Martin W C, Woody R D, Miller B H, Miller A W
College of Dentistry, University of Florida, Gainesville, FL 32608, USA.
J Prosthet Dent. 2001 Jul;86(1):24-32. doi: 10.1067/mpr.2001.116230.
Chronic implant screw loosening remains a problem in restorative practices. Some implant manufacturers have introduced abutment screws with treated surfaces in an effort to increase preload and reduce potential loosening. Purpose. This study evaluated the materials and surfaces of 4 commercially available abutment screws on preload generation.
Twenty of each of the following abutment screws-Gold-Tite (Gt), TorqTite (Tt), gold alloy (Ga), and titanium alloy (Ta)-were divided into 2 groups. Measurements were recorded for each abutment screw on a mounted 3.75 x 18 mm external hex implant with a titanium abutment. Rotational angle measurements were conducted on the 4 abutment screws at 20 and 32 Ncm. Removal torque values were recorded and used to indirectly generate preload values. Random implant block specimens were sectioned and qualitatively evaluated with an SEM.
At 20 and 32 Ncm, the largest rotational angles were recorded for the Tt groups: 21.2 +/- 3.1 degrees and 38.1 +/- 8.7 degrees, respectively. The greatest preload values at 20 and 32 Ncm were calculated for the Gt groups: 596.8 +/- 101.2 N and 1015.3 +/- 191.2 N, respectively. SEM analysis of the 4 implant block specimens revealed mating thread contacts located in the middle portion of the superior surface of the abutment screw thread. The greatest number of mating thread contacts were seen in the Gt implant block specimen (14 of 20 possible thread contacts).
The Gt and Tt abutment screws with enhanced surfaces that help reduce the coefficient of friction produced greater rotational angles and preload values than the conventional gold alloy and titanium alloy screws.
在修复治疗中，种植体螺钉长期松动仍是一个问题。一些种植体制造商推出了表面经过处理的基台螺钉，以增加预紧力并减少潜在的松动。目的。本研究评估了4种市售基台螺钉的材料和表面对预紧力产生的影响。
将以下每种基台螺钉——Gold-Tite（Gt）、TorqTite（Tt）、金合金（Ga）和钛合金（Ta）——各20个分为2组。在安装有钛基台的3.75×18 mm外六角种植体上，对每个基台螺钉进行测量记录。在20和32 Ncm的扭矩下，对4种基台螺钉进行旋转角度测量。记录拆除扭矩值并用于间接产生预紧力值。将随机选取的种植体块状标本进行切片，并用扫描电子显微镜进行定性评估。
在20和32 Ncm扭矩下，Tt组记录到的最大旋转角度分别为：21.2±3.1度和38.1±8.7度。在20和32 Ncm扭矩下，Gt组计算出的预紧力值最大，分别为：596.8±101.2 N和1015.3±191.2 N。对4个种植体块状标本的扫描电子显微镜分析显示，基台螺钉螺纹上表面中部存在配合螺纹接触。在Gt种植体块状标本中观察到的配合螺纹接触数量最多（20个可能螺纹接触中有14个）。
与传统的金合金和钛合金螺钉相比，表面经过强化处理、有助于降低摩擦系数的Gt和Tt基台螺钉产生了更大的旋转角度和预紧力值。
