Cercon Base Research Articles

High-Strength Porcelain Veneering of Zirconia Prosthetic Mimetic Restorations (PRIMERO) by Cognitive Design and Manufacturing

Esthetic prosthetic restorations, with natural reflection, color from within and color gradients influenced by the internal dentinal core anatomy can best be accomplished by veneered zirconia, rather than with crowns of color and structure graded monolithic zirconia. Concern about the high incidence of chipping with some of the porcelains for zirconia substructures has led to a massive shift from veneered zirconia to the use of monolithic zirconia for crowns and bridges. Because zirconia has four times the hardness of metal, initial concern about antagonist abrasion could with numerous studies be negated. Clinical long-term effects of lack of abrasion of full zirconia crowns, in comparison with 30-75 μm/year for surrounding and opposing dentition is still poorly documented. Massive crack formation in enamel probes has been reported in specimens after in-vitro fatigue testing with opposing monolithic zirconia. In-vitro and clinical studies have shown that only reinforcement of the structure of veneering material can prevent chipping. This article compares the fatigue behavior of three-unit bridges with a substructure of Primero zirconia veneered with Primero Enamel (PR) with bridges with Cercon Base zirconia inner-structure veneered with Ceramco PFZ and Cercon Ceram S (CR1 and CR2) and assess the possibilities and increase their scope to cognitive design and manufacturing of porcelain veneered zirconia crowns and bridges. Fatigue testing of four times eight 3-unit bridges were produced for each of the three porcelains and a reference. The results show that efficient crack-stopping prevented chipping with the PR bridges, while the bridges with conventional porcelains CR1 and CR2, showed failures. We conclude that chipping is mainly porcelain related. Cognitive design and fabrication of the dentin zirconia core will lead to prosthetic mimetic restorations (PRIMERO) with natural esthetics.

Transmission of light in the visible spectrum (400-700nm) and blue spectrum (360-540nm) through CAD/CAM polymers.

CAD/CAM-fabricated long-term temporary restorations from high-density polymers can be applied for a wide range of indications. Milled from monolithic, mono-colored polymer blocks, the translucency of the material plays an important role for an esthetically acceptable result. The aim of this study was to compare the transmittance through visible light and blue light of CAD CAM polymers to a glass-ceramic material of the same color. Ambarino High-Class (AM), Telio-CAD (TC), Zenotec PMMA (ZT), Cercon base PMMA (CB), CAD Temp (CT), Artbloc Temp (AT), Polycon ae (PS), New Outline CAD (NC), QUATTRO DISK Eco PMMA (GQ), Lava Ultimate (LU), and Paradigm MZ 100 (PA) were employed in this study using the feldspathic glass-ceramic Vita Mark II (MK) as control group. Using a spectrophotometer, the overall light transmittance was measured for each material (n=40) and was calculated as the integration (t c (λ) dλ [10-5]) of all t c values for the wavelengths of blue light (360-540nm). Results were compared to previous data of the authors for visible light (400 to 700nm). Wilcoxon test showed significant differences between the light transmittance of visible and blue light for all materials. CAD/CAM polymers showed different translucency for blue and visible light. This means clinicians may not conclude from the visible translucency of a material to its permeability for blue light. This influences considerations regarding light curing. CAD/CAM polymers need to be luted adhesively; therefore, clinicians should be aware about the amount of blue light passing through a restoration.

In vitro study of fracture strength of provisional crown materials.

PURPOSEThe purpose of this report was to evaluate the effect of the fabrication method and material type on the fracture strength of provisional crowns.MATERIALS AND METHODSA master model with one crown (maxillary left second premolar) was manufactured from Cr-Co alloy. The master model was scanned, and the data set was transferred to a CAD/CAM unit (Yenamak D50, Yenadent Ltd, Istanbul, Turkey) for the Cercon Base group. For the other groups, temporary crowns were produced by direct fabrication methods (Imident, Temdent, Structur Premium, Takilon, Systemp c&b II, and Acrytemp). The specimens were subjected to water storage at 37℃ for 24 hours, and then they were thermocycled (TC, 5000×, 5-55℃) (n=10). The maximum force at fracture (Fmax) was measured in a universal test machine at 1 mm/min. Data was analyzed by non-parametric statistics (α=.05).RESULTSFmax values varied between 711.09-1392.1 N. In the PMMA groups, Takilon showed the lowest values (711.09 N), and Cercon Base showed the highest values (959.59 N). In the composite groups, Structur Premium showed the highest values (1392.1 N), and Acrytemp showed the lowest values (910.05 N). The composite groups showed significantly higher values than the PMMA groups (P=.01).CONCLUSIONComposite-based materials showed significantly higher fracture strengths than PMMA-based materials. The CAD-CAM technique offers more advantages than the direct technique.

