Effects of different surface treatments on bond strength between resin cements and zirconia ceramics

Influence of Different Surface Treatments on the Bond Strength of Yttria-Stabilized Tetragonal Zirconia Ceramic

Objective: This in vitro study evaluates the shear bond strength (SBS) of yttria-stabilized tetragonal zirconia (Y-TZP) and resin cement after different surface treatments. Materials and methods: Forty-eight ceramic cubes were divided into four groups (n = 12): G1 (control) sandblasting with Al2O3; G2-sandblasting with silica-coated Al2O3 (Rocatec); G3-Rocatec + CO2 laser; and G4-CO2 laser + Rocatec. A metallic primer was applied to the pretreated ceramic. A rubber ring was adapted on the central area, and then, the resin cement was inserted into the matrix and photoactivated. The samples were evaluated regarding surface roughness (Ra), SBS, failure type, and qualitatively with scanning electron microscopy (SEM). The data were analyzed by one-way analysis of variance followed by Tukey's test (p < 0.05). Results: The mean values of Ra (μm) were as follows: G1-4.52a, G2-4.24a,b, G3-4.10a,b, and G4-2.90b and the mean values of SBS (MPa) were as follows: G1-7.84a , G2-4.41b , G3-4.61b and G4-6.14a,b. SEM analyses showed superficial irregularities for all groups, being more prominent for G1. The presence of silica deposits was observed for G2, G3, and G4, but in the last two groups there were some linear areas, promoted by the fusion of silica, due to the thermomechanical action of the CO2 laser. Conclusions: The surface treatment with CO2 laser + Rocatec, using one MDP-based cement, can be an alternative protocol for the adhesion cementation of Y-TZP ceramic since it was as effective as the conventional pretreatment with aluminum oxide sandblasting.

Effect of Surface Treatment of Zirconia on the Shear Bond Strength of Resin Cement: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to evaluate the effect of different surface treatments on the shear bond strength (SBS) values between zirconia and resin cement compared to untreated specimens. The effects of various surface treatments on the bond strength between zirconia and resin cement were investigated by searching relevant articles on PubMed, ScienceDirect, and Google Scholar databases. A total of 13 studies that met the inclusion and exclusion criteria and addressed the research question were selected for statistical analysis. The studies were evaluated for heterogeneity, and a meta-analysis was performed. In total, 13 in vitro studies were included in accordance with the eligibility criteria. All 13 studies consistently demonstrated that silica coating yielded the highest SBS, followed by sandblasting and laser treatments. The meta-analysis using a random-effect model indicated a significant intergroup comparison, except for a few studies. Among the three treatments examined, the silica coating of zirconia was identified as the most effective in enhancing the bond strength between zirconia and resin cement. Further controlled laboratory and clinical studies are necessary to validate these findings and explore additional factors that may influence the effects of these surface treatments.

Ultrashort pulse laser patterning of zirconia (3Y-TZP) for enhanced adhesion to resin-matrix cements used in dentistry: An integrative review

Surface modification of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) using lasers for adhesion enhancement with resin-matrix cement has been increasingly explored. However, Y-TZP is chemically inert and non-reactive, demanding surface modification using alternative approaches to enhance its bond strength to resin-matrix cements. The main aim of this study was to conduct an integrative review on the influence of ultrashort pulse laser patterning of zirconia (3Y-TZP) for enhanced bonding to resin-matrix cements. An electronic search was performed on web of science, SCOPUS, Pubmed/Medline, Google Scholar and EMBASE using a combination of the following search items: zirconia, 3Y-TZP, surface modification, laser surface treatment, AND laser, ultrashortpulse laser, bonding, adhesion, and resin cement. Articles published in the English language, up to January 2022, were included regarding the influence of surface patterning on bond strength of Y-TZP to resin-matrix cements. Out of the 12 studies selected for the present review 10 studies assessed femtosecond lasers while 2 studies assessed picosecond lasers. Ultrashort pulsed laser surface patterning successfully produced different surface morphological aspects without damaging the bulk properties of zirconia. Contrarily, defects such as micro-cracks occurs after surface modification using traditional methods such as grit-blasting or long-pulsed laser patterning. Ultrashort pulsed laser surface patterning increase bond strength of zirconia to resin-matrix cements and therefore such alternative physical method should be considered in dentistry. Also, surface defects were avoided using ultrashort pulsed laser surface patterning, which become the major advantage when compared with traditional physical methods or long pulse laser patterning.

