Influence of dentin bonding agents and polymerization modes on the bond strength between translucent fiber posts and three dentin regions within a post space

Statement of problem. Debonding is the most frequent failure encountered with translucent fiber posts and usually occurs along the post space dentin-adhesive interface

Influence of different surface treatments on the short-term bond strength and durability between a zirconia post and a composite resin core material

Statement of problem. Reliable bonding between zirconia posts and composite resin core materials is difficult to achieve because of the smooth surface texture and lack of silica content of zirconia Posts

Evaluation of Surface Topography of Zirconia Ceramic After Er:YAG Laser Etching

Objective: The aim of this study is to evaluate the effect of Erbium: yttrium-aluminum-garnet (Er:YAG) laser with different pulse lengths on the surface roughness of zirconia ceramic and airborne particle abrasion. Background data: Er:YAG laser treatment is expected to be an alternative surface treatment method for zirconia ceramics; however, the parameters and success of the application are not clear. Methods: One hundred and forty zirconia discs (diameter, 10 mm; thickness, 1.2 mm) were prepared by a computer-aided design and computer-aided manufacturing (CAD/CAM) system according to the manufacturer's instructions. Specimens were divided into 14 groups (n=10). One group was left as polished control, one group was air-particle abraded with Al2O3 particles. For the laser treatment groups, laser irradiation was applied at three different pulse energy levels (100, 200, and 300 mJ) and for each energy level at four different pulse lengths; 50, 100, 300, and 600 mu s. Surface roughness was evaluated with an optical profilometer and specimens were evaluated with scanning electron microscopy (SEM). Results: Data was analyzed with one way ANOVA and Tukey multiple comparison tests (alpha=0.05). For the 100 and 200 mJ laser etching groups, 50 and 100 mu s laser duration resulted in significantly higher surface roughness compared with air-particle abrasion (p0.05). For the 300 mJ laser etching groups; there was no statistically significant difference among the R-a values of 50 mu s, 100 mu s, 300 mu s, 600 mu s, and air-particle abrasion groups (p>0.05). Conclusions: In order to increase surface roughness and promote better bonding to resin luting agents, Er:YAG laser etching may be an alternative to air-particle abrasion for zirconia ceramics. However, high levels of pulse energy and longer pulse length may have an adverse effect on micromechanical locking properties, because of a decrease in surface roughnes

Simultaneous replacement of maxillary central incisors with Cerec biogeneric reference technique: A case report

Biogeneric Reference Technique (BRT) of the CEREC 3D v.3.8 software is an effective technique for single anterior ceramic crowns because it provides computer-controlled match of the tooth form to the contralateral tooth. BRT also enables the fabrication of two or more anterior all-ceramic crowns simultaneously. This clinical report demonstrates the clinical application of BRT for designing and milling two central incisors in one appointment using a single optical impression. After completing the virtual design of the first central incisor, it was copied and a mirror image was created. The second central incisor was designed using this replicated image and therefore a computer-controlled symmetry was obtained. The crowns were milled from monolithic feldspathic ceramic blocks and adhesively luted with dual-cured resin cement following dentin conditioning. At the two-year follow-up appointment, the restorations were intact, no adverse effects were noted, and the resultant appearance was highly satisfactory for the patient. A step-by-step protocol is described from design to cementation of these restorations

Evaluation of five CAD/CAM materials by microstructural characterization and mechanical tests: a comparative in vitro study

Abstract Background Polymer infiltrated ceramics and nano-ceramic resins are the new restorative materials which have been developed in order to enhance the adverse properties of glass-matrix ceramics and resin composites. The aim of the present in vitro study was to evaluate the characteristics of various CAD/CAM materials through mechanical, microstructural, and SEM analysis. Methods Five test groups (n = 22) were formed by using the indicated CAD/CAM blocks: VITA Enamic (VITA Zahnfabrik), Lava Ultimate (3 M ESPE), IPS e.max CAD (Ivoclar Vivadent), IPS Empress CAD (Ivoclar Vivadent), and VITA Mark II (VITA Zahnfabrik). Two specimens from each test group were used for XRD and EDS analysis. Remaining samples were divided into two subgroups (n = 10). One subgroup specimens were thermocycled (5 °C to 55 °C, 30s, 10,000 cycles) whereas the other were not. All of the specimens were evaluated in terms of flexural strength, Vickers hardness, and fracture toughness. Results were statistically analyzed using two-way ANOVA, one-way ANOVA, Tukey’s HSD, and Student’s t tests (α = .05). Fractured specimens were evaluated using SEM. Results The highest Vickers microhardness value was found for VITA Mark II (p < .001), however flexural strength and fracture toughness results were lowest conversely (p < .05). IPS e.max CAD was found to have the highest flexural strength (p < .001). Fracture toughness of IPS e.max CAD was also higher than other tested block materials (p < .001). Lava Ultimate and VITA Enamic’s mechanical properties were affected negatively from thermocycling (p < .05). Microhardness, flexural strength, and fracture toughness values of Lava Ultimate and VITA Enamic were found to be similar to VITA Mark II and IPS Empress CAD groups. Conclusions It should be realised that simulated aging process seem to affect ceramic-polymer composite materials more significantly than glass ceramics

Evaluation of five CAD/CAM materials by microstructural characterization and mechanical tests: a comparative in vitro study

Background: Polymer infiltrated ceramics and nano-ceramic resins are the new restorative materials which have been developed in order to enhance the adverse properties of glass-matrix ceramics and resin composites. The aim of the present in vitro study was to evaluate the characteristics of various CAD/CAM materials through mechanical, microstructural, and SEM analysis