Surface properties of monolithic zirconia after dental adjustment treatments and in vitro wear simulation

ObjectivesTo investigate the surface properties (roughness, composition, phase transformation) of monolithic zirconia specimens after dental adjustment procedures (grinding, polishing) and wear simulation. MethodsZirconia specimens (Cercon base, Cercon ht, DeguDent, G; n=10/material) were successively sintered, ground, and polished with an intraoral polishing kit in a three-step procedure. Sintered zirconia specimens with high surface roughness served as a reference. For each treatment step, wear simulations with steatite plates (d=10mm) as antagonists were conducted as well as surface roughness tests (Ra), EDX analysis, and X-ray diffraction (XRD) measurements. SEM pictures were taken, and data were statistically analyzed (one-way ANOVA, post hoc Bonferroni, α=0.05). ResultsGrinding significantly (p=0.000) increased the roughness of sintered zirconia up to values of 1.36±0.11μm (Ra). Polishing significantly (p=0.000) reduced Ra. The lowest roughness value after the final polishing step was 0.20±0.03μm. Wear testing resulted in a further slight decrease of Ra. After the grinding procedure, SEM pictures showed deep grooves that were progressively smoothed by polishing. The EDX spectra showed that magnesium was transferred from steatite antagonists to zirconia by wear. In the XRD-patterns, monoclinic (m) peaks were observed after grinding and polishing. The maximum intensity ratio between the m (11−1) peak and the tetragonal t (111) peak decreased after the completion of all polishing steps. Wear did not induce phase transformation. ConclusionsAdequate polishing reduced the roughness of ground zirconia. Wear had little influence on roughness and no influence on phase transformation. Clinical significanceCareful polishing is recommended to keep surface roughness and phase transformation low.

Effects of multipurpose, universal adhesives on resin bonding to zirconia ceramic.

This study evaluated the effects of single-bottle, multipurpose, universal adhesives on the bond strength of resin cement to zirconia ceramic. Polished zirconia ceramic (Cercon base) discs were randomly divided into four groups (n=40) according to the applied surface-conditioning agent: Single Bond 2, Single Bond Universal, All-Bond Universal, and Alloy Primer. Cured composite cylinders (Ø 0.8 mm × 1 mm) were cemented to the conditioned zirconia specimens with resin cement (RelyX ARC). The bonded specimens were subjected to a microshear bond-strength test after 24 hours of water storage and after 10,000 cycles of thermocycling. The surface-conditioning agent significantly influenced the bond strength (p<0.05). Single Bond Universal showed the highest initial bond strength (37.7 ± 5.1 MPa), followed by All-Bond Universal (31.3 ± 5.6 MPa), Alloy Primer (26.9 ± 5.1 MPa), and Single Bond 2 (8.5 ± 4.6 MPa). Artificial aging significantly reduced the bond strengths of all the test groups (p<0.05). After 10,000 cycles of thermocycling, All-Bond Universal showed the highest bond-strength value (26.9 ± 6.4 MPa). Regardless of artificial aging, Single Bond Universal and All-Bond Universal showed significantly higher bond strengths than Alloy Primer, a conventional metal primer.

Effect of differences in coefficient of thermal expansion of veneer and Y-TZP ceramics on interface phase transformation

