Private practice, Bellevue, Wash; Adjunct Assistant Professor, Advanced Education Program in Prosthodontics, Loma Linda University, Loma Linda, Calif.
Retired Engineer, Bellevue, Wash.
J Prosthet Dent. 2023 May;129(5):763-768. doi: 10.1016/j.prosdent.2021.07.006. Epub 2021 Sep 2.
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.
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.
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).
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%.
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.
众所周知，牙种植体 toggle 式扭矩扳手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，旨在提供与所需输出扭矩相关的激活率指南，扭矩范围为 Nm。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，并且有关临床医生使用的激活率以及这如何影响输出扭矩的信息很少。
本体外研究的目的是确定在与牙种植体相关的目标扭矩值处，临床医生使用的激活率如何使输出扭矩值发生变化。
为了确定临床相关的激活率，由 5 名修复医生使用定制的下颌和上颌模型牙模型来激活新的可调牙种植体 toggle 式扭矩扳手，该模型牙模型包含带有螺丝的种植体和基台。这提供了激活率（mm/sec）的基线。数据被传输到计算机数控模型中，该模型采用变速直线电机，用于驱动连接到电子扭矩测量装置的牙种植体 toggle 式扭矩扳手。评估了恒速和规定的双速分配 80/20 速率组，其中首先以 80%的目标扭矩值输送，然后暂停，最后以 ISO 6789-1 标准建议的不同速度输送最后 20%。以 10、25 和 35 Ncm 的目标扭矩值分别对快速、中速和慢速进行了分类和应用，共进行了 12 次激活。记录了恒定和 80/20 组的输出扭矩值，并与所需的目标扭矩值进行了比较。使用单向方差分析和 Scheffé 事后配对 t 检验对数据进行了统计学分析（α=.05）。
在 typodont 模型上从 0 到 25 Ncm 的临床医生激活率转换为线性速度，结果为快速=24.19 mm/sec，中速=14.5 mm/sec，慢速=7.25 mm/sec。以恒定速度操作时，输出扭矩值通常按慢速>中速>快速的顺序排列。通常，随着目标扭矩的增加，精密输出扭矩会降低，尤其是在使用慢速和中速时，无论是恒定的还是规定的 80/20 都一样。所有慢速、中速及其 80/20 变体的平均输出扭矩均大于目标扭矩。快速和 80/20 快速在所有扭矩设置下产生的平均输出扭矩值最低，在 35 Ncm 设置下，牙种植体 toggle 式扭矩扳手的输出扭矩平均值低于目标扭矩。组间存在统计学差异（P<.05），尤其是在 80/20 双速组中，尤其是在与 80/20 快速率组的比较中。当目标扭矩值为 10 Ncm 且使用 80/20 快速率时，输出扭矩值偏离 ISO 限值超过 6%。
牙种植体 toggle 式扭矩扳手的操作速度会影响输送的扭矩值，快速操作会产生较低且不太精确的输出扭矩值。
