IPS E-max Research Articles

Effect of Tooth Bleaching on The Color Change of Laminate Veneer Restorations: A Pilot Study

Objective: This pilot study aimed to evaluate the effect of tooth bleaching on the long-term color change of laminate veneers restored with different translucency CAD/CAM materials. Methods: In this study, 20 upper central teeth extracted due to periodontal, orthodontic problems and trauma were used. The teeth were embedded in acrylic blocks and divided into 4 groups of 5 teeth each. Groups A and B were bleached with a vital bleaching agent for two 20-minute sessions before preparation and teeth were prepared for laminate veneer restoration following bleaching. Groups C and D were prepared without bleaching treatment. Groups A and C were restored with high translucent A1 IPS Emax CAD material and Groups B and D were restored with low translucent A1 IPS Emax CAD material. For all restorations adhesive cementation was applied and aged for 2 years by thermal cycling. The color of the restorations was measured using a spectrophotometer after cementation and the measurement was done again after 2 years aging. The Kruskal Wallis test was used to compare data and multiple comparisons were tested with Dunn’s test. Results: The translucency of the blocks and tooth bleaching caused a significant difference between the groups according to the Kruskal Wallis test. Color changes (ΔE00) of Group A, B, C and D was 0.89±0.01, 0.87±0.01, 0.81±0.01, 0.8±0.01 respectively. Conclusion: Tooth bleaching causes a greater color change in laminate veneer restorations and the translucency of the material affects the color change of the laminate veneer restorations after aging.

Effect of thermomechanical aging on marginal fit of three CAD-CAM restorative materials: An in vitro study.

The present study assessed the impact of thermomechanical aging on the marginal fit of hybrid ceramic, reinforced composite resin, and lithium disilicate ceramic. Eighteen human upper first premolars freshly extracted for orthodontic purposes were used to fabricate 18 CAD-CAM veneers and divided into three groups based on materials used: group H (n=6): hybrid ceramics (Vita Enamic), group R (n=6): reinforced composite resin (Brilliant crios), and group L (n=6): lithium disilicate ceramic (IPS e-max CAD). Each material's cementation procedure was carried out according to the manufacturer's instructions. The vertical marginal gap between the laminate veneer margin and the prepared tooth finish line was measured to assess the specimens by digital microscopy. Subsequently, all the samples were thermomechanically cycled (TMC) (5 °C to 55 °C, 30 seconds, 75000 cycles). Then, the vertical marginal gap was re-evaluated. The Brilliant crios group displayed a significantly lower vertical marginal gap mean score (31.36±2.82 µm) followed by Vita Enamic (39.27±6.54 µm) and E max (41.39±3.97 µm) groups. Similarly, after thermomechanical aging, the Brilliant crios group displayed a significantly lower vertical marginal gap mean score (41.83±8.28 µm) followed by Vita Enamic (55.47±18.65 µm), and the E max group showed the greatest vertical marginal gap mean score (59.43±16.27 µm). Thermomechanical aging affected the marginal fit of different materials employed in the current research, and these changes were under the established clinical limit.

Repair Bond Strength of Composite Resin to Dental Ceramic Using Various Surface Treatments: An In Vitro Study

Abstract Aim: This research aims to evaluate and compare the effect of various surface treatments and adhesive types on the bond strength between composite resin and two types of ceramic materials. Materials and Methods: A total of 98 disk-shaped of 10 mm diameter and 4 mm thickness were fabricated for each of the zirconia (H. C. Starck) and lithium disilicate (IPS E-Max computer-aided design), which were implanted individually in the acrylic resin mold leaving one surface exposed. The disks in each group were sub-divided according to the surface treatments into seven groups (n = 14): [hydrofluoric acid (HF, 9.5%), air abrasion, bur, laser, HF + bur, HF + air abrasion, HF + laser]. Each sub-group was further divided into two groups (n = 7) according to the type of adhesive used for the repairing procedure [G-Premio Bond universal adhesive group and intraoral repair kit (BISCO) group]. Each adhesive was applied depending on manufacturer instructions and, then, the composite cylinder (4 mm in diameter and 4 mm in height) was built on the pre-determined treated ceramic surface area by the addition of rubber mold. Then the samples were stored in distal water for 24 h. After that, all groups were submitted to a shear bond test using an Instron testing machine (TSTM 02500; Elista Ltd., Istanbul, Turkey) at 0.5 mm/min a crosshead speed. The data were analyzed by three-way analysis of variance and Tukey post hoc test at (P ≤ 0.05). Results: The HF + air abrasion groups registered the higher bond strength but with no statistically significant difference from groups of HF + bur. While the laser groups showed the lowest mean bond strength. Generally, E-Max registered significantly higher bond strength in comparison to zirconia. Finally, the BISCO repair system registered a significantly higher bond strength value in comparison to G-Premio. Conclusion: Combined surface treatment of HF + air abrasion with an intraoral repair kit can provide a promising method for repairing cracked ceramic restorations. However, repairing lithium disilicate is more predictable and successful than zirconia.

