Influence of different but compatible all-ceramic materials and bonding systems on dentin bonding properties

This study aimed to investigate the effects of various compatible all-ceramic materials and bonding systems, on the bonding properties of dentin. Five types of commonly used all-ceramic materials (Cerec Blocs, IPS e. max Press, IPS e. max ZirCAD, Incoris Alumina, In-Ceram Alumina) were bonded with three types of adhesives (Multilink N, Variolink N, Relyx Unicem) for nuclear porcelain tile preparation. We evaluated the polymerization conversion rates, shear bonding strength (SBS), and micro-tensile bond strength (TBS) for each combination. The polymerization conversion rates, SBS and TBS differed significantly for all 3 adhesives with each all-ceramic group (P < 0.05). The Relyx Unicem agent had higher adhesive properties compared with the Variolink N and Multilink N agents (P < 0.05). The polymerization conversion rate, SBS and TBS of the five all-ceramic materials differed significantly with each adhesive (P < 0.05). The Cerec Blocs had the highest adhesive performance (P < 0.05). The polymerization conversion rate of adhesives differed with each all-ceramic material, while the dentin bonding strength differed with each all-ceramic material and adhesive. Clinically, all-ceramic materials with a high transparency and low refraction are recommended. For opaque all-ceramic restorations, the curing light time and polymerization reaction rate should be increased to improve the dentin bonding performance.

Effect of immediate dentin sealing, bonding technique, and restorative material on the bond strength of indirect restorations

Objective: The objective of this study was to evaluate the effect of immediate dentin sealing, bonding technique, and restorative material on the dentin bond strength of an indirect composite (Solidex) and a resin nanoceramic CAD/CAM block (LAVA Ultimate). Material and Methods: A total of 120 periodontally extracted human molar teeth were abraded horizontally and divided into two groups according to dentin sealing procedures (delayed dentin sealing [DDS] and immediate dentin sealing [IDS]). Next, all teeth were attached to a simulated pulpal pressure mechanism. The specimens were removed from the mechanism after a week. Teeth were subdivided into three groups based on the bonding technique and the type of cement used (Acid-etching + Single Bond Universal + RelyX Ultimate, Single Bond Universal + RelyX Ultimate, RelyX Unicem). Each subgroup was further divided into 2 subgroups according to the type of restorative material used (Solidex [n=10], Lava Ultimate CAD/CAM restorative material [n=10]).. Sixty cylindrical samples prepared using both the restorative materials were bonded to the tooth surface according to their group’s bonding procedures. All specimens were embedded in chemically cured acrylic resin for shear bond strength test. The shear bond strength (SBS) of the specimens was determined by a universal testing machine with a headspeed of 0.5 mm/min. Results: Three-way ANOVA, independent-sample t test and post hoc Tukey comparison tests (α=0.05) were performed on all data. There were significant differences between the groups. It was found that IDS process significantly increased bond strength in all groups. When dentin bond strengths of tested luting cements were compared, the highest bond strength values were recorded in groups in which the specimens were luted with RelyX Ultimate cement using etch-and-rinse technique. The lowest bond strength values were obtained from groups that used RelyX Unicem as the luting cement. Conclusions: IDS improves bond strength of indirect restorations. Moreover, bonding techniques may have critical effects on the dentin bond strength of indirect restorative materials. The cements’ specific affinity levels to both restorative materials and dentin could be considered as the reason of the situation.KEYWORDSIDS; Luting cement; Shear bond strength; Resin nanoceramic; CAD/CAM.

Influence of two different cement space settings and three different cement types on the fit of polymer-infiltrated ceramic network material crowns manufactured using a complete digital workflow

