Microhardness and Chemical Composition of Different Metallic Brackets: An Study.

The purpose of the study is to compare the hardness of different metallic brackets to enamel and to determine their chemical composition and microstructure. Five metallic brackets (0.022″ × 0.

Comparison of shear bond strength and ARI of four different adhesive systems used to bond molar tubes: An in vitro study.

Objective: The purpose of this in vitro study was to determine and compare the shear bond strength and ARI score of one traditional etch-and-rinse adhesive system serving as control, with those of two other all-in-one adhesives but with enamel acid etching preceding their application, and of one new 8th generation all-in-one bonding agent combined with a traditional adhesive used to bond stainless steel buccal tubes to molar teeth.

Material And Methods: Four groups of teeth were formulated according to the adhesive system used to bond the tubes on the molars. Shear bond strength was measured using a universal testing machine (Hounsfield, UK).

Improved consistency of bond-line thickness when conducting single lap-shear joint tests.

This article details a method for improving the consistency of bond-line thickness during lap-shear sample preparation. This includes the schematic for a lap-shear sample test rig and consideration for controlled variation of the bond-line thickness for up to ten pairs of samples at a time. Concerns regarding the curing of the samples when held on a large heat reservoir are addressed through direct measurement of the bond-rig temperature in combination with the cure chamber temperature.

Alteration of the intaglio surface of lithium disilicate glass-ceramic.

Statement Of Problem: Clinical adjustment of a lithium disilicate glass-ceramic (LDGC) restoration may necessitate its return to the laboratory for additional firing. Evidence of how the intaglio surface should be re-etched after internal adjustment, or after refiring, is lacking.

Purpose: The purpose of this in vitro study was to investigate the effects of different sequences of etching, refiring, diamond rotary instrument adjustment, airborne-particle abrasion, and re-etching on the microstructure and surface roughness of the intaglio surface of heat-pressed LDGCs.

Preparation of morselised bone for impaction grafting using a blender method.

Impaction bone grafting is a method of restoring bone stock to patients suffering significant bone loss due to revision total hip surgery. The procedure requires morselised bone (MB) to be impacted into the site of bone loss in order to stabilise the prosthesis with the aim of the long term resorption and reintegration of the impacted bone graft. Currently, the method for producing MB requires the use of expensive surgical bone mills or manually-intensive rongeurs that can produce a limited variety of particle sizes and may have a low throughput.

The use of hardened bone cement as an impaction grafting extender for revision hip arthroplasty.

Impaction bone grafting is a method of restoring bone stock to patients who have suffered significant bone loss due to revision total hip surgery. The procedure requires morsellised cancellous bone (MCB) to be impacted into the site of bone loss in order to stabilise the prosthesis with the aim of long term resorption and reintegration of the impacted bone graft. Due to financial cost and the potential to transmit disease, the use of supplementary material, known as an extender, is frequently used to increase the graft material volume.

An investigation into the factors that influence toolmark identifications on ammunition discharged from semi-automatic pistols recovered from car fires.

Following a shooting incident where a vehicle is used to convey the culprits to and from the scene, both the getaway car and the firearm are often deliberately burned in an attempt to destroy any forensic evidence which may be subsequently recovered. Here we investigate the factors that influence the ability to make toolmark identifications on ammunition discharged from pistols recovered from such car fires. This work was carried out by conducting a number of controlled furnace tests in conjunction with real car fire tests in which three 9mm semi-automatic pistols were burned.

Human plasma protein adsorption onto alumina nanoparticles relevant to orthopedic wear.

Purpose: Wear of ceramic orthopedic devices generates nanoparticles in vivo that may present a different biological character from the monolithic ceramic from which they are formed. The current work investigated protein adsorption from human plasma on alumina nanoparticles and monolithic samples representative of both wear particles and the ceramic components as implanted.

Materials And Methods: A physicochemical characterization of the particles and their dispersion state was carried out, and the protein adsorption profiles were analyzed using 1D SDS-PAGE and mass spectrometry.

Hydroxyapatite and fluorapatite coatings on dental screws: effects of blast coating process and biological response.