The effect of different materials and cavity designs on fracture resistance of ceramic partial coverage.

Two intra-coronal preparation designs with varying extensions of cuspal coverage can perform differently regarding their fracture resistance against introral forces. Two materials (IPS e-max CAD [EX], VITA ENAMIC [EN]), and two different preparation designs (EX-D1), (EX-D2), (EN-D1), and (EN-D2) were investigated to compare their fracture resistance. A total of 40 (n = 40) caries free human mandibular molars were used. All the prepared samples were scanned using CEREC Omnicam scanner and the preparations were checked by the software for any sharpness and undercuts before restoration designing and fabrication. All restorations were milled using Cerec MCXL 4.4 milling machine. Duo-Link resin cement was used for cementation. After thermocycling and chewing simulation, all samples were loaded in the Universal testing machine in order to evaluate fracture resistance of all samples. Fracture resistance testing revealed that e-max CAD (2134 N) showed statistically significantly higher mean fracture resistance values than Vita Enamic (1728 N). On the other hand, there was no statistically significant difference between mean fracture resistances between the two tested designs. Within the confines of this investigation, it can be said that although preparation design had no appreciable impact on fracture resistance, the CAD/CAM ceramic material utilized did. When restoring compound cavitties indirectly; a conservative defect oriented approach should be used. Glass Ceramic are prefered as restorative material.

5-Year clinical performance of ceramic onlay and overlay restorations luted with light-cured composite resin

ObjectivesThis prospective clinical trial evaluated the clinical performance of ceramic partial coverage indirect adhesive restorations (PCIARs) in posterior teeth luted with a light-cured composite resin. MethodsFrom April 2016 to January 2017, a total of 60 patients (27 males, 33 females; mean age: 42.2 ± 10.86 years old) received 83 glass-ceramic PCIARs (26 onlay, 57 overlay) made of IPS Emax CAD (Ivoclar Vivadent). All restorations were luted with a light-cured composite resin (Filtek Z250, 3 M ESPE) by two operators. Two independent calibrated examiners blinded to the operators performing the treatment evaluated the restorations at baseline, 1-year, and 5-year following FDI World Dental Federation criteria including esthetic, functional, and biological properties. Data were analyzed with the Friedman test and the Wilcoxon sign test (p < 0.05). ResultsNone of the restorations failed due to fracture or retention loss. One restoration was clinically unsatisfactory because of secondary caries. Marginal staining (p:0.000), marginal adaptation (p:0.018) showed significant differences between 1-year and 5-year recall. ConclusionsThe PCIARs demonstrated excellent clinical performance at 1-year period. The degradation parameters appeared as minor staining and minor irregularities after 5-year, without any affect on the clinical performance. Clinical SignificanceOur findings provide evidence that the clinical performance of PCIARs luted with a light-cured composite resin was clinically acceptable after a five-year evaluation period. Due to secondary caries, only one restoration was considered clinically unsatisfactory. ClinicalTrials registration number: NCT04838483

The effect of photoinitiator type and filler load on physicochemical and mechanical properties of experimental light-cured resin cements through lithium disilicate ceramics of different shades and thicknesses

