Evaluation of insertional torque and axial pull-out strength of mini-implants for orthodontic anchorage / Avaliação do torque de inserção e da força de arrancamento axial de mini-implantes para ancoragem ortodôntica

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Introduction: The objectives of this study were to evaluate insertional torque of miniimplants (MI) for orthodontic anchorage, to compare MI axial pull-out strength at 0 (T0), 15 (T15) and 60 (T60) days after insertion, to determine initial and final cortical bone thickness, and to analyze the correlations among these variables. Methods: Sixty 1.6 x 6.0 mm MI were inserted in the mandible of ten mongrel dogs. Peak insertional torque values were recorded, and after animal euthanasia, specimens were prepared. MI were aligned with a testing machine to register only axial pull-out strength. Cortical bone thickness was measured after MI removal. Statistical analysis were conducted with ANOVA and Tukeys HSD tests. Results: Pull-out strength and final cortical bone thickness showed differences (p<0.01) among the time points following insertion. The T0 group showed the highest pull-out strength and T60 the smallest final cortical bone thickness. There was a regular correlation between pull-out strength and final cortical bone thickness found in T0 (r=0.44, p=0.05). There was no correlation between insertional torque and pull-out strength, and insertional torque and initial cortical bone thickness. Conclusions: Pull-out strength is greater immediately after MI insertion, cortical bone thickness decreases due to bone resorption, and insertional torque is not an efficient method for predicting MI retention.

ASSUNTO(S)

ortodontia - diagnóstico ortodontia corretiva odontologia ortodontia preventiva

ACESSO AO ARTIGO

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