Influence of core material and occlusal contact pattern on fatigue behavior of different monolithic ceramic crowns.

This study evaluated the effect of substrate core materials and occlusal contact patterns on the fatigue mechanical behavior and stress distribution of single-unit ceramic crowns. One hundred and twenty monolithic crowns were fabricated from zirconia (YZ - IPS e.max ZirCAD, Ivoclar), lithium disilicate (LD - IPS e.

Crystallization by microwave energy: Effects on the survival probability of lithia-based glass ceramics.

This study evaluated the survival probabilities of two lithia-based glass-ceramics after final crystallization in a microwave furnace using conventional crystallization as a reference. Disc-shaped samples of a lithium silicate (LS, Celtra Duo) and a lithium disilicate (LD, e.max CAD) were prepared and divided into two groups according to the crystallization method (n = 30): microwave (M) or conventional furnaces (C).

Dental zirconia microwave-sintering followed by rapid cooling protocol.

Objectives: This study aimed to evaluate the effect of microwave sintering temperature and cooling rate (MS) on 3Y-TZP ceramics and its influence on the ceramic microstructure and mechanical properties. Specifically, to optimize the sintering process, reducing the total sintering time compared to conventional sintering.

Materials And Methods: Eighty-four pre-sintered Y-TZP discs (Vipi block Zirconn, VIPI) (ISO 6872) were divided into seven groups (n = 12) according to the sintering conditions: conventional sintering (CS) at 1530 °C for 120 min and microwave sintering at 1400 °C (MS1400) and 1450 °C (MS1450) for 15 min followed by different cooling conditions: rapid cooling (RC), cooling at 400 °C (C400) and 25 °C (C25).

Are Tooth and Ceramic Fractures Different Sides of the Same Coin? A Report of Two Clinical Cases.

Two clinical cases involving the fracture of a natural tooth and one of a ceramic crown are presented and discussed based on fractography principles. In the first case, a patient reported intense pain in a sound third molar where a longitudinal fracture was identified, and the tooth was extracted. In the second case, a posterior rehabilitation using a lithium silicate ceramic crown was carried out, and the patient returned after 1 year with a fractured piece of the crown.

New adhesive protocol improves shear bond strength of Polyetherketoneketone (PEKK).

Objective: Inert surface of Polyetherketoneketone (PEKK) jeopardizes resin bonding. This study aimed to present a new adhesive protocol to improve PEKK bonding.

Methods: A total of 360 PEKK blocks were milled, polished (maximum roughness of 0.

Polishing the bonding surface, before or after crystallization, does not alter the fatigue behavior of bonded CAD-CAM lithium disilicate.

The aim of this study was to assess if the finishing/polishing of the bonding surface of lithium disilicate ceramic, prior to or after crystallization, would affect the fatigue behavior of a bonded restorations. For this, lithium disilicate ceramic (IPS e.max CAD) discs (n = 15) were milled and randomly divided into 3 groups: CAD-CAM group which remained untouched; PRE group which received a finishing/polishing protocol (OptraFine system) prior to its crystallization; and POST group, which received the treatment after its crystallization.

Effect of Resin Cement at Different Thicknesses on the Fatigue Shear Bond Strength to Leucite Ceramic.

Objectives:  This study was performed to evaluate fatigue survival by shear test in the union of leucite-reinforced feldspathic ceramic using different cement thicknesses.

Materials And Methods:  Leucite-reinforced glass ceramics blocks were sectioned in 2-mm thick slices where resin cylinders were cemented. The samples were distributed in two experimental groups ( = 20) according to the cement thickness (60 and 300 μm).

Impact of different complete coverage onlay preparation designs and the intraoral scanner on the accuracy of digital scans.

Statement Of Problem: The trueness and precision of intraoral scanners (IOSs) and the effect of intracoronal restorations have been reported. However, studies addressing the accuracy of IOSs in reproducing different complete coverage onlay preparation designs are lacking.

Purpose: The purpose of this in vitro study was to evaluate the influence of complete coverage onlay preparation design and intraoral scanning devices on the accuracy of digital scans in terms of trueness and precision.

Effect of active application of self-etching ceramic primer on the long-term bond strength of different dental CAD/CAM materials.

Background: The objective of this in vitro study was to evaluate the effect of the active application of self-etching ceramic primer (ME&P) on the bond strength of different dental CAD/CAM materials (Lithium Disilicate ceramic (LD), Leucite ceramic (LE), Zirconia reinforced lithium silicate ceramic (ZLS), and Hybrid ceramic (HC)) with thermocycling aging.