ObjectiveThis study investigated the influence of photoinitiator types on degree of conversion (DC), rate of polymerization (RP), flexural strength (FS), flexural modulus (FM), and light transmittance (LT) of filled and unfilled light-curable resin cements through different thicknesses and shades of lithium disilicate ceramics. MethodsLithium disilicate ceramic discs (IPS Emax Press, background [0.0], 0.5, 1.0, 2.0, 3.0, and 4.0 mm, shades A1 and BL3) were prepared. Experimental resin-based cements [TEGDMA/BisGMA (50/50 mass%)] were prepared using either camphorquinone (CQ)/amine (0.44/1.85 mol%) or TPO (0.44 mol%)], and a micro and nanofiller loads of nil (unfilled); 40/10 mass%; and 50/10 mass%). Resin cements (0.2 mm thick) were placed on the lower surface of the ceramic specimens and light-activated for 30 s from the upper surface using a Bluephase Style curing light (exitance at tip: 1236 mW/cm2 ± 1.20). LT and distribution of irradiance through the ceramics were measured using a UV–vis spectrometer and a beam profile camera, respectively (n = 3). The DC and RP were measured in real-time using mid infrared spectroscopy in attenuated total reflectance (ATR) mode (n = 3). FS and FM were measured using a universal testing machine (n = 5). Statistical analyses were performed on LT, DC, RP, FS, and FM data using a general linear model, and supplementary ANOVA and post hoc Tukey multiple comparison test were also performed (α = .05). ResultsThicknesses, shades, photoinitiator type, and fillers load significantly influenced the optical and mechanical characteristics of the resin-based materials (p < 0.05). The BL3 shade ceramic provided higher values of DC, RP, FS, FM, and LT compared with the A1 shade (p < 0.05). Increasing ceramic thickness decreased the properties of the resin-based materials (p < 0.05). Generally, TPO improved mechanical properties of the resin cement compared with CQ (p < 0.05). SignificanceThe luting process of indirect restorations may be improved by using high molar absorptivity, more reactive, and more efficient photoinitiators such as TPO, as opposed to conventional CQ. The use of such initiator may allow the placement of thicker and more opaque indirect restorations.

Effect of Acidic Media on Surface Topography and Color Stability of Two Different Glass Ceramics.

The aim of this study was to determine the effect of two acidic beverages (orange juice and H3PO4-containing fizzy drink) on the surface topography and color stability of two commonly used computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic materials. Sixty samples of two CAD/CAM ceramic materials, lithium disilicate (IPS e-max CAD) and zirconia reinforced lithium silicate (Vita Suprinity), were prepared according to the manufacturer's instructions. The samples were immersed in one of three media (artificial saliva, orange juice and H3PO4-containing fizzy drink) and then stored in an incubator at 37 °C for 24 hours). Before and after immersion in different media, the surface roughness (Ra) of the samples was assessed using profilometer (JITAI8101 Surface Roughness Tester-Beijing Jitai Tech Detection Device Co. Ltd, China) and the color parameters were measured using VITA Easyshade Advance 4.01 (VITA shade, VITA made, VITA). Surface topography was observed using scanning electron microscope (SEM) and surface mineral content was compared before and after immersion. Paired sample t-test was used to determine the change in Ra before and after immersion. Two-way analysis of variance was used to determine the effect of different CAD/CAM materials and immersion media on the mean ∆Ra and mean ∆E of the studied groups. Tukey's honest significant difference posthoc test was used for multiple comparisons at a level of significance (α = 0.05). A significant increase in Ra and a decrease in the color stability of the two investigated ceramic materials were detected after immersion in the acidic media than in artificial saliva. SEM and energy-dispersive X-ray results revealed the dissolution of the glassy matrix and the exposure of silicate crystals. The surface topography and color stability of glass ceramics are affected by the pH of different acidic media.

Laser debonding of ultrathin occlusal veneers fabricated from different CAD/CAM ceramic materials