Current scenario on adhesion to zirconia; surface pretreatments and resin cements: A systematic review

Several methods have been proposed to increase bonding of zirconia with resin. However, we are still to find the Holy Grail. A systematic literature review was performed through PubMed on international literature from January 2000 to May 2021 with relevant Medical Subject Headings terms. 56 articles were found to be relevant. Of all the different methods proposed, mechanochemical pretreatment of zirconia surface with alumina oxide and use of 10-methacryloyloxydecyl dihydrogen phosphate were found to be most effective as per majority of studies. New methods that require further research also surfaced.

Bond durability and surface states of titanium, Ti-6Al-4V alloy, and zirconia for implant materials

PURPOSE

Screw-retained implant crowns used as dental implants comprise a zirconia coping and titanium base bonded using resin cement. These devices are prone to debonding failures. This study investigated the bond characteristics of implant materials based on shear bond strength (SBS) and surface characteristics.

METHODS

Chemically pure (CP) titanium grade-4 (Ti), Ti-6Al-4V alloy (Ti-6Al-4V), and tetragonal polycrystalline zirconia (zirconia) were evaluated as adherent materials. Plates of each material were polished, primed for the respective resin cements, and cemented using either methyl methacrylate-based resin cement (Super-Bond) or composite-based resin cement (Panavia). The cemented samples were subjected to 10,000 thermocycles alternating between 5 and 55 °C, and the SBS were obtained before and after thermocycling. The sample surfaces were characterized based on surface observations, roughness, and free energy (SFE).

RESULTS

The SBSs of all materials bonded using Panavia were significantly compromised during thermocycling and reached zero. Although the SBSs of Ti and Ti-6Al-4V bonded using Super-Bond were not significantly affected by thermocycling, those of zirconia decreased significantly. The bond durability between zirconia and Super-Bond was improved via alumina air-abrasion, which caused no significant loss of SBS after thermocycling. Surface analyses of the air-abraded zirconia validated these results and confirmed that its surface roughness and SFE were significantly increased.

CONCLUSIONS

The bond durability between resin cement and zirconia was lower than that between Ti and Ti-6Al-4V. The alumina air-abrasion pretreatment of zirconia improved the SFE and surface roughness, thereby enhancing bond durability.

Effect of laser irradiation on bond strength between zirconia and resin cement or veneer ceramic: A systematic review and meta-analysis

Aim:

This systematic review with meta-analysis aimed to evaluate the effect of the laser treatment on bond strength between Y-TZP and the resin cement or with the veneering ceramic, and the effect on the alteration of the Y-TZP surface roughness.

Settings and Design:

Systematic review and meta analysis following PROSPERO guidelines.

Materials and Methods:

A comprehensive review was performed up to September 2020 on four databases (PubMed/MEDLINE, Embase, Scopus, and Cochrane Library), using the combination of keywords: “laser AND zirconia AND surface treatment AND bond strength”.

Statistical Analysis Used:

The meta-analysis was based on the Mantel–Haenszel and inverse variance methods. The continuous outcome was evaluated by mean difference and the corresponding 95% confidence intervals.

Results:

A total of 37 studies were identified for the inclusion of data, with only in vitro studies. The types of laser reported in the studies were: Er:YAG, Nd:YAG, Er,Cr:YSGG, CO2, Femtosecond, and Yb lasers. A random-effect model found statistically significant differences between lasers and control groups of Y-TZP (P < 0.00001; MD: 3.08; 95% CI: 2.58 to 3.58). Only the bond strength with the Er:YAG laser did not present statistical difference (P = 0.51; MD: 0.22; 95% CI: −0.44–0.88). In another analysis, a random-effect model found a statistically significant difference between the laser and control groups on surface roughness (P < 0.00001; MD: 0.96; 95% CI: 0.86 to 1.06).

Conclusions:

Laser irradiation is capable to improve the Y-TZP surface roughness and the bond strength of zirconia with resin cement and veneering ceramics. However, there is a lack of laser protocol for the zirconia surface, a fact that makes a simple and direct comparison difficult.

