Vita Enamic Groups Research Articles

A Comparison of the Shear Bond Strength between a Luting Composite Resin and Both Machinable and Printable Ceramic–Glass Polymer Materials

This study aims to compare the shear bond strength (SBS) and Weibull characteristics between a luting composite resin and both printable and two different machinable ceramic–glass polymer materials. A total of 36 substrates were prepared, with 12 in each group. Printable substrates (12 mm × 12 mm × 2 mm) were printed by using permanent crown resin (3D-PR). Machinable substrates were obtained from Cerasmart 270 (CS) and Vita Enamic (VE) blocks (2 mm in thickness). The bonding surfaces of substrates were polished and airborne abraded (50 µm Al2O3). A self-adhesive luting composite resin (RelyX U200, 3M ESPE, St. Paul, MN, USA, SLC) was applied on substrates with the help of a cylindrical (Ø3 × 3 mm) mold. The SBS test was conducted using a universal test machine. The SBSs of three materials were compared using a one-way analysis of variance (ANOVA) (α = 0.05). The Weibull modulus was calculated for each material. The Kruskal–Wallis and chi-square tests were carried out for the failure mode analysis. There was no significant difference between the SBSs of the three materials (p = 0.129). The Weibull modulus was 3.76 for the 3D-PR, 4.22 for the CS, and 6.52 for the VE group. Statistical analysis showed no significant difference between the failure modes of the groups (p = 0.986). Mixed-failure fractures were predominantly observed in all three groups. The results show that the SBS of the SLC to printable 3D-PR is comparable to that of CS and VE material. Failure modes of printable 3D-PR show similar results with two different machinable ceramic–glass polymers.

Biodegradation of Urethane Dimethacrylate-based materials (CAD/CAM resin-ceramic composites) and its effect on the adhesion and proliferation of Streptococcus mutans

ObjectiveTo investigate whether urethane dimethacrylate (UDMA) -based dental restorative materials biodegrade in the presence of Streptococcus mutans (S. mutans) and whether the monomers affect the adhesion and proliferation of S. mutans in turn. MethodsCholesterol esterase and pseudocholinesterase-like activities in S. mutans were detected using p-nitrophenyl substrate. Two UDMA-based CAD/CAM resin-ceramic composites, Lava Ultimate (LU) and Vita Enamic (VE), and a light-cured UDMA resin block were co-cultured with S. mutans for 14 days. Their surfaces were characterized by scanning electron microscopy and laser microscopy, and the byproducts of biodegradation were examined by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS). Then, the antimicrobial components (silver nanoparticles with quaternary ammonium salts) were added to the UDMA resin block to detect whether the biodegradation was restrained. Finally, the effect of UDMA on biofilm formation and virulence expression of S. mutans was assessed. ResultsFollowing a 14-day immersion, the LU and UDMA resin blocks' surface roughness increased. The LU and VE groups had no UDMA or its byproducts discovered, according to the UPLC-MS/MS data, whereas the light-cured UDMA block group had UDMA, urethane methacrylate (UMA), and urethane detected. The addition of antimicrobial agents showed a significant reduction in the release of UDMA. Biofilm staining experiments showed that UDMA promoted the growth of S. mutans biofilm and quantitative real-time polymerase chain reaction results indicated that 50 μg/mL UDMA significantly increase the expression of gtfB, comC, comD, comE, and gbpB genes within the biofilm. ConclusionsUDMA in the light-cured resin can be biodegraded to produce UMA and urethane under the influence of S. mutans. The formation of early biofilm can be promoted and the expression of cariogenic genes can be up-regulated by UDMA. Clinical significanceThis study focuses for the first time on whether UDMA-based materials can undergo biodegradation and verifies from a genetic perspective that UDMA can promote the formation of S. mutans biofilms, providing a reference for the rational use of UDMA-based materials in clinical practice.

Color stability of two different resin matrix ceramics: randomized clinical trial