Objectives The study evaluates the influence of two spacer settings and three resin luting materials on the marginal and internal fit of polymer-infiltrated ceramic network (PICN) material crowns manufactured using a complete digital workflow. Methods Optical impressions of fifty identical dies were performed using the 3M scanner (software version 5.0.2). Twenty crowns were designed using Ceramill Mind (version 3.4.10.1163), from which ten with spacer setting of 50 μm (G1) and ten with 80 μm (G2). Thirty crowns (spacer setting of 50 μm) were divided into three groups corresponding to the resin materials used as follows: RelyX Unicem (RX), Variolink Esthetic (VLE), and Nexus 3 (NX3). All crowns were milled from Vita Enamic blocks. After micro-CT scanning, absolute marginal discrepancy (AMD), internal gap (IG), total cement space volume (TCV), and marginal porosities (VP) were measured. Results Significant difference was detected on the VP between the RX and NX3 group (p = 0.033). The mean values of all parameters were the following: AMD (μm): G1 182.6, G2 253.7, RX 210.8, VLE 195.5, NX3 186.6; IG (μm): G1 215.6, G2 173.1, RX 171.1, VLE 198.6, NX3 203; TCV (mm3): G1 22.9, G2 20.49, RX 17.57, VLE 17.49, NX3 20.59; VP (mm3): G1 0.26, G2 0.34, RX 0.32, VLE 0.46, NX3 0.54. Conclusions Fit of PICN material crowns was not significantly influenced by increasing the spacer settings and cementation with different resin materials. Additionally, RelyX Unicem showed significantly less porosities as compared with Nexus3. Clinical relevance Both 50 μm and 80 μm virtual spacer settings can be suggested for the manufacture of PICN crowns when Ceramill Mind (version 3.4.10.1163) is used. Furthermore, a self-adhesive system can be recommended for the cementation.

The Effect of the Use of Different Types of Cement and Zirconium Post Systems on Endondontically Treated Teeth

BACKGROUND: Prefabricated zirconium upgrading systems were examined to satisfy aesthetic needs in endodontically treated teeth. Endodontically treated teeth, together with non-metallic posts and superstructure, are substructures that enable the production of prosthetic structures that will allow aesthetics, resulting from normal light transmission. To investigate and analyse the retention of zirconium post systems cemented with RelyX Unicem 2 Automix (RLX) cement with Pull-out test. AIM: To examine the retention of zirconium post systems, cemented with Multi-Link Automix (MLA) cement and RelyX Unicem 2 Automix (RLX) cement with Pull-out test. MATERIAL AND METHODS: In this study were used, 120 post systems of the company ZIRIX NORDIN - Switzerland, with different diameters d1 = 1.2, were used: d2 = 1.35, d3 = 1.5, and two types of resin cements: Multilink Automix-Ivoclar (MLA), and RelyX Unicem 2 Automix (RLX) - 3 M ESPE. RESULTS: The analysis of the extraction force in newtons (N) zirconium post systems of Multilink Automix cement according to subgroups of three diameters is consequently 481.3 ± 1.9 vs 462.9 ± 4.5 vs 454.2 ± 2.2. The analysis of the extraction strength in the newtons (N) zirconium post systems of RelyX Unicem 2 Automix cement in the entire sample is 577.9 ± 6.1 N. CONCLUSION: The largest diameter of the posts significantly increases the resistance of fractures compared to the smaller two diameters used in the experimental study.

Microshear bond strength of conventional and self-adhesive resin cements to feldsphatic ceramic

Aim: The aim of this study was to verify the microshear bond strength of conventional and self-adhesive resin cements to feldsphatic ceramic. Methods: Twenty discs of Starlight ceramic (Degudent) were made (15mm x 2mm). The bonding procedure was accomplished by insertion of resin cements into tubes of 0.7mm internal diameter in contact with the ceramic. The resin cements used were: RelyX ARC (3M Espe), Panavia F (Kuraray), RelyX Unicem (3M Espe) and seT (SDI). Total of six tubes of each material on each ceramic disc. The specimens were tested for microshear in a universal testing machine, 24hours and 6months after bonding procedure. Values of microshear bonding strength (MPa) were subjected to ANOVA and Fisher PLSD test (p<0.05). Results: For 24hours analysis, RelyX ARC showed the highest microshear bonding strength without statistical difference to RelyX Unicem and seT. Panavia F showed the lowest values of microshear bonding strength in both periods. In the analysis after 6months there was a significant increase in the microshear bonding strength values for all cements compared to 24hours. Only for RelyX ARC, the increase was not statistically significant. Conclusion: In conclusion, the bond strength depends mainly on the type of resin cement used, and the self-adhesive cements behave similarly to conventional resin cement.

