Ansari Tariq Ajaz, Mascarenhas Rohan, Husain Akhter, Salim Mohammed
Department of Orthodontics, Yenepoya Dental College, Yenepoya University, Mangalore, India.
Orthodontics (Chic.). 2011 Winter;12(4):318-29.
To evaluate the effectiveness of the power arm in bringing about bodily movement and to determine the ideal length and location of the power arm.
A geometric model of the maxillary right canine was constructed and subsequently converted to a finite element model. Material property data were represented, boundary conditions were defined, and force was applied. Different situations were simulated in which a power arm of varying vertical lengths were attached at different locations on the tooth--namely, the incisal, middle, and cervical thirds.
The amount of bodily movement is maximum when the force is delivered directly at the cervical third. It decreases at the middle third and is least when attached at incisal third. The varying lengths of the power arm for a particular site of attachment does not bring about any change in the movement.
The attachment of the power arm at the cervical third brought about maximum bodily movement, followed by the middle and incisal thirds. Variations in length of the power arm at different sites of attachment did not bring any change in the outcome. Thus, the point of attachment is critical in bringing about bodily movement.
评估力臂在引起牙齿整体移动方面的有效性,并确定力臂的理想长度和位置。
构建右上颌尖牙的几何模型,随后将其转换为有限元模型。表示材料属性数据,定义边界条件,并施加力。模拟不同情况,即在牙齿的不同位置(即切缘、中部和颈部三分之一处)连接不同垂直长度的力臂。
当力直接施加在颈部三分之一处时,牙齿整体移动量最大。在中部三分之一处移动量减小,而连接在切缘三分之一处时移动量最小。在特定附着部位,力臂长度的变化不会引起移动的任何改变。
力臂附着在颈部三分之一处可引起最大的牙齿整体移动,其次是中部和切缘三分之一处。在不同附着部位力臂长度的变化不会使结果产生任何改变。因此,附着点在引起牙齿整体移动方面至关重要。