Comparison of the shear bond strength of composite resins with zirconia and titanium using different resin cements

PURPOSE

The shear bond strength of conventional zirconia (3Y-TZP), translucent zirconia (5Y-PSZ), and titanium alloy (Ti6Al4V) thermocycled using different phosphate monomer resin cements were investigated.

METHODS

In this study, 120 specimens of 3Y-TZP, 5Y-PSZ, and Ti6Al4V were cemented to nanocomposite resin cylinders using PANAVIA™ V5 and Rely X™ U200. The bond area and resin cement thickness were controlled as per ISO 29022:2013 and 4049:2009. Each resin cement group was used with/without the Clearfil ceramic primer plus. The shear bond strength of the 12 groups was statistically analyzed using two and one-way ANOVA to determine the properties of the different materials and resin cements (α = 0.05). The mode of failure was observed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).

RESULTS

The titanium alloy groups showed better shear bond strength than the zirconia groups (p < 0.05). PANAVIA™ V5 without primer showed significantly lower shear bond strength than other cements in zirconia and titanium alloy specimens (p < 0.05). Titanium alloy with Rely X™ U200 with a Clearfil ceramic primer plus showed the highest shear bond strength (6.37 ± 1.60 MPa). SEM images showed mixed failures in zirconia groups and cohesive failures in titanium alloy groups.

CONCLUSIONS

The titanium alloy showed better shear bond strength than zirconia when the Clearfil ceramic primer plus was used. The primer solution containing MDP and resin cement with phosphoric methacrylate ester showed similar shear bond strength with 3Y-TZP and 5Y-PSZ. The resin cement without phosphate monomers demonstrated the least shear bond strength.

Fracture resistance of maxillary premolars restored with different endocrown designs and materials after artificial ageing

PURPOSE

To evaluate the effect of three different designs and two monolithic ceramic materials on the durability and fracture resistance of endocrowns on maxillary first premolars, in comparison to post-and-core crowns.

METHODS

Fifty-six maxillary premolars were endodontically treated and shortened to a level of 2 mm from the cervical line, and randomly categorized into six endocrown groups and post-and-core crown control group (n=8); E1; endocrowns with flat occlusal table (without ferrule), E2; endocrowns with 1.5 mm circumferential ferrule, E3; endocrowns with 1.5 mm buccal ferrule preparation. Two materials were used for endocrowns: zirconia (4YSZ; Z), and lithium disilicate (L). The control group was restored with zirconia posts, and lithium disilicate crowns. All restorations were bonded using Panavia V5 and its respective primers and underwent thermo-mechanical fatigue with a 10 kg dynamic load for 1,200,000 cycles and thermocycling between 5 and 55 °C. Thereafter all survived specimens were loaded to fracture. The results were statistically analyzed using ANOVA and T-Test.

RESULTS

None of the specimens showed any signs of debonding or fracture caused by the fatigue test. The PC control group showed no statistically significant difference in comparison to groups ZE1, ZE2 and LE2 ( p > 0.05 ). However, it was significantly different from groups LE1, LE3, and ZE3 ( p ≤ 0.05 ).

CONCLUSIONS

Preparation designs and materials affected the fracture resistance of endocrowns. The results showed a superiority of the post-and-core crowns,zirconia/lithium disilicate endocrowns with 1.5 mm circumferential ferrule, and zirconia endocrowns with the flat occlusal table.

The effect of different ceramic surface treatments on the repair bond strength of resin composite to lithium disilicate ceramic

This study aimed to evaluate the bonding abilities and long-term durability of different repair agents when applied to lithium disilicate ceramics (LDS). Blocks of IPS e.max CAD were prepared and divided into four groups according to the surface treatment: Monobond Etch & Prime (ME), K-etchant GEL+Clearfil Universal Bond (UB), Bondmer Lightless (BL), and K-etchant GEL+G-Multi Primer (GMP). All treated ceramic specimens were bonded to resin composite and light-cured. The micro-shear bond strength was measured after 24 h of water storage or 5,000 thermocycles. ME and BL showed significantly higher initial bond strengths than UB and GMP (p<0.05). After 5,000 thermocycles, there was no significant difference in ME (p>0.05), but BL and GMP showed considerable reduction in bond strength (p<0.05); moreover, the samples of UB were all de-bonded before testing. ME and BL proved to be effective surface treatment materials for LDS.

