Publications by authors named "Bruce Matthews"
Objective: Investigate the cause of hypersensitive dentine (HD) by recording the time course of changes in dentine sensitivity, sensory threshold to electrical stimulation (ET) and pulpal blood flow (PBF) following tubular occlusion using in vitro and clinical experiments.
Design: Nineteen teeth with HD and 13 with normal dentine from 8 participants were evaluated, and the intensity of any pain produced by various stimuli was recorded at different times after oxalate treatment. The participants used a visual-analogue scale (VAS) to indicate the intensity of any pain.
Objective: To determine the rate of fluid flow through human dentine due to electroosmosis during iontophoresis of either 2 % lignocaine with epinephrine, Ringer's solution, epinephrine, or distilled water.
Design: Experiments were carried out on 24 intact extracted human premolars. Dentine was exposed at the tip of the buccal cusp.
Article Synopsis
- In 2014, an omnibus spending bill prompted the Department of Energy (DOE) to evaluate its effectiveness in managing public health and safety risks tied to its environmental cleanup responsibilities.
- A committee identified numerous issues and offered recommendations for the DOE, federal agencies, and stakeholders, emphasizing a structured risk review process to better assess and prioritize risks.
- States play a significant role in risk management, influencing DOE resources and approaches through varying laws and priorities, which can lead to inconsistencies in addressing the most pressing human health and safety risks.
Objective: To determine the percentage of the blood flow signal that is derived from dental pulp when recording from exposed dentine in a human premolar.
Design: Recordings were made from 7 healthy teeth in 5 subjects (aged 22-33 yr.) with a laser Doppler flow meter (Periflux 4001) using either a red (635 nm) or an infrared (780 nm) laser.
Objective: To investigate fluid flow through dentine in primary teeth in vitro using the replica technique, and to compare the results with those obtained from permanent dentine.
Design: The experiments were carried out on 22 extracted, mandibular, primary, incisor teeth. The incisal edge was removed to 1mm below the dentino-enamel junction and half the exposed surface etched with phosphoric acid.
Objective: To determine if full crown preparation causes an increase in pulpal blood flow (PBF), indicating inflammation, in human subjects.
Design: The experiments were carried out on 35 intact, mandibular posterior teeth in 13 subjects: 32 were abutments for 16 fixed bridges that replaced first molars; the other 3 were first premolars adjacent to abutment teeth that served as un-operated controls. Crown preparations were made using an air-rotor with water-spray under regional block anaesthesia (4% articaine with epinephrine 1:100,000).
Objective: To determine if dentine at the enamel-dentine junction (EDJ) in man is more sensitive to hydrostatic pressure stimuli then deeper dentine.
Design: Cavities (1mm diam.) were cut at the tips of the buccal and lingual cusps of 8 premolars in 3 subjects (ages: 22-25 years).
Objective: To determine if bleaching a tooth affects significantly laser Doppler recordings of pulpal blood flow that are made through the treated enamel and dentine.
Design: Recordings of blood flow (flux) were made with a laser-Doppler flow meter from the crowns of 14, recently extracted, human premolars while diluted blood was pumped at three different rates through a cannula that was inserted into the pulp cavity with its tip in the coronal pulp chamber. The recordings of flux were made before and after bleaching the crown with 38% hydrogen peroxide for 30min.
Objective: To determine the effectiveness of the iontophoretic delivery of lignocaine with epinephrine through carious dentine for pain control during cavity preparation.
Design: The experiments were carried out on 56 carious molars that required class I restorations in 42 subjects (aged 15-20 years). The overhanging enamel and soft caries were removed then the sensitivity of the exposed dentine was tested with drilling, probing and air blast stimuli.
Objective: To determine the effects of the iontophoretic application of lignocaine and epinephrine to exposed dentine on the sensitivity of the dentine in human subjects.
Design: The experiments were carried out on 13 healthy premolars (13 subjects) that were scheduled for extraction. Dentine was exposed at the tip of the buccal cusp by cutting a cavity which was etched with 35% phosphoric acid.
