Panavia SA Research Articles

In vitro evaluation of a silane containing self-adhesive resin luting agent.

To investigate the setting characteristics, wettability and bonding capacity with a lithium disilicate ceramic of a silane containing self-adhesive resin luting agent (Panavia SA Universal-PU). The degree of conversion (DC %) and extent of acid neutralization (SY %) of PU were measured on dual- (DC) and self-cured (SC) specimens after 10, 30 and 60 min storage by ATR-FTIR spectroscopy, whereas the presence of silanols was traced by curve-fitting the 60 min spectra, using the silane-free analog (Panavia SA Plus-PS) as a control. The role of a dedicated adhesive (Clearfil Universal Bond Quick-CU) in assisting the early DC % in PU-SC was investigated on 10 min-stored specimens. The water contact angles on polished and HF acid-etched lithium disilicate surfaces (IPS e.max Press), were assessed before and after silanization by unset PU or a silane primer (Ultradent Silane-SL). Finally, the shear strength of PU-DC specimens bonded to the acid-etched ceramic surfaces was determined before and after SL treatment. The DC % was higher in DC than SC (PU, PS; all time intervals), in PU-SC than PS-SC (30, 60 min) and in the CU assisted PU-SC group. The SY % was lower in DC than SC (PU, PS) and higher in PS-SC than PU-SC groups. Silanols were found only in unset PU and PU-DC groups. SL treatment provided higher water contact angles on polished and acid-etched ceramic surfaces and higher shear bond strength on acid-etched ceramic surfaces than PU (p < 0.05 for all comparisons). Although the degree of conversion of the silane containing luting agent was improved in the self-curing mode, especially in the adhesive assisted group, it was still inferior to light-curing. Acid-neutralization and presence of silanols were affected by the setting modes. The use of a silane primer enhanced the hydrophobicity and bond strength of the silane containing luting agent with the etched ceramic substrate.

Color Stability of Resin Cements after Water Aging.

The color stability of resin cements plays a key role in the achievement of esthetically-pleasant restorations. Resin luting materials can be mainly divided into two main classes: adhesive (relying on previous application of adhesive systems) or self-adhesive (also known as one-step cements). The different chemical compositions determine their physio-mechanical characteristics which, in turns, influence their color stability. To evaluate the color variations of different dual-cured resin cements after water aging, 80 disc-shaped specimens (15 mm in diameter and 1.2 mm thick) were obtained from the following resin cements (n = 10): (1) Maxcem Elite Universal, MCU (Kerr); (2) RelyX Universal, RXU (3M); (3) Calibra Ceram, CAL (Dentsply); (4) Multilink, MUL (Ivoclar-Vivadent); (5) Panavia V5, PAN (Kuraray); (6) Calibra Universal, CUN (Dentsply); (7) SpeedCEM Plus, SCP (Ivoclar); and (8) Panavia SA, PSA (Kuraray). After light-polymerization, the specimens were measured with a spectrophotometer and CIELab* values were recorded. The specimens were then placed in a digitally controlled thermostatic water bath at 60° for 30 days and afterwards the color measurements were repeated. Color differences were calculated for each specimen before and after water-aging procedures with ΔEab formula and the data were statistically analyzed (p < 0.05). The type of cement statistically influenced the ΔEab (p < 0.05), with MCU showing the lowest color variations (4.3 ± 0.7) whereas RXU and PSA the highest (16.9 ± 1.6 and 16.8 ± 1.2, respectively). No differences were observed between CAL, CUN and SCP (p = 0.05). Color stability is related to the chemical composition of the resinous luting materials, thus material dependent.

Effects of Particle Abrasion Media and Pressure on Flexural Strength and Bond Strength of Zirconia.

