SUMMARY The present in vitro study aimed to assess the effects of root surface mechanical instrumentation on the marginal integrity and adaptation of resin composite crowns. The following null hypotheses were tested: no differences exist between finish line and 1) marginal gap or 2) marginal microleakage before and after manual ...

PURPOSE: To evaluate the stress distribution in peri-implant bone by simulating the effect of an implant with microthreads and platform switching on angled abutments through tridimensional finite element analysis. The postulated hypothesis was that the presence of microthreads and platform switching would reduce the stress concentration in the cortical bone. ...

OBJECTIVE: To assess the impact of oocyte vitrification on aneuploidy and reproductive potential by comparing vitrified and control oocytes from a single patient within a single cycle and a single fresh transfer. DESIGN: Paired randomized controlled trial in which each patient's cohort of mature oocytes was divided into two even ...

BACKGROUND: We examined equity of access to implanted cardioverter defibrillators (ICDs) in New Zealand in 2010 by district health board (DHB), ethnicity and socioeconomic status. METHODS: All new ICD recipients in 2010 were examined according to home district health board, ethnicity according to the national health database, and socioeconomic status ...

OBJECTIVE: To determine the influence of cement thickness and ceramic/cement bonding on stresses and failure of CAD/CAM crowns, using both multi-physics finite element analysis and monotonic testing. METHODS: Axially symmetric FEA models were created for stress analysis of a stylized monolithic crown having resin cement thicknesses from 50 to 500μm ...

OBJECTIVE: The purpose of this investigation was to compare stresses within bonded porcelain and composite resin ultra-thin occlusal veneers to restore advanced erosive lesions. MATERIALS AND METHODS: A sound maxillary molar was digitized with a micro-CT scanner. The 2D image data were converted in a 3D model using an interactive ...

In some cases of aortic valve leaflet disease, the implant of a stentless biological prosthesis represents an excellent option for aortic valve replacement (AVR). In particular, if compared with the implant of mechanical valves, it provides a more physiological haemodynamic performance and a reduced thrombogeneticity, avoiding the use of anticoagulants. ...

INTRODUCTION: The aim was to determine the magnitude of ceramic resin-strengthening with resin-based materials with varying flexural moduli using a regression technique to assess the theoretical strengthening at a 'zero' resin-coating thickness. The hypothesis tested was that experimentally, increasing resin flexural modulus results in increased resin-strengthening observed at a theoretical ...

Background: Cochlear implants provide access to soft intensity sounds and therefore improved audibility for children with severe-to-profound hearing loss. Speech processor programming parameters, such as threshold (or T-level), input dynamic range (IDR), and microphone sensitivity, contribute to the recipient's program and influence audibility. When soundfield thresholds obtained through the speech ...

An important objective of orthodontic treatment is to obtain the correct mesiodistal angulation and faciolingual inclination for all teeth. Current techniques are based on crown angulation and inclination standards, and not enough attention has been given to the roots. In this study, we report the mesiodistal angulation and faciolingual inclination ...

A theoretical model is presented to explain the refractive index change in the ion-implanted KTP waveguide, which includes respective contributions of spontaneous polarization, molar polarization and molar volume, and photoelastic effect. Numerical calculations of refractive indices along different crystalline orientations (X, Y, and Z) as a function of the lattice ...

Purpose: The goal of this study was to compare the stress distribution of tooth-implant?supported prostheses (TISPs) and solely implant-supported prostheses (ISPs) with two different pontic spans (three units versus four units). Materials and Methods: Two-dimensional finite element models were constructed from the radiographs of polyester resin casts to mimic TISPs ...

OBJECTIVE: The aim of this study was to report on the failure rates of two distinct dental implant systems in a clinical practice setting. MATERIALS AND METHODS: Date of implant placement and loss were entered prospectively in a data registry system. Failure rates of two commercially pure titanium implants, one ...

ABSTRACT: BACKGROUND: Effective fixation of fracture requires careful selection of a suitable implant to provide stability and durability. Implant with a feature of locking plate (LP) has been used widely for treating distal fractures in femur because of its favourable clinical outcome, but its potential in fixing proximal fractures in ...

BACKGROUND: The relationships between reaming parameters for glenoid-implant surface area and bone loss in total shoulder arthroplasty have not been well established. The hypotheses of this study are: (1) for large version corrections, a large reaming depth of 5 mm is not sufficient to obtain complete glenoid implant contact; (2) ...

Abstract IntroductionMicromotion between dental implant and bony socket may occur in immediate loading scenarios. Excessive micromotion surpassing an estimated threshold of approximately 150µm may result in fibrous encapsulation instead of osseointegration of the implant. As finite element analysis (FEA) has been applied in this field, it was the aim of ...

OBJECTIVE: To investigate whether or not body mass index (BMI) is associated with oocyte dysmorphisms. STUDY DESIGN: This retrospective study enrolled 1105 patients undergoing intracytoplasmic sperm injection (ICSI). The correlation between BMI and the response to controlled ovarian stimulation (COS) and ICSI outcomes was analysed. Oocyte morphology was determined in ...