The stability of veneering ceramics requires further investigation. The purpose of this study was to investigate, with Raman spectroscopy, the occurrence and extent of the tetragonal to monoclinic phase transformation in yttria partially stabilized tetragonal polycrystalline zirconia (Y-TZP) ceramic at the veneer-framework interface. Three different Y-TZP blanks Cercon base, ZENO TEC, and Zerion were used. The specimens were sintered according to the recommendations of the manufacturers (1350°C Cercon base, 1450°C ZENO TEC, and 1500°C Zerion for 2 hours). Three veneer ceramics with different coefficients of thermal expansion, Cercon ceram kiss, Zirox, and VITAVM9 were used to veneer the Y-TZP frameworks. For the investigation of the temperature gradient on the phase transformation of Y-TZP ceramic, some specimens were fractured, with a universal testing machine along the long axis of thecoping. No evidence was found for the presence of the tetragonal to monoclinic phase transformation for nonabraded andnonveneered specimens. The tetragonal to monoclinic phase transformation was observed at the veneer-framework interface for all veneered specimens and was dependent on the sintering temperature of the framework. The highest volume fractions of the monoclinic phase at the veneer-framework interface amounted to 0.57 (Cercon base), 0.69 (ZENO TEC), and 0.72 for the Zerion framework. The tetragonal to monoclinic phase transformation was not homogenous along the veneer-framework interface and depended on the distance from the cross section of the veneer-framework interface. The greatest tetragonal to monoclinic transformation was observed at the interface and disappeared with increasing distance from it. For the veneered Cercon base specimens, the volume fraction of the monoclinic phase decreased from 0.53 to 0.13 over a distance of 20 μm. No phase transformation was observed at a distance that exceeded 20 μm from the cross section of the veneer-framework interface. This study demonstrated that the firing process of veneer ceramic and the difference in the coefficients of thermal expansion between the ceramic framework and the veneer ceramic significantly influenced the stability of the tetragonal phase of Y-TZP ceramic at the veneer-framework interface.

Translucency of dental ceramics with different thicknesses

The increased use of esthetic restorations requires an improved understanding of the translucent characteristics of ceramic materials. Ceramic translucency has been considered to be dependent on composition and thickness, but less information is available about the translucent characteristics of these materials, especially at different thicknesses. The purpose of this study was to investigate the relationship between translucency and the thickness of different dental ceramics. Six disk-shaped specimens of 8 glass ceramics (IPS e.max Press HO, MO, LT, HT, IPS e.max CAD LT, MO, AvanteZ Dentin, and Trans) and 5 specimens of 5 zirconia ceramics (Cercon Base, Zenotec Zr Bridge, Lava Standard, Lava Standard FS3, and Lava Plus High Translucency) were prepared following the manufacturers' instructions and ground to a predetermined thickness with a grinding machine. A spectrophotometer was used to measure the translucency parameters (TP) of the glass ceramics, which ranged from 2.0 to 0.6 mm, and of the zirconia ceramics, which ranged from 1.0 to 0.4 mm. The relationship between the thickness and TP of each material was evaluated using a regression analysis (α=.05). The TP values of the glass ceramics ranged from 2.2 to 25.3 and the zirconia ceramics from 5.5 to 15.1. There was an increase in the TP with a decrease in thickness, but the amount of change was material dependent. An exponential relationship with statistical significance (P<.05) between the TP and thickness was found for both glass ceramics and zirconia ceramics. The translucency of dental ceramics was significantly influenced by both material and thickness. The translucency of all materials increased exponentially as the thickness decreased. All of the zirconia ceramics evaluated in the present study showed some degree of translucency, which was less sensitive to thickness compared to that of the glass ceramics.

Effect of an experimental zirconia–silica coating technique on micro tensile bond strength of zirconia in different priming conditions

ObjectivesThis study aimed to evaluate the adhesive properties of a MDP-containing resin cement to a colored zirconia ceramic, using an experimental zirconia–silica coating technique with different priming conditions. Methods18 zirconia ceramic discs (Cercon base colored) were divided into two groups: the control group and the experimental zirconia–silica coating group. Specimens in each group were further divided into 3 subgroups (n=3) according to the priming conditions: no primer, a MDP-containing primer (ED Primer II) or a silane coupling primer (RelyX™ Ceramic Primer). Then resin-composite discs (Filtek™ Z250) were bonded to the treated surface using a MDP-containing resin cement (Panavia F 2.0). The bi-layered specimens were cut into microbars and 20 microbars were randomly selected from each specimen, half of which were stored in 37°C water bath for 24h, and the other half were stored for 30days. After water storage, the samples were exposed to a micro tensile bond strength test (MTBS). The results were analyzed by ANOVA, while the fracture surfaces were examined by SEM. ResultsAfter 24h water storage, zirconia–silica coating followed by silanization showed a significantly (P<0.001) higher MTBS value 45.0 (10.9)MPa. Water storage affected (P<0.05) MTBS in the control group (24.1–30.3MPa to 2.8–3.1MPa), but only partially in the zirconia–silica coating group (20.0–45.1MPa to 17.4–25.9MPa). SEM analysis revealed a failure mode change after water storage. SignificanceThe combination of zirconia–silica coating with silane coupling can improve the bonding of resin cement to this colored zirconia.