BackgroundErbium lasers safely offer the possibility of reuse for debonded restorations. Since these lasers have a high affinity for water molecules, they are absorbed by resin cement causing explosive ablation of the cement and thus, the restoration debonds. The efficiency of this process depends on many factors, including the ceramic type, its chemical composition and thickness. Therefore, this study was designed to test the time taken to debond ultrathin occlusal veneers made of three types of milled ceramic materials and evaluate the integrity of these restorations after debonding.MethodsThree ceramic types were evaluated in this study: lithium disilicate (IPS Emax CAD), highly condensed lithium disilicate (GC initial®LiSi), and translucent zirconia (Katana zirconia STML). Each group consisted of 8 occlusal veneers of 0.5 mm thickness. The samples were cemented to the occlusal surfaces of the upper molar teeth. An Er; Cr: YSGG laser was applied to the occlusal veneers using the scanning method, and time until debonding was calculated. The debonded samples were then inspected under a stereomicroscope for possible damage. Numerical data are presented as the mean with 95% confidence interval (CI), standard deviation (SD), minimum (min.) and maximum (max.) values. Normality and variance homogeneity assumptions were confirmed using Shapiro-Wilk’s and Levene’s tests, respectively. Data were normally distributed and were analyzed using one-way ANOVA followed by Tukey’s post hoc test. The significance level was set at p < 0.05 for all tests. Statistical analysis was performed with R statistical analysis software version 4.3.2 for Windows (R Core Team (2023). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/).ResultsThere was no significant difference in debonding time between the different materials (p = 0.995). The longest debonding time was found for Katana STML (87.52 ± 20.45) (seconds), followed by Emax (86.94 ± 20.63) (seconds), while the lowest value was found for LiSi initial (86.14 ± 25.16) (seconds). In terms of damage to the debonded veneers, The Emax and zirconia samples showed no damage. However, 40% of the LiSi samples fractured during debonding, and 20% exhibited cracks. Only 40% of the LiSi samples were sound after debonding.ConclusionEr; Cr: YSGG laser can be used efficiently to remove ceramic occlusal veneers. However, its effect on LiSi restorations needs further research.

Effect of different beverages and polishing techniques on colour stability of CAD/CAM composite restorative materials.

The aim of this article was to compare the colour stability of short fibre-reinforced computer-assisted design/computer-assisted manufacturing (CAD/CAM) composite (SFRC CAD) to commercially available CAD/CAM materials following prolonged immersion in a variety of beverages. Furthermore, the influence of the polishing technique was evaluated. A total of 120 rectangular specimens (10 mm length × 14 mm width × 2 mm thickness) were prepared from SFRC CAD, IPS e-max, Cerasmart 270, Celtra Duo, Enamic, and Brilliant Crios. The specimens underwent polishing through either a laboratory polishing machine equipped with 4000-grit silicon carbide paper or chairside polishing using Sof-Lex spiral. Twenty specimens of each tested CAD/CAM material were randomly divided into four groups (n = 5) based on the staining solution used in order to evaluate the colour stability of the materials. Group 1: distilled water, Group 2: coffee, Group 3: red wine, Group 4: coke. Using a spectrophotometer, the colour changes (∆E) of all CAD/CAM materials were assessed at baseline, and after 1 and 12 weeks of staining. Three-way analysis of variance was used to analyse the data (α = 0.05). The staining solution and material type showed a significant influence on the CAD/CAM specimens' colour stability (p < 0.05), while polishing method had no significant influence (p > 0.05). The average ∆E values for specimens submerged in wine were considerably higher (p < 0.05) than those for the other solutions. SFRC CAD, Cerasmart 270, and Enamic displayed the highest ∆E values in wine (p < 0.05). The colour stability of tested SFRC CAD was comparable to other composite-based CAD/CAM materials, while IPS e.max exhibited the highest level of colour stability.

Color Change of Laminate Veneer Restorations Applied to Bleached Teeth.

The aim of this study was to examine the color stability of laminate veneer restorations restored with CAD/CAM material applied to bleached teeth. In this study, 80 upper central teeth extracted because of periodontal, orthodontic or trauma problems were used. The teeth were embedded in acrylic blocks and divided into 8 groups (n=10). Groups A, B, C and D were bleached with vital bleaching agent before preparation, and teeth were prepared for laminate veneer restorations. Groups E, F, G and H were prepared without bleaching. Groups A and E were restored with A1 GC LiSi İnitial HT blocks, Groups B and F were restored with A1 GC LiSi İnitial LT blocks, Groups C and G were restored with A1 IPS Emax CAD HT blocks, Groups D and H were restored with A1 IPS Emax CAD LT blocks. All restorations were adhesively cemented and aged for 2 and 5 years with thermal cycle. Color measurements of the restorations at the beginning, after 2 and 5 years of aging were measured with a spectrophotometer. All bleached groups had more color changes than the unbleached groups. The least color change after 2 years of aging was observed in GC LiSi Initial LT (ΔE00=0.81) and IPS Emax CAD LT (ΔE00=0.81) materials which were used on unbleached teeth and the most color change was observed in GC Initial LiSi HT (ΔE00=0.93) and IPS Emax CAD HT material (ΔE00=0.92) which were used on bleached teeth. After 5 years of aging, the least color change was observed in IPS Emax CAD LT (ΔE00=0.83) and GC LiSi Initial LT material (ΔE00=0.84) which were used on unbleached and the highest color change was observed in GC Initial LiSi HT (ΔE00=0.96) and IPS Emax CAD HT material (ΔE00=0.94) which were used on bleached teeth. Bleaching and translucency affect the color stability. No difference was detected between the color changes of GC LiSi Initial and IPS Emax CAD materials. The increase in aging time increased the color changes of all materials. Bleaching and laminate veneer restorations may be preferred in many patients. For this reason, the long-term color change of laminate veneer restorations applied to bleached teeth is clinically very important. This study aimed to evaluate the effect of tooth bleaching on the long-term color change of laminate veneer restorations produced with different translucent CAD/CAM materials.

