Biomedical subjects
Publications and source records attributed to A J Ireland.
Orthodontic treatment appears to be in ever-increasing demand, but the number of specialists is insufficient to meet the current need. This article considers the role of the extended practitioner training scheme in the present climate of uncertainty surrounding orthodontics in the general dental services in the UK, particularly for the general dental practitioner.
OBJECTIVES: The objectives of this experiment were twofold. Firstly to determine whether an anaerobic adhesive could be used to bond steel attachments to etched human enamel, following treatment of this surface with various concentrations of copper (II) sulphate solution. Secondly, to determine the effect of 0.05 M solutions of other transition metal sulphates and chlorides on the same bonding process. METHODS: Stainless steel attachments were bonded to human enamel using an anaerobic adhesive. In each case the enamel, which had been ground flat, was etched with 37% o-phosphoric acid and then treated with copper (II) sulphate solution prior to bonding. After bench curing for one hour, the specimens were shear tested to failure, and the load at bebond recorded in each case. The effect of varying the concentration of copper (II) sulphate solution was determined. Following determination of the optimal copper (II) sulphate concentration, the experiment was repeated using the same concentration of various other transition metal sulphates and chlorides. RESULTS: The results were analysed using mean force to debond (N) and 95% confidence intervals. Kaplan-Meier survival probabilities and log-rank tests were also performed. CONCLUSIONS: Under the conditions of this experiment the optimal concentration of copper (II) sulphate solution was found to be 0.05 M. Of the various transition metal sulphates and chlorides under test, the sulphates appeared to provide a more active surface for the polymerisation of the anaerobic adhesive than the chlorides. Of the sulphate solutions, the most effective was that of copper. SIGNIFICANCE: Anaerobic adhesives show promise as dental bonding agents capable of bonding metal attachments to enamel following enamel pretreatment with 0.05 M copper (II) sulphate solution.
OBJECTIVES: Anaerobic adhesives are capable of bonding copper-containing metal attachments to etched human enamel, where the latter surface has been rendered reactive by the use of a copper-containing surface activator. The aims of the present study were to determine whether copper attachments could also be successfully bonded to etched human enamel, using anaerobic adhesives, where no such surface activator was used. In addition, the effect of alteration in the copper content of the attachment alloy was also investigated. METHODS: Metal attachments suitable for use with anaerobic adhesives were made from one of three copper-containing alloys. Their copper contents were 8%, 19% and 99.9%. They were bonded to human enamel, which had been ground flat and etched with 37% o-phosphoric acid, using one of three anaerobic adhesives. After bench curing for one of four time periods, 10 min, 1 h, 24 h and 2 weeks, shear testing to failure was performed. The load at debond was recorded in each case. RESULTS: The results were analysed using mean force to debond (N) and 95% confidence intervals. Kaplan-Meier survival probabilities and log-rank tests were performed for the 10 min and 1 h test times. CONCLUSIONS: Each of the three anaerobic adhesives under test demonstrated a concentration effect for the copper in the metal attachments. The higher the copper content of the attachment the greater the measured force to debond and the more rapid its attainment. As determined by measured force to debond, only one adhesive. Loctite 326, underwent any significant degree of activation and, therefore, polymerisation by the lowest copper content alloy under test.
This review of the published literature on dental materials for the year 1997 has been compiled by the Dental Materials Panel of UK. It continues a series of annual reviews started in 1973. Emphasis has been placed upon publications, which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, ceramometallic restorations and resin-bonded bridges, ceramics, denture base resins and soft lining materials, impression materials, dental implant materials, orthodontic materials, biomechanics and image processing, resin composites, and casting investment materials and waxes). Three hundred and thirty three articles have been reviewed.
A 19-year-old girl with mild asthma had had 16 months of orthodontic treatment as part of the joint orthodontic/orthognathic approach to her 9.5 mm overjet. At the time of banding her second molars she developed latex protein allergy as a reaction to the operator's non-sterile powdered latex gloves. She also gave a history of allergy to other substances as well as of eczema. The patient was confirmed as allergic to latex protein by radioallergosorbent test (RAST) for IgE, requiring precautions be taken during further orthodontic procedures as well as during the subsequent orthognathic surgery for the underlying Class II skeletal pattern.
The need to record clinical images, for use in documenting treatments, patient education, patient contracting, referral letters and sharing information with colleagues, is increasing. This article reviews the advantages and disadvantages of 35 mm and digital photography.