Material And Methods: The samples were randomly divided into 16 groups (n = 20). Dual resin cement cylinders were made and light cured for 10 s (1.

One-piece, CAD/CAM, fiber-reinforced composite post and core: a case report.

Prefabricated glass fiber-reinforced composite posts have been widely used because of their esthetic properties and favorable biomechanical behavior; however, because they are prefabricated, they may not adapt to the anatomy of all root canals. This case report describes a procedure for restoring teeth with a custom, 1-piece, fiber-reinforced composite post and core fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM). The excellent adaptation of this custom endodontic post enables the use of a thinner, homogenous cement layer; in addition, it eliminates the need to construct a composite resin core build-up.

Fatigue behavior and stress distribution of molars restored with MOD inlays with and without deep margin elevation.

Objectives: This study evaluated the effect of deep margin elevation (DME) and restorative materials (leucite-reinforced glass-ceramics [C] vs. indirect resin composite [R]) on the fatigue behavior and stress distribution of maxillary molars with 2-mm deep proximal margins restored with MOD inlay.

Methods: Fifty-two extracted human third molars were randomly assigned into four groups (n = 13): C; DME + C; R; and DME + R.

Feldspathic and Lithium Disilicate Onlays with a 2-Year Follow-Up: Split-Mouth Randomized Clinical Trial.

The present study was a prospective, controlled, randomized, clinical short-term trial aiming to evaluate the clinical performance of adhesively luted, lithium disilicate and feldspathic glass-ceramics onlays over a period up to 2 years. A total of 11 patients (7 female, 4 male; age range: 18-60 years, mean age: 39 years) were selected for this study. Each patient received a maximum of two restorations per group in a split-mouth-design.

Mechanical Behavior of Different Restorative Materials and Onlay Preparation Designs in Endodontically Treated Molars.

This study evaluated the effect of the combination of three different onlay preparation designs and two restorative materials on the stress distribution, using 3D-finite element analysis. Six models of first lower molars were created according to three preparation designs: non-retentive (nRET), traditional with occlusal isthmus reduction (IST), and traditional without occlusal isthmus reduction (wIST); and according to two restorative materials: lithium-disilicate (LD) and nanoceramic resin (NR). A 600 N axial load was applied at the central fossa.

Novel speed sintered zirconia by microwave technology.

Objective: Continuous efforts have been made to hasten the zirconia densification process without compromising properties. This study evaluated the long-term structural durability of microwave speed-sintered zirconia (MWZ) relative to a conventionally sintered zirconia (CZ).

Methods: As-machined dental 3Y-TZP discs (Ø12 × 1.

Impact of simulated toothbrushing on surface properties of chairside CAD-CAM materials: An in vitro study.

Statement Of Problem: Chairside computer-aided design and computer-aided manufacturing (CAD-CAM) materials that do not require any firing steps are a promising option to expedite restoration production; however, little information is available to determine the most suitable material for each clinical situation.

Purpose: The purpose of this in vitro study was to evaluate the effect of simulated toothbrushing on surface gloss, roughness, and wear of chairside CAD-CAM materials.

Material And Methods: Disk-shaped specimens (n=15) were prepared of the following materials: ENA-VITA Enamic; LAV-Lava Ultimate; EMP-IPS Empress CAD; CER-Cerasmart; GRA-Grandio blocs.

Effect of microwave crystallization on the wear resistance of reinforced glass-ceramics.

This study compared the wear resistance of different reinforced glass-ceramics crystalized by conventional or microwave firing. The wear rate of three ceramics [one lithium disilicate ceramic (LD): IPS e.max CAD - Ivoclar Vivadent; and two zirconia reinforced lithium silicates: Suprinity - VITA Zahnfabrik (ZLS1) and Celtra Duo - Dentsply (ZLS2)] crystallized by conventional (c) or microwave (mw) firing protocols were collected according to the contact- [two-body (n = 20/gr)] and contact-free wear tests [three-body (n = 20/gr)].

Lithium Disilicate Crown, Zirconia Hybrid Abutment and Platform Switching to Improve the Esthetics in Anterior Region: A Case Report.

The hybrid abutment emerged as an alternative to maintain a stable and favorable volume of peri-implant tissue; it is composed of a mesostructure in ceramic and a metallic connection, which can be machined according to the peri-implant emergence profile. This case report presented the clinical steps for a dental implant with immediate provisional restoration, followed by the installation of implant-supported all-ceramic crowns with zirconia abutment and platform switching. A 40-year-old male patient was rehabilitated with an implant-supported ceramic crown in the region of element 11 and a ceramic veneer was cemented on the upper right central incisor.