Shear bond strength between gingival composite resin and glazed gingival porcelain for implant-supported prostheses

This study determined the shear bond strength (SBS) between an indirect gingival composite resin and glazed gingival porcelain after various surface treatments. A total of 176 porcelain disks with natural glazing were used and assigned to one of four groups: no surface treatment, airborne-particle abrasion, hydrofluoric acid etching, or a combination of airborne-particle abrasion followed by hydrofluoric acid etching. Each group was divided into two subgroups: one subgroup was unprimed, and the other was silanized. An indirect composite resin was then bonded to the porcelain disks. Half of the specimens in each group (n = 11) were exposed to 5000 thermocycles. SBSs were measured, and data were analyzed with the Kruskal-Wallis and Steel-Dwass tests. Among silanized specimens, those treated with the combination of airborne-particle abrasion and hydrofluoric acid etching exhibited the highest bond strengths both before and after thermocycling. However, the SBS values of the silanized and unprimed hydrofluoric acid etched specimens did not differ significantly. Airborne-particle abrasion followed by hydrofluoric acid etching with silane application yielded stronger, more durable bonds between the indirect gingival composite resin and glazed gingival porcelain.

Influence of roughening procedures and priming agents on shear bond strength of CAD/CAM materials to zirconia frameworks

This study investigated the influence of roughening procedures and application of primers on shear bond strengths of CAD/CAM composite resin material or ceramic material to zirconia frameworks. A CAD/CAM composite resin block (Katana Avencia Block; AVE) and lithium disilicate glass-ceramic block (IPS e.max CAD; IEC) were used as veneer materials. The veneers were divided into three surface treatment groups; HF, hydrofluoric acid etching; AB, airborne-particle abrasion; and CON, no surface treatment. Each veneer was primed with four agents: Clearfil Porcelain Bond Activator (ACT), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Porcelain Bond Activator (CPB+ACT), and no priming (UP). The zirconia frameworks and AVE or IEC veneers were resin-bonded. In the AVE specimen, AB treatment showed significantly higher shear bond strength than the other treatments at 0 and 20,000 thermocycles, except for UP and CPB+ACT groups at 20,000 thermocycles. Airborne-particle abrasion is necessary for resin bonding to Avencia blocks.

Current status on lithium disilicate and zirconia: a narrative review

Background

The introduction of the new generation of particle-filled and high strength ceramics, hybrid composites and technopolymers in the last decade has offered an extensive palette of dental materials broadening the clinical indications in fixed prosthodontics, in the light of minimally invasive dentistry dictates. Moreover, last years have seen a dramatic increase in the patients’ demand for non-metallic materials, sometimes induced by metal-phobia or alleged allergies. Therefore, the attention of scientific research has been progressively focusing on such materials, particularly on lithium disilicate and zirconia, in order to shed light on properties, indications and limitations of the new protagonists of the prosthetic scene.

Methods

This article is aimed at providing a narrative review regarding the state-of-the-art in the field of these popular ceramic materials, as to their physical-chemical, mechanical and optical properties, as well as to the proper dental applications, by means of scientific literature analysis and with reference to the authors’ clinical experience.

Results

A huge amount of data, sometimes conflicting, is available today. Both in vitro and in vivo studies pointed out the outstanding peculiarities of lithium disilicate and zirconia: unparalleled optical and esthetic properties, together with high biocompatibility, high mechanical resistance, reduced thickness and favorable wear behavior have been increasingly orientating the clinicians’ choice toward such ceramics.

Conclusions

The noticeable properties and versatility make lithium disilicate and zirconia materials of choice for modern prosthetic dentistry, requiring high esthetic and mechanical performances combined with a minimal invasive approach, so that the utilization of such metal-free ceramics has become more and more widespread over time.

Bonding of different self-adhesive resins to high-strength composite resin block treated with surface conditioning

PURPOSE

This study aimed to evaluate the effects of chemical conditioning and self-adhesive resins (SARs) on the bonding of mechanically conditioned high-strength composite resin block (HSCRB).

METHODS

Eighteen sections of HSCRB (KZR-CAD HR 3 Gammatheta, Yamakin) were treated with alumina air abrasion and randomly divided into 3 groups according to the SARs for bonding: RelyX Unicem 2 (RXU), SA Luting Plus (SAL), and G-Cem ONE (GCO). The sections were further divided into 3 subgroups according to the chemical conditioning of the adherend surfaces: no conditioning (C), universal adhesive (UA), and a mixture of γ-MPTS and 10-MDP (MM). After the surface conditioning, the sections were cemented with the SARs. Each cemented section was cut into 40 beams. Half of the beams were thermocycled (4°C/60°C, 10,000 cycles). The micro-tensile bond strength (μTBS) values were measured using a universal testing machine. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), contact angles, and surface roughness measurements were performed on the adherend surfaces of each subgroup.

RESULTS

RXU showed the highest μTBS values among the 3 SARs tested, while MM application exhibited the highest μTBS values among the 3 chemical conditioning methods tested. After thermocycling, the samples in the RXU/MM, RXU/UA, and GCO/MM groups showed no significant changes in the μTBS values, whereas the others showed a significant reduction.

CONCLUSIONS

The bond strength of HSCRB was influenced by the chemical conditioning, SARs, and aging. γ-MPTS and 10-MDP application yielded higher μTBS values of mechanically treated HSCRB than the UA.