To compare the effects of particle abrasion medium and pressure on shear bond strength and biaxial flexural strength of three generations of zirconia (Lava Frame, Lava Plus, and Lava Esthetic) with the goal of optimizing the bond to zirconia. 280 discs (14 mm diameter; 1 mm thickness) of each zirconia were milled and sintered. Specimens of each material were randomly distributed into 14 groups (n=20); half were tested for shear bond strength and half were tested for biaxial flexural strength. The specimens were particle abraded on one surface by 2 different media (50 μm alumina particles or 50 μm glass beads) for 10 seconds at three different pressures (15, 30, and 45 psi or 0.1, 0.2, 0.3 MPa). Untreated specimens served as positive control. A tube (1.50 mm diameter) filled with dual cured resin cement (Panavia SA) was placed onto the surface and light cured. Specimens were stored in water (37°C for 24 hours) and shear bond strength was measured in a universal testing machine (Instron). Biaxial flexural strength of each specimen was measured according to ISO 6872. Shear bond strength and biaxial flexural strength were compared individually with a 2-way analysis of variance (ANOVA) for factors surface treatment and zirconia composition. Significant differences were seen between surface treatments (p<0.01), zirconia composition (p<0.01) and their interaction (p<0.01) for both bond strength and flexural strength. With alumina particle abrasion, higher pressure produced higher bonds for Lava Frame and Lava Plus zirconia while the bond of Lava Esthetic declined with increased pressure. Higher pressure (>0.2 MPa or 30 psi) with alumina decreased biaxial flexural strength with Lava Esthetic zirconia. Particle abrasion with alumina produced a significantly better combination of bond strength while maintaining biaxial strength of three zirconia materials than particle abrasion with glass beads. The bond strength also depended upon the pressure of particle abrasion and the generation of zirconia used.

Evaluation of Antimicrobial Effectiveness of Dental Cement Materials on Growth of Different Bacterial Strains.

BACKGROUND The aim of this study was to evaluate the antimicrobial effectiveness of dental cement materials for the prevention of bacterial growth, which can cause failure of fixed cementation. MATERIAL AND METHODS We developed an agar diffusion disk test in-house to evaluate the antibacterial properties of 3 commercially available dental cement materials (Ketac, Harvard FLB, and Panavia SA Universal Dual Resin cements) compared with a negative control. The materials were tested for the inhibition against Streptococcus mutans (ATCC 10449), Streptoccocus salivarius (ATCC 25975), Enterococcus faecalis (ATCC 29212), and Lactobacilus acidophilus (ATCC 4356). The antimicrobial effectiveness of materials was expressed as the diameters of the inhibition zones around the disk. RESULTS Overall, 240 specimens were tested. All cement materials showed antimicrobial effectiveness. Different microbial strains reacted differently to the different dental cements (all P.

Polymerization Kinetics, Shrinkage Stress, and Bond Strength to Dentin of Conventional and Self-adhesive Resin Cements.

To evaluate the kinetics of polymerization and shrinkage stress of resin cements, as well as their bond strength to dentin after 24-h or one-year water storage. Three conventional resin cements were evaluated: RelyX Ultimate (RUL), Panavia V5 (PNV), and Multilink N (MLN); and three self-adhesive resin cements: RelyX Unicem 2 (RUN), Panavia SA Cement Plus (PSA), and G-CEM LinkAce (GCL). Degree of conversion (DC), maximum polymerization rate (RPmax) and gel time values were obtained using Fourier-transform infrared spectroscopy (FTIR/ATR). Shrinkage stress values were determined with a tensiometer, using a universal testing machine (n=5). Indirect resin composite restorations (Solidex) were fabricated and cemented to the dentin surface using self-adhesive resin cements, or conventional resin cements with self-etching adhesive (n=5). Bonding performance was evaluated with the microtensile bond strength (µTBS) test after 24 h or one year of water storage. MLN exhibited a higher DC (76.7%), whereas the percentage of other materials differed slightly (ranging from 54% to 58.5%). The RPmax and shrinkage stress values differed significantly between the cements. PSA showed the longest gel time. Significantly higher µTBS were observed for conventional resin cements after 24-h and one-year storage; a decrease in µTBS was observed for MLN only. Self-adhesive resin cements may not perform as well as conventional resin cements. Although both categories of cements presented similar polymerization kinetics and shrinkage values, the self-adhesive resin cements showed lower µTBS compared to those of conventional resin cements. Nevertheless, storage time only affected the bonding performance of MLN.