BackgroundOne of the most common causes of aesthetic failure and restoration replacement is the tooth restorations color mismatch specifically after aging.MethodsOne hundred and two participants with endodontically treated first molar were selected clinically. The patients were randomly splited into two groups and restored either with Cerasmart hybrid ceramic or Vita Enamic polymer infiltrated ceramic network (PICN) crowns and cemented using dual cure adhesive cement. The color difference (ΔE) values after cementation at 0 (Baseline), 6, and 12 months of use were obtained by quantification of L*, a*, and b* values with a digital spectrophotometer. Mann–Whitney test used to compare between tested groups at each time point and between (α = 0.05).ResultsAt 6 months follow-up intervals, Vita Enamic group showed the highest significant ∆L* (p = 0.035) and ∆a* (p < 0.001) compared to Cerasmart group. ∆b* and ∆E showed no significant difference between both groups (p > 0.05). Furthermore, all color parameters of both groups showed statistically significant difference at 12 months follow-up intervals. After 12 months, Vita Enamic restorations presented higher color change compared to Cerasmart restorations with a (p-value of 0.0120). When comparing the total color difference ∆Et through-out the follow-up intervals of Vita Enamic & Cerasmart groups, there were insignificant difference (p = 0.263).ConclusionBoth hybrid materials demonstrated comparable color stability after 1 year of clinical service within clinical acceptance range. However, Cerasmart demonstrated a better colour stability after 1 year.Trial registrationClinicalTrials.gov (ID: NCT05501808) 15/8/ 2022- ‘retrospectively registered’.

Repair Bond Strength of Two Shadeless Resin Composites Bonded to Various CAD-CAM Substrates with Different Surface Treatments

This study compared the repair bond strength values of two single-shade composite resins bonded to different computer-aided design and computer-aided manufacturing (CAD-CAM) substrates with different surface treatments. A total of 80 slice-shaped specimens were fabricated using two CAD-CAM materials: Lava Ultimate and VitaEnamic. The substrates were thermocycled and then, based on the surface treatment, each substrate material was subdivided into four groups: the air abrasion group (APA), the hydrofluoric-acid-etched group (HF) and two silicon carbide ground groups (SiCr). All of the groups received silane followed by Single Bond Universal Adhesive application prior to being repaired with a resin composite of a smaller disc shape. All the specimens were thermocycled prior to shear bond strength testing and subsequent failure analyses. Statistical analyses were conducted, and the level of statistical significance was set at 0.05. A comparison of the mean values showed a highly statistically significant difference among the eight groups. The highest value of mean shear bond strength was associated with Lava Ultimate substrates repaired using the Charisma Diamond ONE composite after APA surface treatment (36.7 ± 1.99). Meanwhile, the lowest value was recorded for the Vita Enamic group repaired using the OMNICHROMA composite after SiCr surface treatment (17.8 ± 1.6). The failure analysis revealed that cohesive failure in the substrate was the most predominant. Within the limitations of this study, Charisma Diamond ONE showed better bond strength values compared to Omnichroma. Meanwhile, APA is recommended for improved bond strength in repairs of Lava Ultimate restorations.

Fracture Strength of Endocrowns Fabricated From Three Different Computer-Aided Design/Computer-Aided Manufacturing Ceramic Materials: An In-Vitro Study.

Endocrown restorations have increased in popularity in recent years due to the advancement of both adhesive and restorative materials. The clinical success of endocrowns depends on several factors, including preparation design, material selection, fracture resistance, and marginal adaptation. The aim of this in vitro study was to compare the fracture strength of endocrown restorations fabricated from three different computer-aided design (CAD)/computer-aided manufacturing (CAM) materials. Thirty extracted mandibular first molars were selected. The teeth underwent conventional root canal treatment before being prepared for endocrown restoration. The teeth were allocated to three groups (n=10), corresponding to each of the three ceramic materials used to fabricate the endocrowns they would receive. The ceramic materials used were zirconia-reinforced lithium silicate glass-ceramic (VITA Suprinity, VITA Zahnfabrik, Bad Säckingen, Germany), polymer-infiltrated hybrid ceramic (VITA Enamic, VITA Zahnfabrik, Bad Säckingen, Germany), and lithium disilicate glass-ceramic (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein). The specimens were scanned, and the digital impressions were transferred into design software to construct the endocrowns. The endocrowns were then milled and cemented. A universal testing machine (5969L3504, Instron, USA) was used for the fracture strength test at a crosshead speed of 1 mm/min until catastrophic failure occurred. Statistical analysis was performed using IBM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp. The one-way analysis of the variance test indicated a significant difference in the fracture strength between the different ceramic groups tested (P=0.037). The Tukey posthoc test showed that the IPS e.max CAD group had marginally higher fracture strength values than the VITA Enamic group (P=055). No significant differences in fracture strength values were found between the VITA Enamic and VITA Suprinity groups or between the VITA Suprinity and IPS e.max CAD groups (P>0.05). The reported fracture strength values for all the tested materials were higher than the strength required to resist masticatory forces. Therefore, endocrowns fabricated using VITA Enamic, IPS e.max CAD, and VITA Suprinity CAD/CAM materials present restorations with a clinically acceptable fracture strength.

