临床常见前牙缺失的420~#义齿,基托在隙卡的连接体转弯处容易断裂。其原因:一是420~#义齿是横向线支承轴,当上前牙咬合用力时,此处正好处于应力集中区,容易断裂;二是连接体的转弯处形成直角,使连接体上段与基托内之应力方向成正交(图1)。因此当咬合力通过时易顺着上段延长方向断裂。 Clinical common anterior teeth missing 420 ~ # denture, the base of the gap in the card connector bend easily broken. The reason: First, 420 ~ # denture is a transverse line support shaft, when the anterior teeth occlusal force, here just in the stress concentration zone, easy to break; the second is the connecting body corner formed at right angles, so that the upper body and the base connection The stress direction of the proponents is orthogonal (Figure 1). So when the bite force easily along the extension of the upper direction of fracture.