Biomedical subjects
Publications and source records attributed to O Keith.
This is the second of two articles looking at dental care for the patient with a cleft lip and palate. Part 1 looked at the needs of the child from birth through to the mixed dentition stage. Part 2 looks at dental care from the mixed dentition stage through to adolescence and young adulthood.
This is the first of two articles looking at dental care for the patient with a cleft lip and palate. Part 1 looks at the needs of the child with a cleft lip and palate from birth through to the mixed dentition stage.
Currently two-thirds of European countries employ orthodontic auxiliaries and the UK is therefore unusual in not permitting their use. There is support from the orthodontic specialty for the concept of delegating routine intra-oral tasks to auxiliary personnel. The following describes a pilot project undertaken to determine the possible training structure for orthodontic auxiliaries. The modular course, which took place over a period of 4 weeks, is described and the results and implications are discussed.
AIM: To undertake a pilot study to determine a possible training programme for orthodontic auxiliaries. DESIGN AND SETTING: Trainee hygienists who had been accepted onto a 2-year programme were asked to attend the Bristol Dental School well before their course was due to begin in order to participate in a pilot orthodontic assistant auxiliary training programme. METHODS: A modular course of one month's duration was constructed based on the programme at the University of British Columbia. This aimed to teach skills such as impression taking, bond placement, debracketing, band cementation as well as core knowledge relevant to these procedures. RESULTS: At the end of the course all participants were judged to be performing the tasks they had been taught competently and safely. CONCLUSION: UK dental nurses can be trained to fill the role of an orthodontic auxiliary. It would appear that an introductory clinical skills course of one week followed by an orthodontic skills training of three weeks is sufficient for a qualified dental nurse of above average abilities such as typifies those who are currently applying for places on UK dental hygiene courses. It is estimated that a further period of nine months supervised training will be necessary for those who have successfully completed such a training to develop clinically useful speeds when delivering these skills.
A questionnaire survey was carried out to ascertain a profile of orthodontic postgraduates in training in the United Kingdom during 1993. Information about the postgraduates, their programmes and their career plans was collected. Eighty-nine questionnaires were distributed to those enrolled in 13 of the training programmes in the U.K. at that time from which the response rate was 64 per cent. The results can be compared with a similar survey carried out in the United States of America in 1992 (Keith and Proffit, 1994).
Orthodontic brackets were bonded to 180 faces of 45 porcelain cubes that were divided into three groups according to their surface preparation. In group I, the glaze had been removed with a sandpaper disk, whereas in group II, it was maintained. A solution of acidulated phosphate fluoride (APF) gel was applied to the samples in groups I and II for 5 minutes after pumicing. In group III, the glaze had been removed with a coarse diamond bur. Each group was further divided into four subgroups, depending on whether a priming agent had been used, and the type of composite used to bond the brackets. Shear force was used to debond the brackets, and the results showed that the APF solution was unable to provide enough retention on porcelain surface to bond brackets. Mechanical retention, obtained with a coarse diamond bur, was necessary to increase bond strength, which can be further improved by chemical bonding, with a silane priming agent. Therefore bonding to porcelain is clinically possible and is an acceptable procedure in orthodontic treatment.
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The frictional characteristics of two types of zirconia (Harmony, Hudson Ltd., Sheffield, U.K., and Toray, Yamaura Corp., Tokyo, Japan) brackets were compared with those of polycrystalline alumina (Transcend 2000, Unitek Corp., Monrovia, Calif.) brackets in both dry and wet states. To compare the couples, four arch wire alloys were studied: stainless steel, cobalt-chromium, nickel titanium, and beta-titanium. Under dry conditions, the highest frictional coefficients were seen with the Harmony/beta-titanium couple (uk = 0.64); the lowest values were seen with both Transcend 2000/stainless steel (uk = 0.13) and Toray/cobalt-chromium couples (uk = 0.13). Beta-titanium arch wires produced the highest coefficients of friction against each type of ceramic bracket, except against Toray arch wires in the wet state. The presence of human saliva produced only slight changes in the frictional behavior of zirconia brackets. We conclude that currently available zirconia brackets offer no significant improvement over alumina brackets with regard to their frictional characteristics.