The Use of Lasers in Dental Materials: A Review

Lasers have been well integrated in clinical dentistry for the last two decades, providing clinical alternatives in the management of both soft and hard tissues with an expanding use in the field of dental materials. One of their main advantages is that they can deliver very low to very high concentrated power at an exact point on any substrate by all possible means. The aim of this review is to thoroughly analyze the use of lasers in the processing of dental materials and to enlighten the new trends in laser technology focused on dental material management. New approaches for the elaboration of dental materials that require high energy levels and delicate processing, such as metals, ceramics, and resins are provided, while time consuming laboratory procedures, such as cutting restorative materials, welding, and sintering are facilitated. In addition, surface characteristics of titanium alloys and high strength ceramics can be altered. Finally, the potential of lasers to increase the adhesion of zirconia ceramics to different substrates has been tested for all laser devices, including a new ultrafast generation of lasers.

Effects of Universal Adhesive on Shear Bond Strength of Resin Cement to Zirconia Ceramic with Different Surface Treatments

Aim

This study aimed to assess shear bond strength (SBS) of resin cement to zirconia ceramic with different surface treatments by using Single Bond Universal.

Methods

In this in vitro study, 50 zirconia discs (2 × 6 mm) were divided into 5 groups of (I) sandblasting with silica-coated alumina (CoJet)  + silane + Single Bond 2, (II) sandblasting with CoJet + Single Bond Universal, (III) sandblasting with alumina + Single Bond Universal, (IV) sandblasting with alumina + Z-Prime Plus, and (V) Single Bond Universal with no surface treatment. Resin cement was applied in plastic tubes (3 × 5 mm²), and after 10,000 thermal cycles, the SBS was measured by a universal testing machine. The mode of failure was determined under a stereomicroscope at × 40 magnification. Data were analyzed using one-way ANOVA.

Results

The maximum (6.56 ± 4.29 MPa) and minimum (1.94 ± 1.96 MPa) SBS values were noted in groups III and I, respectively. Group III had the highest frequency of mixed failure (60%). Group V had the maximum frequency of adhesive failure (100%).

Conclusion

Single Bond Universal + sandblasting with alumina or silica-coated alumina particles is an acceptable method to provide a strong SBS between resin cement and zirconia.

Effect of silica coating and laser treatment on the flexural strength, surface characteristics, and bond strength of a dental zirconia

This study investigated the effect of irradiation with an erbium-doped yttrium aluminium garnet (Er:YAG) laser and coating with silica on the surface characteristics, bond strength, and flexural strength of dental zirconia. Three hundred and forty-three standard zirconia specimens were created, and 49 were assigned to each of seven surface treatment groups: (i) no treatment; Er:YAG laser (80 mJ/2 Hz) with pulse widths of 50 μs (ii), 100 μs (iii), 300 μs (iv), or 600 μs (v); or tribochemical silica coating at the partially sintered stage (vi) or after sintering was complete (vii). All specimens were sintered after the surface treatments, except for the group in which specimens were sintered before treatment. The study outcomes were roughness, surface loss, microshear bond strength (μSBS), and biaxial flexural strength (BFS). Mean roughness and surface loss values were significantly higher in specimens from irradiated groups than in those from silica-coated groups. Regarding μSBS, after aging, specimens from all experimental groups presented very low and similar μSBS values, irrespective of the surface treatment. Silica coating after sintering yielded the highest BFS (1149.5 ± 167.6 MPa), while coating partially sintered specimens with silica resulted a BFS (826.9 ± 60.9 MPa) similar to that of the untreated control group (794.9 ± 101.7 MPa). Laser treatments, irrespective of pulse width used, significantly decreased the BFS. In the group treated with laser at 300 μs pulse width, specimens exhibited the lowest BFS value (514.1 ± 71.5 MPa). Adhesion to zirconia was not stable after aging, regardless of the surface treatment implemented.

Adhesive strength of bioactive resin for endodontic tooth build up to dentin treated with conventional and contemporary treatments

AIM

The aim of present ex-vivo study was to assess and evaluate the influence of alternative dentinal conditioning methods- Er,Cr:YSGG (ECL) and Photodynamic therapy (PDT) in comparison to traditional etching regimes- Self Etch Resin (SER) and total etch and rinse (TER) on the bond values of Bioactive restorative material (BA) and Multicore (MC) bulk filled resin composite restorations.

