Effect of neutralization and hydrofluoric acid precipitate remotion on the compressive strength of monolithic lithium disilicate crowns.

Background: The cleaning protocol for the ceramic surface after acid etching resulted in a decrease in bond strength and flexural strength of a glass ceramic. This study aims to evaluate the effect of different ceramic surface treatments after hydrofluoric acid etching (HF) on the compressive strength of monolithic lithium disilicate crowns.

Methods: Forty (40) human third molars received conventional full coverage preparation.

Effect of repeated firings and staining on the mechanical behavior and composition of lithium disilicate.

Objective: To evaluate the composition, flexural strength and fatigue behaviour of lithium disilicate ceramic (LD) after repeated firings and different staining techniques.

Methods: LD discs were fabricated and divided according to number of firing cycles and staining technique: CO - control, discs were crystallized (850°C/10min); SC - single-step characterization - crystallization and staining (applied with a thin brush) were performed in a single step with one firing cycle (850°C/10min); and DC - double-step characterization - crystallization firing cycle was performed first (850°C/10min), followed by staining firing cycle (770°C/90s). Specimens were fired two, four or six times (one crystallization firing cycle and one, three or five staining firing cycles), resulting into 9 groups (n=30): COII, COIV, COVI, SCII, SCIV, SCVI, DCII, DCIV and DCVI.

Effect of staining and repeated firing on the surface and optical properties of lithium disilicate.

Objective: Evaluate the effect of staining and repeated firings on color, translucency and surface proprieties of CAD/CAM lithium disilicate (LD).

Material And Methods: One hundred eighty LD discs were made (ISO 6872) and distributed in different groups (n = 20): control (CO)-no treatment; single-step characterization (SC)-crystallization and staining fired together; and double step characterization (DC)-crystallization and then staining. The samples were submitted to two, four, or six firings, resulting in nine groups: COII, COIV, COVI, SCII, SCIV, SCVI, DCII, DCIV, and DCVI.

Can low-fusing glass application affect the marginal misfit and bond strength of Y-TZP crowns?

To evaluate the effect of different surface treatments on the marginal misfit and retentive strength between Y-TZP crowns and an epoxy resin. Forty (40) epoxy resin (G10) abutments (height: 5mm, conicity: 60, finish line: large chamfer) with equal dimensions were milled and included in polyurethane to simulate the periodontal ligament. Next, 40 Y-TZP crowns (thickness: 1mm) were milled (Cerec in Lab) and randomly divided into four groups (n=10) according to the surface treatment: GS(glaze spray), GP(glaze powder/liquid), P(zirconia primer) and RS(tribochemical silica coating).

Effect of fatigue protocols on flexural strength of lithium disilicate bars with clamped-ends.

The aim of this study was compare the effect of two in vitro ageing protocols to intraoral aging on the flexural strength of a lithium disilicate (LD) ceramic bars with clamped ends. After polishing and crystallization, the both ends of the bars were cemented to a metallic device and subjected to mechanical cycling, thermomechanical cycling, or intraoral ageing. Ten volunteers used an intraoral device - similar to an occlusal splint with a balanced contact condition on the occlusal surface of the ceramic bar - during 8 h night time / 30 days.

Effect of air-abrasion regimens and fine diamond bur grinding on flexural strength, Weibull modulus and phase transformation of zirconium dioxide.

Purpose: This study evaluated the effect of air abrasion and polishing regimens on the flexural strength of yttrium stabilized polycrystalline tetragonal zirconia (Y-TZP).

Methods: From Y-TZP blocks (InCeram 2000 YZ Cubes; Vita Zahnfabrik, Bad Säckingen, Germany) 120 bars (25 mm × 4 mm × 1.2 mm) were obtained according to ISO 6872:2008 and randomly divided into 4 groups: Group C: (control) without surface treatment (n = 30); Group APA: Air abrasion with aluminum oxide (44 µm) (n = 30); Group SC: Silica-coating (CoJet, 30 µm) (n = 30); Group FD: Fine diamond bur (n = 30).

Influence of CAD-CAM diamond bur deterioration on surface roughness and maximum failure load of Y-TZP-based restorations.

Purpose: To investigate the influence of CAD-CAM diamond bur deterioration on surface roughness (Ra) and maximum failure load (Lf) of Y-TZP-based ceramic (YZ) substructures (SB) veneered with a feldspathic porcelain.

Methods: Two sets of burs (B1 and B2) were used to fabricate 30 YZ SB each in a CAD/CAM system (Cerec InLab). The SB were identified (1-30) according to the milling sequence (MS).

Heat treatment of pre-hydrolyzed silane increases adhesion of phosphate monomer-based resin cement to glass ceramic.

