Is It Necessary to Photoactivate the Adhesive System Inside Ceramic Laminate Veneers in a Luting Procedure?

Purpose: To investigate the need for photoactivation of the adhesive system inside ceramic laminates before the luting procedure and to evaluate the color stability, nanohardness, and elastic modulus of the adhesive interface activated with singlewave and polywave light-curing units.

Materials And Methods: A total of 44 lithium disilicate ceramic veneers (7.0 mm × 8.

Effect of previous photoactivation of the adhesive system on the color stability and mechanical properties of resin components in ceramic laminate veneer luting.

Statement Of Problem: The color stability and mechanical properties of luting agents influence the esthetics and longevity of ceramic restorations. However, studies evaluating the color changes and mechanical properties of luting agents under ceramic laminates activated by using different methods are lacking.

Purpose: The purpose of this in vitro study was to evaluate the effects of different modes of photoactivation on the nanohardness and elastic modulus of resin cements and dental adhesives and on the color stability of ceramic laminate veneers.

Effect of different aging methods on the mechanical behavior of multi-layered ceramic structures.

Objective: To evaluate the effect of two aging methods (mechanical cycling and autoclave) on the mechanical behavior of veneer and framework ceramic specimens with different configurations (monolithic, two and three-layers).

Methods: Three ceramics used as framework for fixed dental prostheses (YZ-Vita In-Ceram YZ; IZ-Vita In-Ceram Zirconia; AL-Vita In-Ceram AL) and two veneering porcelains (VM7 and VM9) were studied. Bar-shaped specimens were produced in three different designs: monolithic, two layers (porcelain-framework) and three layers (porcelain-framework-porcelain).

Systematic approach to preparing ceramic-glass composites with high translucency for dental restorations.

Objective: Ceramic composites are promising materials for dental restorations. However, it is difficult to prepare highly translucent composites due to the light scattering that occurs in multiphase ceramics. The objective of this work was to verify the effectiveness of a systematic approach in designing specific glass compositions with target properties in order to prepare glass infiltrated ceramic composites with high translucency.

Effect of fiber addition on slow crack growth of a dental porcelain.

Aims: To evaluate the effect of the processing method (conventional sintering, S, and heat-pressing, HP) and addition of potassium titanate fibers, PTF, on the microstructure, mechanical properties (flexural strength, σf, and Weibull parameters, m and σ5%), slow crack growth parameters n (stress corrosion susceptibility coefficient), and optical properties (translucency parameter, TP, and opalescence index, OI) of a feldsphatic dental porcelain.

Methods: Disks (n = 240, Ø12 × 1 mm) of porcelain (Vintage-Halo, Shofu) were produced using S and HP methods with and without addition of 10 wt% (conventional sintering) or 5 wt% (heat-pressing) of PTF. For the S method, porcelain was sintered in a conventional furnace.

Flexural strength and failure modes of layered ceramic structures.

Objective: To evaluate the effect of the specimen design on the flexural strength (σ(f)) and failure mode of ceramic structures, testing the hypothesis that the ceramic material under tension controls the mechanical performance of the structure.

Methods: Three ceramics used as framework materials for fixed partial dentures (YZ--Vita In-Ceram YZ; IZ--Vita In-Ceram Zirconia; AL--Vita In-Ceram AL) and two veneering porcelains (VM7 and VM9) were studied. Bar-shaped specimens were produced in three different designs (n=10): monolithic, two layers (porcelain-framework) and three layers (TRI) (porcelain-framework-porcelain).

Determination of the slow crack growth susceptibility coefficient of dental ceramics using different methods.

This study compared three methods for the determination of the slow crack growth susceptibility coefficient (n) of two veneering ceramics (VM7 and d.Sign), two glass-ceramics (Empress and Empress 2) and a glass-infiltrated alumina composite (In-Ceram Alumina). Discs (n = 10) were prepared according to manufacturers' recommendations and polished.

Effect of the microstructure on the lifetime of dental ceramics.

Objectives: To evaluate the effect of the microstructure on the Weibull and slow crack growth (SCG) parameters and on the lifetime of three ceramics used as framework materials for fixed partial dentures (FPDs) (YZ - Vita In-Ceram YZ; IZ - Vita In-Ceram Zirconia; AL - Vita In-Ceram AL) and of two veneering porcelains (VM7 and VM9).

Methods: Bar-shaped specimens were fabricated according to the manufacturer's instructions. Specimens were tested in three-point flexure in 37°C artificial saliva.

Effect of test environment and microstructure on the flexural strength of dental porcelains.

Purpose: The objective of this study was to verify the influence of test environment on the flexural strength of dental porcelains with distinct microstructures.

Material And Methods: Disk-shaped specimens from three dental porcelains with distinct leucite content (VM: zero; CE: 12; NS: 22 vol%) were manufactured and tested for biaxial flexural strength in air and immersed in artificial saliva. The results were analyzed by means of two-way ANOVA and Tukey's test (α= 0.

Slow crack growth and reliability of dental ceramics.

Objective: To determine the slow crack growth (SCG) and Weibull parameters of five dental ceramics: a vitreous porcelain (V), a leucite-based porcelain (D), a leucite-based glass-ceramic (E1), a lithium disilicate glass-ceramic (E2) and a glass-infiltrated alumina composite (IC).

Methods: Eighty disks (Ø 12 mm × 1.1mm thick) of each material were constructed according to manufacturers' recommendations and polished.

