feldspar and Dental-Leakage

The purpose of this in vitro study was to determine if packable resin composite with/without flowable resin composite has the ability to prevent coronal leakage in restored endodontic access openings following aging.. Eighty simulated standardized access cavities of metal-ceramic crowns were fabricated and fixed on Vitrebond cavities filled with an epoxy resin. The specimens were randomly divided into two main groups: (1) Group A-Access cavities filled with only packable composite (Filtek P60); (2) Group B-Access cavities filled with Filtek P60 and a flowable composite (Filtek Z350) as liner. Each main group was further subdivided randomly into four subgroups according to water storage and thermocycling periods. All specimens were immersed in blue ink solution for 24 hours and then sectioned into quadrants. The extension of blue ink along the metal-ceramic crown/composite resin interface was measured linearly using image analyzer and then analyzed by three-way ANOVA and independent t-test with a Mann-Whitney test. The level of significance was set at p < 0.05.. All tested subgroups demonstrated different levels of microleakage. There was no significant difference related to restorative technique; however, there was a significant difference related to water storage and thermocycling.. All tested techniques and materials in this study showed microleakage. Packable composite while a flowable liner showed a marginally better result than packable composite alone. Excessive thermocycling resulted in significant differences among the test groups.

Topics: Aluminum Silicates; Coloring Agents; Composite Resins; Crowns; Dental Alloys; Dental Leakage; Dental Materials; Dentin-Bonding Agents; Epoxy Resins; Glass Ionomer Cements; Humans; Image Processing, Computer-Assisted; Ink; Materials Testing; Metal Ceramic Alloys; Potassium Compounds; Resin Cements; Root Canal Therapy; Temperature; Time Factors; Water

To compare in vitro the influence of 3 cementation techniques on leakage and fracture strength of alumina all-ceramic crowns after cyclic loading in an artificial chewing simulator.. Forty-eight extracted molars were mounted in a way that simulates natural tooth mobility. Crowns (Procera Alumina, Nobel Biocare) were fabricated and inserted with either conventional cementation with zinc phosphate cement without pretreatment (group ZOP); cementation with a universal adhesive resin cement without pretreatment (group HYB); or adhesive bonding with composite resin after pretreatment of the tooth (dentin bonding agent) and the crown (airborne-particle abrasion and a special ceramic priming agent containing adhesive monomers that bond to metal-oxide ceramics) (group ADH). All specimens were stored in artificial saliva and subjected to 1.2 million load cycles in a dual-axis chewing simulator (Willytec). Eight specimens per group were subjected to compressive load until failure, while the remaining 8 specimens were stained and sectioned for measuring of dye penetration. One-way ANOVA and Tukey HSD were used for statistical analyses (alpha = .05).. Cementation techniques were significantly different (P = .009) in regard to mean load at failure. Fracture strength was significantly greater for ADH (mean load at fracture, 2,782 +/- 419 N) as compared to HYB (1,980 +/- 270 N) or ZOP (1,788 +/- 242 N). All groups differed significantly for leakage values (P < .001), with ADH showing the lowest mean leakage (0.04 +/- 0.07 mm), followed by HYB (0.96 +/- 0.16 mm) and ZOP (2.44 +/- 0.19 mm).. Cementation technique affects fracture strength and leakage of all-ceramic molar crowns. Fracture strengths were well above natural chewing forces for all cementation methods. However, adhesive bonding significantly increased fracture strength and improved marginal seal of alumina crowns.

Topics: Aluminum Oxide; Aluminum Silicates; Bite Force; Cementation; Composite Resins; Crowns; Dental Bonding; Dental Cements; Dental Leakage; Dental Porcelain; Dental Restoration Failure; Dentin-Bonding Agents; Humans; Materials Testing; Metal Ceramic Alloys; Methacrylates; Potassium Compounds; Resin Cements; Saliva, Artificial; Stress, Mechanical; Titanium; Zinc Phosphate Cement

The objective of this in vitro study was to evaluate the microleakage in ceramic inlays using different resin cements with margins in enamel and cementum/dentin interfaces.. Standard Class II MOD inlay cavities were prepared in 32 noncarious human premolars. The cavities were randomly divided into 4 groups (n = 8):. cavities were treated with Single Bond and incrementally filled with a composite resin (P60); Enforce group: feldspathic ceramic inlays were luted using Prime & Bond 2.1 and Enforce; RelyX group: inlays were cemented with Single Bond and RelyX ARC; Resin Cement group: ceramic inlays were bonded using Single Bond and Resin Cement. Ceramic inlays were previously treated with 10% hydrofluoric acid for 2 min, followed by silane application. After 7 days of storage in distilled water, teeth were submitted to thermocycling. After applying nail varnish, specimens were immersed in 2% aqueous solution of methylene blue for 8 h. After washing, teeth were cut into three sections through the restorations, and the leakage was assessed using a standardized score.. Data were submitted to statistical analysis using nonparametric tests (Mann-Whitney and Kruskal-Wallis). Dye leakage at margins in enamel was statistically lower (p < 0.01) than at cementum/dentin interfaces. RelyX ARC performed better (p < 0.05) than resin cement (enamel) and composite restorations (cementum/dentin). No other statistical differences were observed.. Both the material and the substrate interface influenced microleakage of the ceramic inlays.

