Effect of sintering time on the marginal and internal fit of monolithic zirconia crowns containing 3-4 mol% YO.

Background: Short-term sintering may offer advantages including saving time and energy but there is limited evidence on the effect that altering sintering time has on the accuracy of monolithic zirconia crowns. The purpose of this in vitro study was to investigate the effect of shortened sintering time on the marginal and internal fit of 3Y-TZP and 4Y-TZP monolithic crowns.

Methods: Sixty monolithic zirconia crowns were fabricated for the maxillary first molar tooth on the prefabricated implant abutment.

Zirconia Cantilever Fixed Dental Prostheses Supported by One or Two Implants: An In Vitro Study on Mechanical Stability and Technical Outcomes.

Purpose: To evaluate the mechanical stability of highly translucent zirconia (Zr) cantilevered fixed dental prostheses (cFDPs) and to investigate the influence of the number of implants (one versus two) supporting cFDPs with different restorative materials on their mechanical stability and load-bearing capacity.

Materials And Methods: Thirty-two specimens consisting of implant-supported prostheses embedded in resin blocks were fabricated. Sixteen specimens received one implant (bone-level implant, 4.

Effect of irrigants on the color stability, solubility, and surface characteristics of calcium-silicate based cements.

Objectives: This study aimed to investigate the color stability, solubility, and surface characteristics of 3 calcium silicate-based cements (CSCs) after immersion in different solutions.

Materials And Methods: ProRoot white mineral trioxide aggregate (MTA), Biodentine, and Endosequence Root Repair Material (ERRM) were placed in cylindrical molds and stored at 37°C for 24 hours. Each specimen was immersed in distilled water, 5% sodium hypochlorite (NaOCl), 2% chlorhexidine, or 0.

Mechanical Stability of Zirconia Implant Abutments Supporting Cantilevered Fixed Dental Prostheses After Fatigue Loading.

Purpose: To evaluate the mechanical stability and complication rates of titanium (Ti) or zirconia (Zr) abutments restored with cantilevered fixed dental prostheses (cFDPs) when supported by 1 or 2 implants.

Materials And Methods: A total of 32 samples were fabricated. Half of the samples received 1 implant, and the other half received 2 implants (Bone Level Implant, Ø 4.

Effect of Anti-Rotational Abutment Features and Novel Computerized Fabrication Techniques on the Marginal Fit of Implant-Supported Metal Copings.

Purpose: An in vitro study to compare the marginal fit of cobalt-chromium (Co-Cr) metal copings fabricated with selective laser melting (SLM), computer-aided design and computer-aided manufacturing (CAD/CAM) milling, and lost-wax (LW) techniques, on abutments with two different antirotational features.

Materials And Methods: A total of 60 stainless steel abutments with the same length and convergence angles were fabricated using a numerical control machining. Half of the abutments had one flat plane, while the other half had three grooves as an antirotation feature.

Biomechanical Behavior of Implants with a Sloped Marginal Configuration.

Purpose: To evaluate the biomechanical behavior of implants with different neck designs.

Materials And Methods: Finite element models of implants with two different neck designs (OsseoSpeed EV and OsseoSpeed Profile EV) were generated. Implants and abutments were subjected to buccally and lingually directed 30-degree oblique loads of 200 N.

The Fracture Resistance of Composite Core Materials Reinforced by Varying Fiber Orientations.

This study aimed to compare the fracture resistance of composite core materials reinforced with varying fiber orientations. Composite cores of endodontically treated roots were prepared by reinforcing with woven fiber discs, fiber strips, or fiber chips, and their fracture resistance was compared to those with no reinforcement using a universal test machine (Instron, Lloyd Instruments). Reinforcement with fiber chips showed the highest fracture resistance and 50% retrievability, while no reinforcement showed the lowest fracture resistance with 62.

Effect of timing of post space preparation on the apical seal when using different sealers and obturation techniques.

Background/purpose: To prepare the post apace, some of the root-canal filling material has to be removed, which can affect the apical seal. The aim of this study was to compare the effect of immediate post space preparation to that of delayed post space preparation on apical sealing using three different endodontic sealers and obturation techniques.

Materials And Methods: In total, 90 decrowned single-rooted human teeth were studied.

Comparison of implant versus tooth-supported zirconia-based single crowns in a split-mouth design: a 4-year clinical follow-up study.

Objectives: This study aims to evaluate the 4-year clinical performance of tooth versus implant-supported single-unit zirconia crowns (LAVA™) placed on posterior region.

Materials And Methods: Twenty-four patients (10 men and 14 women) who had received 48 single crowns (24 implant-supported and 24 tooth-supported) from January 2007 to December 2009, were included. California Dental Association (CDA) quality assessment system, plaque and gingival index scores were used to evaluate the performance of the crowns at baseline and at all follow-up examinations.

The Effect of Water or Wax-based Binders on the Chemical and Morphological Characteristics of the Margin Ceramic-Framework Interface.

This study evaluated the effect of binder choice in mixing ceramic powder on the chemical and morphological features between the margin ceramic-framework interfaces. Titanium and zirconia frameworks (15 x 5 x 0.5 mm3) were veneered with margin ceramics prepared with two different binders, namely a) water/conventional or b) wax-based.

Zirconia-based crowns up to 5 years in function: a retrospective clinical study and evaluation of prosthetic restorations and failures.

Purpose: The purpose of this retrospective study was to evaluate the 5-year clinical performance and failure rate of single- or multiple-unit zirconia-based crowns.

Materials And Methods: A total of 148 patients (39 men and 109 women, mean age: 46.9 ± 10.

Effect of engraving speeds of CO₂ laser irradiation on In-Ceram Alumina roughness: a pilot study.

Objectives: The aim of the study was to determine the effect of CO₂ laser on surface roughness of In-Ceram-Alumina-ceramic.