Objective: To determine the effect of topical applications of 50% (w/v) lignocaine HCl on the sensitivity of human dentine.
Design: The experiments were carried out on 12 premolars scheduled for extraction as part of orthodontic treatment in nine subjects (ages: 16-29 years). Dentine was exposed by cutting a cavity at the tip of the buccal cusp of each tooth, and etched with 35% phosphoric acid.
Objective: To compare red (635 nm) and infrared (780 nm) light for recording pulpal blood flow from human anterior teeth with a laser Doppler flow meter.
Design: Recordings were made from 7 healthy teeth in 5 subjects (aged 22-55 years) using a laser Doppler flow meter (Periflux 4001) equipped with both red and infrared lasers. Average blood flow signals were obtained with both light sources alternately from each tooth under five conditions: intact tooth without opaque rubber dam, intact tooth with dam, after injecting local anaesthetic (3% Mepivacaine) (LA) over the apex of the tooth and cavity preparation to almost expose the pulp, after removal and replacement of the pulp, and with the root canal empty.
Objective: To compare red (635 nm) and infrared (780 nm) light for recording pulpal blood flow from human premolar teeth.
Design: Recordings were made from 11 healthy teeth in 9 subjects (aged 16-30 years) using a laser Doppler flow meter (Periflux 4001) equipped with both red and infrared lasers. Average blood flow signals were obtained with both light sources alternately from each tooth under five conditions: intact tooth without opaque rubber dam, intact tooth with dam, after injecting local anaesthetic (3% Mepivacaine) (LA) over the apex of the tooth and cavity preparation to almost expose the pulp, after removal and replacement of the pulp, and with the root canal empty.
Objective: To determine the effects of applying KCl solutions to exposed dentine at atmospheric pressure on pain evoked by probing and air blast stimuli in human subjects.
Design: The experiments were carried out on 24 premolars in 16 subjects (aged 16-30 years). A cavity (diameter 3mm, depth 3mm) was cut at the tip of the buccal cusp and etched with 35% orthophosphoric acid.
Introduction: Hyperthyroidism is a well established cause of atrial fibrillation (AF). Thyroid Stimulating Hormone-secreting pituitary tumours are rare causes of pituitary hyperthyroidism. Whilst pituitary causes of hyperthyroidism are much less common than primary thyroid pathology, establishing a clear aetiology is critical in minimising complications and providing appropriate treatment.
View Article and Find Full Text PDFObjective: To determine the effect of applying 500 mmol/l KCl at a pressure of 150 mm Hg above atmospheric to exposed dentine on pain sensation evoked by probing and air blast stimuli in human subjects.
Design: The experiments were carried out on 14 pairs of premolars in 14 human subjects (aged 17-30 years). Dentine was exposed at the tip of the buccal cusp, etched with acid and covered with saline, then 500 mmol/l KCl in Ringer's was applied at a pressure of 150 mm Hg for 4 min.
Objective: To investigate further the relationship between dentinal tubular flow and the discharge evoked in intradental nerves.
Design: In anaesthetised cats, recordings were made of fluid flow through dentine during the application of hydrostatic pressure stimuli of 5 s duration in the range +500 to -500 mm Hg to exposed dentine and of the nerve impulses evoked by these stimuli. Single unit recordings were obtained from filaments dissected from the inferior alveolar nerve and multi-unit recordings, from the exposed dentine.
Objective: To determine the relationship between pain intensity and the rate of fluid flow through dentine in human subjects.
Design: The experiments were carried out on 16 premolars in 13 human subjects (aged 15-25 years). Dentine was exposed at the tip of the buccal cusp, etched with acid and covered with saline.
Objective: To determine the effects on the sensitivity of exposed dentine to cold that are produced when dentine is etched to remove the smear layer and when the tubules are blocked again with calcium oxalate. Separate in vitro observations were made on the effects of these procedures on fluid flow through the dentine.
Design: The experiments were carried out on 24 premolars in 17 subjects.