Adhesion of auto-mixed and manual-mixed self-adhesive resin cements to dentin on exposure to long-term high-altitude pressure

PurposeThe purpose of this study is to test the shear-bond-strengths of auto-mixed and manual-mixed self-adhesive resin cement to dentin on long-term high-altitude pressure.Design/methodology/approachHuman molars were embedded in acrylic resin. Sixty composite resin discs were obtained. The composite resin discs were bonded to dentin using hand-mixed and auto-mixed self-adhesive resin cement. After cementation, the samples were stored in artificial saliva and divided into two subgroups (n = 30), hypobaric pressure and the atmospheric pressure group. The specimen underwent three pressure cycles per day for 100 days. The failure types were evaluated after debonding with scanning electron microscopy. The shear bond strength was tested with Universal Testing Machine. Analysis of variances/Tukey post hoc tests were used for statistical analysis. Groups were also evaluated by the Weibull modulus.FindingsRegardless of hypobaric pressure changes, the highest bond strength was examined in auto-mixed Panavia SA samples. A significant difference was found in both auto-mixed MaxCem EC and hand-mixed RelyX U200 group after exposure to hypobaric pressure compared to the control group.Originality/valueThe luting cement-type, mixing methods of cements and environmental pressure changes significantly influence the bond strengths. Dentists can use auto-mixed self-adhesive resins in patients likely to be exposed to hypobaric pressure.

Comparative evaluation of frictional resistance of extracoronal attachments of different designs and lengths in fixed partial denture

Aim: The purpose of this study was to evaluate the effects of different extracoronal attachment lengths and designs on frictional resistance and the vertical force required to create that resistance in fixed partial dentures (FPD). Setting and Design: Finite element analysis. Materials and Methods: Four manufacturers were considered for the FPD's extracoronal attachments because to their varying designs and length options (3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm). Catia V5 software was used to create 3D models of the samples and perform simulations on them. To simulate medical facilities, the application was adjusted to take into consideration the characteristics. The amount of frictional resistance and the required vertical force for that resistance were calculated by finite element analysis using ANSYS workbench 15.0. Statistical Analysis Used: ANOVA and Tukey's post hoc test. Results: When compared to Panavia SA cements, the average microhardness of Variolink N resin cements was much higher (P 0.001). Compared to Panavia SA resin cements, the sorption/solubility of Variolink N cements was statistically substantially lower at the 0.05 level.

Different Cavity Designs with Additional Wings Increase the Fracture Resistance of Inlay-Retained Monolithic Zirconia Fixed Dental Prostheses.

To evaluate the effect of different cavity designs and cement types on the fracture resistance of monolithic zirconia inlay-retained fixed dental prostheses (IRFDPs). Four study models consisting of a second premolar, a missing first molar, and a second molar were used for the different cavity designs. Four different inlay cavity designs were prepared: DO-MO (disto-occlusal-mesio-occlusal cavity), MOD-MOD (mesio-occlusodistal-mesio-occlusodistal cavity), WDO-WMO (DO-MO with additional wings), and WMOD-WMOD (MOD-MOD with additional wings). A total of 64 epoxy resin models were produced and scanned individually. IRFDPs were then fabricated from monolithic zirconia using CAD/ CAM software. The bonding surface of the IRFDPs was airborne particle abraded (50-μm alumina/2 MPa), then cemented onto the epoxy resin models using two cementation protocols (n = 8 per group): (1) P = cemented with Panavia SA Cement Plus Automix; and (2) Z/C = cemented with MDP-containing primer (Z-Prime Plus) combined with Calibra Universal resin cement. All IRFDPs were fatigued through thermal aging (6,000 cycles/5°C to 55°C) and chewing simulations (600,000 cycles × 50-N load, 2.1 Hz). All IRFDPs were then subjected to a fracture resistance test using a universal testing machine with a crosshead speed of 0.2 mm/minute. Data were statistically analyzed using one- and two-way ANOVA and Bonferroni multiple comparisons test (P = .001). The mean fracture load (N) of the designs were as follows: WMODWMOD = 1,111.1; WDO-WMO = 1,057.4; MOD-MOD = 725.6; DO-MO = 682.7. According to two-way ANOVA, the differences among the cavity designs were statistically significant (P < .05). The cavity design of IRFDPs affected the fracture resistance. However, the fracture resistance of monolithic zirconia IRFDPs with any cavity design was enough to withstand expected posterior chewing forces.

