Graduate Program student in Advanced Education Program in Prosthodontics, Loma Linda University, Loma Linda, Calif; Teaching Assistant, Prosthodontics Department, School of Dentistry, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia.
Adjunct Assistant Professor, Advanced Education Program in Prosthodontics, Loma Linda University, Loma Linda, Calif.
J Prosthet Dent. 2021 Mar;125(3):486-490. doi: 10.1016/j.prosdent.2020.02.035. Epub 2020 May 14.
Implant abutment screw loosening is a common prosthetic complication of implant-supported crowns. However, reports that have objectively evaluated the effectiveness of different tightening protocols on reverse tightening values are sparse.
The purpose of this in vitro study was to determine the optimal tightening protocol for implant abutment screws.
Fifty Neoss implants were randomly distributed to 5 groups (n=10). The implants received a cover screw and mounted, and the impression coping was tightened. Tightening was measured by using a digital measuring device. Then, the implant abutments were placed and tightened to 32 Ncm by using a Crystaloc screw. In Group 2T10I, the screws were tightened twice with an interval of 10 minutes between the first and second tightening. In Group 2T0I, the screws were tightened twice with no interval time. In Group 1T, the screws were tightened 1 time only. In Group TCT, the screws were tightened, counter-tightened, and then tightened again. In Group TCTCT, the abutment screws were tightened, counter-tightened, tightened, counter-tightened, and then tightened again. All the mounted implants were left in the same environment for 3 hours, and the reverse tightening values were then measured.
The mean reverse tightening values of the first 4 groups ranged from 21.49 Ncm to 22.57 Ncm, whereas the reverse tightening value for the fifth group was 25.51 Ncm. A significant difference was found among the groups (P<.05) with reverse tightening data.
No significant difference was found in tightening the abutment screw 2 times with a 10-minute interval time, no interval time, or tightening it 1 time only. However, a significant difference was found in reverse tightening in the 3-time tightening and counter-tightening group.
种植体基台螺钉松动是种植体支持冠修复的常见修复体并发症。然而，目前鲜有报道客观评估不同紧固方案对反向紧固值的影响。
本体外研究的目的是确定种植体基台螺钉的最佳紧固方案。
将 50 个 Neoss 种植体随机分为 5 组（n=10）。种植体安装覆盖螺丝并安装印模帽，紧固印模帽。使用数字测量设备测量紧固程度。然后，将种植体基台放置并用 Crystaloc 螺钉以 32 Ncm 的扭矩拧紧。在 2T10I 组中，螺钉第一次和第二次拧紧之间间隔 10 分钟，共拧紧两次。在 2T0I 组中，螺钉不间隔时间共拧紧两次。在 1T 组中，螺钉仅拧紧一次。在 TCT 组中，螺钉先拧紧，然后反向拧紧，再拧紧一次。在 TCTCT 组中，螺钉先拧紧，反向拧紧，拧紧，反向拧紧，再拧紧一次。所有安装好的种植体都放在相同的环境中 3 小时，然后测量反向紧固值。
前 4 组的平均反向紧固值范围为 21.49 Ncm 至 22.57 Ncm，而第 5 组的反向紧固值为 25.51 Ncm。各组间的反向紧固数据差异有统计学意义（P<.05）。
两次间隔 10 分钟、不间隔时间或仅一次拧紧种植体基台螺钉没有明显差异。然而，三次拧紧和反向拧紧组的反向紧固值差异有统计学意义。