This study evaluated the influence of different forms of heat treatment on a pre-hydrolyzed silane to improve the adhesion of phosphate monomer-based (MDP) resin cement to glass ceramic. Resin and feldspathic ceramic blocks (n=48, n=6 for bond test, n=2 for microscopy) were randomly divided into 6 groups and subject to surface treatments: G1: Hydrofluoric acid (HF) 9.6% for 20 s + Silane + MDP resin cement (Panavia F); G2: HF 9.

Effect of ceramic thickness and shade on mechanical properties of a resin luting agent.

Purpose: This study aimed to investigate the influence of ceramic thickness and shade on the Knoop hardness and dynamic elastic modulus of a dual-cured resin cement.

Materials And Methods: Six ceramic shades (Bleaching, A1, A2, A3, A3.5, B3) and two ceramic thicknesses (1 mm, 3 mm) were evaluated.

Can heat treatment procedures of pre-hydrolyzed silane replace hydrofluoric acid in the adhesion of resin cement to feldspathic ceramic?

Purpose: To evaluate the influence of heat treatment (HT) procedures of a pre-hydrolyzed silane on bond strength of resin cement to a feldspathic ceramic.

Materials And Methods: Ceramic and composite blocks (N = 30) were divided into six groups (n = 5) and subjected to the following conditioning procedures: G1: 9.6% hydrofluoric acid (HF) for 20 s + silane (RelyX Ceramic Primer, 3M ESPE) + resin cement (Panavia F2.

Disinfection protocols to prevent cross-contamination between dental offices and prosthetic laboratories.

Control of cross-contamination between dental offices and prosthetic laboratories is of utmost importance to maintain the health of patients and dental office staff. The purpose of this study was to evaluate disinfection protocols, considering antimicrobial effectiveness and damage to the structures of prostheses. Solutions of 1% sodium hypochlorite, 2% chlorhexidine digluconate, 50% vinegar and sodium perborate were evaluated.

Bond strength of different resin cement and ceramic shades bonded to dentin.

Purpose: To evaluate the microtensile bond strength (MTBS) of ceramic cemented to dentin varying the resin cement and ceramic shades.

Materials And Methods: Two VITA VM7 ceramic shades (Base Dentine 0M1 and Base Dentine 5M3) were used. A spectrophotometer was used to determine the percentage translucency of ceramic (thickness: 2.

Effect of ceramic shade on the degree of conversion of a dual-cure resin cement analyzed by FTIR.

Objectives: The aim of this research was to evaluate the degree of monomer conversion of different resin cement shades when photocured under different feldspathic ceramic shades. The photocuring time was also evaluated as well as the translucency of each ceramic shade.

Methods: Three VITA VM7 ceramic shades (Base Dentin 0M1, Base Dentin 2M2 and Base Dentin 5M3) were used to determine the translucency percentage.

CO(2) Laser Surgery and Prosthetic Management for the Treatment of Epulis Fissuratum.

The aim of this study was to present a case report of the surgical removal of hyperplasia in the oral cavity, using carbon dioxide (CO(2)) laser radiation and rehabilitation with a complete denture. Epulis fissuratum occurs in complete denture patients, because a constant irritative action induces the mucosa to grow under poorly fitting dentures. These lesions must be removed, and to avoid a relapse, new complete dentures should be made to maintain healthy surgical tissues.

Effect of hydrofluoric acid etching duration on the roughness and flexural strength of a lithium disilicate-based glass ceramic.

The aim of this study was to examine the effect of different acid etching times on the surface roughness and flexural strength of a lithium disilicate-based glass ceramic. Ceramic bar-shaped specimens (16 mm x 2 mm x 2 mm) were produced from ceramic blocks. All specimens were polished and sonically cleaned in distilled water.

Evaluation of flexural resistance of a denture base acrylic resin reinforced with glass fiber and with composite resin.

The objective of this study was to evaluate the flexural strength of denture base resin reinforced with glass fibers and with a laboratorial composite resin. Group G1 was formed with specimens made of acrylic resin. Group G2 was formed with the same acrylic resin but reinforced with a glass-fiber system, and G3 was reinforced with the composite resin.

The effect of carbamide peroxide bleaching agents on the microhardness of dental ceramics.

This study examined the effect of 10% and 16% carbamide peroxide bleaching agents on the surface microhardness of micro-particulate feldspathic ceramics (VM7 and VM13, Vita Zahnfabrik). Forty specimens (8-mm diameter, 2-mm thickness) were divided into four groups (n=10): GI-VM7 + 10% Whiteness, G2-VM7 + 16% Whiteness, G3-VM13 + 10% and G4-VM13 + 16% Whiteness. The home-use bleaching agents were applied for 8 hours on 15 days, and the specimens were stored in distilled water at 37 degrees C.