Topics: Acid Etching, Dental; Aluminum Silicates; Bisphenol A-Glycidyl Methacrylate; Ceramics; Coloring Agents; Composite Resins; Dental Cavity Preparation; Dental Cementum; Dental Enamel; Dental Leakage; Dental Marginal Adaptation; Dentin; Dentin-Bonding Agents; Humans; Inlays; Materials Testing; Polyethylene Glycols; Polymethacrylic Acids; Potassium Compounds; Resin Cements; Silanes; Statistics, Nonparametric; Surface Properties; Time Factors

To evaluate the microleakage of Cerec 3, IPS e.max Press, and Turkom-Cera inlays cemented with three self-adhesive resin cements.. Ninety standardized class III MOD cavities were prepared in intact human mandibular third molars. Ceramic inlays were fabricated according to the manufacturer's instructions and were cemented using three self-adhesive resin cements (RelyX Unicem, Smartcem 2, and SpeedCEM). The specimens were stored in distilled water at 37°C for 24 h and subjected to 1000 thermocycles in water between 5°C and 55°C with a dwell time of 30 s. Subsequently, the specimens were subjected to 100,000 cycles of mechanical loading of 50 N at 1.6 Hz in 37°C water. The specimens were immersed in 0.5% basic fuchsine for 24 h and were sectioned using a low-speed diamond blade. The percentage of dye leakage at the tooth/restoration interface was measured and compared by Kruskal-Wallis tests with Bonferonni correction and Mann-Whitney U-tests at a significance level of p<0.05.. Microleakage at the RelyX Unicem interface was lower than that with Smartcem 2 and SpeedCEM resin cements (p<0.05). Microleakage of the Turkom-Cera system was higher than Cerec 3 and IPS e.max Press ceramic inlays (p<0.05).. Regardless of the ceramic system and self-adhesive resin cement used, dentin margins were associated with higher microleakage than enamel margins.

Topics: Acid Etching, Dental; Aluminum Oxide; Aluminum Silicates; Cementation; Ceramics; Coloring Agents; Dental Enamel; Dental Leakage; Dental Porcelain; Dentin; Humans; Inlays; Materials Testing; Potassium Compounds; Resin Cements; Rosaniline Dyes; Silanes; Stress, Mechanical; Surface Properties; Temperature; Time Factors; Water

The advantages of minimally invasive dentistry are well established, especially for direct restorations. However, when it comes to indirect restorations traditional tooth preparation designs are still advised by most manufacturers. The purpose of this in vitro study was to investigate the ability of a CAD/CAM machine (Cerec) to produce minimal preparation designs and identify limiting parameters. Crown preparations based on the proposed minimal design were made using phantom teeth. Gauged burs (Intensiv SA; Meissinger, Germany) and a paralleling device were used to standardize preparations. Cerec Scan/Cerec 3D was used for scanning and designing. The materials tested were a resin composite (Paradigm MZ100, 3M ESPE) and two ceramic materials (ProCAD, Ivoclar Vivadent, and VITA Mark II, Vita). The morphology, marginal integrity, and materials' integrity were examined. The design was subjected to an interactive process as material property limitations and constraints imposed by the system became apparent. SEM, optical microscopy, and transillumination were used for the qualitative control of the crowns. The results of this study showed that only the composite material produced acceptable crowns with intact margins for the minimal design initially proposed. The ceramic materials required a wider preparation design in order to produce acceptable crowns. Within the limitations of this study, the null hypothesis was partially rejected as it was found that only the composite material could produce acceptable crowns based on the proposed minimal design. It was also found that the materials' properties, the milling mode, and cutting instruments are determining factors in establishing the extent of the minimal preparation.

Topics: Aluminum Silicates; Ceramics; Coloring Agents; Composite Resins; Computer-Aided Design; Crowns; Dental Bonding; Dental Leakage; Dental Materials; Dental Porcelain; Dental Prosthesis Design; Humans; Microscopy; Microscopy, Electron, Scanning; Minimally Invasive Surgical Procedures; Potassium Compounds; Rosaniline Dyes; Surface Properties; Tooth Preparation, Prosthodontic; Transillumination; Zirconium