Resin Nanoceramic Research Articles

Effect of surface treatments and universal adhesive application on the microshear bond strength of CAD/CAM materials.

PURPOSEThe aim of this study was to evaluate the microshear bond strength (µSBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols.MATERIALS AND METHODSFour different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, μSBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests.RESULTSThe findings revealed that silane application yielded higher µSBS values (P<.05). All surface treatments were showed a significant increase in µSBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05).CONCLUSIONSurface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases.

Effect of surface finishing treatments on the color stability of CAD/CAM materials.

PURPOSEThe aim of this study was to evaluate the effect of different surface finishing processes on the color stabilities of lithium disilicate glass-ceramics, zirconia-reinforced lithium silicate ceramics, and resin nanoceramics after artificial ageing.MATERIALS AND METHODS216 samples were prepared from 3 different CAD/CAM materials (LAVA Ultimate, IPS e.max CAD, VITA Suprinity) with A1 HT color at a size of 14 × 12 mm and a thickness of 0.5 ± 0.05 mm. Color measurements of the samples were performed with a spectrophotometer using color parameters and CIE Lab color system on a gray backing between baseline color and after 5000 cycles of artificial ageing in 4 stages (i.e. the first measurement before the treatment, the second measurement after polishing, the third measurement after cement application, and the fourth measurement after artificial ageing). The results were evaluated using the Variance analysis and Fisher's LSD test.RESULTSResin nanoceramics (LU) exhibited higher color change values than zirconia-reinforced lithium silicate (VS) and lithium disilicate (EC) ceramics after artificial ageing. Manual polishing and glazing resulted in similar color change for LU and VS (P>.05). In the EC group, glazing provided statistically different results as compared to the manual polishing and control groups (P<.05). Among the ceramic groups, color change values of the subgroup, which was treated by glazing, of the zirconia-reinforced lithium silicate (VS) and lithium disilicate (EC) samples were below the clinically acceptable level (ΔE < 3.5).CONCLUSIONThe lowest color change for all stages was observed in Vita Suprinity.

Repair Bond Strength of a CAD/CAM Nanoceramic Resin and Direct Composite Resin: Effect of Aging and Surface Conditioning Methods.

To evaluate the effect of surface conditioning methods and aging on the repair bond strength between resin composite and nanoceramic CAD/CAM resin. Twenty-four blocks of nanoceramic CAD/CAM resin (NCR) (Lava Ultimate, 3M Oral Care) (10 x 5 x 2 mm3) and resin composite (Filtek Z350, 3M Oral Care) (RC) were made, embedded in acrylic resin, polished (#600, #800, #1200) and randomly divided into 8 groups (n = 12 each) according to surface conditioning methods (air abrasion with 30-μm CoJet [CJ] or air abrasion with 50-μm Al2O3 [AB]) and aging prior to repair (without aging, 24 h in water at 37°C; with aging 6 months in water at 37°C). The blocks were air abraded (20 s, 2.5 bar, 10 mm) using a standardized device. A layer of adhesive resin (Scotchbond Universal) was applied (20 s) and photopolymerized for 20 s. RC cylinders (Ø = 2 mm; h = 2 mm) were then bonded to the NCR substrates using a Teflon matrix and photopolymerized for 40 s. All specimens were thermocycled (10,000 cycles, 5°C-55°C) and submitted to the shear bond test (50 kgf, 0.5 mm/min) to measure repair strength. Data (MPa) were analyzed using 3-way ANOVA and Tukey's test (α = 0.05). Failure analysis was performed using stereomicroscopy (20X). ANOVA revealed a significant effect of only the "material" factor (p = 0.00). The group NCR6mCJ presented bond strengths (29.37 ± 5.41) which were significantly higher than those of the NCR24hCJ (20.88 ± 5.74) and RC groups (p < 0.05). The group RC24hCJ (19.71 ± 4.21) presented the lowest shear bond strength (p < 0.05). Failure analysis revealed predominantly type B mixed failures (adhesive+cohesive in the substrate material) except for the groups NCR24hCJ and NCR6mAB, where mainly type C failure (adhesive+cohesive at the RC) was observed. Air abrasion with Al2O3 particles or silicatization with CoJet followed by adhesive resin application are effective surface conditioning methods for the repair of nanoceramic CAD/CAM resin with resin composite.