Short communication: Influence of retainer configuration and loading direction on the stress distribution of lithium disilicate resin-bonded fixed dental prostheses: 3D finite element analysis.

The present study elucidates the mechanical performance of different designs of resin-bonded fixed dental prostheses made of lithium disilicate simulating masticatory loads of anterior or canine guidance. A three-dimensional model of maxilla was constructed containing central incisor and canine teeth, with edentulous space of the lateral incisor. Three designs of prosthesis were created: retained in central incisor (1-I), retained in canine (1-C) and fixed in both teeth (2-IC).

Influence of resin cement rigidity on the stress distribution of resin-bonded fixed partial dentures.

The mechanical properties of the adhesive cement used in resin-bonded fixed partial dentures (RBFPD) can modify the clinical performance of the rehabilitation. The goal of this study was to evaluate the influence of the elastic modulus of different cements on the stress distribution in RBFPD using finite element analysis. For that an anterior 3-unit prosthesis was modeled based in a stereolithography file.

Color Stability of Resin Cements Exposed to Aging.

The aim of this study was to evaluate the color stability of light-cured and dual-cured resin cements after artificial accelerated aging. Ten specimens (6-mm diameter and 2-mm thickness) for each of five resin cements were prepared: GC (dual-cured cement, GCem), Vb (light-cured cement, Variolink II only the base), Vbc (dual-cured cement, Variolink II base with catalyst), VV (light-cured cement, Variolink Veneer), and FR (flowable resin composite, light cured). The samples were polished and stored in an accelerated artificial aging machine for 308 hours (160 klx), with cycles of 120 minutes under light and 60 minutes in the dark.

Self-etching Primers vs Acid Conditioning: Impact on Bond Strength Between Ceramics and Resin Cement.

This study tested whether a self-etching surface agent and the conventional hydrofluoric acid (HF) would provide the same bonding capacity between resin cement and feldspathic (Fd) and lithium disilicate (Ld) ceramics. Ceramic blocks were cut with a low-speed diamond saw with water cooling (Isomet 1000, Buehler, Lake Bluff, IL, USA) into 20 blocks of 5 × 7 × 4 mm, which were ground flat in a polishing machine (EcoMet/AutoMet 250, Buehler) under water cooling. The blocks were randomly divided into eight groups (n=5), according to ceramic type (Ld or Fd), surface conditioning (HF + Monobond Plus or Etch and Prime), and aging by thermocycling (TC or absence-baseline).

Zirconia-Reinforced Lithium Silicate Ceramic - A 2-Year Follow-up of a Clinical Experience with Anterior Crowns.

The aim of this manuscript is to describe 2-year follow-up of a clinical experience with a zirconia-reinforced lithium silicate ceramic for an anterior rehabilitation with single metal-free crowns. The maxillary-central incisor teeth crowns were made by zirconium-reinforced lithium silicate and covered with porcelain were obtained with a digital impression with the intra-oral scanner of the CEREC system as a basis for virtual design, as well as a laminate for the left lateral maxillary incisor, based on a "double scanning" technique. Lithium silicate material seems to be a safe and satisfactory alternative for anterior crowns' rehabilitation.

Color stability of composites: effect of immersion media.

Coloring in drinks decreases the color stability of composite restorations, reducing their longevity. The purpose of this in vitro study was to evaluate the effect of immersion media on color stability of seven different composite resins (Solidex - Shofu, Resilab-Wilcos, Signum - Heraeus, Epricord - Tokuyama, Adoro - Ivoclar Vivadent, Admira - Voco and Sinfony - 3MESPE). Seven resin-based composite specimens were prepared using a cylindrical teflon mold 2 mm thick and 10 mm in diameter Fifteen specimens of each resin were light-cured according to manufacturers' instructions and randomized into 3 groups (n= 5) according to immersion media: coffee, cola beverage and water A digital spectrophotometer Easy Shade (VITA) was used to evaluate the color changes at baseline and 7 days after immersion in each solution.

Flexural strength of four adhesive fixed dental prostheses of composite resin reinforced with glass fiber.

Purpose: To evaluate the flexural strength of two fixed dental prosthesis (FDP) designs simulating frameworks of adhesive fixed partial prostheses, reinforced or not by glass fiber.

Materials And Methods: Forty specimens, made with composite resin, were divided into 4 groups according to the framework design and the presence of fiber reinforcement: A1 - occlusal support; A2: occlusal support + glass fiber; B1: occlusal and proximal supports; B2: occlusal and proximal supports + glass fiber. The specimens were subjected to the three-point bending test, and the data were submitted to two-way ANOVA and Tukey's test (5%).