OBJECTIVE: To determine the impact, in terms of new attendance figures and types of patients attending, on a city centre accident and emergency (A & E) department following the establishment of out-of-hours primary care emergency centres (PCECs) in Glasgow. METHODS: A questionnaire survey of A&E patients attending out-of-hours at Glasgow Royal Infirmary A&E department, a city centre department with approximately 68,000 new annual attendances, one week before (Group A), twelve weeks after (Group B) and one year after (Group C) the introduction of PCECs. Main outcome measures were attendance numbers within working hours and out-of-hours, reason for A&E attendance, duration of presenting condition, whether primary care services were contacted and awareness of the new primary care emergency centres. RESULTS: In respect of out-of-hours attendances, 612 questionnaires were completed for group A, 715 for group B and 645 for group C. There was no significant difference in the type of presenting complaints between the groups, i.e. illness or injury. The majority of patients presented within 24 hours of the onset of their condition (82%, 79% and 80% of patients in groups A, B and C respectively). There was a reduction in those attending with conditions of more than one week's duration (8% in group A, 7% in group B and 5% in group C). There was a decrease in the number of patients who considered their problem to be non-urgent (27% in group A, 22% in group B and 16% in group C). Prior to the introduction of the PCEC service 18% of patients (108) had contacted their GP before attending, compared with only 9% (63) of group B and 9% (57) of group C patients. Of these patients there was a significant decrease in the number of patients attending following GP referral. Of the patients who had not contacted the primary care services only 35% (201) knew of the introduction of PCECs 12 weeks later, increasing to 52% (291) after one year (p < 0.01). Significance calculations were performed using a Difference of Proportion Test with a 99% significance level. CONCLUSIONS: Our results suggest that the new PCEC service has not had a significant impact on the number or type of patients attending this A&E department, with fewer self-referred patients contacting primary care services after its introduction. Following the introduction of the PCECs there was a trend towards more patients attending A&E following telephone advice although amongst self-referred A&E patients there remained a large proportion who claimed to be unaware of the new service 12 weeks after, and one year after, the introduction of PCECs. Continued evaluation of the effect on A&E of the new centres will be required to plan future resources for the provision of emergency care.
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OBJECTIVES: Single-component anaerobic adhesives are in common use in the electronics and engineering industries. They are generally diacrylate monomers which do not require conventional sources of heat, light or chemicals for activation. Their advantages include activation by the bonding substrate, as well as inhibition of polymerisation until the necessary anaerobic environment is created. The aim of this experiment was to determine whether metal attachments could be successfully bonded to enamel in vitro by such adhesives. METHODS: Metal attachments capable of providing an anaerobic environment were fabricated from one of three alloys: stainless steel, copper or cobalt-chromium. They were bonded to prepared human enamel with one of four adhesives: Orthodontic Concise, as a control, and three anaerobic adhesives, Perma Metal, Permabond A134 and Loctite 326. The specimens were then bond tested in shear to failure after bench curing for one of four time periods. RESULTS: The results were analysed in terms of mean force to debond (N) and 95% confidence intervals. Kaplan-Meier survival probabilities and log-rank tests were performed for the 10 min test times. CONCLUSIONS: Both Orthodontic Concise and the three anaerobic adhesives displayed a specificity towards different attachment alloys. Whereas Orthodontic Concise displayed the highest force to debond with stainless steel attachments, for the anaerobic adhesives this was true of the copper attachments. With stainless steel attachments, however, the force to debond with the anaerobic adhesives was similar to that observed with Orthodontic Concise and steel, at least after the relatively short 10 min bench curing time.
This critical review of the published literature on dental materials for the year 1996 has been compiled by the Dental Materials Panel of the UK. It continues the series of annual reviews started in 1973 and published in the Journal of Dentistry. Emphasis has been placed upon publications which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, resin-bonded bridges and ceramo-metallic restorations, ceramics, denture base resins and soft lining materials, impression materials, implants materials, orthodontic materials, biomechanics and image processing, resin composites and casting investment materials and waxes). Three hundred and thirteen articles have been reviewed.
This critical review of the published literature on dental materials for the year 1996 has been compiled by the Dental Materials Panel of the UK. It continues the series of annual reviews started in 1973 and published in the Journal of Dentistry. Emphasis has been placed upon publications which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, resin-bonded bridges and ceramo-metallic restorations, ceramics, denture base resins and soft lining materials, impression materials, implants materials, orthodontic materials, biomechanics and image processing, resin composites and casting investment materials and waxes). Three hundred and thirteen articles have been reviewed.
It is well known that elastomers exhibit viscoelasticity and as such have their mechanical properties modified by temperature. Nickel titanium archwires are also affected by temperature and have been modified with specific temperature related properties for clinical use. What is less well known is the effect that other environmental factors, such as food, might have on the force delivery properties of both elastomeric materials and nickel titanium coil springs used for space closure. For instance gross colour change in elastomeric chain is a common clinical finding in patients who consume spiced foods. The aim of this work was to determine the effect three common environmental factors namely, water, Coke, and turmeric solution have on elastomeric chain and nickel titanium coil springs. In addition, it was decided to re-examine the effect of temperature at 10, 22, and 37 degrees C on both these space closing materials. Unlike many previous investigations, the test specimens were held at a constant stretch throughout the test period, including during their transfer to the Instron Universal Testing machine for force measurement. Six force measurements were made over the first hour, then at 24 hours and 7 days. A control group of dry specimens, maintained at 22 degrees C, had additional measurements made weekly for a 4-week period. The results indicated that elastomeric chain was affected by all the test environments while nickel titanium springs were only affected by temperature.
