Direct veneer

Successful recruitment in corals is important for the sustenance of coral reefs, and is considered a demographic bottleneck in the recovery of reef populations following disturbance events. Yet several factors influence larval settlement behaviour, and here we quantified thresholds associated with light attenuation and accumulated sediments on settlement substrates. Sediments deposited on calcareous red algae (CRA) directly and indirectly impacted coral settlement patterns. Although not avoiding direct contact, Acropora millepora larvae were very reluctant to settle on surfaces layered with sediments, progressively shifting their settlement preference from upward to downward facing (sediment-free) surfaces under increasing levels of deposited sediment...

BACKGROUND AND OBJECTIVES: Nowadays, the integrated CAD/CAE systems are favored solutions for the design of simulation models for casting metal substructures of metal-ceramic crowns. The worldwide authors have used different approaches to solve the problems using an expert system. Despite substantial research progress in the design of experts systems for the simulation model design and manufacturing have insufficiently considered the specifics of casting in dentistry, especially the need for further CAD, RE, CAE for the estimation of casting parameters and the control of the casting machine...

Direct composite resin restorations have been recognized for their valuable clinical service and respect of intact hard tissue. The cost-effectiveness and inherent minimally invasive approach of resin-based materials means that they are also gaining popularity for use in computer-aided design/computer-aided manufacture (CAD/CAM) procedures. Several cases from the student clinics at the Herman Ostrow School of Dentistry of USC are presented that could have been resolved either with direct composite resin restorations or with indirect porcelain veneers...

Objective: The aim of the study was to make an inventory of current literature on the bond strength between zirconia and veneering porcelain after surface treatment of zirconia by grinding with diamond bur and/or with airborne-particle abrasion. Material and methods: The literature search for the present review was made following recommended guidelines using acknowledged methodology on how to do a systematic review. The electronic databases PubMed, Cochrane Library, and Science Direct were used in the present study...

OBJECTIVE: Laser modalities and direct metal laser sintering (DMLS) have a potential to enhance micromechanical bonding between dental super- and infrastructures. However, the effect of different manufacturing methods on the metal-ceramic bond strength needs further evaluation. We investigated the effect of surface treatment with Er:YAG, Nd:YAG, and Ho:YAG lasers on the shear bond strength (SBS) of high-fusion dental porcelains (Vita and G-Ceram) to infrastructures prepared with DMLS in vitro settings...

In the direct-indirect composite technique, composite is applied to a nonretentive tooth preparation (eg, a noncarious cervical lesion or a veneer/inlay/onlay preparation) without any bonding agent, sculpted to a primary anatomic form, and light-cured. The partially polymerized restoration is then removed from the preparation and finished and tempered extraorally chairside. The finished inlay is bonded to the preparation using a resin-based luting agent. Advantages of this technique include enhanced physical and mechanical properties afforded by the extraoral chairside tempering process because of increased monomer conversion, and greater operator control over the final marginal adaptation, surface finishing and polishing, and anatomy of the restoration, given that these elements are defined outside of the patient's mouth...

This case report presents a retrieval analysis of a screw-retained one-piece restoration with the veneering ceramic fired directly onto the zirconia abutment that fractured during insertion. A patient who experienced root fracture of a maxillary left central incisor received a titanium implant on the same day as extraction. After delayed implant loading, a two-piece zirconia abutment with metallic insertion was customized. Upon installation, a horizontal fracture of the crown just above the metallic portion was detected...

Esthetic or cosmetic dentistry is one of the main areas of dental practice. Increasing demand of patients for esthetics has resulted in the development of several techniques for restoring the anterior teeth. Composite resin restorations have become an integral part of contemporary restorative dentistry and can be called "star of minimal invasion" due to its conservative concepts. The direct composite veneering allows restoring the tooth in a natural way and preservation of sound tooth structure when compared to indirect restorations...

BACKGROUND: Zirconia abutments are frequently used for implant-supported single crowns. Even though demonstrating esthetic benefits compared to metal abutments, zirconia abutments lead to an increased brightness of the peri-implant mucosa compared to natural teeth and are not ideal from an esthetic point of view. PURPOSE: To test whether or not a fluorescent hybrid zirconia abutment offers superior esthetics compared to a non-fluorescent one-piece zirconia abutment based on spectrophotometric analysis...

Objective. This report presents a comprehensive esthetic treatment with adhesive tooth-colored restorations in a combination with hyaluronic acid (HA) fillers of diastema in an orthodontic patient with relapse. Case Report. A 36-year-old female patient consulted about 1.5-2 mm midline diastema after an orthodontic relapse of replacing missing central incisors with lateral incisors and dark-colored gingival tissue as a result of a metal post and core with porcelain fused to a metal (PFM) crown at the left lateral incisor...

The reported failure rate for full veneer crowns of canine teeth of dogs is suboptimal, particularly in teeth with naturally poor retentive features, such as those with low height/diameter (H/D) ratios or high convergence angles (CAs). The objective of the present study was to evaluate the application of axial grooves in an effort to develop a crown preparation design that enhances the retention of full veneer crowns in dogs. Crown dislodgment testing was performed on cast alloy dies of canine teeth with unfavorable retention features (low H/D and high CA) prepared with (n = 14) and without axial grooves (n = 15) to evaluate the force required to dislodge a cemented full veneer crown...