Evaluation and Comparison of Mechanical Properties of Lithium Disilicate-Based CAD/CAM Blocks

Lithium disilicate are commonly used in dental restoration due to its aesthetic and mechanical performance. However, the patent expiration of the IPS emax system has led to the emergence of other variations of the system. Data and studies concerning mechanical properties of these recent lithium disilicate-based CAD/CAM are scarce and it warrants for an investigation to provide scientific evidence to support its routine use. The aim of this study was to investigate and compare the mechanical properties of lithium disilicate-based CAD/CAM blocks from four different brands. Four CAD/CAM lithium disilicate brands were investigated; IPS emax, Mazic Claro, Cameo, and Tessera. Specimens (n=10) were prepared accordingly; for flexural strength (16 × 4 × 1.2 mm) and microhardness test (15 × 13 × 2 mm). One specimen from each brand was analysed for the microstructure, elemental composition and distribution before and after heat treatment using scanning electron microscope and energy dispersive x-ray spectroscopy. The three-point flexural strength test (n=10) and microhardness test (n=10) was performed. Data were analysed using one-way ANOVA and Dunnett’s T3 test. The results showed that the highest mean flexural strength was from Group 4 Tessera (540.52 ± 143.33 MPa). For microhardness, the highest mean was from Group 1 Mazic Claro (667.70 ± 9.41 HV). Within the four groups, statistically significant difference is noted for flexural strength and microhardness. As a conclusion, Tessera demonstrated significantly higher flexural strength than IPS emax and Cameo. Mazic and Tessera demonstrated significantly higher microhardness than IPS emax and Cameo. All materials tested were above the threshold of 300 MPa.

Two‑year clinical performance of indirect restorations fabricated from CAD/CAM nano hybrid composite versus lithium disilicate in mutilated vital teeth. A randomized controlled trial

Trial designThis is a randomized, controlled, superiority, double-blinded, parallel-group, two-arms trial with an allocation ratio of 1:1. The aim of this trial was to compare the two-year clinical performance of partial indirect restorations fabricated from CAD/CAM nano-hybrid composite and ceramic lithium disilicate blocks using the modified USPHS criteria.MethodsIn two parallel groups (n = 50 restorations), fifty participants having mutilated vital teeth with a minimum of two remaining walls were randomly enrolled in this trial and received indirect restorations of either nano-hybrid composite resin blocks (Brilliant, Coltene, Switzerland) or Lithium Disilicate (IPS Emax CAD). The restorations were assessed using modified USPHS criteria by two independent blinded assessors at baseline, six months, one-year and two years follow-up visits. Categorical and ordinal data were presented as frequencies and percentages. Categorical data were analyzed using the chi-square test. Ordinal data were analyzed using the Mann-Whitney U test for intergroup comparisons and Freidman’s test followed by the Nemenyi post hoc test for intragroup comparisons. Numerical data were presented as mean and standard deviation values. They were analyzed for normality using the Shapiro-Wilk test. Data were found to be normally distributed and were analyzed using the independent t-test. The significance level was set at p ≤ 0.05 within all tests.ResultsForty-eight participants received the allocated intervention and completed the follow-up periods. There was a statistically significant difference between both tested materials for all USPHS criteria regarding Marginal integrity and Marginal discoloration at six-months Follow-up, but with no statistically significant difference at one- and two-year follow-up.ConclusionsBoth materials showed an acceptable, successful clinical performance along the two-years follow-up period.Clinical relevanceThe CAD/CAM nano-hybrid composite blocks are as reliable as Lithium disilicate for restoring mutilated vital teeth.

