Statement of problem

The output torque delivered by a dental implant toggle-style torque wrench is known to be affected by activation rate. The International Organization for Standardization (ISO) established the ISO 6789-1 standard to provide guidance on activation rates relative to desired output torque in the Nm torque range. Whether the ISO 6789-1 standard applies at the relatively lower dental torque ranges is not known, and little information is available on the activation rates that clinicians use and how this may affect output torque.

Purpose

The purpose of this in vitro study was to determine how output torque values vary with the activation rates used by clinicians at dental implant-relevant target torque values.

Material and methods

To determine clinically relevant activation rates, a new adjustable dental implant toggle-style torque wrench was activated from 0 to 25 Ncm target torque by 5 prosthodontists by using a custom mandibular and maxillary typodont model containing implants and abutments with screws. This provided a baseline of activation rates (mm/sec). Data were transferred to a computerized numerical control model incorporating a variable speed linear motor, which was used to drive a dental implant toggle-style torque wrench attached to an electronic torque measuring device. Constant speed and a regulated dual-speed-assigned 80/20 rate group, where 80% of target torque value was delivered first, then a pause, and the final 20% at different speeds as suggested by the ISO 6789-1 standard, were evaluated. Fast, medium, and slow rates were categorized and applied with target torque values of 10, 25, and 35 Ncm, respectively, for n=12 activations. The output torque values were recorded for both constant and 80/20 groups and compared with the desired target torque values. Data were statistically analyzed with 1-way ANOVA and the Scheffé post hoc paired t test (α=.05).

Results

The clinicians’ activation rates from 0 to 25 Ncm on the typodont model converted into linear speeds resulted in fast =24.19 mm/sec, medium =14.5 mm/sec, and slow =7.25 mm/sec. When actioned at a constant rate, the mean output torque values were generally in the order of slow > medium > fast in activation rates. Generally, precision output torque decreased as target torque increased, especially when slow and medium rates, either constant or regulated 80/20 were used. All mean output torque for slow, medium, and their 80/20 variants were greater than target torque. Fast and 80/20 fast produced the lowest mean output torque values for all torque settings, and at the 35 Ncm setting, the dental implant toggle-style torque wrench output torque mean values were lower than target torque. Statistically significant differences (P<.05) were found among groups, most notably in the 80/20 dual-speed groups, especially in comparisons with the 80/20 fast rate group. When the target torque value was 10 Ncm with the 80/20 fast rate, the output torque value deviated from the maximum ISO limit by more than 6%.

Conclusions

The rate of actioning a dental implant toggle-style torque wrench influenced the delivered torque value, with fast rate actioning producing lower and less precise output torque values.

中文翻译：

---

激活率对牙种植体肘节式扭矩扳手输出扭矩值的影响

问题陈述

众所周知，牙种植体肘节式扭矩扳手提供的输出扭矩会受到激活率的影响。国际标准化组织 (ISO) 制定了 ISO 6789-1 标准，为 Nm 扭矩范围内与所需输出扭矩相关的激活率提供指导。ISO 6789-1 标准是否适用于相对较低的牙科扭矩范围尚不清楚，关于临床医生使用的激活率以及这如何影响输出扭矩的信息也很少。

目的

这项体外研究的目的是确定输出扭矩值如何随临床医生在牙种植体相关目标扭矩值上使用的激活率而变化。

材料与方法

为了确定临床相关的激活率，5 名口腔修复医师使用包含种植体和带螺钉的基台的定制下颌和上颌畸形模型，以 0 至 25 Ncm 目标扭矩激活了一种新的可调式牙科种植体肘节式扭矩扳手。这提供了激活速率 (mm/sec) 的基线。数据被传输到包含变速线性电机的计算机化数控模型，该模型用于驱动连接到电子扭矩测量装置的牙科植入肘节式扭矩扳手。恒定速度和调节双速分配的 80/20 速率组，其中首先提供 80% 的目标扭矩值，然后暂停，最后 20% 以不同的速度按照 ISO 6789-1 标准的建议，是评估。快速，中等，对 n=12 次激活，分别使用 10、25 和 35 Ncm 的目标扭矩值对和慢速进行分类和应用。记录恒定和 80/20 组的输出扭矩值，并与所需的目标扭矩值进行比较。使用单向方差分析和 Scheffé 事后配对对数据进行统计分析t检验 (α=.05)。

结果

临床医生在 typodont 模型上从 0 到 25 Ncm 的激活率转换为线速度导致快速 =24.19 毫米/秒，中等 =14.5 毫米/秒，慢速 =7.25 毫米/秒。当以恒定速率作用时，平均输出扭矩值通常按激活速率的顺序为慢 > 中 > 快。一般来说，随着目标扭矩的增加，精确输出扭矩会降低，尤其是在使用恒定或调节 80/20 的慢速和中速时。慢速、中速及其 80/20 变体的所有平均输出扭矩均大于目标扭矩。快速和 80/20 快速产生所有扭矩设置的最低平均输出扭矩值，并且在 35 Ncm 设置下，牙种植体肘节式扭矩扳手输出扭矩平均值低于目标扭矩。统计学上的显着差异（P<.05) 在各组中被发现，尤其是在 80/20 双速组中，尤其是在与 80/20 快速组的比较中。当目标扭矩值为 10 Ncm 和 80/20 快速速率时，输出扭矩值偏离最大 ISO 限制超过 6%。

结论

牙科植入物肘节式扭矩扳手的作用速率会影响传递的扭矩值，快速作用会产生较低且不太精确的输出扭矩值。