Biomedical subjects
Publications and source records attributed to K M Postlethwaite.
Orthodontists have a wide choice of companies offering a comprehensive recycling service at competitive prices. Careful debonding procedures should be used before sending bands and brackets for recycling. None of the companies make a charge for recycling damaged brackets, and some companies have established advanced systems of quality control.
Many new developments in design and materials have made it easier for orthodontists to produce good results with fixed appliances in a shorter time. Orthodontic treatment has also become more comfortable and aesthetically pleasing for patients. This is the second of two papers which are intended to provide an update on fixed appliance design and use, so patients can be informed of relevant advances before they are referred to a specialist for orthodontic advice. Part 1 discussed the development in brackets and archwires. Part 2 will now cover recent advances in ligatures and elastomeric ties, intraoral auxiliaries, adhesives, products to assist oral hygiene and prevention during fixed appliance treatment, and new methods of debonding.
Many new developments in design and materials have made it easier for orthodontists to produce good result with fixed appliances in a shorter time. Orthodontic treatment has also become more comfortable and aesthetically pleasing for patients. This is the first of two papers which are intended to provide an update on fixed appliance design and use, so patients can be informed of relevant advances before they are referred to a specialist for orthodontic advice. Part 1 discusses the developments in brackets and archwires. Part 2 will cover recent advances in ligatures and elastomeric ties, intra-oral auxiliaries, adhesives, products to assist oral hygiene and prevention during fixed appliance treatment, and new methods of debonding.
During 1989 I visited the Institute of Postgraduate Dental Education, Jonkoping, Sweden. The trip was funded by a T.C. White Travel Grant from the Royal College of Physicians & Surgeons of Glasgow and the Cordent Dental Trust. The aim of the visit was to observe the methods of teaching orthodontics to general dental practitioners, in Jonkoping, and to discover the role of dental nurses in providing orthodontic treatment in Sweden.
A survey of safety products in the U.K. demonstrates that the orthodontic companies have responded to the need for improvements, and consequently there is a wide choice available. Laboratory tests have shown that there is a large difference in the effectiveness of safety release headgear systems. Further work is needed on safety facebow design to develop a version which meets both the requirements of increased safety, and ease of use. Such a safety facebow, used in conjunction with an effective 'breakaway' headcap will produce a safer system. The safety elements are an integral part of breakaway headgears and safety facebows, and when they are used together--no additional cooperation is required from the patient to increase the margin of safety.
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This paper describes and discusses the results of a survey, conducted by the Consultant Orthodontists Group in the United Kingdom in 1987, which examined the nature and distribution of clinical assistant posts, and consultants' attitudes to the concept of appointing orthodontic auxiliaries. This survey demonstrated a large regional variation in the number of clinical assistant posts and in the number of 'specialist practitioners' and community orthodontists. More than 90% of consultants teach their clinical assistants how to use removable appliances, headgear and simple fixed appliances. More than 70% of consultants also teach their clinical assistants how to use multi-bracketed techniques and functional appliances. Ninety-one per cent of consultants would give their support to developing regional training schemes for clinical assistants in orthodontics. Eighty-eight per cent of consultant orthodontists favoured the appointment of orthodontic auxiliaries to carry out intra-oral work, and 75% believed that they already had a member of staff capable of doing these duties with some further training.
In transverse sections the areas of enamel, dentine and pulp were determined using image analysis morphometry, and the mineralization levels of enamel, dentine and alveolar bone using quantitative microradiography and a microphotometric-microdensitometric technique. There were significant differences in the ratios of dentine to pulp area, and in the enamel to total area in the incisors from dwarf and normal animals. The mean dentine to pulp ratio for dwarf incisors was more than six times greater than in normal incisors. There was also a significantly greater variation in the dentine to pulp ratio in dwarfs, which was attributed to their greater variation in pulp size. Values for mineral density of enamel, dentine and bone were similar to those found by other investigators. For example, for normal specimens, the mean mineral density of outer enamel was 2.84 g/cm3 (SD = 0.38), percentage mineralization 92%; outer labial dentine was 1.64 g/cm3 (SD = 0.15), percentage mineralization 52%; and alveolar bone was 1.53 g/cm3 (SD = 0.13), percentage mineralization 49%. The variation in mineralization within each tissue confirmed previous work in rodents. There was a consistent trend for mineralization levels of all hard tissues in the dwarf sample to be less than in the normal sample but the difference was not statistically significant for any one tissue.
This case report describes an unusual phenomenon related to bilaterally displaced canines, where both upper lateral incisors were absent, but where the canines produced extensive root resorption of both upper first premolars, necessitating their removal.