A comparative study on color and dimensional stability of esthetic indirect dental materials

In selecting dental materials, color and dimensional stability play key roles in mechanical characteristics as well as esthetic aspects. While resin nano ceramics have been examined to determine their mechanical characteristics in carious experiments, few studies have focused on their intra-oral stability, specifically their long-term color stability or water sorption. In this study, ceramic, resin nano ceramic, and composite resin were analyzed to evaluate their color stability, water sorption, and solubility. The amount of characteristic changes was measured using a spectrometer, an electronic scale, and a caliper for durations of 1, 2, 4, and 8 weeks. The results showed that ceramic was the most stable among all materials, whereas resin nano ceramic and composite resin demonstrated time-dependent changes, which require more clinical considerations for long-term use.

Cytotoxicity and inflammatory response of different types of provisional restorative materials

AimTo evaluate the cytotoxicity and inflammatory response of different types of provisional restorative materials to mice gingival fibroblasts. MethodsCytotoxicity of provisional material discs (thermal-polymerized acrylic resin; auto-polymerized acrylic resin; bisacrylic resin; nano-ceramic resin for CAD/CAM and prefabricated polymer block for CAD/CAM) to Mice (Balb/c) gingival cell were investigated under direct and indirect contact (extracts) at 24, 48 and 72 h, using the MTT and Alamar blue assays. Materials extracts (24 h) were applied to the cell culture (indirect contact) or cells were seeded on discs of provisional materials, and the cytotoxicity and production of IL-6, IL-1β and TNF-α after 24, 48 and 72 h were analyzed through MTT, Alamar Blue® and ELISA. Culture medium was used as control for indirect contact assay (extract) and the surfaces of the wells without discs of provisional materials were used as control for direct contact assay. Results were analysed statistically by ANOVA followed by the Bonferroni-Test correction. Statistically significant differences were considered if P was < .05. ResultsAuto-polymerized and bisacrylic resins (direct contact) reduced cell viability after 24, 48 and 72 h compared to control (P < .05). Indirect contact (extract) was not cytotoxic to cells at all periods compared to control (P > .05). Auto-polymerized and bisacrylic resins increased IL-6, IL-1β and TNF-α levels mainly at 24 h when compared to the other materials (P < .001). ConclusionAuto-polymerized and bisacrylic were more cytotoxic to mice gingival fibroblasts. CAD/CAM nano ceramic resin and prefabricated polymer blocks are more predictable materials to preserve the periodontal soft tissues.

Mechanical Wear and Surface Roughness of Glass and Hybrid Ceramics

Aim: The purpose of this invitro study was to evaluate wear resistance and surface roughness of two hybrid ceramics in comparison to lithium disilicate glass ceramic before and after mechanical abrasion. Materials and Methods: Thirty samples were divided according to material of construction into three groups, group (1): Lithium disilicate glass ceramic (IPS e.max, n=10), group (2): Resin nanoceramic (Lava Ultimate, n=10), group (3): Polymer infiltrated ceramic (Vita Enamic, n=10). All samples were fabricated out of CAD CAM ceramic blocks, weighed and evaluated for surface roughness before and after mechanical wear. Results: Resin nanoceramic (Lava ultimate), showed significantly low weight loss and surface roughness change after mechanical wear than IPS e.max. The polymer infiltrated ceramic (Vita Enamic) showed significantly high surface roughness than Resin nanoceramic (Lava ultimate), while IPS e.max showed the highest weight loss and surface roughness change. Conclusion: Resin nanoceramics revealed highest mechanical wear resistance contributed by terms of weight loss and surface roughness change, while Lithium disilicate glass ceramic showed the least wear resistance.