Delayed Photo-activation Effects on Mechanical Properties of Dual Cured Resin Cements and Finite Element Analysis of Shrinkage Stresses in Teeth Restored With Ceramic Inlays

SUMMARY Objective: The aim of this study was to investigate the effect of delayed photo-activation on elastic modulus, Knoop hardness, and post-gel shrinkage of dual cure resin cements and how this affects residual shrinkage stresses in posterior teeth restored with ceramic inlays. Methods and Materials: Four self-adhesive (RelyX Unicem, 3M ESPE; GCem, GC; MonoCem, Shofu; and seT, SDI) and two conventional (RelyX ARC, 3M ESPE; and AllCem, FGM) dual cure resin cements for cementing posterior ceramic inlays were tested. Strain gauge and indentation tests were used to measure the post-gel shrinkage (Shr), elastic modulus (E), and Knoop hardness (KHN) when photo-activated immediately and 3 and 5 minutes after placement (n=10). Shr, E, and KHN results were analyzed using two-way analysis of variance followed by Tukey honestly significant difference post hoc tests (α=0.05). The experimentally determined properties were applied in a finite element analysis of a leucite ceramic inlay (Empress CAD, Ivoclar Vivadent) cemented in a premolar. Modified von Mises stresses were evaluated at the occlusal margins and cavity floor. Results: Shr, E, and KHN varied significantly among the resin cements (p&lt;0.001). Highest overall Shr values were found for RelyX Unicem; GCem had the lowest. Increasing the photo-activation delay decreased Shr significantly. Delayed photo-activation had no effect on E (p=0.556) or KHN (p=0.927). RelyX Unicem had the highest E values; seT and MonoCem had the lowest E values. AllCem and RelyX Unicem had the highest KHN and MonoCem had the lowest KHN. Cements with high Shr and E values caused higher shrinkage stresses. Stresses decreased with delayed photo-activation for all cements. Conclusions: KHN and E values varied among the different resin cements. Residual shrinkage stress levels decreased with increasing photo-activation delay with all resin cements.

Push-Out Bond Strength Evaluation of Glass Fiber Posts With Different Resin Cements and Application Techniques

SUMMARY The purpose of this study was to evaluate the push-out strength of two different adhesive cements (total etch and self-adhesive) for glass fiber post (GFP) cementation using two different techniques (microbrush and elongation tip) of cement application. In addition, this study evaluated the effect of total-etch conditioning before the use of a self-adhesive cement. Sixty premolar specimens with a single root canal were selected, endodontically treated, and shaped for GFP cementation. The specimens were randomly placed into one of six groups according to the cement and technique used: RelyX ARC (ARC): ARC + microbrush, ARC + elongation tip; RelyX Unicem (RU): RU + microbrush, RU + elongation tip; or RelyX Unicem + 37% phosphoric acid (RUE): RUE + microbrush, RUE + elongation tip. Each specimen root was cut perpendicular to the vertical axis yielding six 1.0-mm-thick sections. Push-out strength test was performed, followed by statistical analysis using three-way analysis of variance and the Games-Howell test (p&lt;0.05). Statistically significant differences between the groups were found (p&lt; 0.05). The cervical third of the roots had the highest mean push-out strength values, while the apical third had the lowest mean values regardless of the technique used. The elongation technique produced higher mean push-out strength values compared to the microbrush technique. The self-etch adhesive cement had the highest mean push-out strength value in all thirds. The addition of a conditioning step before the self-etch adhesive cementation appears to be effective in enhancing push-out strength with GFPs.

Microshear Bond Strength of Resin Cements to Lithium Disilicate Substrates as a Function of Surface Preparation

