Internal coating of zirconia restoration with silica-based ceramic improves bonding of resin cement to dental zirconia ceramic

Full-Mouth Rehabilitation of a Patient with Gummy Smile-Multidisciplinary Approach: Case Report

The impairment of aesthetic function leads to a decreased quality of life. An unaesthetic smile due to excessive gingival exposure demands, most of the time, a complex treatment in which the objective is the vertical reduction of the amount of exposed fixed gingiva by obtaining a complete exposure of the anatomical crown of the teeth and restoring the ideal dimensions of the biological width. This paper presents a case of a 48-year-old female patient who was unsatisfied with her aesthetics and had disturbed masticatory function due to the absence of some posterior teeth. The cone beam computed tomography was performed to evaluate the facial and dental morphology. The treatment plan included diode laser and piezo-surgery utilization for the frontal area of the upper arch and implants to restore the distal area of the lower and upper arch. Zirconia ceramic was used for the final restorations. This complex and multidisciplinary full-mouth rehabilitation lasted for two years, and the patient was pleased with the result. This case showed that a well-established treatment plan is necessary to obtain long-lasting results. The use of adequate procedures and equipment ensures a predictable result.

Construction of a silicate-based epitaxial transition film on a zirconia ceramic surface to improve the bonding quality of zirconia restorations

The effect of a silicate-based epitaxial transition film on zirconia produced by a silicate solution during zirconia-resin bonding was investigated. The airborne-particle abraded zirconia was placed in different concentrations of silicate solutions and heated at 50 °C. The silicate transition film was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), contact angle measurement and profilometry. The silicate-based epitaxial transition film was successfully constructed on the surface of zirconia, and the surface morphology and composition of zirconia changed. After coupling with KH570 hydrolysate, the shear bond strength (SBS) of zirconia-resin after either 24 h water storage or 5000 thermal cycles can be significantly improved by a silicate-based epitaxial transition film on the surface of zirconia, and all the samples had no cytotoxicity. This may provide a new strategy for improving the bonding quality of zirconia restorations.

Effect of ceramic material type on the fracture load of inlay-retained and full-coverage fixed dental prostheses

Objective: Ceramic inlay-retained fixed partial denture (IRFPD) is a conservative prosthetic option but the mechanical durability of new high strength zirconia reinforced glass ceramic FPDs is not investigated. The purpose of this study was to compare fracture load of 3-unit ceramic FPDs. Materials and methods: Extracted premolars and molars (N = 64) were used to create three test groups (IRFPDs) and one control group (full coverage FPD) (n = 8). The teeth were embedded in PMMA resin with a mesiodistal distance of 6 mm. Premolars had a distal and molars had a mesial inlay preparation (width: 3 mm; height: 4 mm) in the test groups. IRFPDs were made from a zirconia reinforced lithium silicate (VS) or a monolithic zirconia. Zirconia IRFPDs received 2 types of surface treatments: sandblasting (Zr-IRFPD) or internal coating with feldspathic porcelain (ZrC-IRFPD). Control group was made from monolithic zirconia with the same connector size and zirconia surfaces were sandblasted (Zr-FPD). All restorations were cemented using a resin luting cement. After 5000 thermo-cycles, fracture load values (N) were determined with a universal testing machine at a crosshead speed of 0.75 mm/min. Data were analyzed using 1-way ANOVA and Tukey`s post hoc test (p ˂ .05). Result: Fracture load (mean ± SD) of Zr-FPDs, Zr-IRFPDs and ZrC-IRFPDs were 672 ± 183, 672 ± 123 and 638 ± 59, respectively, being not statistically different (p > .05). VS-IRFPD exhibited statically lower values (391 ± 136). The predominant mode of failure was fracture at the connector area in all groups. Conclusion: The fracture load of 3-unit IRFPD was significantly affected by types of ceramics but the retainer design and surface treatment in Zr groups did not show a significant effect.

The Effect of Sandblasting and Coating of Zirconia by Nano Composites on Bond Strength of Zirconia to Resin Cements

Statement of the Problem:

Despite yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) high strength in dental restoration application, Zr- the framework has a low tendency to react chemically with cement which is the main reason of these restoration failures.

Purpose:

The aim of this in vitro study was to evaluate the effect of Y-TZP coating by nanocomposite of silica and aluminosilicate according to the sol-gel dip-coating technique on the bond strength of resin cement to Y-TZP.

Materials and Method:

In this experimental study, Y-TZP blocks (10×10×3mm³) were prepared and sintered and assigned into 4 groups (n=10) for coating including control group without any further surface treatment, sandblasted using 110μm alumina particles under 2.5 bar and tip distance of 10 mm, silica sol dip coating+calcination, aluminosilicate sol dip coating+ calcinations. To confirm chemical bonds of sol-gel covers, Fourier transforms infrared spectroscopy (FT-IR) technique was used. The surface of the sample was investigated by scanning electron microscopy (SEM), energy-dispersive spectroscopy detector (EDS) and x-ray diffraction (XRD) methods. Micro-shear bond strengths (µSBS) of zirconia-cement specimens were evaluated. Data were analyzed with a one-way ANOVA test in SPSS version 11.5 software with a confidence interval of 95%.

Results:

µSBS of sandblasting, nano-silica, and nano-aluminosilicate specimens were significantly higher than control. µSBS of nano-silica was higher than other groups but no significant difference was observed in µSBS of sandblasting nano-silica, and nano-aluminosilicate groups (p> 0.05).