Single blinded in-vitro study comparing microleakage between CAD/CAM crowns milled out of feldspathic ceramic and resin nano ceramic, cemented with three resin cements

Background: Studies on microleakage of Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) crowns are abundant. However many of them are inconclusive, especially those using self adhesive cements.&#x0D; Aims: To compare the microleakage between CAD/CAM crowns milled out of feldspathic ceramic and resin nano ceramics, cemented with three resin cements.&#x0D; Materials and Methods: Crown preparation was made on 54 extracted human premolars. Impressions were captured optically using CEREC 3D machine intraoral camera, and crowns were milled from feldspathic ceramic (CEREC® Blocs PC, VITA) and resin nano ceramic (Lava™ Ultimate CAD/CAM Restorative, 3M ESPE) blocks. The crowns were then cemented with three cements (n = 9); RelyX™ U200 Self-Adhesive Resin Cement (3M ESPE); NX3 Nexus ® cement with two-step etch-and-rinse adhesive (Kerr Corporation) or three/multistep etch-and-rinse resin cement, Variolink® II/Syntac Classic (Ivoclar Vivadent). The specimens were kept in water for 24 hours, thermocycled, and then soaked in methylene blue dye for 24 hours, before being sectioned mesiodistally. Microleakage was assessed using a fivepoint scale using stereomicroscope. Statistical analysis of the data was carried out using ONEWay ANOVA.&#x0D; Results: CEREC® Blocs PC crowns showed significantly less microleakage (p&lt; 0.001) compared to Lava™ Ultimate. RelyX™ U200 showed significantly lower microleakage (p&lt; 0.001) compared to other cements. Combination of Lava™ Ultimate crown cemented with RelyX™ U200 showed the least microleakage (p&lt; 0.001).&#x0D; Conclusions: The microleakage scores were affected by the types of crown and cements.&#x0D; Bangladesh Journal of Medical Science Vol.18(4) 2019 p.764-772

Influence of universal adhesive system application strategies on the long-term bond strength to dentin of CAD-CAM restorative materials

The objective of this study was to evaluate the influence of dentin application strategies of the universal adhesive system (Scotchbond Universal 3 M/ESPE) on the bond strength of a lithium disilicate-based ceramic and a nanoceramic resin, using the microshear test. A total of 40 healthy third molars were sectioned to expose flat occlusal medium dentin, and separated into four groups (n = 10). The molars were selected according to dentin treatments (application or nonapplication of phosphoric acid prior to universal Scotchbond Universal adhesive), and to the indirect materials obtained by CAD-CAM (lithium disilicate ceramics – IPS e.max CAD, and nanoceramic resin – Lava Ultimate), under study. Ceramic sticks of lithium disilicate and nanoceramic resin measuring 1 mm2 were cemented with Rely XTM Ultimate resin cement on the dentin surface, and stored in distilled water for 48 h or 12 months at 37 °C. The microshear test was performed using a universal testing machine, at a speed of 0.5 mm/min. The values were recorded in MPa, and submitted to three-way ANOVA with a significance level of 5%. The results indicated that the interactions among restorative material, dentin treatment and timepoint was not significant (p = 0.841). However, the 12-month storage time significantly affected the bond strength (p = 0.016) of all the groups. It was concluded that bond strength to dentin decreased over time, regardless of the mode of application of the universal adhesive system or the type of restorative material.

Fracture resistance and the mode of failure produced in metal-free crowns cemented onto zirconia abutments in dental implants.

The purpose of the investigation was to analyze fracture resistance and mode of failure of zirconium oxide (zirconia) abutments placed on dental implants bearing crowns of different esthetic materials: zirconia, lithium disilicate (LDS), and nano-ceramic resin, for replacing single teeth in the anterior sector. Eighty implant-abutment-crown units were divided into four groups: Group T-MC (control): 20 metal-ceramic crowns cemented onto titanium abutments; Group Z-Z: 20 zirconia crowns on zirconia abutments; Group Z-LD: 20 lithium disilicate crowns on zirconia abutments; and Group Z-NCR: 20 nano-ceramic resin crowns on zirconia abutments. Specimens underwent a fatiguing process (dynamic loading and thermocycling), followed by static loading to evaluate mechanical fracture resistance, and the mode of failure produced. Mean fracture resistance values were: Control Group T-MC, 575.85±120.01 N; Group Z-Z 459.64±66.52 N; Group Z-LD, 531.77±34.10 N; and Group Z-NCR, 587.05±59.27 N. In Group T-MC, fracture occurred in the prosthetic fixing screw in 100% of specimens. In Group Z-Z, 80% of fractures occurred in the fixing screw, 15% in the abutment, and 5% in the abutment and crown. In Group Z-LD, 60% of fractures were produced in the fixing screw and 40% in the abutment. In Group Z-NCR, 70% of fractures were produced in the fixing screw and 30% in the abutment. All the abutments and crowns analyzed have the potential to withstand the physiological occlusal forces to which they would be subject in the anterior region. Lithium disilicate and nano-ceramic resin crowns cemented onto zirconia abutments are a good restoration alternative for single implants in the anterior sector.

