Objectives

To compare blood flow (BF) changes of teeth subjected to orthodontic forces during curve of Spee (COS) leveling using different archwires (AW).

Material and methods

Thirty subjects with COS > 5 mm were randomly assigned (1:1:1) into three groups based on the AW used: group 1: 0.017 × 0.025-inch stainless-steel (SS)AW, group 2: 0.019 × 0.025-inch SSAW, and group 3: 0.021 × 0.025-inch β-titanium (TMA)AW. In the 3 groups, a 5 mm-depth reverse COS was placed in the AWs. A laser Doppler flowmeter was used to measure BF at different time intervals (T0–T4).

Results

In the 3 AWs group, BF of all measured teeth was reduced 20 min after force application. Afterwards, the BF values started to increase until the baseline values were almost restored within 1 week. Differences in BF changes between the extrusion and intrusion subgroups were observed within groups 1 and 3 during the first 20 min of force application (P < 0.05). Similar BF changes were recorded using the 3 different AWs. BF changes were associated with tooth type and the amount of COS depth change.

Conclusions

During CoS leveling, similar BF changes were recorded using the 3 different AWs. Tooth type and the amount of COS depth change were associated with BF changes within the first 20 min of force application. Greater BF reduction was found in premolars compared to incisors during the first 20 min of AW placement.

Clinical relevance

It is important to select a type of applied forces that minimally affect the BF. Intrusive forces appeared to have lower negative effects on the BF of teeth during COS leveling.

Trial registration

ClinicalTrial.gov (# NCT04549948).

中文翻译：

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使用不同尺寸的弓丝调平 Spee 曲线：血流变化的随机临床试验

目标

比较使用不同弓丝 (AW) 进行 Spee 曲线 (COS) 调平过程中受正畸力作用的牙齿的血流 (BF) 变化。

材料与方法

根据所使用的 AW，将 30 名 COS > 5 mm 的受试者随机分配 (1:1:1) 分为三组：第 1 组：0.017 × 0.025 英寸不锈钢 (SS)AW，第 2 组：0.019 × 0.025 英寸SSAW 和第 3 组：0.021 × 0.025 英寸 β-钛 (TMA)AW。在 3 组中，将 5 mm 深的反向 COS 放置在 AW 中。使用激光多普勒流量计在不同时间间隔（T0-T4）测量 BF。

结果

在3个AW组中，所有测量的牙齿的BF在施力后20分钟减少。此后，BF值开始增加，直至1周内几乎恢复基线值。在施力的前 20 分钟内，第 1 组和第 3 组中观察到挤压亚组和侵入亚组之间 BF 变化存在差异（P  < 0.05）。使用 3 种不同的 AW 记录了类似的 BF 变化。BF 变化与牙齿类型和 COS 深度变化量相关。

结论

在 CoS 调平期间，使用 3 个不同的 AW 记录了类似的 BF 变化。牙齿类型和 COS 深度变化量与施力前 20 分钟内 BF 变化相关。在 AW 放置的前 20 分钟内，与切牙相比，前磨牙的 BF 减少幅度更大。

临床相关性

选择一种对 BF 影响最小的外加力类型非常重要。在 COS 矫治过程中，侵入力似乎对牙齿 BF 的负面影响较小。

试用注册

ClinicalTrial.gov（# NCT04549948）。