Surface degradation of glass ceramics after exposure to acidulated phosphate fluoride.

Objective: This study evaluated the surface degradation effect of acidulated phosphate fluoride (APF) gel exposure on the glassy matrix ceramics as a function of time.

Material And Methods: Disc-shaped ceramic specimens (N = 120, 10/per ceramic material) were prepared in stainless steel molds (inner diameter: 5 mm, height: 2 mm) using 6 dental ceramics: 3 indicated for ceramic-fused-to-metal (Vita Omega 900, Carmen and Vita Titankeramik), 2 for all-ceramic (Vitadur Alpha and Finesse Low Fusing) and 1 for both types of restorations (IPS d.SIGN).

Evaluation of a new intraoral paralleling device for creating guiding planes: a pilot study.

Aim: The aim of the study was to assess the accuracy of a new intraoral paralleling device for creating proximal guiding planes for removable partial dental prostheses.

Methods And Materials: Thirty gypsum casts were divided into two groups in which the proximal surfaces of selected teeth were prepared using either a surveying device (Group 1) or the new ParalAB paralleling device (Group 2). In each cast guiding planes were prepared on the distal surface of the maxillary left canine (A), on the mesial and distal surfaces of the maxillary left second molar (B and C), and on the distal surface of the maxillary right canine (D).

Does adhesive resin application contribute to resin bond durability on etched and silanized feldspathic ceramic?

Purpose: To assess the effect of adhesive application and aging on the bond durability of resin cement to etched and silanized feldspathic ceramic.

Materials And Methods: Twenty blocks (6.4 x 6.

Effectiveness of six different disinfectants on removing five microbial species and effects on the topographic characteristics of acrylic resin.

Purpose: The aim of this study was to evaluate the effectiveness of disinfectant solutions (1% sodium hypochlorite, 2% chlorhexidine digluconate, 2% glutaraldehyde, 100% vinegar, tabs of sodium perborate-based denture cleanser, and 3.8% sodium perborate) in the disinfection of acrylic resin specimens (n = 10/group) contaminated in vitro by Candida albicans, Streptococcus mutans, S. aureus, Escherichia coli, or Bacillus subtilis as measured by residual colony-forming unit (CFU).

Evaluation of interface characterization and adhesion of glass ceramics to commercially pure titanium and gold alloy after thermal- and mechanical-loading.

Objectives: This study evaluated the effect of thermal- and mechanical-cycling on the shear bond strength of three low-fusing glassy matrix dental ceramics to commercial pure titanium (cpTi) when compared to conventional feldspathic ceramic fused to gold alloy.

Methods: Metallic frameworks (diameter: 5 mm, thickness: 4 mm) (N=96, n=12 per group) were cast in cpTi and gold alloy, airborne particle abraded with 150 microm aluminum oxide. Low-fusing glassy matrix ceramics and a conventional feldspathic ceramic were fired onto the alloys (thickness: 4 mm).

Bond strength durability of direct and indirect composite systems following surface conditioning for repair.

Purpose: This study evaluated the effect of surface conditioning methods and thermocycling on the bond strength between a resin composite and an indirect composite system in order to test the repair bond strength.

Materials And Methods: Eighteen blocks (5 x 5 x 4 mm) of indirect resin composite (Sinfony) were fabricated according to the manufacturer's instructions. The specimens were randomly assigned to one of the following two treatment conditions (9 blocks per treatment): (1) 10% hydrofluoric acid (HF) for 90s (Dentsply) + silanization, (2) silica coating with 30-im SiOx particles (CoJet) + silanization.

Shear bond strength of a ceramic to Co-Cr alloys.

Statement Of Problem: Different combinations of Co-Cr alloys bonded to ceramic have been used in dentistry; however, the bond strength of ceramic to metal can vary because of different compositions of these alloys.

Purpose: The purpose of this study was to evaluate the shear bond strength of a dental ceramic to 5 commercially available Co-Cr alloys.

Material And Methods: Five Co-Cr alloys (IPS d.

Effect of cast rectifiers on the marginal fit of UCLA abutments.

Objectives: This study assessed the effect of cast rectifiers on the marginal misfit of cast UCLA abutments compared to premachined UCLA abutments. The influence of casting and porcelain baking on the marginal misfit of these components was also investigated.

Methods: Two groups were analyzed: test group - 10 cast UCLA abutments, finished with cast rectifier and submitted to ceramic application; control group - 10 premachined UCLA abutments, cast with noble metal alloy and submitted to ceramic application.