RESUMO
Palatal finger springs are often used in removable orthodontic appliances to tip teeth in a mesiodistal direction. There is general consensus that a force of 30-50 g is required to tip a single-rooted tooth, with an activation of about 3 mm for a spring with a load/deflection rate (LDR) of 15 g/mm. The purpose of this report is to establish the magnitude of forces for finger springs made from different types of wires (i.e. those from different manufacturers and of different diameters and lengths). The findings were that springs made from ordinary 18/8 stainless steel wire showed a lower LDR than previously reported. The 18/9 stainless steel springs gave yet a lower LDR. Definite specifications are given for forming springs. For example, a Unitek 0.51 x 17 mm spring can be used when the traditional activation of 2-4 mm is applied, but should increased activation be required (advocated in this report), the spring length would have to be increased to 20 mm to keep the force within the specified range.
Assuntos
Desenho de Aparelho Ortodôntico , Aparelhos Ortodônticos Removíveis , Fios Ortodônticos , Técnicas de Movimentação Dentária/instrumentação , Análise do Estresse Dentário , Elasticidade , Humanos , Teste de Materiais , Palato Duro , Aço InoxidávelRESUMO
This survey was undertaken to determine the occlusal status of a selected group of urban Zambian Black 9-12 year old children at 5 different schools in the same geographical area in order to determine their need for orthodontic treatment. The examination criteria of the Occlusal Index of Summers (1966) were used. Six hundred and one children who had not previously received orthodontic treatment were examined. The data were analysed statistically by using the calculated Summers Index. The results showed that 83 per cent of the subjects required no orthodontic treatment. Of the 17 per cent who did require orthodontic treatment, 5.2 per cent needed specialized treatment. The malocclusion status of Black Zambian children is very similar to that recorded in epidemiological studies on South African and Swazi Black children. This study indicates that only a small need exists for orthodontic treatment amongst Black Zambian children.
Assuntos
Má Oclusão/epidemiologia , População Negra , Criança , Dentição Mista , Dentição Permanente , Feminino , Necessidades e Demandas de Serviços de Saúde/estatística & dados numéricos , Humanos , Masculino , Má Oclusão/etnologia , Variações Dependentes do Observador , Índice de Gravidade de Doença , Síndrome , Saúde da População Urbana , Zâmbia/epidemiologiaRESUMO
The response by orthodontists to a 1988/89 National Oral Health Survey questionnaire is reported. The 54 predominantly white male respondents reflected a balanced age distribution. The majority were in solo private practice. Almost half employed oral hygienists, 96 per cent worked between 40 and 49 weeks per year and 61 per cent worked between 35 and 44 hours per week. Half were satisfied with their busyness and the remainder were evenly divided between being too busy or not busy enough. The majority of patients were white. It is recommended that imbalances in race and gender amongst orthodontists be redressed.