Assessment of marginal adaptation of lithium disilicate and nanoceramic resin crowns using CAD/CAM system

Assessment of marginal adaptation of lithium disilicate and nanoceramic resin crowns using CAD/CAM system

Effects of Different Surface Treatments on the Bond Strength of CAD/CAM Resin Nano Ceramic or Ceromer to Resin Cement

Objectives: The purpose of this study was to evaluate the effects of different surface treatments on the micro-tensile bond strength (MTBS) of two different indirect restoration materials (resin nano ceramic CAD/CAM material [Lava Ultimate, 3M ESPE]; ceromer material [Estenia C&amp;amp;B, Kuraray Medical]). Materials and Methods: Specimens were prepared from each test material in dimensions of 3×10×10 mm. The specimens were divided into five different surface treatment groups: group 1 (control [C]), no treatment; group 2 (acid etching [A]); group 3 (acid etching + universal adhesive [AA]); group 4 (sandblasting [S]); and group 5 (sandblasting + universal adhesive [SA]). The prepared specimens were cemented to composite parts (Filtek Z250 Universal Restorative, 3M ESPE) of the same size using dual-cure adhesive resin cement (Panavia F2.0, Kuraray Medical). A total, 100 bar-shaped specimens (6×1×1 mm) were cut using a low-speed diamond saw (n=10 in each group). The MTBS test was performed in all groups (Shimadzu AG-50 kNG, Kyoto, Japan, 1 mm/min). Data were analyzed using a two-way analysis of variance (ANOVA) and Tukey’s multiple comparison tests at a significance level of p&amp;lt;0.05. Results: The MTBS values were significantly influenced by the type of restorative material and surface treatment (p&amp;lt;0.05). There were statistically significant differences between the materials and surface treatments procedures (p&amp;lt;0.05). For Lava Ultimate and Estenia C&amp;amp;B materials, the highest MTBS value was obtained in the SA surface treatment (p&amp;lt;0.05) and the lowest MTBS value was obtained in the control groups (p&amp;lt;0.05). Conclusions: The application of silane-containing universal adhesive material after sandblasting was the ideal surface treatment for both materials.

Marginal Gap Evaluation of Metal Onlays and Resin Nanoceramic Computer-Aided Design and Computer-Aided Manufacturing Blocks Onlays.

Objective This study was carried out to assess and compare the marginal gap of conventionally used metal onlays and new resin nanoceramic (RNC) (Lava Ultimate block) onlays. Materials and Methods This is an in vitro study using two extracted sound human mandibular molars. One tooth was prepared to receive the metal onlays and another one for the RNC onlays which were fabricated using the computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Twelve metals and 12 ceramic onlays were fabricated before they were placed at their respective preparation and examined under the Leica stereomicroscope, M125C (Leica Microsystems, Wetzlar, Germany) for a marginal analysis. The gap width was measured at 10 predefined landmarks which included 3 points on the buccal and lingual surfaces each and 2 points each on the mesial and distal surfaces, respectively. Statistical Analysis Mann–Whitney post hoc test was used for statistical analysis ( P ≤ 0.05). Results Overall, the RNC onlays showed significant lower marginal gap with the exception of the landmarks 5 and 6 (on distolingual) and no significant difference at landmark 7 (on midlingual). It was observed that the marginal gap were all within the clinically acceptable limit of 120 μm. Conclusions Based on the results obtained, it can be concluded that the RNC CAD/CAM onlays are a promising alternative to the metal onlays.