Direct Metal Laser Sintering (DMLS) technology was used to produce tensile and flexural samples based on the Ti-6Al-4V biomedical composition. Tensile samples were produced in three different orientations in order to investigate the effect of building direction on the mechanical behavior. On the other hand, flexural samples were submitted to thermal treatments to simulate the firing cycle commonly used to veneer metallic devices with ceramics in dental applications. Roughness and hardness measurements as well as tensile and flexural mechanical tests were performed to study the mechanical response of the alloy while X-ray diffraction (XRD), electron microscopy (SEM, TEM, STEM) techniques and microanalysis (EDX) were used to investigate sample microstructure...

OBJECTIVE: To analyse the stress distribution in monolithic- and bilayer-structured ceramic crowns by means of the finite element method (FEM), as a function of elastic modulus of the core ceramic, Ecor, and that of the cement used to lute the crown, Ecem, with a view to identifying an ideal stiffness for the cement. METHODS: A two-dimensional axisymmetric FEM model was created to represent tooth structure with a cemented ceramic crown in place. The value of Ecor was set at 70, 100, 150 and 200  GPa representative of the range of commercially available materials...

STATEMENT OF PROBLEM: Few studies have investigated the volumetric polymerization shrinkage and film thickness of the different cementation techniques used to cement veneers. PURPOSE: The purpose of this in vitro study was to evaluate the volumetric polymerization shrinkage (VS) and film thickness (FT) of various cementation techniques through 3-dimensional (3D) microcomputed tomography (μCT). MATERIAL AND METHODS: Forty-eight artificial plastic maxillary central incisors with standard preparations for veneers were provided by a mannequin manufacturer (P-Oclusal) and used as testing models with the manufacturer's plastic veneers...

OBJECTIVES: The aim of the randomized controlled trial was to analyze time-efficiency of a treatment with implant crowns made of monolithic lithium disilicate (LS2) plus titanium base vs. porcelain fuse to zirconium dioxide (ZrO2 ) in a digital workflow. MATERIALS AND METHODS: Twenty study participants were included for single-tooth replacement in premolar and molar sites. Baseline was the start of the prosthetic treatment. All patients received transocclusal screw-retained implant reconstructions on a soft tissue level-type implant...

The required connector dimension for zirconia fixed dental prostheses (FDPs) may be a clinical limitation due to limited space in the occlusogingival direction. Using no veneering in the gingival regions of the pontics and connectors may solve this problem. This study evaluated the mechanical durability of zirconia FDPs with and without veneering in the gingival area of the connectors and pontics and subsequent air abrasion of this region with different protocols. Models were made of resin abutments (diameter = 6 or 8 mm, height = 6 mm, 6 degrees convergence) and embedded in polyurethane resin (distance = 11 mm)...

OBJECTIVE: To evaluate the fatigue life of zirconia-veneered and metal-ceramic crowns comprised by an even thickness or a modified framework design when loaded on marginal ridges. METHODS: Eighty marginal ridges were present after fabrication of forty molar crowns cemented onto composite-resin replicas and divided (n=20/each), in the following groups: metal-ceramic with even thickness (MCev) or with a modified framework design (MCm, lingual collar with proximal struts); porcelain-fused to zirconia with even thickness (PFZev) or with the modified framework design (PFZm)...

OBJECTIVE: The aim of this in vitro study was to evaluate the effect of core ceramic grinding on the fracture behaviour of bilayered zirconia under two loading schemes. METHODS: Interfacial surfaces of sandblasted zirconia disks (A) were ground with 80 (B), 120 (C) and 220 (D) grit diamond discs, respectively. Surface roughness and topographic analysis were performed using a confocal scanning laser microscope (CSLM) and a scanning electron microscopy (SEM). Relative monoclinic content was evaluated using X-ray diffraction analysis (XRD) then reevaluated after simulated veneer firing...

OBJECTIVES: To evaluate the clinical outcome of custom-made zirconia abutments for implant-supported single-tooth restorations 10-11 years after insertion. MATERIAL AND METHODS: The study comprises a clinical examination of 23 patients with 30 restorations placed 10-11 years ago. Oral surgeons placed the implants. The prosthodontic treatment was provided at a prosthodontic specialist clinic. The restoration was either an all-ceramic crown for cementation or a screw-retained one-piece restoration with the veneering porcelain baked directly to the zirconia abutment...

Defensins are cationic antimicrobial peptides that serve as important components of host innate immune defenses, often by targeting cell membranes of pathogens. Oligomerization of defensins has been linked to their antimicrobial activity; however, the molecular basis underpinning this process remains largely unclear. Here we show that the plant defensin NsD7 targets the phospholipid phosphatidic acid (PA) to form oligomeric complexes that permeabilize PA-containing membranes. The crystal structure of the NsD7-PA complex reveals a striking double helix of two right-handed coiled oligomeric defensin fibrils, the assembly of which is dependent upon the interaction with PA at the interface between NsD7 dimers...