MATERIAL AND METHODS

Eighty caries free mandibular molars were disinfected and embedded in acrylic resin up to Cemento enamel junction (CEJ). Buccal surfaces of all samples were grounded to depth of 2 mm. Specimens were divided into eight groups (n = 20) based on surface treatment received. Samples in group 1 and 2 conditioned with ECYL, group 3 and 4 pre-treated with methylene blue photosensitizer (MBP), group 5 and 6 surfaces conditioned with TER and samples in group 7 and 8 conditioned with SER. Dentin bonding agent was applied and samples of group 1, 3, 5 and 7 were bonded with BA and 2,4,6,8 bonded to MC. Samples were placed in universal testing machine for SBS testing. Data was assessed using analysis of variance (ANOVA) and Tukey multiple comparisons test.

RESULTS

Specimens in group 6 treated with TER and bonded with MC demonstrated maximum SBS (19.61 ± 0.587 MPa). Whereas, group 3 dentin conditioned to MBP and bonded to BA displayed lowest bond values (12.01 ± 0.892 MPa). Samples in group 3 and group 4 dentin treated with MBP bonded to MC (13.68 ± 0.221 MPa) and BA (12.01 ± 0.892 MPa) displayed comparable bond integrity (p > 0.05) CONCLUSION: Dentin pre-treated with TER still remains the gold standard. ECYL as an alternative approach to condition dentin has shown potential and can be recommended in clinical settings. MC as bulk fill composite is recommended over BA irrespective of dentine conditioning technique. MBP as dentin conditioner needs further investigation.

Influence of photodynamic therapy and different lasers Er,Cr:YSGG and Er,YAG on dentin conditioning bonded to conventional and bioactive cement

AIM

The aim of the present study was to evaluate the bond integrity of bioactive cement (BA_c) in contrast to conventional cement Calibra (C) after dentin treated with different surface conditioners (PDT, EYL, ECL) MATERIALS AND METHODS: Sixty non-carious permanent mandibular molars were disinfected and embedded in acrylic resin till cement-o-enamel junction. For homogeneity the buccal surface were grounded and polished. Samples were categorized into three main groups based on conditioning technique. Samples in group 1 and 2 dentin conditioned with Er,Cr:YSGG (ECL), group 3 and 4 surface treated with Er:YAG (EYL) and group 5 and 6 treated with photodynamic therapy (PDT).On conditioned surface bonding agent was applied and light cured. Samples from group 1,3,5 were bonded to Calibra (C). Whereas, specimens in group 2,4,6 were conditioned with bioactive cement (BA_c) and subjected to ageing followed by shear bond strength testing (SBS) in universal testing machine. To detect significance difference between means of different groups analysis of variance (ANOVA) was performed followed by Tukey's post-hoc tests.

RESULTS

The maximum SBS was displayed in group 1, dentin conditioned with ECL and bonded to C (20.23 ± 0.47 MPa). Whereas, group 6, PDT of dentin to BA_c demonstrated lowest bond integrity among experimental groups (12.97 ± 0.25 MPa). Bond strength of group 1, ECL-C (21.55 ± 3.08 MPa) and group 3 EYL-C (19.11 ± 0.65 MPa) were comparable (p > 0.05). Group 5 samples treated with PDT, MB-C (13.41±0.32 MPa) and group 6, MB-BA_c (12.97 ± 0.25 MPa) were also comparable (p > 0.05) CONCLUSION: BAc bonded to dentin after surface conditioning with ECL, EYL and PDT presented lower SBS in comparison to conventional cement C. Further studies are required to extrapolate the current findings.

Influence of Surface Treatment and Resin Cements on the Bond Strength between the Y-TZP Zirconia and Composite Resin Interface