Spectral Transmittance of Six All-Ceramic Core Materials after Veneering Ceramic

The spectral transmittance of six kinds of Vita In-Ceram and Cercon all-ceramic core materials after veneering ceramic was determined. Based on the production method recommended by the manufacturer, specimens of the same thickness are made. PERKIN ELMER Spectrophotometer is adopted to measure the spectral transmittance of In-Ceram AL2 slip-casting glass/alumina composite, AL2 electroformed alumina, Z21 slip-casting glass/zirconia composite, Z21 electroformed zirconia, Cercon base color zirconia and Cercon base zirconia all-ceramic core materials, after veneering ceramic. The results show that, after veneering ceramic, Cercon base Zirconia has the highest spectral transmittance, followed by AL2 Electroformed Alumina and Z21 Electroformed Zirconia, whereas the transmittance of Z21 slip-casting Glass/Zirconia composite has the lowest. Statistical data show that, among the groups, In-Ceram slip-casting Glass/Alumina composite (AL2), Electroformed Alumina (AL2), Cercon base color Zirconia and Cercon base Zirconia have significant differences between every group. On the other hand, there is no significant difference between In-Ceram slip-casting Glass/Zirconia composite (Z21) and Electroformed Zirconia (Z21). Therefore, we should choose all-ceramic restoration materials based on the spectral transmittance of all-ceramic core materials after veneering ceramic and transparency of the remaining natural teeth of patients.

Effect of Background Color on In-Ceram and Cercon All-Ceramic Core Material

The present paper probes into the effect of background color of different post-core materials on the core materials of In-Ceram AL2 Electroformed Alumina, Z21 Electroformed Zirconia, Cercon base color Zirconia, and Cercon base Zirconia. The spectrocolorimeter was used to measure colorimetric values of all groups of samples against the background of noble metal, nickel-chromium alloy, silver amalgam and resin, and to calculate the color difference among the groups. The result showed that the color difference of Cercon base color Zirconia viewed against different backgrounds was identifiable by human eyes (ΔE &gt; 1.5). In contrast, the color differences of In-Ceram AL2 Electroformed Alumina, Z21 Electroformed Zirconia and Cercon base Zirconia viewed against different backgrounds were unidentifiable by human eyes (ΔE &lt; 1.5). Based on this, it can be stated that Cercon base color Zirconia is significantly affected by background color. Thus, proper method to shelter the background color should be adopted. In addition, AL2 Electroformed Alumina, Z21 Electroformed Zirconia, and Cercon base color Zirconia are less influenced by the background color, thus it is not necessary to cover the background color.

Fracture strength of temporary fixed partial dentures: CAD/CAM versus directly fabricated restorations

Objectives This study aimed at investigating the influence of fabrication method, storage condition and material on the fracture strength of temporary 3-unit fixed partial dentures (FPDs). Methods A CrCo-alloy master model with a 3-unit FPD (abutment teeth 25 and 27) was manufactured. The master model was scanned and the data set transferred to a CAD/CAM unit (Cercon Brain Expert, Degudent, Hanau, Germany). Temporary 3-unit bridges were produced either by milling from pre-fabricated blanks (Trim, Luxatemp AM Plus, Cercon Base PMMA) or by direct fabrication (Trim, Luxatemp AM Plus). 10 FPDs per experimental group were subjected either to water storage at 37 °C for 24 h and 3 months, respectively, or thermocycled (TC, 5000×, 5–55 °C, 1 week). Maximum force at fracture (Fmax) was determined in a 3-point bending test at 200 mm/min. Data was analyzed using parametric statistics ( α = 5%). Results Fmax values ranged from 138.5 to 1115.5 N. FPDs, which were CAD/CAM fabricated, showed a significant higher Fmax compared to the directly fabricated bridges ( p < 0.05). TC significantly affected Fmax for Luxatemp ( p < 0.05) but not for the PMMA based materials ( p > 0.05). CAD/CAM milled FPDs made of Luxatemp showed significantly higher Fmax values compared to Trim and Cercon Base PMMA ( p < 0.05). Significance CAD/CAM fabricated FPDs exhibit a higher mechanical strength compared to directly fabricated FPDs, when manufactured of the same material. Composite based materials seem to offer clear advantages versus PMMA based materials and should, therefore, be considered for CAD/CAM fabricated temporary restorations.