Evaluation of Marginal and Internal Adaptation of Crowns Fabricated with Three Different Zirconia CAD/CAM Materials.

Marginal and internal adaptation are key factors that determine the clinical success of dental restorations. The aim of this study is to evaluate the marginal and internal fit of crowns fabricated with three different CAD-CAM zirconia materials; two monolithic zirconia materials and one veneered zirconia copings in comparison with conventional metal-ceramic crowns. Ninety-six extracted molars (n = 96) were selected. Teeth were randomly divided into four groups (n = 24), and the following restorations were fabricated: Metal-ceramic crowns (Control group) (Group CG); monolithic zirconia crowns (GC initial) (Group MZ1); monolithic zirconia crowns (InCoris TZI),(Group MZ2); bilayered zirconia crowns, cores (InCoris ZI) veneered with a low-fusing glass-ceramic (IPS Emax Ceram),(Group BZ). Internal and marginal adaptations were evaluated using the silicone replica technique. A total of 20 points were recorded for every tooth under the light microscope at 20x magnifications. Results were compared using one-way analysis of variance (ANOVA) and the posthoc Tukey's test at a significance level of 0.01. Marginal, marginal-internal, axial, and occlusal gaps between CG, MZ1, MZ2, and BZ crowns showed statistically significant differences (P < 0.01). Monolithic zirconia groups showed better marginal adaptation compared with the veneered zirconia crowns.

Estimate the Self-Adhesive Resin Effect on the Bonding Strength in a New Technique for Artificial Scleral Construction

Background. The Eye is the most noticeable features of the person face, the causes of ocular trouble may be congenital anomaly or acquired, Prosthetic rehabilitation attempts to restore these disfigurements to improve esthetic, function and psychic statue of the patient. Objective of this in vitro study were to estimate the effect using of various resin cements on the shear bond strength between (Heat Clear Acrylic Resin with Heat Clear Acrylic Resin) and (Heat Clear Acrylic Resin with E-max Heat Press Veneer) for construction of artificial scleral as a new technique. Material and Methods Clear heat cure acrylic resin and Lithium disilicate ceramic ingots (IPS E-max Heat Press Veneer) using for construction samplesstudy, total number are (50) samples rectangle shape for shearbond strength test and using two types of adhesives theconventional Glass ionomer cement and Breeze self -adhesiveresin cement for linked process. Results. One-way ANOVAtest was used to analyze the results, there was a highstatistically significant difference between the groups.Conclusion the use of E-max heat press as a new techniquefor construction of artificial scleral provide acceptable shearbond strength when using Breeze self- adhesive resin.

Influence of the Crystallization Firing Process on Marginal and Internal Adaptation of Silicate-based Glass-ceramic Inlays Fabricated With a CAD/CAM Chairside System.

Computer-aided design/computer-aided manufacturing (CAD/CAM) systems are widely used in dental treatment. Clinicians can use chairside CAD/CAM technology, which has the advantage of being able to fabricate inlays on the same day. We aimed to evaluate the effects of crystallization firing processes, fabrication methods (one-step and two-step), and materials on marginal and internal adaptations of silicate-based glass-ceramic all-ceramic inlays fabricated with CAD/CAM chairside systems. Ten artificial mandibular left first molars were prepared with standardized ceramic class II mesial-occlusal (MO) inlay cavities. Optical impressions were obtained using CEREC Omnicam Ban. IPS e-max CAD (IE), (Ivoclar Vivadent, Schaan, Liechtenstein), Initial LiSi Block (LS) (Hongo, Bunkyoku, Tokyo, Japan), VITA Suprinity (SP), (Vita Zahnfabrick, Bad Säckingen, Germany), and Celtra Duo (CD) (Ivoclar Vivadent, Schaan, Liechtenstein) (n=10) were milled using CEREC MC XL (Bensheim, Germany). IE and SP were crystallization-fired using CEREC Speed Fire. The silicone replica technique was used for the measurement of internal (axial and pulpal walls) and marginal (cervical and occlusal edge) adaptations. The adaptations were measured using a thin layer of light-body polyvinyl siloxane impression material placed between the master tooth inlay preparation and restoration. Marginal and internal adaptations of IE, LS, SP, and CD were measured using a stereomicroscope (500×). For IE and SP, marginal and internal adaptations were measured before and after the crystallization firing process. Data analyses were conducted using one-way ANOVA and the Tukey test. For IE and SP, marginal and internal adaptations before and after the crystallization firing process were analyzed using the t-test. The significance level was set at α=0.05. One-way ANOVA revealed statistically significant differences in occlusal and cervical edge marginal adaptations among the material groups (p<0.001). The Tukey HSD test revealed a significant difference in marginal occlusal and cervical edge adaptations between LS and CD groups and IE and SP groups (p≤0.05). For IE and SP inlays, the t-test revealed a significant difference between occlusal and cervical edge adaptations before the crystallization firing process and those after the crystallization firing process, with the latter group showing a more significant discrepancy in adaptation than the former group (p≤0.05). Fabrication methods (one- and two-step) affected the marginal adaptation compatibility but not internal compatibility of MO inlays. The crystallization firing process affected the marginal adaptation of inlays using lithium silicate or lithium disilicate glass-ceramics. However, adaptation to the cavity was considered clinically acceptable for all materials.