Effect of Tannic Acid and Quercetin Antioxidants on Bond Strength of Resin Cement to Dentin after Internal Bleaching.

To evaluate the influence of tannic acid and quercetin on the immediate microshear bond strength (μSBS) of two resin cements to dentin after internal bleaching. The access cavity in eighty extracted maxillary incisors was internally bleached except the control groups. The labial surfaces were ground to expose a flat dentin surface. The specimens were randomly divided into eight groups (n=10) as follows: 1) Control/Dou; Doulink without bleaching, 2) Bl/Dou; Bleaching+Doulink, 3) Bl+Ta/ Dou; Bleaching+Tannic acid+Doulink, 4) Bl+Qu/Dou;Bleaching+Quercetin+Doulink, 5) Control/ PSA; Panavia SA without bleaching, 6) Bl/PSA;Bleaching+Panavia SA, 7) Bl+Ta/ PSA; Bleaching+Tannic acid+Panavia SA, 8) Bl+Qu+PSA; Bleaching+Quercetin+Panavia SA. After 24 hours, the μSBS of the specimens was tested and the obtained data were analyzed with two-way ANOVA and Tamhane test (p⟨0.05). The µSBS of Doulink groups were higher than the PSA groups (p⟨0.001). The μSBS of Bl+Ta/Dou and Bl+Qu/ Dou groups did not differ from Bl/Dou (p⟩0.05). The μSBS of Bl+Ta/PSA group was statistically significantly higher than the Bl/PSA group (p⟨0.001). There was no significant difference between µSBS of Bl+Qu/PSA and Bl/PSA groups (p=0.39). TA partially reversed the negative influence of internal bleaching on the µSBS of Panavia SA while quercetin did not increase the bond strength of both resin cements.

Effect of airborne particle abrasion and primer application on the surface wettability and bond strength of resin cements to translucent zirconia

The purpose of this study was to evaluate the effect of sandblasting and primer application on the immediate and long-term shear bond strength of resin cements to translucent zirconia. Zirconia plates (Katana STML, Kuraray Noritake Dental) were divided into six groups (n = 10) for shear bond strength evaluation using three resin cements (Panavia V5, Kuraray Noritake Dental; Variolink Esthetic LC, Ivoclar-Vivadent; and Panavia SA Cement Universal, Kuraray Noritake Dental). The zirconia was sandblasted or left unabraded. Each cement was used with the indicated primer. Two cylinders of cement were placed on the zirconia, one for evaluation after 24 h and the other after 1 year of storage in water. The fracture pattern and the contact angle were observed on all groups. At 24 h, there were no differences in bond strength of the cements for equal sandblasting conditions. After 1-year, the bond strength of all groups decreased, except for Panavia V5 associated with sandblasting. For all the cements, the unabraded zirconia showed a lower bond strength and a higher rate of adhesive failures. The application of primers reduced the contact angle. Higher bond strength is obtained when primers are combined with sandblasting using aluminum oxide particles. Clinical significance: Translucent zirconia restorations should be treated by airborne particle abrasion and phosphate-based primers before bonding, to improve the wettability of the cements and obtain a more durable bonding between the cement and the zirconia.

The Effectiveness of Various Functional Monomers in Self-adhesive Resin Cements on Prosthetic Materials.