OBJECTIVE: To determine whether a swimmer's view or supine (trauma) oblique views are more likely to visualise the lower cervical spine when a lateral view fails to show the cervicothoracic junction. DESIGN: A prospective study comparing two 20 week periods. In the first phase the swimmer's view was performed as an additional view when the cervicothoracic junction was not demonstrated. In the second phase paired supine oblique views replaced the swimmer's view. RESULTS: 230 patients were included in the first phase, of whom 60 required swimmer's views. In the second phase 62 of 197 patients required supine oblique views. Radiology analysis of 53 pairs of supine oblique views showed that the vertebral bodies were adequately demonstrated at the cervicothoracic junction in only 20 patients (38%) compared with 22 in the swimmer's group (37%). The facet joints and posterior elements were, however, clearly seen in 37 (70%) of the supine oblique patients compared with 22 (37%) of the swimmer's group (p < 0.001, chi2 test). Exposure dose calculations showed a substantial reduction for a pair of supine oblique views (1.6 mGy) over a single swimmer's view (7.2 mGy). CONCLUSIONS: In injured patients for whom the standard three view series fails to demonstrate the cervicothoracic junction, swimmer's views and supine oblique views show the alignment of the vertebral bodies with equal frequency. However, supine oblique films are safer, expose patients to less radiation, and are more often successful in demonstrating the posterior elements.
This in vitro investigation was designed to establish not only how clinicians apply forces for space closure when using the straight wire appliance and sliding mechanics, but also to quantify the initial force levels produced. A single typodont, with residual extraction space in each quadrant, was set up to simulate space closure using sliding mechanics. On two occasions, at least 2 months apart, 18 clinicians were asked to apply three force delivery systems to the typodont, in the manner in which they would apply it in a clinical situation. The three types of force delivery system investigated were elastomeric chain, an elastomeric module on a steel ligature, and a nickel-titanium closed coil spring. A choice of spaced or unspaced elastomeric chain produced by a single manufacturer was provided. The amount of stretch which was placed on each type of system was measured and, using an Instron Universal Testing Machine, the initial force which would be generated by each force delivery system was established. Clinicians were assessed to examine their consistency in the amount of stretch which each placed on the force delivery systems, their initial force application and their ability to apply equivalent forces with the different types of force delivery system. The clinicians were found to be consistent in their method of application of the force delivery systems and, therefore, their force application, as individuals, but there was a wide range of forces applied as a group. However, most clinicians applied very different forces when using different force delivery systems. When using the module on a ligature the greatest force was applied, whilst the nickel titanium coil springs provided the least force.
At the commencement of fixed appliance therapy the operator has the choice of either placing bands, brackets, and archwires at one visit, and hence loading the brackets within an hour of initial placement, or placing the brackets and separators at one visit, and the bands and archwires at a subsequent visit. In the case of the latter, the brackets will only be loaded intermittently during the intervening period, for example during mastication. The present study investigated the effect of loading bonded brackets for 2 weeks prior to measuring shear debonding force in vitro, and compared the results with in vivo bond failure rates for two groups of patients whose brackets were loaded by the archwire either immediately after bonding, or not less than 1 week later. Shear testing and survival analysis indicated in vitro loading prior to testing had no significant effect on the shear debonding force. When the in vivo data were studied there was no significant difference in the rate of bond failure between those patients whose archwires were placed at the time of fitting the appliance, and those whose archwires were placed no less then 1 week after bracket placement.
Severe accidental hypothermia in an urban environment is usually associated with drug or alcohol abuse or serious illness in elderly or debilitated patients. In the presence of cardiovascular instability, extracorporeal rewarming by cardiopulmonary bypass is the gold standard of treatment of such patients. Three cases of profound hypothermia with circulatory collapse are presented. Each was successfully resuscitated to a full neurological recovery using this method in an accident and emergency (A&E) department, although one died later of respiratory complications. All three cases had a serum potassium in the normal range at the start of treatment. Where facilities exist, extracorporeal rewarming can be performed in A&E for patients with profound hypothermia and circulatory collapse. Cardiopulmonary resuscitation must be continued throughout the rewarming process.
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The aim of this investigation was to determine the effect of static loading on the measured shear bond strength of steel attachments bonded to enamel. Sixty steel attachments were bonded to extracted and prepared premolar teeth with Orthodontic Concise (3M St Paul, Minnesota, USA) and allowed to bench cure for 2 weeks. Half the specimens had 78 g weights suspended from the attachment, close to the bondline, prior to testing. The mean shear bond strength for the statically loaded samples was 127 N and for the unloaded 85.4 N. The 95 per cent confidence intervals for the difference between the means was 26.7-56.8 N indicating that static loading prior to shear testing significantly increases shear bond strength.