This paper describes the deposition of hydroxyapatite (HA) and fluorapatite (FA) onto titanium dental screws using a novel ambient temperature coating technique named CoBlast. The process utilises a coating medium and a blast medium sprayed simultaneously at the substrate surface. The blast medium was a sintered apatite (sHA) and two particles sizes (<106 and <180 µm) were used to assess their influence on the coating process.

Effects of repeated processing on the strength and microstructure of a heat-pressed dental ceramic.

Statement Of Problem: The excess material produced after heat pressing a lithium disilicate glass ceramic restoration can be either discarded or reused. The reuse of this material requires that any degradation of the material quality be investigated.

Purpose: The purpose of this study was to investigate the number of times that leftover lithium disilicate material can be re-pressed and to determine the effect that repeated use has on material properties.

Co-blasting of titanium surfaces with an abrasive and hydroxyapatite to produce bioactive coatings: substrate and coating characterisation.

The aim of this work is to assess the influence of two blast media on the deposition of hydroxyapatite onto a titanium substrate using a novel ambient temperature coating technique named CoBlast. CoBlast was developed to address the problems with high temperature coating techniques. The blasting media used in this study were Al2O3 and a sintered apatite powder.

Harmonizing the diagnosis of metabolic syndrome--focusing on abdominal obesity.

In 2009, important health organizations met to construct a Joint Scientific Statement (JSS) intended to harmonize the diagnosis of metabolic syndrome worldwide. The JSS aimed to unify the diagnostic criteria of metabolic syndrome, particularly in relation to whether to include abdominal obesity as a criterion of diagnosis. A large part of the JSS is devoted to discussing the diagnosis of abdominal obesity.

Optimisation of the enamelling of an apatite-mullite glass-ceramic coating on Ti6Al4V.

Apatite-mullite glass-ceramics (AMGCs) are under investigation as a potential alternative to hydroxyapatite (HA) as a coating for cementless fixation of orthopaedic implants. These materials have tailorable mechanical and chemical properties that make them attractive for use as bioactive coatings. Here, AMGC coatings on Ti(6)Al(4)V were investigated to determine an improved heat treatment regime using a systematic examination of the different inputs: composition of glass, nucleation hold and crystallisation hold.

Microwave-assisted rapid discharge sintering of a bioactive glass-ceramic.

Bioactive glass-ceramics have been developed as successful bone graft materials. Although conventional sintering in an electrically-heated furnace is most commonly used, an alternative microwave plasma batch processing technique, known as rapid discharge sintering (RDS), is examined to crystallise the metastable base glass to form one or more ceramic phases. Apatite-mullite glass-ceramics (AMGC) were examined to elucidate the effects of RDS on the crystallization of a bioactive glass-ceramic.

The synthesis and characterization of nanophase hydroxyapatite using a novel dispersant-aided precipitation method.

The synthesis of nanophase hydroxyapatite (nHA) is of importance in the field of biomaterials and bone tissue engineering. The bioactive and osteoconductive properties of nHA are of much benefit to a wide range of biomedical applications such as producing bone tissue engineered constructs, coating medical implants, or as a carrier for plasmid DNA in gene delivery. This study aimed to develop a novel low-temperature dispersant-aided precipitation reaction to produce nHA particles (<100 nm), which are regarded as being preferable to micron-sized agglomerates of nHA.

Development and characterisation of a collagen nano-hydroxyapatite composite scaffold for bone tissue engineering.

Bone regeneration requires scaffolds that possess suitable mechanical and biological properties. This study sought to develop a novel collagen-nHA biocomposite scaffold via two new methods. Firstly a stable nHA suspension was produced and added to a collagen slurry (suspension method), and secondly, porous collagen scaffolds were immersed in nHA suspension after freeze-drying (immersion method).

Study of the interfacial reactions between a bioactive apatite-mullite glass-ceramic coating and titanium substrates using high angle annular dark field transmission electron microscopy.

Glass of generic composition SiO(2) . Al(2)O(3) . P(2)O(5) .

The infrastructure of obesity and the obesity epidemic: implications for public policy.

If present increases in the rate of obesity persist, by 2015 half of the population in the US could be obese. This article presents the case that the reason for the epidemic is an 'infrastructure of obesity' that fuels the phenomenon. To control this epidemic, public policy in general and health policy in particular need to shift from market oriented policies that favour individual choice to policies that regulate the food supply, to help dismantle the infrastructure of obesity.