ABSTRACTAim:This study examined the influence of various functional monomers in two self-adhesive resin cements (SACs) on prosthetic materials.Materials and Methods:Base metal alloy, lithium disilicate glass-ceramic, and zirconia were used as bonding materials. Silicon carbide paper was used to polish the specimens. Two self-adhesive resin cements (Panavia SA luting multi, PAM, and Maxcem elite chroma, MAC) were used. Ten specimens for each material were produced and resin cements were bonded to each material. The specimens were stored in 37°C distilled water in an incubator for 24 hours. A universal testing machine was used to measure the shear bond strength. The data were statistically examined using one-way ANOVA and Tukey’s test.Results:In all prosthetic materials, PAM had the highest bond strength. In lithium disilicate glass-ceramic, the lowest bond strength was found with MAC.Conclusion:The self-adhesive resin cement (PAM) containing 10-MDP monomer and long carbon-chain silane was performed the greatest outcome in the shear bond strength on the prosthetic materials and self-adhesive resin cement interface.

Influence of curing modes on monomer elution, sorption and solubility of dual-cure resin-cements

ObjectiveTo explore the effect of two curing modes, for dual-cure resin cements, on their monomer elution, water sorption and solubility after 30 d water storage and 30 d dry reconditioning. MethodsEight dual-cure resin-cements were investigated (Bifix SE, Nexus Third Generation, PANAVIA SA, PANAVIA V5, RelyX Ultimate Universal, RelyX Unicem 2, RelyX Universal and SpeedCEM Plus). Six disk-shaped specimens were made per curing mode: light-cure (LC) versus self-cure (SC) to measure amounts of eluted monomers after 30 d of water storage at 37 °C. Ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC MS/MS) was performed to identify and quantify three eluted monomers (Bis-GMA, UDMA and TEGDMA). Water sorption/ solubility specimens were prepared according to ISO 4049. Specimens from each curing mode (LC/SC) were immersed separately in distilled water for 30 d and then reconditioned for 30 d; all at 37 °C. Mass change was measured at different time intervals. Data were analyzed via one-way ANOVA, Tukey post-hoc tests and independent sample t-tests (α = 0.05). ResultsAfter 30 d of water storage, the three monomers Bis-GMA, UDMA and TEGDMA were detected in water. All monomers showed a variable extent of elution into water and were significantly higher (p < 0.0001) with SC compared to LC curing modes. BSE had the highest quantity of eluted monomers. After 30 d of water sorption (μg/mm3), all rein-cements showed significantly higher sorption (p < 0.05) of SC compared to LC curing modes except for PV5, RXU and CEM (p > 0.05). After 30 d of water solubility (μg/mm3), all resin-cements showed significantly higher solubility (p < 0.0001) of SC compared to LC curing mode. BSE had the highest water sorption and solubility. The total amounts of eluted monomers correlated positively with solubility: r2 = 0.95 for LC and r2 = 0.93 for SC. SignificanceWhenever light access is possible, light curing remains beneficial to reduce the extent of resin degradation and related properties of dual-cure resin cements. BSE showed statistically the highest extent of eluted monomers, sorption and solubility.

Bonding Strength of Lithium Disilicate Adhesive Crowns with Different Occluso-Cervical Preparation Heights and Cement Types

The aim of this study was to evaluate if adhesion technology with CAD/CAM can compensate for the reduction of occluso cervical preparation heights using different types of dental cement. The de-bonding failure types were then assessed. Here, 72 caries-free extracted human premolar teeth were prepared to have a remaining occlusal height of two, three, and four mm. IPS e.max lithium disilicate CAD/CAM crowns were cemented with adhesive resin cement Panavia SA, self-adhesive resin cement, RelyX Unicem Aplicap, and zinc phosphate cement. The cementation techniques were based on the manufacturer’s instructions. After thermocycling, all samples were tested for tensile bond strength via an Instron machine. One-way analysis of variance (ANOVA) with post hoc testing (P &lt; 0.05) was performed. The means TBS for the two, three, and four-mm OCHP groups were 2.72±0.69, 3.06±0.82, and 3.25±0.79.0 MPa; ARC, SARC, and ZPC were 3.41±0.51, 3.45±0.41, 2.08±0.35 MPa, respectively with significant differences in both. The mixed cement had failures in the resin cement groups. Failure was predominantly cohesive in the zinc phosphate group. Resin cement had the highest SBS values versus ZPC values when both bonded to lithium disilicate crowns with different occlusal heights. The failure of the adhesive to the crown and/or to the tooth were the highest for the four types of resin cement. Around 25% were cohesive failures with resin cement, but this was predominately adhesive in crowns in zinc phosphate regardless of the preparation heights.