AbstractThe evolution of dental materials and the improvement of ceramic systems stimulated the increased use of Y-TZP zirconia-based ceramics. Despite the excellent mechanical performance, this material has low adhesion potential. The objective of this work was to evaluate the surface treatments and resin cements influence on bond strength between Y-TZP zirconia and composite resin interface. A total of 60 blocks of Y-TZP zirconia (3x8x8mm) were prepared and divided into 3 groups according to the surface treatments: (C) control - extra fine diamond bur, (J) sandblasting with Al2O3 and (JP) sandblasting with Al2O3 + ceramic primer. Each group was subdivided into two groups according to type of resin cement used for cementing composite resin discs (2mm thick x 5mm diameter): self-adhesive and conventional (n=10). The samples were stored in distilled water for 24 hours at 37±1°C in a incubator and subsequently submitted to the shear bond test to determine the bond strength (RU). There was no significant difference in RU among the  surface treatments when using conventional resin cement. For the self-adhesive resin cement, Al2O3 blasting and Al2O3 + primer blasting increased the RU but did not present significant differences between them (p<0.05). Comparing the cements, it was observed that regardless of the surface treatment, the highest values were for the self-adhesive resin cement (p<0.05). Application of the primer after blasting with Al2O3 did not increase RU. Keywords: Dental Prosthesis. Ceramics. Dental cements. Shear Strength.  ResumoA evolução dos materiais odontológicos e o aprimoramento dos sistemas cerâmicos impulsionaram o aumento da utilização da cerâmica a base de zircônia Y-TZP. Apesar do excelente desempenho mecânico, este material apresenta baixo potencial de adesão. O objetivo deste trabalho foi avaliar a influência dos tratamentos de superfícies e dos cimentos resinosos na resistência de união entre a interface zircônia Y-TZP e resina composta. Foram confeccionados 60 blocos de zircônia Y-TZP (3x8x8 mm) e divididos em 03 grupos de acordo com os tratamentos de superfícies que receberam: (C) controle - ponta diamantada extrafina, (J) jateamento com Al2O3 e (JP) jateamento com Al2O3 + primer cerâmico. Cada grupo foi subdividido em dois novos grupos de acordo com tipo de cimento resinoso utilizado para cimentação de discos de resina composta (2mm de espessura x 5mm de diâmetro): autoadesivo e resinoso convencional (n=10). As amostras foram armazenadas em água destilada por 24 horas a 37±1°C em estufa e posteriormente submetidas ao teste de cisalhamento para averiguar a resistência de união (RU). Não houve diferença significativa na RU entre os tratamentos de superfície quando utilizado o cimento resinoso convencional. Para o cimento resinoso autoadesivo o jateamento com Al2O3 e o jateamento de Al2O3 + primer aumentaram a RU porém não apresentaram diferenças significativas entre si (p<0,05). Comparando os cimentos observou-se que, independente do tratamento de superfície, os maiores valores foram para o cimento resinoso autoadesivo (p<0,05). A aplicação do primer após o jateamento com Al2O3 não proporcionou aumento da RU. Palavras-chave: Prótese Dentária. Cerâmica. Cimentos Dentários. Resistência ao Cisalhamento.

Adhesion to Zirconia: A Systematic Review of Current Conditioning Methods and Bonding Materials

Background. Reliable bonding between resin composite cements and high strength ceramics is difficult to achieve because of their chemical inertness and lack of silica content that makes etching impossible. The purpose of this review is to classify and analyze the existing methods and materials suggested to improve the adhesion of zirconia to dental substrate by using composite resins, in order to explore current trends in surface conditioning methods with predictable results. Methods. The current literature, examining the bond strength of zirconia ceramics, and including in vitro studies, clinical studies, and a systematic review, was analyzed. The research in the literature was carried out using PubMed and Cochrane Library databases, only papers in English, published online from 2013 to 2018. The following keywords and their combinations were used: Zirconia, 3Y-TZP, Adhesion, Adhesive cementation, Bonding, Resin, Composite resin, Composite material, Dentin, Enamel. Results. Research, in PubMed and Cochrane Library databases, provided 390 titles with abstracts. From these, a total of 93 publications were chosen for analysis. After a full text evaluation, seven articles were discarded. Therefore, the final sample was 86, including in vitro, clinical studies, and one systematic review. Various adhesive techniques with different testing methods were examined. Conclusions. Airborne-particle abrasion and tribo-chemical silica coating are the pre-treatment methods with more evidence in the literature. Increased adhesion could be expected after physico-chemical conditioning of zirconia. Surface contamination has a negative effect on adhesion. There is no evidence to support a universal adhesion protocol.

Adhesion behavior of conventional and high-translucent zirconia: Effect of surface conditioning methods and aging using an experimental methodology

OBJECTIVE

Evaluate the adhesive behavior of conventional and high-translucent zirconia after surface conditioning and hydrothermal aging.

MATERIALS AND METHODS

Conventional (ZrC) and high-translucent zirconia (ZrT) specimens were divided into six groups: without surface treatment (ZrC and ZrT), air-borne particle abrasion with 50-μm Al₂ O₃ sized particles (ZrC-AO and ZrT-AO), and tribochemical treatment with 30-μm silica modified Al₂ O₃ sized particles (ZrC-T and ZrT-T). Zirconia specimens were treated using an MDP-containing universal adhesive and bonded to two resins blocks with an adhesive luting cement. Microbar specimens with cross-sectioned areas of 1 mm² were achieved. Half of the microbars were subjected to hydrothermal aging. Bond strength was evaluated by microtensile bond strength test and statistically evaluated by the Weibull analysis.