PURPOSE:: To determine the influence of number and location of implants loaded on the stress to the bone in an edentulous maxilla using a three-dimensional finite element model (3D FEM). MATERIAL AND METHODS:: Computed tomographic data with the bone density of a dry skull were used to construct a 3D ...

BACKGROUND: Bisphenol A (BPA) is a synthetic chemical widely used in the production of polycarbonate plastic and epoxy resins used in numerous consumer products. In experimental animals, BPA increased embryo implantation failure and reduced litter size. OBJECTIVE: We evaluated the association of urinary BPA concentrations with implantation failure among women ...

Biventricular device implantation with the insertion of a transvenous left ventricular (LV) lead can be challenging. The aim of this study was to identify predictors of procedural difficulty measured by fluoroscopy time and predictors of LV lead implantation failure. A single-center, retrospective study of 272 consecutive patients who underwent biventricular ...

OBJECTIVE: The objectives of this study were to analyze retrospectively the long-term survival and success rates of Narrow implants (NIs) placed with various implant systems, and the association with biological and technical complications. MATERIAL AND METHODS: In total, 338 patients (men = 45.6%, women = 54.4%) who received 541 NIs (≤3.5 mm in diameter) for ...

Data are presented to demonstrate that the circumpulpal dentine of deciduous teeth can be used to reconstruct a detailed record of childhood exposure to lead. By combining high spatial resolution laser ablation ICP-MS with dental histology, information was acquired on the concentration of lead in dentine from in utero to ...

Currently, no large animal model exists for surgical-experimental exploratory analysis of implantable hearing devices. In a histomorphometric study, we sought to investigate whether sheep or pig cochleae are suitable for this purpose and whether device implantation is feasible. Skulls of pig and sheep cadavers were examined using high-resolution 128-slice computed ...

There is less information on the quality of fit of zirconia frameworks with or without ceramic veneer than on anatomically contoured milled zirconia restorations. The purpose of this in vitro study was to evaluate the strain development of CAD/CAM fabricated zirconia ceramic frameworks with and without ceramic veneering, copy-milled zirconia ...

Antibiotics are commonly mixed with polymethylmethacrylate (PMMA) cement to suppress severe periprosthetic infections associated with total joint arthroplasty. The relationship between antibiotic concentration and the resulting elution kinetics remains unclear. The purpose of this study was to characterize the release of daptomycin from PMMA cement and the subsequent effects on ...

This in-vitro study investigated the marginal fit of two all-ceramic copings with 2 finish line designs. Forty machined stainless steel molar die models with two different margin designs (chamfer and rounded shoulder) were prepared. A total of 40 standardized copings were fabricated and divided into 4 groups (n=10 for each ...

When a cylinder is connected to an abutment it is expected that abutment and cylinder will be subjected to compression forces throughout their periphery because of the clamping force exerted by the screw. The deformation resultant of this compression should be measurable and uniform along the periphery of the abutment. ...

OBJECTIVE: Surface roughness parameters of various intraocular lenses (IOLs) biomaterials using atomic force microscopy (AFM) are compared. Variation, if any, in the micro-roughness properties of different IOLs made up of the same biomaterial is also explored. Retrospective analysis of posterior capsular opacification (PCO) incidence has been followed up for a ...

In the present paper, a model for the early stages of peri-implant bone regeneration is developed. This model is able to capture some important characteristics of endosseous healing, which were not incorporated in the existing models. It is a well known fact, that during peri-implant osseointegration, bone forms only by ...

Impact of Recalls on ICD Utilization. Introduction : Underutilization of ICDs is well documented. It has been hypothesized that device recalls, and the resultant negative publicity, may contribute. Methods and Results: To determine if the October 2007 recall of the Medtronic Fidelis lead was associated with a decrease in volume ...

Some studies have reported the presence of audible squeaking in ceramic-on-ceramic total hip arthroplasty (THA), and several factors such as implant malposition or poor soft tissue recovery have been described as the cause. Our purpose was to determine the squeaking rate in the Asian population with a consecutive series of ...

PURPOSE: Limited or absent axial rotation of the mobile insert of total knee prostheses could lead to high contact stresses and stresses at the bone-implant interface, which in turn might lead to implant loosening. The aim of this study was to assess knee kinematics and muscle activation and their possible ...

We evaluated the effects of sperm concentration, progressive motility, sperm morphology, duration of abstinence and collection season on the progressive motility recovery rate of human frozen spermatozoa to identify characteristics that predict the progressive motility recovery rate of human frozen spermatozoa and improve the protocol for sperm collecting in sperm ...

OBJECTIVES: Test the hypotheses that there are equivalent wear rates for enamel-versus-enamel and ceramic-versus-enamel, analyzing the in vivo wear of crown ceramics, their natural enamel antagonists, and the corresponding two contralateral teeth; and, that bite force does not correlate with the wear. METHODS: A controlled, clinical trial was conducted involving ...