Effects of Three Novel Bracket Luting Agents Containing Zirconia Primer on Shear Bond Strength of Metal Orthodontic Brackets Attached to Monolithic Zirconia Crowns: A Preliminary In Vitro Study.

Background The increased use of zirconia crowns in adult orthodontic patients warrants the establishment of methods and materials to adhere orthodontic brackets properly to zirconia crowns. However, studies in this regard are scarce, and many materials remain untested. This preliminary study aimed to examine three new adhesives containing zirconia primers for the first time. Methods Sixty identical monolithic zirconia crowns were fabricated and randomly divided into 4 groups of 15 each (Panavia SA Cement Plus, G-CEM, TheraCem, and Transbond XT Composite (control)). After glaze removal with a diamond bur, a metal orthodontic bracket was attached to the surfaces of the crowns using the respective adhesive. Specimens were incubated at 37°C and then thermocycled for 2000 cycles. Shear bond strengths (SBS) of brackets in different groups were estimated using a universal testing machine. Mean SBS values were compared with the values 6, 8, and 10 (as acceptable SBS values) and 13 MPa (as the maximum SBS tolerable by zirconia) using the one-sample t-test. They were also compared with each other using the one-way ANOVA and Tamhane post hoc test (α = 0.05). Results The ANOVA indicated a significant overall difference; the Tamhane test showed that the difference between the control group and all test groups was significant (P < 0.0005); however, the 3 test groups were not significantly different from each other (P > 0.30). The SBS of the control group was significantly lower than the minimum acceptable SBS (6 MPa, P < 0.0005). The mean SBS of the TheraCem was not significantly different from 10 MPa (P = 0.902), while the mean SBS values of Panavia SA Cement Plus and G-CEM were significantly greater than 10 MPa (P < 0.05). None of the three zirconia adhesives had mean SBS values higher than 13 MPa. Conclusion All novel zirconia adhesives (Panavia SA Cement Plus, G-CEM, and TheraCem) generated SBS values adequate to attach metal orthodontic brackets to zirconia prostheses (at or greater than 10 MPa) without damaging the zirconia during bracket removal (not above 13 MPa).

Influence of autoclave sterilization on bond strength between zirconia frameworks and Ti-base abutments using different resin cements

Statement of problemZirconia frameworks luted on titanium bases have been increasingly used for implant-supported prostheses. A reliable bond strength between the framework and the base is a key factor for clinical success. Autoclaving of the abutments before clinical use has been strongly suggested since abutments have been classified as class II medical devices. However, comprehensive knowledge on the susceptibility of the composite resin luting agents’ adhesion to autoclave sterilization is lacking. PurposeThe purpose of this in vitro study was to assess the bond strength between zirconia frameworks and titanium bases using different composite resin luting agents with and without thermocycling and autoclaving. Material and methodsA total of 200 titanium implants were copy milled and 200 zirconia frameworks (Cercon) were generated by computer-aided design and computer-aided manufacturing (CAD-CAM). They were adhesively luted using Multilink Hybrid Abutment (MHA), Panavia F2.0 (PF2), Panavia V5 (PV5), RelyX Ultimate (RXU), or Panavia SA Cement Plus (PSA). Autoclaving (134 °C, 0.21 MPa, 5.5 minutes) and thermocycling (3000 cycles, 5 °C and 55 °C) were performed. The push out bond strength was tested at a crosshead speed of 1 mm/min. Statistical analysis was performed by using the Mann-Whitney U test (α=.05) and the family-wise error rate method. ResultsMedian bond strength values (interquartile range) after autoclaving and thermocycling ranged between 33.7 (26.7-41.8) MPa for MHA and 7.6 (7.3-8.5) MPa for PF2. MHA showed significantly higher values than all other composite resin luting agents regardless of thermocycling or autoclaving. PV5 showed equal or higher bond strength values than PSA, RXU, and PF2. Autoclaving had no significant influence on MHA or PV5, but had a negative effect on PSA and RXU. The family-wise error rate method showed that both the composite resin luting agent and autoclave sterilization had an overall influence on bond strength. ConclusionsMHA and PV5 were not significantly influenced by autoclaving and showed acceptable bond strength values. Because MHA showed significantly higher bond strength than all other materials and is released for autoclaving by the manufacturer, it is the first choice for extraoral bonding of zirconia frameworks to titanium bases. Manufacturers who state the indication of extraoral cementation of frameworks on titanium bases should also indicate whether their composite luting material is affected by autoclaving.