Al2O3/GdAlO3 fiber for dental porcelain reinforcement.

The aim of this study was to test the hypothesis that the addition of continuous or milled GdAlO3/Al2O3 fibers to a dental porcelain increases its mechanical properties. Porcelain bars without reinforcement (control) were compared to those reinforced with long fibers (30 vol%). Also, disk specimens reinforced with milled fibers were produced by adding 0 (control), 5 or 10 vol% of particles.

Effect of processing induced particle alignment on the fracture toughness and fracture behavior of multiphase dental ceramics.

Objective: To investigate the processing induced particle alignment on fracture behavior of four multiphase dental ceramics (one porcelain, two glass-ceramics and a glass-infiltrated-alumina composite).

Methods: Disks (Ø12 mm x 1.1mm-thick) and bars (3 mm x 4 mm x 20 mm) of each material were processed according to manufacturer instructions, machined and polished.

Effect of ion exchange on strength and slow crack growth of a dental porcelain.

Objectives: To determine the effect of ion exchange on slow crack growth (SCG) parameters (n, stress corrosion susceptibility coefficient, and sigma(f0), scaling parameter) and Weibull parameters (m, Weibull modulus, and sigma(0), characteristic strength) of a dental porcelain.

Methods: 160 porcelain discs were fabricated according to manufacturer's instructions, polished through 1 microm and divided into two groups: GC (control) and GI (submitted to an ion exchange procedure using a KNO3 paste at 470 degrees C for 15 min). SCG parameters were determined by biaxial flexural strength test in artificial saliva at 37 degrees C using five constant stress rates (n=10).

Subcritical crack growth in porcelains, glass-ceramics, and glass-infiltrated alumina composite for dental restorations.

The objective was to compare fracture toughness (K(Ic)), stress corrosion susceptibility coefficient (n), and stress intensity factor threshold for crack propagation (K(I0)) of two porcelains [VM7/Vita (V) and d.Sign/Ivoclar (D)], two glass-ceramics [Empress/Ivolcar (E1) and Empress2/Ivlocar (E2)] and a glass-infiltrated alumina composite [In-Ceram Alumina/Vita (IC)]. Disks were constructed according to each manufacturer's processing method, and polished before induction of cracks by a Vickers indenter.

Influence of leucite content on slow crack growth of dental porcelains.

Objectives: To determine the stress corrosion susceptibility coefficient, n, of seven dental porcelains (A: Ceramco I; B: Ceramco-II; C: Ceramco-III; D: d.Sign; E: Cerabien; F: Vitadur-Alpha; and G: Ultropaline) after aging in air or artificial saliva, and correlate results with leucite content (LC).

Methods: Bars were fired according to manufacturers' instructions and polished before induction of cracks by a Vickers indenter (19.

Influence of pH on slow crack growth of dental porcelains.

Objectives: To evaluate the effect of pH of storage medium on slow crack growth (SCG) parameters of dental porcelains.

Methods: Two porcelains were selected: with (UD) and without (VM7) leucite particles, in order to assess if the microstructure would affect the response of the material to the pH variation. Disc specimens were produced following manufacturers' instructions.

Stress intensity factor threshold in dental porcelains.

The stress intensity factor threshold (KI0) is related to the stress level at which cracks start to grow stably, causing the weakening of porcelain prostheses during their use. The values of KI0 of seven dental porcelains (with and without reinforcing leucite crystal, KAlSi2O6) stored in air (22 degrees C, 60% relative humidity) and artificial saliva (37 degrees C) were determined by measuring the crack growth velocity of radial cracks generated at the corner of Vickers indentations. The results of KI0 were correlated with the leucite content, fracture toughness (KIc), and chemical composition of the porcelains.

Effect of ion exchange on hardness and fracture toughness of dental porcelains.

The objective of this study was to evaluate the effect of ion exchange, IE, on fracture toughness K(Ic) and hardness H of five dental porcelains with different microstructures: B, Ceramco II/Dentstply; C, Finesse/Dentsply; Cb, Cerabien/Noritake; D, d.Sign/Ivoclar; V, Vitadur Alpha/Vita. Specimens were sintered according to manufacturers' instructions, n = 10.

Influence of the finishing technique on surface roughness of dental porcelains with different microstructures.

Unlabelled: This study compared the surface roughness of 4 dental porcelains with different microstructures (d.Sign-D, Finesse-F, Noritake-N and Symbio-S) using varied surface treatments. The porcelain surfaces were submitted to the following surface treatments: 1) g (glazing only); 2) rg (polishing with a rubber wheel before glazing); 3) 2g (reglazing); 4) r (rubber wheels); 5) rp (rubber wheels + diamond paste); 6) d (sandpaper discs) and 7) dp (sandpaper discs + diamond paste).

Relationship between fracture toughness and flexural strength in dental porcelains.

The aim of this study was to investigate the correlation between fracture toughness (K(Ic)) and flexural strength (FS) in dental porcelains. Porcelains with different leucite contents and clinical indications were used (A, B, C, D, and E). K(Ic) was determined by surface crack in flexure method (SCF) and FS was determined by four-point-bending test.

Correlation between fracture toughness and leucite content in dental porcelains.

Objectives: To determine the correlation between fracture toughness and leucite content in dental porcelains. The mechanisms by which leucite influences the fracture toughness of dental porcelains were also investigated.

Methods: Six porcelains were tested: A (Ceramco I/Dentsply), B (Ceramco II/Dentsitply), C (Finesse/Dentsply), D (d.