Erratum: Marginal Gap Evaluation of Metal Onlays and Resin Nanoceramic Computer-Aided Design and Computer-Aided Manufacturing Blocks Onlays.

Erratum: Marginal Gap Evaluation of Metal Onlays and Resin Nanoceramic Computer-Aided Design and Computer-Aided Manufacturing Blocks Onlays.

Fatigue performance of adhesively cemented glass-, hybrid- and resin-ceramic materials for CAD/CAM monolithic restorations

ObjectiveTo evaluate the fatigue failure load, number of cycles until failure, and survival probability of adhesively cemented materials with different microstructures (glass-, hybrid- and resin-ceramic) used to manufacture CAD/CAM monolithic restorations. MethodsDisc-shaped specimens (n=15; Ø=10mm; thickness=1.0mm) were produced from CAD/CAM blocks as follows: feldspathic (FEL); leucite (LEU); lithium disilicate (LD); zirconia-reinforced lithium silicate (ZRLS); polymer-infiltrated ceramic network (PICN); and resin nanoceramic (RNC). Adhesive cementation was performed onto epoxy discs (dentin analogue- Ø=10mm; thickness=2.5mm). The cemented assemblies were subjected to fatigue testing using a step–stress approach (400N–2200N; step-size of 200N; 10,000 cycles per step; 1.4Hz). Fatigue data were analyzed using Kaplan–Meier and Mantel–Cox (log-rank) tests (p<0.05) and Weibull statistical analysis. Fractographic analysis was also performed. ResultsAll RNC specimens survived the fatigue test (100% probability of survival at 2200N; 100,000 cycles) and presented occlusal deformation in response to loading, while all other tested materials failed in distinct loading steps with radial cracks starting from the bonding surface. LD (1146.7N; 47,333) and ZRLS (1013.3N; 40,666) materials obtained the highest fatigue failure loads and cycles until failure, meanwhile all PICN specimens failed during the first step (0% probability of survival at 400N; 10,000). FEL had similar Weibull modulus to LD and ZRLS and higher than LEU for both load and number of cycles outcomes. SignificanceThe microstructure of adhesively cemented glass-, hybrid- and resin-ceramic CAD/CAM restorative materials influence their response during fatigue testing, which aids in suggesting the best clinical indications.

Evaluation of the Adaptation and Fracture Resistance of Three CAD–CAM Resin Ceramics: An In vitro Study

The internal fit and resistance to fracture of resin ceramics are to be evaluated compared to that of lithium disilicate as the control group. Four groups of 20 crowns each (GC Cerasmart, Vita Enamic, Coltène Brilliant Crios, and e.max CAD) were cemented on identical metal dies. Marginal gaps were measured before cementation and load to fracture was applied after cementation, half of each group was thermodynamically aged (3,000 cycles of 5° to 55° immersion followed by 200,000 cycles of 100 N load), finally the crowns were loaded until fracture in a universal testing machine. Statistical package for social sciences (SPSS) package 23 was used for statistical work. Marginal gaps ranged between 68.5 ± 23.8 µm and 87 ± 29.1 µm while occlusal gaps ranged from 220.7 ± 33.3 µm to 275.5 ± 46.5 µm and were not significantly different between groups. Fracture loads ranged from 633.8 ± 127.3 N to 1596.4 ± 497.7 N with lithium disilicate glass ceramics (LDGCs) and Enamic having higher values than resin nano-ceramics (RNCs). The fracture resistance was more related to material than aging and gap value. The margin adaptation of resin ceramics was comparable to lithium disilicate with no significant difference. Lithium disilicate showed a higher resistance than resin ceramics and there was a higher resistance to fracture for polymer-infiltrated ceramic-network (PICN) than RNCs. Resin ceramics can have marginal adaptation and fracture resistance within clinical acceptance; therefore, they can be a good chair-side solution achieved in a single appointment session.