RESULTS

Roughness of the ZrC-AO and ZrT-AO groups were statistically higher. Bond strength analysis revealed higher bond strength for ZrC-AO and ZrC-T groups compared to ZrT-AO and ZrT-T, respectively. Mixed failure was the most frequent for the mechanically treated groups, while no cohesive failures were obtained.

CONCLUSION

Lower values of bond strength were obtained for the mechanically treated high-translucent zirconia groups when compared to their conventional zirconia counterparts. Mechanical surface treatment significantly improved the bond strength to conventional and high-translucent zirconia.

CLINICAL SIGNIFICANCE

Mechanical surface treatment (air-borne particle abrasion or tribochemical treatment) associated with the use of universal adhesives containing MDP could provide a durable bonding to conventional and high-translucent zirconia.

Shear bond strength of ceramic bracket bonded to different surface-treated ceramic materials

Background

This study evaluated the effect of ceramic surface treatments on bond strength of ceramic brackets to machine-able ceramics and ceramic veneering metal.

Material and Methods

Machined ceramic specimens (10x10x1.5 mm) were prepared from Empress® CAD (EP), and e.max® CAD (EM). Ceramic veneering metal specimens (PF) were fabricated from sintered d.Sign® porcelain (1.27 mm thickness) over d.Sign®10 metal (0.23 mm thickness). Each ceramic was divided into 3-groups and treated surface by Er-YAG laser (LE) or etching with 9.6% HF acid for 5 seconds (A5) or 15 seconds (A15). Resin adhesive (Transbond™-XT) was used for attaching ceramic brackets for each group (n=15) and cured with LED (Bluephase®) for 50 seconds. Specimens were immersed in distilled water for 24 hours before testing for shear bond at crosshead speed of 1.0 mm/min. The data were analyzed for the differences in bond strength with ANOVA and Tukey’s multiple comparisons (α = 0.05). De-bond surfaces were microscopically examined.

Results

Bond strength (MPa) were 12.65±1.14 for EMA5, 14.50±2.21 for EMA15, 13.97±1.17 for EMLE, 12.40±1.95 for PFA5, 15.85±3.13 for PFA15, 14.06±2.17 for PFLE, 12.12±1.54 for EPA5, 15.65±1.57 for EPA15, 12.89±1.17 for EPLE. Significant differences in bond strength among groups were found related to surface treatment (p<0.05), but not significant difference upon type of ceramics (p>0.05). A15 provided higher bond strength than LE and A5 (P<0.05). No damage of ceramic surface upon de-bonding was indicated except for A15 tends to exhibit ditching. LE showed more uniform treated surface for bonding and no surface destruction upon de-bond compared to others.

Conclusions

Bond strength was affected by surface treatment. Both LE and A15 treated surface provided higher bond strength than A5. Considering possibly inducing defect on ceramic surface, LE seems to provide better favorable surface preparation than others. Treated ceramic surface with Er-YAG prior to bracket bonding is recommended.

Key words:Ceramic, ceramic bracket, Er-YAG, laser, shear bond strength, surface treatment.

Comparison of Micro-Shear Bond Strength of Resin Cement to Zirconia With Different Surface Treatments Using Universal Adhesive and Zirconia Primer

Introduction: Increased demand for metal free fixed partial denture in recent years led to the developing of all ceramic material with excellent mechanical properties. One of the most popular all ceramic is zirconia which shows poor bonding properties. Recently, universal primer contains of silane and phosphate monomer for bond to zirconia have been introduced. The aim of this study is determination of the best method for bonding to zirconia based on the selection of the correct primer, suitable adhesive and best surface pretreatment. Methods: In this in vitro experimental study 16 sintered-zirconia blocks prepared in dimension of (18×6×2 mm) by CAD/CAM technology. Sample cleansed by ultrasonic device contain of 96% ethanol in 6 minutes, after air-drying, based on surface treatment randomly divided into 4 groups which each group divided into 2 sub-groups based on the use of a primer or universal bond: (1) no treatment: (a) cement + zirconia primer, (b) cement + universal bond. (2) Alumina pretreatment: (a) cement + zirconia primer, (b) cement + universal bond. (3) Cojet sand pretreatment: (a) cement + zirconia primer, (b) cement + universal bond. (4) laser pretreatment (a) cement + zirconia primer, (b) cement + universal bond. Composite disc prepared with condensation of composite resin in Tygon tube with integral diminution of 0.7 mm which cured for 40 sconds. Universal bond or zirconia primmer apply on the surface of the zirconia samples then cemented to composite disks by Panavia F2 according manufacture instructions. Microshear bond strength determined with universal testing machine. Failure mode assessed under stereomicroscope. Selected sample based on surface treatment evaluated under SEM. Data were analyzed using one-way analysis of variance (ANOVA). Results: Comparison of the 4 surface treatment groups revealed a significant difference and the highest bond belonged to Cojet and the lowest one to laser group. Conclusion: It seems that Universal Adhesive can to be considered as an alternative to bond to zirconia but the Cojet method is still required.