Impact of different CAD/CAM materials on internal and marginal adaptations and fracture resistance of endocrown restorations with: 3D finite element analysis

PurposeTo assess and compare the impact of various computers aided design/manufacturing (CAD/CAM) materials on internal and marginal discrepancies, fracture resistance and failure probability of Endocrown restorations with 3D Finite Element analysis.Material and methodsForty devitalized human maxillary first molars were collected. After endodontic treatment, they classified into 4 groups (n = 10) based on the materials used for endocrown fabrication. Group V (Vita-Enamic), Group N (Nacera Hybrid), Group T (Translucent Prettau Zirconia) and Group P (Pekkton ivory). All samples were exposed to artificial aging method simulating one year of clinical service. Silicone replica technique and stereomicroscope (25X) utilized to evaluate the marginal and internal gaps of endocrowns at different areas. Fracture resistance test used for cemented specimens followed by qualitative investigation utilizing Stereomicroscopy. Four models representing four endocrown systems used for restoration of severely-damaged endodontically treated upper first molar were generated for finite element analysis (FEA). Axially and centrally static occlusal compressive load was applied. Modified Von Mises and maximum principal stress values on the remaining tooth structure, cement lines and restorative materials were assessed independently. Resulted data were statistically analyzed at P-value ≤ 0.05.ResultsIn the current study, the highest mean values of internal and marginal discrepancies (μm) among studied groups were reported for Zirconia group (100.300 and 102.650) respectively, while the lowest mean value of internal discrepancy (μm) was observed for Nacera group (69.275) and the lowest mean value of marginal discrepancy (μm) was observed for PEKK group (78.4750). Regarding internal discrepancy, Vita-Enamic and PEKK groups did not exhibit any statistically significant differences (P = 0.293), however zirconia and the other tested groups exhibited statistically significant differences in the mean values of the marginal gap region (p 0.05).On the other hand, PEKK group showed the highest mean value of fracture resistance (1845.20 N) and the lowest value was observed for Vita-Enamic group (946.50 N). Regarding to stress distributions through 3D FEA, and according to modified von Mises (mvM) analysis, the greatest possible stress values were noticed in PEKK model in relation to tooth structure, cement line, and flowable composite as the following: (93.1, 64.5, 58.4 MPa) respectively, while Zirconia revealed lower maximum stress values (11.4, 13.6, 11.6 MPa) respectively.ConclusionsStatistically excellent marginal and internal fit was observed for PEKK in relation to other used endocrown materials. Also, PEKK material explained fracture resistance comparable to zirconia value while the lowest value was detected for Vita Enamic material.

Effects of repeated home bleaching on the surface roughness of CAD-CAM restoration materials

Aim: This study aimed to investigate the effects of the repeated usage of a home-bleaching agent (16% carbamide peroxide) on the surface roughness of commonly used computer-aided design-computer-aided manufacture (CAD-CAM) restoration materials. Methodology: Five different CAD-CAM restoration materials were used in this study: feldspathic ceramic (Vita Mark II—Group VM II), leucite-reinforced glass ceramic (IPS Empress CAD—Group EMP), lithium disilicate-reinforced glass ceramic (IPS e.max CAD—Group EMAX), polymer infiltrated network hybrid ceramic (Vita Enamic—Group VE), and resin nanoceramic (Lava Ultimate—Group LU). A home-bleaching agent containing 16% carbamide peroxide was applied in three repeated periods (10 days, 20 days, and 30 days of exposure). A surface profilometer was used to determine the roughness average (Ra) values of the specimens. The data obtained were statistically analyzed using repeated measures of the analysis of variance (ANOVA) and Bonferroni post-hoc test at a 5% level of significance. Results: All materials exhibited a rougher surface after the first treatment period (10 days of exposure). The roughness of Group VM II continued to increase for up to 20 days. With the exception of Group LU, all groups exhibited a significantly rougher surface after 30 days of exposure compared to the baseline values (p &lt; 0.05). The greatest variation in surface roughness was observed for the ceramic-based groups (VM II, EMP, and EMAX) rather than the hybrid groups (LU and VE). Conclusion: Patients with ceramic-based CAD-CAM restorations should be careful during home-bleaching treatment, especially when repeated applications are involved. Hybrid materials, particularly Lava Ultimate, seem more resistant to the effects of repeated bleaching cycles than ceramic-based materials. How to cite this article: Çölgeçen Ö, Köse M. Effects of repeated home bleaching on the surface roughness of CAD-CAM restoration materials. Int Dent Res 2022;12(3):143-8. https://doi.org/10.5577/intdentres.2022.vol12.no3.6 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Effect of Thermocycling on Color, Surface Characteristics, Compressive Fracture, and Fracture Modes of Prosthetic CAD/CAM Ceramics After Smokeless Tobacco Immersion.

