Sorensen J A, Engelman M J
University of California, School of Dentistry, Los Angeles.
J Prosthet Dent. 1990 May;63(5):529-36. doi: 10.1016/0022-3913(90)90070-s.
This study evaluated the fracture resistance of pulpless teeth with various ferrule designs and amounts of coronal tooth structure. One millimeter of coronal tooth structure above the crown margin substantially increased the fracture resistance of endodontically treated teeth, whereas a contrabevel at either the tooth-core junction or the crown margin was ineffective. The thickness of axial tooth structure at the crown margin did not appreciably improve resistance to fracture.
本研究评估了具有不同箍设计和冠部牙体组织量的无髓牙的抗折性。在冠边缘上方1毫米的冠部牙体组织显著提高了根管治疗后牙齿的抗折性，而在牙本质-核交界处或冠边缘处的反斜面则无效。冠边缘处轴向牙体组织的厚度并未明显提高抗折性。