SUMMARY Objectives To investigate the effect of hydrofluoric acid (HF) etching, silane solution, and adhesive system application on the microshear bond strength (μSBS) of lithium disilicate glass-ceramic (LD) to three resin cements. Materials and Methods Circular bonding areas were delimited on the lithium disilicate surfaces using a perforated adhesive tape. Specimens were assigned to 18 subgroups (n=12) according to surface treatment: NT = no treatment; HF = 4.8% HF for 20 seconds; silane solution: (1) no silane; (2) Monobond Plus, a silane/10-methacryloyloxydecyl dihydrogen phosphate solution for 60 seconds; (3) Monobond Plus+ExciTE F DSC, a dual-cure adhesive; and resin cement: (1) Variolink II, a bisphenol A diglycidyl ether dimethacrylate (bis-GMA)–based, hand-mixed, dual-cure resin cement; (2) Multilink Automix, a bis-GMA–based, auto-mixed, dual-cure resin cement; (3) RelyX Unicem 2, a self-adhesive, auto-mixed, dual-cure resin cement. Tygon tubes (Ø=0.8 mm) were used as cylinder matrices for resin cement application. After 24 hours of water storage, the specimens were submitted to the μSBS test. Mode of failure was evaluated under an optical microscope and classified as adhesive, mixed, cohesive in resin cement, or cohesive in ceramic. Data were statistically analyzed with three-way analysis of variance and Dunnett test (p&lt;0.05). Results When means were pooled for the factor surface treatment, HF resulted in a significantly higher μSBS than did NT (p&lt;0.0001). Regarding the use of a silane solution, the mean μSBS values obtained with Monobond Plus and Monobond Plus+ExciTE F DSC were not significantly different but were higher than those obtained with no silane (p&lt;0.001). Considering the factor resin cement, Variolink II resulted in a significantly higher mean μSBS than did RelyX Unicem 2 (p&lt;0.03). The mean μSBS for Multilink Automix was not significantly different from those of Variolink II and RelyX Unicem 2. According to Dunnett post hoc test (p&lt;0.05), there was no significant difference in μSBS between the different resin cements for HF-etched and silanized (with or without adhesive application) LD surfaces. Conclusion LD may benefit from pretreatment of the inner surface with HF and silanization, regardless of the resin cement used.

Effect of Photoactivation Timing on the Mechanical Properties of Resin Cements and Bond Strength of Fiberglass Post to Root Dentin

SUMMARY Objectives This study tested the hypothesis that photoactivation timing and resin cement affect mechanical properties and bond strength of fiberglass posts to root dentin at different depths. Methods Fiberglass posts (Exacto, Angelus) were luted with RelyX Unicem (3M ESPE), Panavia F 2.0 (Kuraray), or RelyX ARC (3M ESPE) using three photoactivation timings: light curing immediately, after three minutes, or after five minutes. Push-out bonding strength, PBS (n=10) was measured on each root region (coronal, middle, apical). The elastic modulus (E) and Vickers hardness (VHN) of the cement layer along the root canal were determined using dynamic indentation (n=5). A strain-gauge test was used to measure post-gel shrinkage of each cement (n=10). Residual shrinkage stress was assessed with finite element analysis. Data were analyzed with two-way analysis of variance in a split-plot arrangement and a Tukey test (α=0.05). Multiple linear regression analysis was used to determine the influence of study factors. Results The five-minute delay photoactivation timing significantly increased the PBS for all resin cements evaluated. The PBS decreased significantly from coronal to apical root canal regions. The mean values for E and VHN increased significantly with the delayed photoactivation for RelyX Unicem and decreased from coronal to apical root regions for all resin cements with the immediate-curing timing. Conclusions The PBS of fiber posts to root dentin, E, and VHN values were affected by the root canal region, photoactivation timing, and resin cement type. Shrinkage stress values decreased gradually with delayed photoactivation for all the cements.

Confocal laser scanning microscopy investigation of bond interfaces involved in fiber glass post cementation

<p><strong>Objective</strong>: This confocal microscopy study evaluated the cement/dentin and cement/post interfaces along the root canal walls when fiber glass posts were bonded to dentin using different types of cements.</p><p><strong>Material and methods</strong>: Thirty endodontically treated premolars were divided into 3 groups according to the adhesive materials used in the bonding procedure: Prime &amp; Bond 2.1/Self Cure + Enforce, RelyX Unicem and RelyX Luting. Rhodamine B dye was incorporated in the luting materials for the cementation of the fiber glass posts (Exacto, Angelus) to dentin. Three transversal slices (apical, middle and coronal) were examined under confocal laser scanning microscopy. Statistical analysis was performed using the Kappa, Kruskal-Wallis and Dunnet tests.</p><p><strong>Results</strong>: The Prime &amp; Bond 2.1/Self Cure + Enforce presented a uniform formation of tags in the dentin but gaps in the cement/dentin interface. The RelyX Unicem and RelyX Luting presented an adhesive interface with a fewer amount of gaps, but showed shorter tag formation than the Enforce system. All cements presented the same pattern of bubbles inside the cements<strong>. </strong>The<strong> </strong>RelyX Luting presented a greater amount of cracks inside the cement in comparison with the other cements in the coronal third, while no difference was observed between RelyX Unicem and Enforce. The RelyX Luting showed the lowest quantity of cement penetration into the post.</p><p><strong>Conclusions</strong>: In general, the quality of bonding interfaces of fiber posts luted to root canals was affected by both location and type of cement.</p>