BackgroundThe study aimed to assess effect of smokeless tobacco (ST) immersion with thermocycling (TC) on color of Vita Classical shade-guide, surface roughness (Ra) and roughness depth (Rz), and compressive fracture force (CFF) of hybrid polymer-infiltrated-feldspathic ceramic (Vita Enamic), leucite-Feldspathic glass (Vitablocs® Mark II), and zirconia-reinforced lithium silicate (Vita Suprinity) CAD/CAM prosthetic ceramic materials.Material/MethodsA 48 samples were milled from Vita Enamic, Vita mark II, and Vita Suprinity. VitaPan shade-guide, Ra, and Rz were registered before ST immersion. Then, the same parameters were recorded again after 15 days of ST staining with and without TC. CFFs and fracture modes of samples after 3 months of aging were documented.ResultsA slight change was observed in VitaPan shade-guide. Ra and Rz of Vita Suprinity (VS) recorded the highest values among ceramic groups at 3 time intervals. Increases in Ra and Rz were observed after immersion and staining with TC. ANOVA and Bonferroni post hoc tests were used. Significant differences among and between groups were noticed only before immersion in ST and TC, with P value ≥0.00. The highest mean value and SD of CFFs (MPa and Newton) were recorded in Vita Suprinity, followed by Vita Enamic (VE) and Vita mark II (VMII). Reparable fracture was higher in VMII and VS.ConclusionsST staining and TC caused color changes in VitaPan shade-guide and increases in Ra and Rz of tested materials, with highest and lowest values recorded in VS and VE. CFFs were marginally equal to clinically accepted values for VS and equal or slightly higher than the half values for VE and VMII groups.

Long-term effect of gastric juice alternating with brushing on the surface roughness, topography, and staining susceptibility of CAD-CAM monolithic materials

Statement of problemStudies on the behavior of computer-aided design and computer-aided manufacturing (CAD-CAM) monolithic materials subjected to gastric juice alternating with brushing—as occurs in patients with bulimia nervosa—are lacking. PurposeThe purpose of this in vitro study was to evaluate, over a simulated 5-year period, the effect of gastric juice alternating with brushing on the roughness, topography, and staining susceptibility of CAD-CAM monolithic materials. Material and methodsDisks of Lava Ultimate (LU), Vita Enamic (VE), IPS Empress CAD (EMP), IPS e.max CAD (EMAX), and Vita Suprinity (VS) were randomly allocated to artificial saliva+brushing or gastric juice+brushing groups, simulating 1, 3, and 5 years of clinical function. The roughness (Sa) and topography were evaluated at baseline (T0) and at each simulated year. For the staining susceptibility (ΔE00), the CIELab color coordinates were registered at baseline, and, at the end of the fifth simulated year, the specimens were immersed in deionized water, coffee, or cola before the second reading. Roughness data were submitted to mixed repeated-measures ANOVA and Bonferroni, and the staining susceptibility data were analyzed by 3-way ANOVA and the Games-Howell test (α=.05). ResultsThe gastric juice+brushing led to higher roughness than artificial saliva+brushing only in the VE at T3 and T5 (P<.01). In both treatments, the LU and VE showed topography changes and an increase in roughness over time (P<.001), in addition to higher roughness than the other materials (P<.001). The staining susceptibility of the materials to each staining solution was not affected by the treatment (P>.05). The LU and VS groups were more stained by coffee (P<.001), while the VE and EMP groups were more stained by cola (P≤.016), except for the EMP in the gastric juice+brushing, where no significant difference was found between cola and coffee (P>.05). The EMAX was imperceptibly affected by the 3 solutions. ConclusionsConcerning roughness and topography, the LU and VE were the most affected by both treatments. The staining susceptibility of the materials was not affected by the treatment.

Effect of Simulated Gastric Acid on Surface Roughness of Different Types of Dental Ceramics

