Papa J, Wilson P R, Tyas M J
School of Dental Science, University of Melbourne, Australia.
J Dent. 1993 Oct;21(5):259-64. doi: 10.1016/0300-5712(93)90103-w.
Self-threading dentine pins permit the retention of large complex direct restorations but there are problems associated with their placement. Strain and crazing of dentine following pin insertion and pulpal and lateral perforations are common. Perforations can be avoided by operator awareness of tooth morphology. Strain and crazing has been found to be minimized by unscrewing the pin slightly after insertion, by using pins with a tap thread, and by using the smallest pin possible. Twist drill form and dulling affects the pin channel shape which in turn influences pin seating. A lack of standardization of pin and twist drill diameter and length has been implicated as the cause of poor pin retention. Manufacturers, in an attempt to standardize the depth of penetration of pins, have incorporated shoulders at the midpoint of the pin, which has met with varying success. More research in the area of limiting pin penetration is necessary, as well as attempts to improve the quality control of pin and twist drill manufacture.
自攻牙本质钉有助于固位大型复杂的直接修复体，但在放置过程中存在一些问题。钉插入后牙本质的应变和裂纹以及牙髓和侧穿是常见的。通过术者了解牙齿形态可以避免穿孔。已发现通过插入后稍微拧松钉子、使用带螺距螺纹的钉子以及使用尽可能小的钉子可将应变和裂纹降至最低。麻花钻的形状和钝度会影响钉道形状，进而影响钉子就位。钉和麻花钻的直径及长度缺乏标准化被认为是钉子固位不佳的原因。制造商为使钉子的穿透深度标准化，在钉子中点处设置了肩部，但效果不一。有必要在限制钉子穿透方面开展更多研究，并努力改进钉子和麻花钻制造的质量控制。