Conclusion:

Covering the zirconia surface with non-invasive nano-silica and nano-aluminosilicate using the sol-gel technique leads to improved cement bond strength.

Effect of high-power-laser with and without graphite coating on bonding of resin cement to lithium disilicate ceramic

The present study evaluated the effect of different high-power-laser surface treatments on the bond strength between resin cement and disilicate ceramic. Lithium disilicate ceramic specimens with truncated cones shape were prepared and divided into 5 groups: HF (hydrofluoric acid-etching), Er:YAG laser + HF, Graphite + Er:YAG laser + HF, Nd:YAG laser + HF, and Graphite + Nd:YAG laser + HF. The treated ceramic surfaces were characterized with scanning electron microscopy and surface roughness measurement. Hourglasses-shaped ceramic- resin bond specimens were prepared, thermomechanically cycled and stressed to failure under tension. The results showed that for both the factors "laser" and "graphite", statistically significant differences were observed (p < 0.05). Multiple-comparison tests performed on the "laser" factor were in the order: Er:YAG > Nd:YAG (p < 0.05), and on the "graphite" factor were in the order: graphite coating < without coating (p < 0.05). The Dunnett test showed that Er:YAG + HF had significantly higher tensile strength (p = 0.00). Higher surface roughness was achieved after Er:YAG laser treatment. Thus Er:YAG laser treatment produces higher bond strength to resin cement than other surface treatment protocols. Surface-coating with graphite does not improve bonding of the laser-treated lithium disilicate ceramic to resin cement.

Effects of Different Surface Treatment Methods and MDP Monomer on Resin Cementation of Zirconia Ceramics an In Vitro Study

INTRODUCTION

Resin cements are generally preferred for cementation of zirconia ceramics. Resin bonding of zirconia ceramics cannot be done with the same methods of traditional ceramics because zirconia is a silica-free material. In recent years, many methods have been reported in the literature to provide the resin bonding of zirconia ceramics. The purpose of this in vitro study is to evaluate effects of different surface treatments and 10-metacryloxydecyl dihydrogen phosphate (MDP) monomer on shear bond strength between zirconia and resin cement.

METHODS

120 zirconia specimens were treated as follows: Group I: sandblasting, group II: sandblasting + tribochemical silica coating + silane, group III: sandblasting + Nd:YAG (neodymium: yttrium-aluminum-garnet) laser. One specimen from each group was evaluated under scanning electron microscope (SEM). Specimens in each group were bonded either with conventional resin cement Variolink II or with a MDP containing resin cement Panavia F2.0. Subgroups of bonded specimens were stored in distilled water (37°C) for 24 hours or 14 days. Following water storage shear bond strength test was performed at a crosshead speed of 1 mm/min in a universal test machine. Then statistical analyses were performed.

RESULTS

Highest shear bond strength values were observed in group II. No significant difference between group I and III was found when Panavia F2.0 resin cement was used. When Variolink II resin cement was used group III showed significantly higher bond strength than group I. In group I, Panavia F2.0 resin cement showed statistically higher shear bond strength than Variolink II resin cement. In group II no significant difference was found between resin cements. No significant difference was found between specimens stored in 37°C distilled water for 24 hours and 14 days. In group I surface irregularities with sharp edges and grooves were observed. In group II less roughened surface was observed with silica particles. In group III surface microcracks connecting each other were observed.

CONCLUSION

Tribochemical silica coating is an effective method for achieving an acceptable bond between zirconia and resin cement. Use of a MDP monomer containing resin cement increases the bond strength of sandblasted zirconia.

The effect of sandblasting and different primers on shear bond strength between yttria-tetragonal zirconia polycrystal ceramic and a self-adhesive resin cement

PURPOSE

To evaluate the effect of zirconia primers, air-abrasion, and tribochemical surface treatment methods on the shear bond strength between yttria-tetragonal zirconia polycrystal (Y-TZP) ceramic and self-adhesive resin cement.

METHODS AND MATERIALS

Y-TZP ceramic surfaces were ground flat with 600-grit silicon carbide paper and then divided into seven groups of 10 and treated as follows: untreated (control), Monobond Plus, Z-PRIME Plus, ESPE Sil with CoJet, air-abrasion, Monobond Plus with air-abrasion, and Z-PRIME Plus with air-abrasion. Self-adhesive resin cement was placed onto the treated Y-TZP specimens for each group. All specimens were thermocycled and subjected to a shear bond strength test. Scanning electron microscope images of the fractured areas and x-ray diffraction (XRD) analysis of the surface-treated Y-TZP specimens were performed. Data were statistically analyzed using one-way analysis of variance and the Student-Newman-Keuls multiple comparison test (p<0.05).

RESULTS

The Z-PRIME Plus treatment in combination with air-abrasion produced the highest bond strength (16.50±2.26 MPa), followed by air-abrasion (10.56±3.32 MPa), and then Monobond Plus combined with air-abrasion (8.93±3.13 MPa), ESPE Sil after CoJet application (8.54±3.98 MPa), and the Z-PRIME Plus group (8.27±2.79 MPa). The control (3.91±0.72 MPa) and Monobond Plus (4.86±1.77 MPa) groups indicated the lowest results (p<0.05). The XRD results showed the peaks of the monoclinic phase for the air-abrasion and CoJet treatment groups compared with the Y-TZP control.

CONCLUSION

Z-PRIME Plus primer application after air-abrasion presented the best results for improving the bond strength between Y-TZP ceramic and self-adhesive resin cement.