Purpose: The purpose of this in vitro study was to evaluate the effect of simulated gastric acidity on surface roughness of different types of dental ceramics. Methods: Fifty specimens were divided according to type of the material into five groups (n=10), as follows: Partially stabilized zirconia (PSZ) (Prettaue),Fully stabilized zirconia (FSZ) (Prettaue Anterior), lithium disilicate ceramics (IPS. Emax), Zirconia-containing lithium silicate ceramics (ZLS) (Vita Suprinity) and Hybrid ceramics (Vita Enamic). Specimens were cut using a low-speed diamond saw (Isomet) into a rectangular shape with the following dimension: 12mm width x 14mm length x 1 mm thickness. Surface roughness was evaluated by optical profilometer. Each specimen was immersed in 5 ml of the simulated acid of ph 1.2 for 96 h in a37◦C incubator. Surface roughness of all tested groups was revaluated. One-way ANOVA was used to compare mean difference between groups. Paired t-test was used for comparing (before and after) roughness in each group. Results: There was significant difference (P=0.002) between all groups. There was increase in surface roughness for all materials tested, but it was non-significant (P>0.05) for Prettaue (P=0.607), Prettaue Anterior (P=0.273) and Vita Suprinty group (P=0.201). There was significant increase (P≤0. 05) for IPS. Emax group (P=0.007) and Vita Enamic groups (P=0.021). Prettaue Anterior group showed the least amount of surface roughness change (0.0006±0.002), while Vita Enamic group showed the highest surface roughness change (0.0100±0.011). Conclusions: The gastric acid significantly increased the surface roughness of hybrid ceramics and lithium disilicate ceramics

Repair bond strength and surface topography of resin-ceramic and ceramic restorative blocks treated by laser and conventional surface treatments.

This study intended to compare the repair bond strength of computer-aided design/computer-aided manufacturing (CAD/CAM) blocks consisting of resin and feldspathic ceramics following different surface treatments using the microtensile bond strength (μTBS) test. Ten specimens were prepared with 4 mm height for Vita Enamic (VE), Lava Ultimate (LU), Vita Mark II (VM), and thermocycled (10,000 cycle, 5-55°C). Each material was categorized into one of five subgroups according to following surface treatments: (a) bur grinding (BG), (b) hydrofluoric acid etching (HF), (c) neodymium-doped yttrium aluminum garnet (Nd:YAG or NY), (d) erbium-doped yttrium aluminum garnet (Er:YAG or EY), and (e) erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG or ECY) laser conditioning. After surface treatment procedures, specimens were properly restored to 4 mm high with a micro-hybrid composite resin. Bar specimens (1 × 1 × 8 mm) were obtained using a low-speed cutting machine and then thermocycled (10,000 cycle, 5-55°C). The μTBS was tested at 1 mm/min crosshead speed, and failure modes were evaluated. Data were analyzed with two-way ANOVA and post hoc Tukey tests. LU-BG showed significantly higher μTBS (32.94 ± 5.80 MPa) compared to LU-laser groups (p < .05). VE-BG showed significantly higher μTBS (22.06 ± 4.26 MPa) compared to other VE groups (p < .05). Among the laser groups, the NY laser produced the lowest (p < .05) μTBS for LU (13.42 ± 3.44 MPa) and VE (2.27 ± 0.85 MPa), while EY showed the highest (p < .05). Laser-treated VM groups were all prefailured. VM-HF produced a higher μTBS (18.73 ± 3.75 MPa) than VM-BG (5.05 ± 1.76 MPa) (p < .05).

Influence of fatigue loading on fracture resistance of endodontically treated teeth restored with endocrowns.

This in vitro study aimed to evaluate the influence of fatigue loading on fracture resistance of endodontically treated molars restored with endocrowns using different machinable blocks. Endodontically treated mandibular first molars were prepared using a standardized method. Specimens were divided into 4 groups (n = 10).Anatomically shaped endocrowns groups were manufactured using VITA ENAMIC (VE) and KATANA Zirconia (KZ). Layered endocrowns groups were manufactured using IPS e.max CAD (EM) and BioHPP (BH). Half of the specimens of each group were subjected to fracture resistance test, while the other half were subjected to thermocycling and chewing simulation. After fatigue loading, specimens were loaded until failure. Specimens were examined using stereomicroscopy. Data were analyzed using ANOVA analysis of variance and Bonferroni post hoc test (α=0.05). KZ group had the highest initial fracture resistance value (1810.20± 119.56 N) and BH had the lowest value (579.50± 76.15 N). The reduction of fracture resistance after fatigue loading was significant for KZ group (1588.30±216.25 N) and BH group (502.60±11.53 N) and non-significant to VE group (1101.70±77.05 N) and EM group (1112.10±74.12 N). Failure modes of KZ and EM groups showed high percentage of non-restorable fractures, while VE and BH groups showed high percentage of restorable fractures. Within the limitations of this study, the following can be concluded: Poly infiltrated ceramics should be considered as a proper material to be used as an endocrown material because of its ability to be restorable if failure occurred.

