John Neil Waddell

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Bolus propulsion during the normal oral phase of swallowing is thought to be characterised by the sequential elevation of the front, middle, and posterior regions of the dorsum of the tongue. However, the coordinated orchestration of lingual movement is still poorly understood. This study examined how pressures generated by the tongue against the hard(More)
This article introduces a new way of recording intraoral pressures from a range of locations within the oral cavity. To measure pressure flow dynamics during swallowing, we fitted eight miniature pressure transducers capable of measuring absolute pressures to a chrome-cobalt palatal appliance with a labial bow. Unlike previous devices, our design provides a(More)
To describe a novel approach for continuous measurement of intra-oral pH and temperature in individuals carrying out normal daily activities over 24 h. We designed, validated and constructed a custom-made appliance fitted with a pH probe and a thermocouple. Six subjects wore the appliance over a 24-h period for two non-consecutive days, while the intra-oral(More)
The purpose of this literature review was to identify the etiological factors of failure of soldered bars in bar attachment systems for removable implant overdentures. A search of MEDLINE using the key words "bar attachment systems" was performed of English language peer-reviewed journals published between 1975 and 2005. Clinical studies of implant(More)
PURPOSE The purpose of this study was to measure the tear strength and hardness of four different dental silicones in comparison to that of porcine skin. METHODS Specimens were prepared (n = 20/group) according to ASTM D624-00, using three hydrophilic vinyl polysiloxane impression materials, one duplication silicone, and fresh porcine skin. A universal(More)
Titanium (Ti) and its alloys have been popularly used as implant biomaterial for decades. Recently, titanium-zirconium (TiZr) alloy has been developed as an alternative implant material with improved strength in load bearing areas. Surface modification is one of the key factors to alter the surface properties to hasten osseointegration. Spark anodic(More)
PURPOSE One of the current limitations of computer software programs for the virtual articulation of the opposing teeth is the static nature of the intercuspal position. Currently, software programs cannot identify eccentric occlusal contacts during masticatory cyclic movements of the mandible. MATERIALS AND METHODS Chewing trajectories with six degrees(More)
OBJECTIVES To compare the crystalline phases present, quantify the adhesion to zirconia and measure the mechanical properties of four commercially available pressed ceramics suitable for zirconia substructures. MATERIALS AND METHODS This study compares the X-ray diffraction response and the mechanical properties of four different pressed ceramics(More)
OBJECTIVE To determine the adhesion at the titanium-porcelain interface using a fracture mechanics approach, and to investigate the bonding mechanism using SEM. METHODS Specimens of five different titanium-porcelain and one base metal-porcelain bonding systems were prepared for a four-point bending interfacial delaminating test on a universal testing(More)
OBJECTIVES The aim of this study was to measure the influence of water on the adhesion between titanium and porcelain by means of the strain energy release rate (G-value or interfacial toughness). METHODS Rectangular specimens of grade II titanium and a reference gold-palladium porcelain fused to metal (PFM) alloy were veneered with feldspathic(More)