A survey was carried out at the Graduate Orthodontic Residents' Conference at the University of Michigan, Ann Arbor in August 1991. Questionnaires were distributed to the attending residents who included representatives from 41 of the 51 orthodontic programs in the United States at that time. Of the questionnaires 81% were completed and returned by residents at the schools. Information was gathered relating to the residents themselves, as well as their programs, educational backgrounds, and career plans. The assimilated opinions of the residents on various aspects of their training are presented.
Planar static frictional phenomena were investigated for two types of ceramic and one type of stainless steel orthodontic bracket against rectangular stainless steel archwire. The brackets studied were 'Starfire' (single crystal aluminium oxide), 'Allure III' (polycrystalline aluminium oxide), and 'Dentaurum' (stainless steel). The investigative parameters were: bracket material, force of ligation and whether the brackets were new or 'worn'. Without exception, both types of ceramic bracket produced greater frictional resistance than the stainless steel brackets throughout testing. At a ligation force of 500 g, the Starfire bracket gave the greatest frictional resistance. At ligation forces of 200 and 50 g, the greatest frictional resistance was seen with Allure III. After a period of simulated wear, frictional resistance of Starfire tended to increase at the greatest ligation load while that of both ceramics decreased slightly at the two lower ligation loads. The ceramic brackets caused abrasive wear of the archwire surfaces and the consequent wear debris may have contributed to the changes in frictional resistance seen with Starfire and Allure III. Dentaurum brackets produced minimal frictional resistance in any test and negligible change with wear.
The aim of this study was to evaluate clinically a bonded space maintainer, which would reduce chair-side time and cost. Sixty appliances were fabricated from 0.7 mm stainless steel round wire and bonded using light-cured composite to the two teeth adjacent to the site of extraction of a posterior primary tooth. Twenty males and sixteen females (age range 5-9-years-old) were selected from the Pedodontic clinic of the State University of Rio de Janeiro. The sixty space maintainers were divided into two groups according to the site in which they were placed: a) absent first primary molar and b) absent second primary molar. Impressions and study models were obtained prior to and 6 months after bonding the appliances. During this period only 8.3% of failures were observed, most of them from occlusal or facial trauma. Student t-test did not show statistically significant alterations in the sizes of the maintained spaces during the trial period.
A group of thirty-four patients with recurrent aphthous stomatitis (RAS) and single hematinic deficiencies were given replacement therapy after any reason for the deficiency had been sought and excluded. The response of the RAS was assessed in an open trial. The aphthae in 70% of patients subjectively improved with hematinic replacement therapy, a benefit exceeding the defined placebo response in recurrent aphthous stomatitis.
Scheie syndrome is a rare inborn error of metabolism, a mucopolysaccharidosis in which deficiency of the lysosomal enzyme alpha-L-iduronidase leads to tissue accumulation of mucopolysaccharides. Scheie syndrome is a forme fruste of Hurler syndrome (gargoylism), and some patients have the phenotype of Hurler-Scheie compound syndrome. The craniofacial abnormalities include coarse facies, mandibular condylar hypoplasia, retarded tooth eruption, and cystic jaw radiolucencies--particularly about the molars. Corneal clouding may lead to blindness but, in contrast to some other mucopolysaccharidoses, mental handicap is rare in Scheie syndrome. Cardiac valve incompetence is common, as are recurrent respiratory infections. Two brothers with Hurler-Scheie syndrome are presented and the oral and systemic complications each patient had described. The syndrome is discussed with particular reference to the orofacial features.
A case of compound fracture of the articular eminence is presented. The injury was sustained as a result of direct trauma which also caused a mandibular symphyseal fracture. Management comprised repositioning and support of the fractured fragment by means of sutures and the application of intermaxillary fixation. There was no long-term limitation of mandibular movement nor was there neurological or hearing deficit as a result of either injury or treatment.
A 30-year-old female patient suffering from anorexia nervosa, developed an acute submandibular cellulitis. She was found to have a lingual abscess, for which the only detectable source of infection was a grossly carious lower molar. The oral features of the more common eating disorders are described.
A case is presented of an inverted upper lateral incisor in an 11-year-old patient. It is believed that involvement of this tooth is previously unreported.
Hereditary hemorrhagic telangiectasia is reviewed, and the orofacial features of the condition are illustrated by details of an affected family and in particular a male patient who is now 63 years old. The nature of the disease from its insidious onset in the second and third decades to involve not only the mucous membranes but all cutaneous and visceral structures is noted, together with medical complications. Aspects of general and dental management are summarized.