Examination of Streptococcus Mutans Adhesion in Current Hybrid Ceramics and Composites

This study evaluated the surface topography and bacterial adhesion of a different hybrid ceramics and resin composites after optimal surface finishes. A total of disk samples were prepared using two different CAD/CAM blocks [Vita Enamic (VE), Shofu HC (SHC)] and two different composites [Tetric N Ceram bulk-fill (TNC), Estelite Sigma Quick (ESQ)] with diameter 10 mm and thickness 4.0 ± 0.2mm. Fifteen disc samples were produced for each group (n=15). Surfaces of the sample disks were polished according to the manufacturer’s recommendations with the specially produced polish sets. The surface roughness of specimens was analyzed parameter (Ra), sterilized, and subjected to bacterial adhesion. Data were submitted to one-way ANOVA and Tukey’s test (α= 0.05). TNC and ESQ groups had lower surface roughness than VE and SHC groups (p<0.05). There was no difference in bacterial adhesion between hybrid CAD/CAM blocks and composite materials. The material type and surface finishing system did not significantly interfere with surface roughness parameters and bacterial adhesion. The surface polishing of nanocomposite resins performed is better than hybrid ceramic after polishing. An adequate finishing/polishing technique should always be applied after any adjustments made to indirect restorations with these materials tested. There is no difference between bacterial adhesions of the tested materials. If appropriate and sufficient, polishing is performed.

Mrginal Accuracy of Hybrid and different Machinable Ceramic Crowns

Purpose: The aim of the present study was to evaluate marginal accuracy of hybrid and different ceramic crowns. Material and Methods: Forty sound human maxillary central incisors were selected and received standardized preparation with shoulder finish line. They were divided into four groups according to the material of construction: Group I: VITA Enamic , Group II: E.max CAD, Group III Celtra-Duo ,Group IV: VIA Suprinity (n=10). The crowns were fabricated from blocks using CAD/CAM system. All crowns were cemented using self adhesive resin cement. Marginal discrepancy (pre and post cementation) was tested for all samples. Data were tabulated and statistically analyzed. The results were collected, arranged and tabulated to be statistically analyzed. Results: The highest mean value of marginal gap was found in E-max cad group, followed by Celtra-Duo group, followed by VITA Suprinity group while the lowest mean value was found in VITA Enamic group. The samples of VITA Enamic showed the lower marginal gap values compared to the other samples either before (29.5 μm ± 1.5) or after cementation 20.97 μm ± 1.45). The samples of E-max cad showed the highest marginal gap values compared to the other samples either before (33.8 μm ± 0.75) or after cementation (30.6 μm ±.0.6). Conclusion: Hybrid ceramics crowns introduced the highest marginal accuracy while E-max cad crowns introduced the lowest marginal accuracy. Zirconia reinforced Lithium silicate restorations, particularly the partially crystalline form, introduced better marginal accuracy than Hybrid ceramics restorations.

Effect of Surface Treatment of Two Ceramic Materials by Er,Cr:YSGG Laser Irradiation on The Shear Bond Strength to Resin Cement “A Comparative in-Vitro Study”

Objective: The aim of this study is to assess the effect of Er,Cr:YSGG laser on the shear bond strength (SBS) and surface topography of two CAD/CAM ceramic materials bonded with self-adhesive resin cement. Material and methods: sixty ceramic CAD/CAM discs were obtained, 30 lithium disilicate (IPS Emax) and 30 hybrid resin ceramic (Vita Enamic). The Slices were allocated into six groups (n=10) according to ceramic material and surface treatment; Group (LD-C): IPS Emax treated with 9% hydrofluoric acid(HF), Groups (LD-P1) and (LD-P2): IPS Emax treated with Er,Cr:YSGG laser with parameters 1.5 W and 2.5 W, respectively. Group (RC-C): Vita Enamic treated with 9% hydrofluoric acid (HF), Groups (RC-P1) and (RC-P2): Vita Enamic treated with Er,Cr:YSGG laser with parameters 1.5 W and 2.5 W, respectively. All samples were cemented with self-adhesive resin cement and thermocycled for 5000 cycles. The SBS was measured using a universal testing machine and the mean values (MPa) were analyzed using Two-way (ANOVA) (P ? 0.05) and Bonferroni’s post-hoc test. Results: RC-C (16.55) showed highest SBS followed by LD-C (13.79), which revealed no statistically significant difference with RC-P1 (12.33) and RC-P2 (11.2). The lowest SBS values were found with LD-P1 (2.7) and LD-P2 (2.1). SEM analysis revealed Vita Enamic to have the highest surface roughness. Fracture pattern analysis showed adhesive failure with IPS Emax groups and mixed failure with Vita Enamic groups. Conclusion: Er,Cr:YSGG laser irradiation with the parameters used did not increase SBS of IPS Emax and Vita Enamic with composite resin compared to HF acid etching.KeywordsEr,Cr:YSGG laser; Shear bond strength; Surface treatment; Ceramic materials.