ABSTRACT: BACKGROUND: Set up a banna mini-pig 125I implantation model, and investigate the consequence of radiation-related impairments. METHODS: In present study, 125I seeds were implanted into spinal canal of T13 level of spine in banna mini-pigs. After operation, the pigs were raised up to 8 months, behavior changes were recorded ...

The survival of dental implants, in particular immediately loaded implants, critically depends on the biomechanical properties of the bone bed surrounding them. In experimental animal investigations of immediately loaded implants the initial stability, implant design as well as stress and strain distributions in the surrounding bone have been extensively studied. ...

In this study, Ti-35Nb-2.5Sn/xhydroxyapatite (HA) composites were sintered by pulse current activated sintering (PCAS) from powders milled for different time. These sintered composites were expected to be potential biomaterials. Ca(3)(PO(4))(2) phase which could increase hardness of sintered composites was found in the Ti-35Nb-2.5Sn/15HA composite sintered from 12 h milled powders. ...

Abstract The use of provisional resin implant-supported complete dentures is a fast and safe procedure to restore mastication and aesthetics of patients soon after surgery and during the adaptation phase to the new denture. This study assessed stress distribution of provisional implant-supported fixed dentures and the all-on-four concept using self-curing ...

Objective. To test the strength of internal fixation of mandibular condyle fractures repaired with titanium miniplates versus titanium intramedullary implants.Study Design. Prospective laboratory experimentation in urethane mandible models and human cadaveric mandibles.Setting. Materials testing laboratory at an academic medical center.Methods. Osteotomies of the mandibular condyle were created in 40 urethane ...

Data sourcesPubmed, Medline and SCOPUS databases together with hand searching of the identified key journals' indexes, bibliographies, special issues and reference lists of identified articles were scanned to identify other potentially relevant articles.Study selectionControlled trials comparing calcium hydroxide versus MTA in immature permanent teeth where the aim was apexification where ...

Purpose: The aim of the present study was to perform a finite element (FE) analysis of a modified sinus elevation procedure involving additional implantation of a cortical bone graft block for stabilization of an implant. A secondary aim was to compare the modified sinus augmentation with the standard technique and ...

Preclinical endurance testing of total knee replacements (TKRs) is performed using International Organization for Standardization (ISO) load and motion protocols. The standards are based on data from normal subjects and may not sufficiently mimic in vivo implant conditions. In this study, a mathematical model was used to calculate the axial ...

OBJECTIVES: The aim of this study was to analyse micromotion and stress distribution at the connections of implants and four types of abutments: internal hexagonal, internal octagonal, internal conical and trilobe. METHODS: A three dimensional (3D) model of the left posterior mandible was reconstructed from medical datasets. Four dental implant ...

An implantable cardioverter-defibrillator (ICD) experienced electromagnetic interference from a laptop computer's hard disk. The patient with the ICD was using his laptop computer at home while lying on his bed. The laptop was positioned on his chest, when he heard a beeping sound from the ICD, indicating magnet mode conversion. ...

PurposeTo compare intraocular pressure (IOP) over time after standard trabeculectomy vsEx-PRESS implantation in patients with bilateral primary open-angle glaucoma (POAG).DesignProspective, randomised study.Patients and methodsThis study included adult patients with bilateral POAG necessitating surgery. Each patient underwent trabeculectomy in one eye and Ex-PRESS implantation under a scleral flap in the other ...

The assessment of knee joint laxity is clinically important but its quantification remains elusive. Calibrated, low dosage fluoroscopy, combined with registered surfaces and controlled external loading may offer possible solutions for quantifying relative tibio-femoral motion without soft tissue artefact, even in native joints. The aim of this study was to ...

Xu H, Jiang Z, Xiao X, Fu J, Su Q. Influence of cavity design on the biomechanics of direct composite resin restorations in Class IV preparations. Eur J Oral Sci 2012; 120: 161-167. © 2012 Eur J Oral Sci This study evaluated the effect of cavity design on stress distribution ...

This study reconstructs incremental enamel development for a sample of modern human deciduous mandibular (n = 42) and maxillary (n = 42) anterior (incisors and canines) teeth. Results are compared between anterior teeth, and with previous research for deciduous molars (Mahoney: Am J Phys Anthropol 144 (2011) 204-214) to identify ...

A comparative approach was used to evaluate semen cooling rates, thawing rates and freezing volume on the cryosurvival of avian sperm. Turkey (Meleagris gallopavo) and sandhill crane (Grus canadensis) sperm were cryopreserved with dimethylacetamide (DMA) concentrations ranging from 6% to 26%. Experiments evaluated the efficacy of (1) rapid, moderate and ...

BACKGROUND: Polyethylene wear is often cited as the cause of failure of TKA. Rotating platform (RP) knees show notable surface damage on the rotating surface raising concerns about increased wear compared to fixed bearing inserts. QUESTIONS/PURPOSES: We therefore addressed the following questions: Is wear in RP inserts increased compared to ...