Bonding ability of resin cements to different types of CAD/CAM composite blocks.

This study investigated the bonding performance of two different types of resin cements to computer-aided design/computer-aided manufacturing (CAD/CAM) composite blocks based on the shear bond strength (SBS) test. A silane-containing self-adhesive resin cement (Panavia SA Cement Universal) and resin luting cement (Block HC Cem) with a primer, were used. Specimens were fabricated from three different types of CAD/CAM composite blocks, and their surfaces were blasted with alumina. Resin cements were bonded to the specimens, and their SBSs were measured after 15 min, 24 h, and after being subjected to thermal cycling for 10,000 and 30,000 cycles. Three-way ANOVA for bond strength revealed that CAD/CAM composite block, resin cement and storage time significantly influenced the SBS values, and the three-way interactions between the evaluated factors, and all the interactions were significant. It was concluded that the bonding performance of resin cements to CAD/CAM composite blocks were material and storage period dependent.

Effect of Thermocycling on the Bond Strength of Self-Adhesive Resin Cements Used for Luting CAD/CAM Ceramics to Human Dentin.

The aim of the study was to evaluate the influence of thermocycling on the shear bond strength of self-adhesive, self-etching resin cements luted to human dentin and computer-aided design/computer-aided manufacturing (CAD/CAM) ceramics. Three modern self-adhesive dental cements (Maxcem Elite, RelyX U200, Panavia SA) were used to lute three CAD/CAM ceramics (IPS Empress CAD, IPS e.max CAD, IPS e.max ZirCAD) onto the dentin. One conventional cement (Panavia V5) served as a control. After preparation, the samples were subjected to thermocycling as a method of artificial aging of dental materials applied to simulate long-term use in oral conditions. Shear bond strength was evaluated according to PN-EN ISO 29022:2013-10 and failure modes were observed under a light microscope. Statistical analysis was performed. The study demonstrated that a combination of ceramics and cements directly impacts the bond strength. The highest bond strength was observed in Panavia V5, lower in Panavia SA and Maxcem Elite and the lowest–in RelyX U200. Adhesive failure between human dentin and cements was the most common failure mode. Moreover, thermocycling highly decreased bond strength of self-adhesive, self-etching cements.

Does Resin Cement Type and Cement Preheating Influence the Marginal and Internal Fit of Lithium Disilicate Single Crowns?