The effects of lasers on bond strength to ceramic materials: A systematic review and meta-analysis

Lasers have recently been introduced as an alternative means of conditioning dental ceramic surfaces in order to enhance their adhesive strength to cements and other materials. The present systematic review and meta-analysis aimed to review and quantitatively analyze the available literature in order to determine which bond protocols and laser types are the most effective.

A search was conducted in the Pubmed, Embase and Scopus databases for papers published up to April 2017. PRISMA guidelines for systematic review and meta-analysis were followed.

Fifty-two papers were eligible for inclusion in the review. Twenty-five studies were synthesized quantitatively. Lasers were found to increase bond strength of ceramic surfaces to resin cements and composites when compared with control specimens (p-value < 0.01), whereas no significant differences were found in comparison with air-particle abraded surfaces.

High variability can be observed in adhesion values between different analyses, pointing to a need to standardize study protocols and to determine the optimal parameters for each laser type.

Shear bond strength of indirect composite material to monolithic zirconia

PURPOSE

This study aimed to evaluate the effect of surface treatments on bond strength of indirect composite material (Tescera Indirect Composite System) to monolithic zirconia (inCoris TZI).

MATERIALS AND METHODS

Partially stabilized monolithic zirconia blocks were cut into with 2.0 mm thickness. Sintered zirconia specimens were divided into different surface treatment groups: no treatment (control), sandblasting, glaze layer & hydrofluoric acid application, and sandblasting + glaze layer & hydrofluoric acid application. The indirect composite material was applied to the surface of the monolithic zirconia specimens. Shear bond strength value of each specimen was evaluated after thermocycling. The fractured surface of each specimen was examined with a stereomicroscope and a scanning electron microscope to assess the failure types. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey LSD tests (α=.05).

RESULTS

Bond strength was significantly lower in untreated specimens than in sandblasted specimens (P<.05). No difference between the glaze layer and hydrofluoric acid application treated groups were observed. However, bond strength for these groups were significantly higher as compared with the other two groups (P<.05).

CONCLUSION

Combined use of glaze layer & hydrofluoric acid application and silanization are reliable for strong and durable bonding between indirect composite material and monolithic zirconia.

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.

Effect of surface treatments on the bond strength between resin cement and differently sintered zirconium-oxide ceramics

PURPOSE

This study investigated the effects of surface treatments on bond strength between resin cement and differently sintered zirconium-oxide ceramics.

METHODS

220 zirconium-oxide ceramic (Ceramill ZI) specimens were prepared, sintered in two different period (Short=Ss, Long=Ls) and divided into ten treatment groups as: GC, no treatment; GSil, silanized (ESPE-Sil); GSilPen, silane flame treatment (Silano-Pen); GSb, sandblasted; GSbSil, sandblasted+silanized; GSbCoSil, sandblasted+silica coated (CoJet)+silanized; GSbRoSil, sandblasted+silica coated (Rocatech-Plus)+silanized; GSbDSil, sandblasted+diamond particle abraded (Micron MDA)+silanized; GSbSilPen, sandblasted+silane flame treatment+silanized; GSbLSil, sandblasted+Er:Yag (Asclepion-MCL30) laser treated+silanized. The composite resin (Filtek Z-250) cylinders were cemented to the treated ceramic surfaces with a resin cement (Panavia F2.0). Shear bond strength test was performed after specimens were stored in water for 24h and thermo-cycled for 6000 cycles (5-55 °C). Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tamhane's multiple comparison test (α=0.05).

RESULTS

According to the ANOVA, sintering time, surface treatments and their interaction were statistically significant (p<0.05). The highest bond strengths were obtained in GSbCoSil (Ss=13.36/Ls=11.19MPa) and lowest values were obtained in GC (Ss=4.70/Ls=4.62 MPa) for both sinter groups.

