Statement of problem

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.

Purpose

The purpose of this in vitro study was to determine the optimal tightening protocol for implant abutment screws.

Material and methods

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.

Results

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.

Conclusions

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.

中文翻译：

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评估种植体基台螺钉拧紧方案对反向拧紧值的影响：一项体外研究

问题陈述

种植体基台螺钉的松动是种植体支撑牙冠的常见假体并发症。但是，客观评估了不同拧紧方案对反向拧紧值的有效性的报告很少。

目的

这项体外研究的目的是确定植入物基台螺丝的最佳拧紧方案。

材料与方法

将五十个Neos植入物随机分为5组（n = 10）。植入物被盖上螺钉并安装，并且压印帽被拧紧。通过使用数字测量装置测量拧紧度。然后，放置植入物基台，并使用Crystaloc螺丝将其拧紧至32 Ncm。在2T10I组中，第一次和第二次拧紧之间的间隔为10分钟，两次拧紧螺钉。在2T0I组中，没有间隔时间将螺钉拧紧两次。在1T组中，仅将螺钉拧紧1次。在TCT组中，将螺钉拧紧，反向拧紧，然后再次拧紧。在TCTCT组中，将基台螺丝拧紧，反向拧紧，拧紧，反向拧紧，然后再次拧紧。将所有已安装的植入物在相同的环境中放置3个小时，

结果

前四组的平均反向拧紧值范围为21.49 Ncm至22.57 Ncm，而第五组的平均反向拧紧值范围为25.51 Ncm。在反向拧紧数据下，各组之间存在显着差异（P <.05）。

结论

在以10分钟的间隔时间（无间隔时间）将基台螺钉拧紧2次或仅将其拧紧1次时，没有发现显着差异。但是，在3次拧紧和反拧紧组中，反向拧紧存在显着差异。