonresinous materials, including low strength, high solubility, and opacity. Successful cementation of esthetic restorations depends on appropriate treatment to the tooth substrate and intaglio surface of the restoration, which in turn, depends on the ceramic characteristics. A reliable resin cementation procedure can only be achieved if the operator is aware of the mechanisms involved to perform the cementation and material properties. This article addresses current knowledge of resin cementation concepts, exploring the bonding mechanisms that influence long-term clinical success of all-ceramic systems.