CONCLUSIONS

Sintering time may be effective on the bond strength and 30 μm silica coating (Cojet) with silane coupling application technique increased the bond strength between resin cement and differently sintered zirconium-oxide ceramics.

Effect of femtosecond laser beam angle on bond strength of zirconia-resin cement

Yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic is widely used as an all-ceramic core material because of its enhanced mechanical and aesthetic properties. The bond strength of Y-TZP restorations affects long-term success; hence, surface treatment is required on ceramic boundaries. This study evaluated the effect of different laser beam angles on Y-TZP-resin cement shear bond strength (SBS). Forty plates of Y-TZP ceramics were randomly assigned to four groups (n = 10). A femtosecond amplifier laser pulse was applied on Y-TZP surface with different incidence angles (90°, 75°, 60°, 45°). The resin cement was adhered onto the zirconia surfaces. The SBS of each sample was measured using universal testing machine at crosshead speed of 1 mm/min. The SBS was analyzed through one-way analysis of variance (ANOVA)/Tukey tests. The results showed that the degree of laser beam angle affects the SBS of resin cement to Y-TZP. The laser beam was applied to a surface with a 45° angle which resulted in significantly higher SBS (18.2 ± 1.43 MPa) than other groups (at 90° angulation (10.79 ± 1.8 MPa), at 75° (13.48 ± 1.2 MPa) and at 60° (15.85 ± 0.81 MPa); p < 0.001). This study shows that decreasing of the angle between the ceramic surface and the laser beam increased the SBS between the resin cement and the ceramic material, as well as the orifice.

Lasers in esthetic dentistry: soft tissue photobiomodulation, hard tissue decontamination, and ceramics conditioning

The increasing concern and the search for conservative dental treatments have resulted in the development of several new technologies. Low and high power lasers can be cited as one of these new technologies. Low power lasers act at cellular level leading to pain reduction, modulation of inflammation, and improvement of tissue healing. High power lasers act by increasing temperature and have the potential to promote microbial reduction and ablation of hard and soft tissues. The clinical application of both low and high power lasers requires specific knowledge concerning laser interaction with biological tissues, so that the correct irradiation protocol can be established. The present case report describes the clinical steps of two metal-ceramic crowns development in a 60-year-old patient. Three different laser wavelengths were applied throughout the treatment with different purposes: Nd:YAG laser (1,064 nm) for dentin decontamination, diode (660 nm) for soft tissue biomodulation, and Er:YAG laser (2,940 nm) for inner ceramic surface conditioning. Lasers were successfully applied in the present case report as coadjutant in the treatment. This coadjutant technology can be a potential tool to assist treatment to reach the final success.

Bond strength of resin cement to CO2 and Er:YAG laser-treated zirconia ceramic

Objectives

It is difficult to achieve adhesion between resin cement and zirconia ceramics using routine surface preparation methods. The aim of this study was to evaluate the effects of CO₂ and Er:YAG laser treatment on the bond strength of resin cement to zirconia ceramics.

Materials and Methods

In this in-vitro study 45 zirconia disks (6 mm in diameter and 2 mm in thickness) were assigned to 3 groups (n = 15). In control group (CNT) no laser treatment was used. In groups COL and EYL, CO₂ and Er:YAG lasers were used for pretreatment of zirconia surface, respectively. Composite resin disks were cemented on zirconia disk using dual-curing resin cement. Shear bond strength tests were performed at a crosshead speed of 0.5 mm/min after 24 hr distilled water storage. Data were analyzed by one-way ANOVA and post hoc Tukey's HSD tests.

Results

The means and standard deviations of shear bond strength values in the EYL, COL and CNT groups were 8.65 ± 1.75, 12.12 ± 3.02, and 5.97 ± 1.14 MPa, respectively. Data showed that application of CO₂ and Er:YAG lasers resulted in a significant higher shear bond strength of resin cement to zirconia ceramics (p < 0.0001). The highest bond strength was recorded in the COL group (p < 0.0001). In the CNT group all the failures were adhesive. However, in the laser groups, 80% of the failures were of the adhesive type.

Conclusions

Pretreatment of zirconia ceramic via CO₂ and Er:YAG laser improves the bond strength of resin cement to zirconia ceramic, with higher bond strength values in the CO₂ laser treated samples.