Translucency of zirconia copings made with different CAD/CAM systems

Zirconia cores are reported to be less translucent than glass, lithium disilicate, or alumina cores. This could affect the esthetic appearance and the clinical choices made when using zirconia-based restorations. The purpose of this in vitro study was to evaluate the translucency of zirconia copings for single crowns fabricated using different CAD/CAM systems, using lithium disilicate glass ceramic as a control. Using impressions made from a stainless steel complete-crown master die, 9 stone cast replicas were fabricated, numbered, and distributed into 8 ceramic ZrO(2) CAD/CAM system groups (Lava Frame 0.3 and 0.5, IPS e.max ZirCAD, VITA YZ, Procera AllZircon, Digizon, DC Zircon, and Cercon Base) and to a lithium disilicate glass-ceramic control group (IPS e.max Press) using a simple computer-generated randomization method. From each die, the manufacturer's authorized milling centers supplied 5 copings per group without applying any dying technique to the ceramic base material. The copings were prepared to allow for a 40-mum cement layer and were of different thicknesses according to system specifications. Translucency was measured by the direct transmission method with a digital photoradiometer mounted in a dark chamber. The light source was a 150-W halogen lamp beam. Measurements were repeated 3 times for each specimen. Data obtained were analyzed using 1-way ANOVA and the Bonferroni multiple comparison test (alpha=.05). Among ZrO(2) copings, Lava (0.3 mm and 0.5 mm thick) showed the highest (P<.05) values of translucency measured as light flow units (3.572 + or - 018 x 10(3) lx and 3.181 + or - 0.13 x 10(3) lx, respectively). These values represent 71.7% and 63.9%, respectively, of the glass-ceramic control group (4.98 x 10(3) lx). All ZrO(2) copings demonstrated different levels of light transmission, with the 2 Lava specimens showing the highest values. Translucency of zirconia copings was significantly lower (P=.001) than that of the lithium disilicate glass-ceramic control.

Influence of background color on chromatic value of four all-ceramic system core materials

To investigate the influence of post-core background color on chromatic value of four all-ceramic system core materials at clinically appropriate thicknesses. Disc specimens of 15 mm in diameter and 0.80 mm in thickness (Empress II: Group A), and 0.50 mm in thickness (In-Ceram Zirconia core: Group B; Cercon base color zirconia core: Group C; Cercon base zirconia core: Group D) were fabricated, five in each group. Au-Pt alloy, Ni-Cr alloy and visible light cured dental composite resin (A2 color) background were prepared. Samples were put on different background and their chromatic values were measured with colorimeter (CIE-1976-L(*)a(*)b(*)). Color differences of each specimen on different background material were calculated. The color differences among specimens of Group A on different background material were more than 1.5 (2.83 ± 0.70) which meant it could be noticeable to eyes. Those of zirconia were less than 1.5 [Group B: (0.14 ± 0.08); Group C: (0.90 ± 0.20); Group D: (0.99 ± 0.09)]. The influence of background color on Group A was noticeable to human eyes, and as a result, tooth-colored post should be used for this all-ceramic system. For the other three kinds of zirconia core materia1 system, the color differences among specimens on different background material were unnoticeable. Therefore the three all-ceramic systems have excellent color masking ability and can be used on all color background.

Influence of Background Color on the Chromatic Value of Four All-Ceramic System Core Materials

This study aims to investigate the effect of background color on the chromatic value of four all-ceramic system core materials at clinically appropriate thicknesses. Disc specimens with 15 mm in diameter and thicknesses ranging from 0.5±0.01mm In-Ceram zirconia core, Cercon base zirconia core, and Cercon base color zirconia core) to 0.8±0.01mm (Empress II) were fabricated. A colorimeter (CIE- 1976-Lab) measured the chromatic value of all samples placed on a high-noble metal-ceramic alloy and a visible light-cured dental composite resin (A2 color) background, after which the color difference was calculated. The color difference of Empress II samples was more than 1.5 among different background color groups, while that of Zirconia was less than 1.5. The influence of background color on the Empress II dentin was visible, such that it could be used on a tooth color post. Meanwhile, the influence of background color was invisible for the three kinds of Zirconia core materia1s, such that the materials developed excellent color-masking abilities and could be adapted for use on any color background.