Biomechanical behavior of endocrown restorations with different CAD-CAM materials: A 3D finite element and in vitro analysis

Statement of problemThe performance of endocrowns fabricated with different types of computer-aided design and computer-aided manufacturing (CAD-CAM) materials is unclear. PurposeThe purpose of this finite element analysis (FEA) and in vitro study was to compare and evaluate the stress distribution, failure probability, and fracture resistance of endodontically treated teeth restored with endocrowns from CAD-CAM milling blocks including ceramic, polymer-infiltrated ceramic (PICN), and composite resin. Material and methodsAn endodontically treated first mandibular molar restored with an endocrown was modeled by using a CAD software program and imported into an FEA software program. The model was duplicated and received restorations made from CAD-CAM blocks: Vita Suprinity (VS), IPS e.max CAD (EMX), Vita Enamic (VE), Lava Ultimate (LU), and Grandio blocs (GR). Stress distributions under axial and oblique loading were analyzed. The Weibull function was combined with the FEA results to predict long-term failure probability. The mechanical failure behavior of endocrowns manufactured with these materials was tested by using a universal testing machine. Load-to-failure was recorded, and fractured specimens were subjected to fractography. The data were analyzed by 1-way ANOVA and the post hoc Tukey test (α=.05). ResultsThe models of GR and LU exhibited a more even stress distribution. The Weibull analysis revealed that 5 models performed in a similar manner under normal occlusal forces, while LU and VE models achieved the highest probabilities during clenching. The fracture loads of GR (3808 ±607 N) were significantly higher than those of other materials (P<.05). More favorable failure modes were observed in the GR and VE groups. Fractography showed a greater probability of compression curls and arrest lines in the endocrowns of VE, LU, and GR groups. ConclusionsWhen restoring endodontically treated teeth, endocrown fabricated with composite resin exhibited a more uniform stress distribution and higher fracture resistance. More evidence from long-term clinical studies is needed to verify this effect.

Effect of Various pH Media on Fracture Toughness and Hardness of Bilayered Reinforced Polymer and Monolithic Hybrid Ceramic

Objective: This study evaluated the effect of various pH media on fracture toughness and hardness of bi layered reinforced polymer and monolithic hybrid ceramic. Materials and Methods: Total of 80 samples were used in this study. Samples were divided into two main groups , Poly Ether Ether Ketone (PEEK) group and Vita Enamic group. Each PEEK and Vita Enamic group were subdivided into 4 subgroups according to PH media used, control group, strong acid media (Pepsi),weak acid media(coffee),distilled water. Testing was performed before and after 24 days of pH media storage. Data was statistically analyzed using Student t-test ,paired t-test and the significance level was set at p ≤ 0.05 . Results: Hardness results with irrespective of material type, was found that baseline subgroup recorded statistically significant highest hardness followed by pH 5.5 subgroup then pH 7 subgroup while pH 2.5 subgroup recorded statistically significant lowest hardness. Fracture toughness results with irrespective of material type, was found that baseline subgroup recorded statistically significant highest fracture toughness followed by pH 7 subgroup then pH 2.5. subgroup while pH 5.5 subgroup recorded statistically significant lowest fracture toughness Conclusion: PEEK material recorded higher fracture toughness mean value than Vita enamic while Vita Enamic material recorded higher hardness mean value than PEEK . Both material affected more by pH2.5(Pepsi)sub group followed by pH 5.5 (coffee) subgroup then pH7 subgroup when measuring hardness. Both material affected more by pH5.5(coffee) subgroup followed by pH2.5 (Pepsi) subgroup then by pH 7 subgroup when measuring fracture toughness.

The effects of different surface treatments on the shear bond strengths of two dual-cure resin cements to CAD/CAM restorative materials.

PURPOSEThe aim of the present study was to investigate the effects of surface treatments on the bond strengths between polymer-containing restorative materials and two dual-cure resin cements.MATERIALS AND METHODSIn the present study, rectangular samples prepared from Lava Ultimate (LU) and Vita Enamic (VE) blocks were used. The specimen surfaces were treated using CoJet sandblasting, 50 µm Al2O3 sandblasting, % 9 HF (hydrofluoric) acid, ER,Cr:YSGG laser treatment, and Z-Prime. Dual-cure resin cements (TheraCem and 3M RelyX U 200) were applied on each specimen's treated surface. A micro-tensile device was used to evaluate shear bond strength. Statistical analysis was performed using the SAS 9.4v3.RESULTSWhile the bond strength using TheraCem with LU or VE was not statistically significant (P=.164), the bond strength using U200 with VE was statistically significant (P=.006). In the TheraCem applied VE groups, Z-Prime and HF acid were statistically different from CoJet, Laser, and Sandblast groups. In comparison of TheraCem used LU group, there was a statistically significant difference between HF acid and other surface treatments.CONCLUSIONThe bonding performance between the restorative materials and cements were material type-dependent and surface treatment had a large effect on the bond strength. Within the limitations of the study, the use of both U200 and TheraCem may be suggested if Z-prime was applied to intaglio surfaces of VE. The cementation of LU using TheraCem is suitable after HF acid conditioning of the restoration surfaces.