Long-term effect of firing protocols on surface roughness and flexural strength of lithium disilicate glass-ceramic.

This study evaluated the effect of different firing protocols on the surface roughness and flexural strength of CAD/CAM lithium disilicate glass-ceramic (LD) after aging methods. Forty-two LD bars of 16 x 4 x 2 mm (IPS e-max CAD, Ivoclar) were randomly separated into two groups according to firing protocols: Single firing-Staining, glazing, and crystallization in a single step; Multiple firings-Crystallization+First staining+Firing+Second staining+Firing+Glazing+Firing. After protocols, initial surface roughness readings were taken (Surfcorder SE1700, Kosakalab). Samples were then randomly separated into three groups (n=7) according to the aging methods they were submitted: Thermomechanical cycling (TMC, ER System, Erios, 1,200,000 cycles, 0.3 MPa, 2 Hz and 5°C/37°C/55°C, 30 s swell time); Simulated toothbrushing (STB, Pepsodent, MAVTEC, 73,000 cycles), and Control (no aging). Final surface roughness readings were done, and samples were submitted to a three-point bending test (OM100, Odeme Dental Research) and fractographic analysis by scanning electron microscopy (EVO-MA10, ZEISS). Data were analyzed (2-way ANOVA, (α=.05). There was no difference (p>.05) in the flexural strength between the firing protocols, regardless of the aging method. STB decreased the flexural strength of samples submitted to multiple firings, different from control (p<.05). Without aging (Control), before TMC, and after STB, LD had lower surface roughness when submitted to multiple firings than to single firing (p<.05). The firing protocols did not affect the flexural strength or the surface roughness of the lithium disilicate glass-ceramic, even after aging. However, toothbrushing negatively affected the flexural strength and smoothed the surface of the ceramic submitted to multiple firings.

Effect of Different Polishing Systems on Surface Roughness of IPS Empress Ceramic Materials

For evaluation and comparison of the effect of surface treatment (glazings, polishing with rubber wheel and diamond paste, and polishing with rubber wheel) on pressable porcelain (IPS Emax porcelain) surface roughness in comparison with non-treated surface. Forty-disc shaped specimens of baseplate wax with 10 mm diameter and 2 mm thickness have been prepared. They were invested and subjected to lost wax technique in fabricate the pressable ceramic. Following pressing, they have been divided randomly into four groups: Group A: no surface treatments, Group B: glazing (paste, HT, Ivoclar, Vivadent, Germany) glazing (paste, HT, Ivoclar, Vivadent, Germany), Group C: polishing with burs (DIAPRO TWIST, EVE, GmbH, Germany), and Group D: polishing with burs (DIAPRO TWIST, EVE, GmbH, Germany) and diamond paste (All in one, RENFERT, GmbH, Germany). For each specimen, examination of mean roughness profile (Ra) was performed for total surface roughness description. Specimens were stabilized with the acrylic holder used previously in the initial polishing procedure. A contact stylus profilometer was used to conduct a quantitative measurement of surface roughness in micrometers (µm) for all specimens. The highest (Ra) value was for control group (1.9520), whereas the lowest values were in group D (Polishing by rubber wheel .4670. One-way ANOVA test showed a high significant value at (P &lt;. 000), and LSD test showed a high significant value at (P &lt;. 000) when comparison was established among groups. From the results of the current study, we can conclude the following; polishing procedure for the surface of pressable ceramic with or without diamond paste produced better surface smoothness than glazed surface and non-treated surface and polishing with burs could be an alternative to glazing to provide smooth surface.