A study on stress distribution to cement layer and root dentin for post and cores made of CAD/CAM materials with different elasticity modulus in the absence of ferrule

BackgroundTo evaluate the stress distribution in a maxillary central incisor with different post and cores made of six CAD/CAM materials with different elastic modulus in the absence of ferrule using the finite element analysis.Material and MethodsA three-dimensional endodontically treated maxillary central incisor restored with an all-ceramic crown was modelled in Rhinoceros (5.0 SR8, McNeel). The geometries were analyzed in ANSYS 17.2 (ANSYS Inc.) considering isotropic, homogeneous, linearly elastic materials with perfectly bonded contacts. The elastic moduli (E) of the post-and-cores defined the groups to be compared: nanoceramic resin (E=12.8GPa); composite resin (E=16GPa); hybrid ceramic (E=34.7GPa); lithium disilicate (E=95GPa); titanium (Ti-Al6-V4) (E=112GPa); and Y-TZP material (E=209.3GPa). The set was constrained in the cortical bone and loaded (45°/100 N) on the incisor palatine face. Stress distribution was analyzed by Maximum Principal Stress criteria for the crown-core cement line, Post-and-core’s cement line, Post-and-core system and Dentin.ResultsThe stress distribution at the crown-core cement line (11.4 – 13.2 MPa) was inversely proportional to the increase of the elastic modulus of the post-core approaches, while it was direct proportional on the post-and-core (4.7 – 40 MPa) and cement line (4.1 – 6.2 MPa). Stress distribution on the dentin was similar for all groups (24.7 - 25.3).ConclusionsPost-and-core made by CAD/CAM seems to be an efficient treatment alternative, since it is a conservative approach, promotes better aesthetic quality and it allows the control of the cement line thickness. Key words:Endodontically treated teeth, Post-and-core technique, Ceramic crown, Finite element analysis, Biomimetics.

Effect of surface treatments on the bond strength of indirect resin composite to resin matrix ceramics

PURPOSEThe purpose of this study was to evaluate the shear bond strength (SBS) of an indirect resin composite (IRC) to the various resin matrix ceramic (RMC) blocks using different surface treatments.MATERIALS AND METHODSNinety-nine cubic RMC specimens consisting of a resin nanoceramic (RNC), a polymer-infiltrated hybrid ceramic (PIHC), and a flexible hybrid ceramic (FHC) were divided randomly into three surface treatment subgroups (n = 11). In the experimental groups, untreated (Cnt), tribochemical silica coating (Tbc), and Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) laser irradiation (Lsr) with 3 W (150 mJ/pulse, 20 Hz for 20 sec.) were used as surface treatments. An indirect composite resin (IRC) was layered with a disc-shape mold (2 × 3 mm) onto the treated-ceramic surfaces and the specimens submitted to thermal cycling (6000 cycles, 5 – 55℃). The SBS test of specimens was performed using a universal testing machine and the specimens were examined with a scanning electron microscope to determine the failure mode. Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tukey HSD test (α=.05).RESULTSAccording to the two-way ANOVA, only the surface treatment parameter was statistically significant (P<.05) on the SBS of IRC to RMC. The SBS values of Lsr-applied RMC groups were significantly higher than Cnt groups for each RMC material, (P<.05). Significant differences were also determined between Tbc surface treatment applied and untreated (Cnt) PIHC materials (P=.039).CONCLUSIONFor promoting a reliable bond strength during characterization of RMC with IRC, Nd:YAG laser or Tbc surface treatment technique should be used, putting in consideration the microstructure and composition of RMC materials and appropriate parameters for each material.

Shade Stability of Polymer Infiltrated and Resin Nano Ceramic Crowns after Dynamic Chewing Simulation.

Investigation of the shade stability of polymer-infiltrated and resin nano ceramic crowns before and after artificial aging. 40 identical crowns of each of the materials VITA Enamic (VE) and Lava Ultimate (LU) were manufactured. Half of the crowns went through a dynamic chewing simulation (CS) with thermocycling. Material subgroups: 1. VE, 2. VE/CS, 3. LU, 4. LU/CS (each n=20). These were divided into 4 groups (n=5) and distributed in usual stain solutions. The shade of each crown was measured occlusally and vestibularly before and after insertion using a spectrophotometer (n=5). The data were analyzed using ANOVA and Tukey's test (p≤0.05). Sum scores (SSC) of the occlusal ΔE values: LU/CS: 7.99, VE: 5.75 VE/CS: 5.44, LU: 5.17. The total sum of the SSC yielded, for the materials: SSCtotal(VE): 20.0 and SSCtotal(LU): 24.0. Occlusally, there were significant shade differences for VE/CS (p=0.025) and LU/CS (p=0.014) between red wine and distilled water. LU/CS is significantly more clearly stained occlusally by coffee in comparison to the other three material subgroups (VE: p=0.007, LU: p=0.026, VE/CS: p=0.013). The shade stability of VITA Enamic crowns is superior to that of Lava Ultimate crowns. Only Lava Ultimate is affected by chewing simulation.