Materials And Methods: Four aluminum-oxide ceramic disc specimens were prepared of In-Ceram Alumina. Discs received CO₂ laser irradiation with different engraving speeds (100, 400, 600 and 800 mm/min) as a surface treatment.

Effect of mixing techniques on bacterial attachment and disinfection time of polyether impression material.

Objective: The aim of this study was 2-fold. The first aim was to evaluate the effects of mixing technique (hand-mixing or auto-mixing) on bacterial attachment to polyether impression materials. The second aim was to determine whether bacterial attachment to these materials was affected by length of exposure to disinfection solutions.

Correlation between clinical and magnetic resonance imaging findings in the treatment of anterior disc displacement.

Purpose: This study aimed to compare the agreement of clinical examination and magnetic resonance imaging (MRI) results before and after the treatment of nonreduction temporomandibular joint (TMJ) disc displacement.

Materials And Methods: The study group consisted of 22 patients, each with anterior disc displacement without reduction in at least one TMJ. Diagnosis was performed clinically and with MRI prior to treatment.

Effect of preparation taper and height on strength and retention of zirconia crowns.

This study aimed to determine the effect of the taper and height of tooth preparations on the fracture strength and retention of zirconia crowns. Sixty-four dies were designed to simulate a crown preparation. Dies were machined with a height of either 4 mm (n = 16) or 7 mm (n = 16) and a taper of either 6 degrees (n = 16) or 20 degrees (n = 16).

Effect of repeated firings on microtensile bond strength of In-Ceram Alumina with two different veneering ceramics.

Microtensile bond strengths of In-Ceram Alumina cores veneered with two ceramics after different numbers of firing cycles were evaluated. After In-Ceram Alumina cores were fabricated, they were veneered with either Vitadur Alpha or Vita VM7. A control group of each core-veneer combination was fired twice, and a second group was fired five times to induce thermal fatigue.

Comparison of 3 luting agents on retention of implant-supported crowns on 2 different abutments.

Background: For fixed prostheses, retention is one of the most important factors for clinical success. It is unknown whether grooves that increase surface area of implant abutment while retaining the diameter and wall height provide greater uniaxial retention force. The purpose of this study was to determine the retention of 3 different cements on 2 implant abutments with different surface configurations.

Does the surface treatment affect the bond strength of various fibre-post systems to resin-core materials?

Objectives: The aim of this study was to evaluate the effects of surface treatments on bond strength of resin-core materials to three different types of fibre posts.

Methods: Prefabricated glass (FRC Postec, Ivoclar), quartz (DT light, Bisco) and individually formed glass (Everstick, Stick Tech) fibre posts with a coronal diameter of 1.5 mm were randomly divided into three groups according to the surface treatment performed.

Bonding of resin core materials to lithium disilicate ceramics: the effect of resin cement film thickness.

The aim of this study was to investigate the effect of different resin cement film thicknesses on the shear bond strength of resin core materials to lithium disilicate ceramics. Forty IPS Empress 2 ceramic disks were bonded to the core materials (Bis-core and Smile) with resin cement film thicknesses of 50 or 100 μm. Shear bond strength was measured using a universal testing machine.

Influence of thermomechanical fatigue loading on the fracture resistance of all-ceramic posterior crowns.

This study evaluated the fracture resistance and the survival rate of different all-ceramic crowns in-vitro after thermomechanical fatigue loading in comparison to porcelain-fused-to-metal posterior crowns. Sixteen crowns for human mandibular first molars were made of each of the following: Cercon, IPS-Empress 2 In-Ceram Zirconia, Procera AllZircon and porcelain-fused-to-metal. Half of the specimens of each group was thermocycled and dynamically loaded using a chewing simulator All samples were thereafter tested for the maximum fracture resistance.

Effect of different polymerization methods on the cytotoxicity of dental composites.

Objectives: The aim of this study was to compare the cytotoxic effects of various dental composites polymerized with two different curing units.

Methods: Disc-shaped test samples of composites Filtek Z250, Filtek A110, Filtek P60, Filtek Supreme, and SDI Rok were polymerized using one quartz tungsten halogen (QTH) and one light emitting diode (LED) light curing unit (LCU), namely Optilux 501 (QTH) and Elipar Freelight 2 (LED). L-929 mouse fibroblast cultures (3x10(4) cells/ml) were incubated with the samples in 96 well culture plates for evaluation after 8, 24, 48, 72 h.

Numerical simulation of the effect of time-to-loading on peri-implant bone.

Purpose: To evaluate the effect of time-to-loading on trabecular bone around single-tooth dental implants using numerical solutions based on computer models.

Materials And Methods: A global model with a coarse mesh carrying a Straumann dental implant (043.033S; Institut Straumann, Basel, Switzerland) was created.

Surface roughness and bond strengths of glass-infiltrated alumina-ceramics prepared using various surface treatments.

Objectives: To compare and evaluate effects of CO(2) laser and conventional surface treatments on surface roughness and shear bond strengths of glass-infiltrated alumina-ceramics to dentin.

Methods: One hundred fifty ceramic discs of In-Ceram Spinell, In-Ceram Alumina and In-Ceram Zirconia (n=50) were prepared. Specimens which were divided into 5 groups (n=10) were untreated (control group), sandblasted, airborne particle abraded, etched with 9.

Biomechanical aspects of bone-level diameter shifting at implant-abutment interface.

Purpose: To evaluate the effect of diameter shifting at implant-abutment interface on load distribution at periimplant bone and within implant-abutment complex.

Materials: Eight different implant-abutment connections were designed and simulated numerically. Implant-abutment microgap at bone level was hypothetically set-off inward toward the central axis of implant to create "diameter shifting" or "platform switching" concept.