Comparison of Mechanical Properties of Aged All-Ceramic Materials

Background: Our research aimed to compare the biaxial flexural strength of glass ceramic and two different monolithic zirconias after aging, examine the fracture surfaces with scanning electron microscopy (SEM) and perform elemental analysis with energy dispersive spectroscopy (EDS). Methods: Two types of monolithic CAD/CAM materials (Katana UTML and Prettau Anterior) and a lithium disilicate material (IPS emax Press) were selected for this study. All samples were aged with a thermal cycle of 10000 cycles. The biaxial flexural strength of the disc specimens was determined using the three-ball piston test and a universal testing machine. Biaxial flexural strengths were compared for each group (n = 10). All fractured samples were examined by SEM and elemental analyzes were performed with EDS. Data were analyzed by 1-way ANOVA and Tukey post hoc (p&amp;lt;0.05). Results: Prettau Anterior showed a statistically significant difference between the other groups (p&amp;lt;0.05). Following Prettau Anterior (1141.81 MPa), IPS Emax Press (278.86 MPa) and Katana UTML (216.14 MPa) showed biaxial flexural strength, respectively. Conclusion: Compared to the other materials evaluated, Prettau Anterior had much higher biaxial flexural strength. Katana UTML and IPS emax Press show similar strength over the long term. It is seen that the chemical structure of the materials has an effect on the mechanical capacity. KEYWORDS: Biaxial Flexural Strength, Lithium Disilicate Glass-Ceramic, Monolithic Zirconia

Evaluation of mechanical properties of different polyetheretherketone endodontic post systems: an in vitro study

BackgroundSurvival of endodontically treated teeth depends on an efficient restoration of the missing tooth structure.ObjectivesThis study aimed to investigate the mechanical properties of different endodontic post systems.Materials and methodsHuman permanent maxillary central incisors (no.=58) were decoronated and root-filled. The specimens with prepared root canals were randomly divided into Group P: Polyether Ether Ketone (PEEK) post and composite core and Group C: custom-made post-core of PEEK. The cementation of the posts was carried out using self-adhesive resin cement. Nano-hybrid composite resin was used for core fabrication. After cementation, the specimens from each group were randomly divided into two subgroups according to the types of tests utilized: 14 from each group were for the fracture strength test, which was restored with IPS e-max CAD crown, and 15 from each group for the pullout resistance test. A universal testing machine was used for the test performance.ResultsThe fracture resistance test showed that the values significantly differed among tested posts (P = 0.013). Group P showed the highest fracture resistance. Group C exhibited higher mean pullout resistance values than the other group (P) (P = 0.059). In the two-piece PEEK post and composite core, the predominant type of failure was a core fracture, while in the one-piece PEEK post-core, most types of failures were either in the crown or in the post.ConclusionsThe prefabricated posts are more resistant to fracture than the custom-made posts, with fracture and displacement mainly of the core. In contrast, both showed similar pullout resistance.

Wear characteristics of esthetic resin matrix and zirconia reinforced lithium disilicate CAD/CAM materials: two-body wear and surface topography analysis.

This in vitro study assessed the wear behavior of different CAD-CAM blocks and the abrasion of the enamel antagonist against these materials. 64 disk-shaped specimens were prepared from 8 different CAD/CAM blocks as follow: one lithium disilicate glass ceramics block "IPS Emax CAD" as control group, two zirconia reinforced lithium silicate "Vita Suprinity & Celtra DUO," one interpenetrating network ceramic block "Vita Enamic," Three resin-based block composites "Lava Ultimate, Cerasmart & Brilliant-crios" as well as one hybrid nanoceramic "Shofu block HC". All specimens were mounted against canine and tested for two body wear analysis using a chewing simulating loading machine (100,000 cycles, 50 N, 5/55 °C). The amount of wear loss was measured for each specimen using a digital precise scale. Wear area before and after the chewing simulation were evaluated using an optical profilometer. Data analysed using one-way ANOVA test followed by Tukey's post hoc. The results showed a significantly higher wear loss in resin matrix ceramics in comparison to glass ceramics. However, for tooth wear glass ceramics had significantly higher value than hybrid ceramics. Resin based CAD/CAM Blocks gives a superior result when evaluating the wear behavior and its effect on the opposing tooth surface.