This paper assesses the effect of cement type and cement preheating on the marginal and internal fit of lithium disilicate single crown. Methods: 40 maxillary premolars were selected, restored with lithium disilicate single crowns. Teeth were randomly assigned into four groups (n = 10) based on cement type (Panavia SA or LinkForce) and preheating temperature (25 °C or 54 °C). After fabrication of the restoration, cements were incubated at 25 °C or 54 °C for 24 h, and each crown was cemented to its corresponding tooth. After 24 h, all specimens were thermally aged to (10,000 thermal cycles between 5 °C and 55 °C), then load cycled for 240,000 cycles. Each specimen was then sectioned in bucco-palatal direction and inspected under a stereomicroscope at x45 magnification for marginal and internal fit evaluation. The data were statistically analyzed (significance at p ≤ 0.05 level). Results: At the mid-buccal finish line, mid-buccal wall, palatal cusp, mid-palatal wall, mid-palatal finish line, and palatal margin measuring points, there was a significant difference (p ≤ 0.05) between the lithium disilicate group cemented with Panavia SA at 25 °C and the group cemented with LinkForce at 25 °C, while there was no significant difference (p > 0.05) at the other points. At all measuring points, except at the palatal cusp tip (p = 0.948) and palatal margin (p = 0.103), there was a statistically significant difference (p ≤ 0.05) between the lithium disilicate group cemented with Panavia SA at 54 °C and the group cemented with LinkForce at 54 °C. Regardless of cement preheating, statistically significant differences were found in the buccal cusp tip, central groove, palatal cusp tip, and mid-palatal wall (p ≤ 0.05) in the lithium disilicate group cemented with Panavia SA at 25 °C and 54 °C, as well as the mid-palatal chamfer finish line and palatal margin in the LinkForce group cemented with Panavia SA at 25 °C and 54 °C. At the other measurement points, however, there was no significant difference (p > 0.05). Conclusions: The type of resin cement affects the internal and marginal fit of lithium disilicate crowns. At most measuring points, the cement preheating does not improve the internal and marginal fit of all lithium disilicate crowns.

Cytotoxicity Comparison of a Calcium Silicate-Based Resin Cement versus Conventional Self-Adhesive Resin Cement and a Resin-Modified Glass Ionomer: Cell Viability Analysis

Objective: To compare the cytotoxicity level of a new calcium silicate-based resin cement (TheraCem) with two commonly used cements, including a conventional self-adhesive resin cement (Panavia SA) and a resinmodified glass ionomer cement (FujiCem2), on the human gingival fibroblast cells after 24 and 48 hours. Material and Methods: Twelve discs of each cement type were fabricated. The extract of cement disks was made by incubating them in the cell medium. Human gingival fibroblast cells were cultured and exposed to cement extracts for 24 h and 48 h. MTT assay was performed on extracts and optical density and cell viability rates were calculated by the spectrophotometer device at 570 nm. Data were analyzed using ANOVA and Tukey HSD tests. Results: The cell viability rates after 24 hours and 48 hours were as follows: TheraCem: 89.24% and 85.46%, Panavia SA: 49.51% and 46.57% and FujiCem2: 50.63% and 47.36%. TheraCem represented the highest cell viability rate. However, no significant difference was noted between Panavia SA and FujiCem2. Time had no significant effect on cell viability. Conclusion: TheraCem exhibited the best results among three tested cements and was considered non-toxic. Panavia SA and FujiCem2 were not significantly different regarding the cell viability rate. Time had no significant effect on the cytotoxicity level of cements.

Effect of surface treatment, ferrule height, and luting agent type on pull-out bond strength of monolithic zirconia endocrowns.

To evaluate the effect of different surface treatments, ferrule heights, and luting agents on the pull-out bond strength (PBS) of computer-aided design/computer-aided manufacturing (CAD-CAM) monolithic endocrowns. After endodontic treatment and preparation for two endocrown designs (ferrule height 0 mm or 2 mm), CAD-CAM monolithic zirconia endocrowns were fabricated for 80 mandibular molars. Each endocrown design group was then divided on the basis of surface treatment into two groups: half were air-abraded and half were air-abraded/laser-irradiated. Then, all treated groups were further divided into two subgroups (n = 10) and cemented to teeth with either a 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing resin luting agent (Panavia SA) or a combination of MDP-containing primer and MDP-free resin luting agent (Monobond Plus/Multilink Automix). PBS was measured with a universal test machine after simulated chewing and thermocycling. Three-way ANOVA and the post-hoc Bonferroni test were used for statistical analysis. PBS was significantly associated with type of surface treatment, type of luting agent, and ferrule height. Air-abraded/laser-irradiated endocrowns with a 2-mm ferrule that were cemented with Monobond Plus/Multilink Automix had the highest PBS (P < 0.05). Surface treatment with air abrasion/laser irradiation, presence of a ferrule, and priming with an MDP-containing primer increased the PBS of monolithic zirconia endocrowns.