Changes in Optical Characteristics and Surface Topography of CAD/CAM Materials after Bleaching Applications: An AFM Evaluation.

To evaluate the effect of in-office and at-home bleaching agents on color changes (ΔE00 ), translucency (TP00 ), whiteness (WID ), surface roughness (Ra ), and surface topography (Rsk and Rku ) of a resin nano-ceramic and a polymer-infiltrated ceramic network CAD/CAM material. Sixty specimens (6 mm × 7 mm × 1.3 mm) were prepared from Lava Ultimate (LU) and Vita Enamic (VE). The specimens were divided into 6 groups according to the bleaching agents applied (n = 10/group): control, Perfect Bleach Office + (PBO), Opalescence Boost (OB), Perfect Bleach (PB) with 10% and 16% carbamide peroxide and Whiteness Perfect (WP). ΔE00 values were calculated before and after bleaching procedures with a spectrophotometer using the CIEDE2000 formula. ΔTP00 and ΔWID values were calculated for each material. Ra , Rsk , and Rku values of the specimens were evaluated with an Atomic Force Microscope. Two-way ANOVA was used for statistical analyses of the parameters measured after bleaching. For pairwise comparisons, Tukey test was performed. For LU, no statistically significant difference among the ΔE00 values of the groups was observed (p = 1.000). For VE, only WP group presented significantly higher values (2.12 ± 2.66) than the other groups (p < 0.001). For both materials; ΔTP00 values of at-home bleaching groups were significantly higher than in-office bleaching groups and control group (p < 0.001). For VE, ΔWID values did not demonstrate statistically significant difference (p = 1.000); however, for LU, PBO applied group showed statistically higher ΔWID values (3.00 ± 2.38) (p = 0.010) and WP applied group showed lower ΔWID values (0.47 ± 0.31) than the other groups (p = 0.030). For both LU and VE, there was no statistically significant difference among the groups regarding Ra (F = 4.544), Rsk (F = 2.369), and Rku values (F = 2.391) (p = 1.000). All of the VE groups presented Ra values higher than 0.2 µm. The optical properties of LU and VE after bleaching applications were affected by the contact time with bleaching agents rather than concentration. Bleaching procedure had no effect on the surface properties of these materials.

Optical Properties of Novel Resin Matrix Ceramic Systems at Different Thicknesses

Objectives: The purpose of this study was to investigate the effect of material and thickness on the translucency parameters (TP) and opalescence parameters (OP) for resin matrix ceramic blocks. Materials and Methods: 90 disc-shaped specimens (8 mm diameter and A2 shade, High Translucency) were fabricated from Vita Enamic, Lava Ultimate and GC Cerasmart resin-matrix ceramic blocks and prepared to thicknesses of 0.5 mm, 1 mm and 1.5 mm (n=10). A dental spectrophotometer (VITA Easyshade Advance) was used to calculate the TP and OP. All specimens were placed on white and black backgrounds. The color measurements were repeated three times for each of the specimens and the mean values of L, a and b were calculated. Data were analyzed by a two-way analysis of variance (ANOVA) and Tukey’s test. Results: For the 0.5 mm thickness groups, GC Cerasmart had the highest and Vita Enamic had the lowest TP values. For the 1 mm thickness groups, GC Cerasmart had the highest TP, whereas Vita Enamic had the lowest TP. For the 1.5 mm thickness groups, Lava Ultimate had the highest TP, whereas Vita Enamic had the lowest TP. For the 0.5 mm thickness groups, Vita Enamic, and GC Cerasmart had the highest and lowest OP, respectively. The OP values in the 1 mm thickness group of Vita Enamic groups were higher than the GC Cerasmart and Lava Ultimate groups. The OP values in the 1.5 mm thickness group Lava Ultimate group were higher than the GC Cerasmart and Vita Enamic groups. In all groups, the OP values showed an increase in parallel with the increase in thicknesses, in contrast, the TP values showed a decrease. Conclusions: Type and thickness of the resin matrix ceramics affect the optical properties of the materials.