Shade Stability of Polymer-Infiltrated and Resin Nano Ceramics.

Background:The esthetics plays an increasingly significant role in today's dentistry.Objective:The objective was to investigate the shade stability of a polymer-infiltrated and a resin nano ceramic in comparison to a conventional feldspar ceramic and an acrylate polymer.Methods:20 specimens of each of the materials, CAD-Temp (CT), Mark II (M), VITA Enamic (VE) and Lava Ultimate (LU), were prepared using the standard method. These were divided into groups (n=5) and placed in the following stain solutions: Distilled water, coffee, Coca-Cola and red wine for 14 days. The shade of each specimen was measured before and after using a spectrophotometer (n=5). The data were analyzed using ANOVA and Tukey's test (p ≤ 0.05).Results:The largest ΔE mean values were observed in CT by Coca-Cola (4.38 ± 0.41), in M by coffee (5.95 ± 0.62), in VE (6.02 ± 0.78) and LU (8.61 ± 0.30) by red wine. LU had the largest and strongest overall shade differences (total score: SSC=16.95) and CT the least (SSC=8.74). Overall shade differences of VE (SSC=12.03) and M (SSC=12.48) were statistically indistinguishable. After 14 days, only Coca-Cola caused clinically relevant shade differences in CT (ΔE > 2.7); this was also caused by coffee, Coca-Cola and red wine in M and coffee and red wine in VE and LU.Conclusion:On average, VE showed fewer shade differences than LU. After 14 days of immersion, shade differences which exceeded the clinical acceptance threshold of ΔE=2.7 were shown by CT in Coca-Cola, by M in coffee, Coca-Cola and red wine, and by VE and LU in coffee and red wine.

The clinical performance of all-ceramic implant-supported single crowns: A systematic review and meta-analysis.

This review aimed at evaluating the survival and technical complication rates of all-ceramic implant-supported single crowns (SC). Three electronic databases were searched for clinical studies conducted at ≥15 patients examining implant-supported all-ceramic SCs over ≥12months. Survival rates of implants and restorations plus technical complication rates of SCs were calculated and tested for statistical correlation with confounding variables. Statistical analysis was performed using a negative binomial distribution model to calculate 5- and 10-year survival and complication estimates. Forty-one included studies reported on implant-supported SCs made of veneered and monolithic high-strength oxide ceramics, monolithic, and veneered glass-based ceramics and of a monolithic resin-nano-ceramic (RNC). Survival estimates for SCs of 93% (95% CI: 86.6%-96.4%) after 5years and 94.4% (95% CI: 91.1%-96.5%) after 10years were calculated, corresponding values for implant survival were 95.3% (95% CI: 90.6%-97.7%) and 96.2% (95% CI: 95.1%-97.1%). Technical complication rates after 5/10years were as follows: chipping 9.0% (95% CI: 5.4%-14.8%)/2.7% (95% CI: 2.1%-3.5%), framework fractures 1.9% (95% CI: 0.7%-4.9%)/1.2% (95% CI: 1%-1.5%), screw loosening 3.6% (95% CI: 1.6%-8.4%)/5.2% (95% CI: 3.6%-7.5%), and decementations with 1.1% (95% CI: 0.4%-2.8%) after 5years. Some confounding variables influenced the above-mentioned estimates significantly. All-ceramic implant-supported SCs showed-with the exception of a RNC material-high survival rates. However, failures and technical complications occurred which have to be considered when informing patients on the treatment with implant-supported all-ceramic SCs.