Effect of an internal coating technique on tensile bond strengths of resin cements to zirconia ceramics

This study was conducted to enhance the tensile bond strengths of resin cements to zirconia ceramics. Fifty-six zirconia ceramic specimens (Cercon Base) and twenty-eight silica-based ceramic specimens (GN-1, GN-1 Ceramic Block) were air-abraded using alumina. Thereafter, the zirconia ceramic specimens were divided into two subgroups of 28 each according to the surface pretreatment; no pretreatment (Zr); and the internal coating technique (INT). For INT, the surface of zirconia was coated by fusing silica-based ceramics (Cercon Ceram Kiss). Ceramic surfaces were conditioned with/without a silane coupling agent followed by bonding with one of two resin cements; Panavia F 2.0 (PF) and Superbond C&B (SB). After 24 hours storage in water, the tensile bond strengths were tested (n=7). For both PF and SB, silanization significantly improved the bond strength to GN-1 and INT (p<0.05). The INT coating followed by silanizaton demonstrated enhancement of bonding to zirconia ceramics.

Shear bond strengths between different zirconia cores and veneering ceramics and their susceptibility to thermocycling

Objectives The purpose of this study was to evaluate the shear bond strength between various commercial zirconia core and veneering ceramics, and to investigate the effect of thermocycling. Methods The Schmitz–Schulmeyer test method was used to evaluate the core–veneer shear bond strength (SBS) of three zirconia core ceramics (Cercon Base, Vita In-Ceram YZ Cubes, DC-Zirkon) and their manufacturer recommended veneering ceramics (Cercon Ceram S, Vita VM9, IPS e.max Ceram). A metal ceramic system (Degudent U94, Vita VM13) was used as a control group for the three all-ceramic test groups ( n = 30 specimens/group). Half of each group ( n = 15) was thermocycled (5–55 °C, 20,000 cycles). Subsequently, all specimens were subjected to shear force in a universal testing machine. Fractured specimens were evaluated microscopically to determine the failure mode. Results The initial mean SBS values in MPa ± S.D. were 12.5 ± 3.2 for Vita In-Ceram YZ Cubes/Vita VM9, 11.5 ± 3.4 for DC-Zirkon/IPS e.max Ceram, and 9.4 ± 3.2 for Cercon Base/Cercon Ceram S. After thermocycling mean SBS values of 11.5 ± 1.7 MPa for DC-Zirkon/IPS e.max Ceram, 9.7 ± 4.2 MPa for Vita In-Ceram YZ Cubes/Vita VM9, and 9.6 ± 4.2 MPa for Cercon Base/Cercon Ceram S were observed. Neither the differences between the SBS values of the all-ceramic test groups nor the influence of thermocycling on all groups were statistically significant. Irrespective of thermocycling the metal ceramic control group (27.6 ± 12.1 MPa, 26.4 ± 13.4 MPa) exhibited significantly higher mean SBS than all three all-ceramic groups tested. The all-ceramic groups showed combined failure modes as cohesive in the veneering ceramic and adhesive at the interface, whereas the metal ceramic group showed predominately cohesive fractures. Significance The results indicated that the SBS between zirconia core and veneering ceramics was not affected by thermocycling. None of the zirconia core and veneering ceramics could attain the high bond strength values of the metal ceramic combination.

Translucency and biaxial flexural strength of four ceramic core materials

Objectives To assess the relative translucencies and flexural strengths of four dental restorative ceramic core materials. Methods Eight disk specimens (14 mm in diameter × 0.5 ± 0.05 mm in thickness) were prepared for each group of four ceramic core materials (IPS Empress 2 dentin, VITA In-Ceram Alumina, VITA In-Ceram Zirconia, Cercon Base Zirconia), according to the manufacturers’ instructions. A color meter was used to measure the relative translucencies of the specimens. The biaxial flexure test (ISO 6872) was then used to measure their flexural strengths. Data for relative translucency (0.0–1.0), fracture load (N) and biaxial flexural strength (MPa) were analyzed by one-way ANOVA, followed by Tukey's multiple comparison test for significant findings ( α = 0.05). Results For relative translucency: IPS Empress 2 (0.78 ± 0.03), VITA In-Ceram Alumina (0.94 ± 0.01), VITA In-Ceram Zirconia (1.00 ± 0.01), Cercon Base Zirconia (1.00 ± 0.01), P < 0.0001. For biaxial flexural strength: IPS Empress 2 (355.1 ± 25.7), VITA In-Ceram Alumina (514.0 ± 49.5), VITA In-Ceram Zirconia (592.4 ± 84.7), Cercon Base Zirconia (910.5 ± 95.3), P < 0.0001. Significance IPS Empress 2 and VITA In-Ceram Alumina were significantly more translucent than the two opaque zirconia-containing core materials. IPS Empress 2 was significantly weaker, and Cercon Base Zirconia was significantly stronger, than the other two ceramic core materials.