Jorge Dias Lopes

Comparison of condylar displacement between three biotypological facial groups by using mounted models and a mandibular position indicator.

Objective Facial-type-associated variations in diagnostic features have several implications in orthodontics. For example, in hyperdivergent craniofacial types, growth imbalances are compensated by displacement of the condyle. When diagnosis and treatment planning involves centric relation (CR), detailed knowledge of the condylar position is desirable. The present study aimed to measure condylar displacement (CD) between CR and maximum intercuspation in three facial types of an asymptomatic orthodontic population. Methods The study was conducted in 108 patients classified into three groups of 36 individuals each (27 women and 9 men; mean age, 20.5 years), based on the following facial patterns: hyperdivergent, hypodivergent, and intermediate. To quantify CD along the horizontal and vertical axes, the condylar position was analyzed using mounted casts on a semi-adjustable articulator and a mandibular position indicator. The Student t-test was used to compare CD between the groups. Results Vertical displacement was found to be significantly different between the hyperdivergent and hypodivergent groups (p < 0.0002) and between the hyperdivergent and intermediate groups (p < 0.0006). The differences in horizontal displacement were not significant between the groups. In each group, vertical CD was more evident than horizontal displacement was. Conclusions All facial types, especially the hyperdivergent type, carried a significantly high risk of CD. Therefore, the possibility of CD should be carefully evaluated and considered in the assessment of all orthodontic cases in order to accurately assess jaw relationships and avoid possible misdiagnosis.

I-46. REPRODUTIBILIDADE DE DIFERENTES INSTRUMENTOS DE MEDIÇÃO NA ANÁLISE DE BOLTON.

analisados, 2 foram excluidos e a amostra de validacao passou a ser de 58. Posteriormente realizou-se uma analise estatistica, utilizando os programas MatLab e Excel, obtendose as diferencas entre os valores previstos, segundo os varios metodos, e os valores reais observados nos modelos. Resultados: O metodo de Moyers pelo percentil 50 apresenta uma percentagem de erro superior a 1mm de 29%, o de Tanaka e Johnston de 38% e o de Moyers pelo percentil 75 de 45%. O metodo de Moyers pelo percentil 75 e o de Tanaka e Johnston subestimam o valor real em mais de 1mm em cerca de 3% da amostra. Este ultimo metodo sobrestima por mais de 1mm em 35% dos casos e o metodo de Moyers pelo percentil 75 em 42%. O metodo de Moyers pelo percentil 50 apresenta erros superiores a 1mm de 12% na subestimacao e 17% na sobrestimacao. Conclusoes: Deste trabalho pode concluir-se que a analise da denticao mista atraves do metodo de Moyers pelo percentil 50 e a que apresenta menor frequencia de erros superiores a 1mm. Este metodo tambem apresenta uma distribuicao mais equilibrada dos erros superiores a 1mm na subestimacao e na sobrestimacao. Conclui-se que, de entre os metodos analisados, o de Moyers no percentil 50, e aquele que com mais fiabilidade pode ser aplicado na populacao portuguesa.