Abstract：
BACKGROUND: Extraction space closure is a challenging phase during orthodontic treatment that affects not only the total treatment duration but also the whole treatment outcome.
OBJECTIVE: To compare the efficiency of friction and frictionless mechanics during en-masse retraction of maxillary anterior teeth in adult patients with bimaxillary dentoalveolar protrusion.
METHODS: Two-arm parallel group, single-center randomized clinical trial.
METHODS: Thirty-two adult patients with bimaxillary protrusion were recruited and randomly allocated to two different retraction mechanics. A friction group, using NiTi coil springs and a frictionless group using closing T-loops for en-masse retraction. Randomization in a 1:1 ratio was generated by Microsoft Excel. The randomization numbers were secured in opaque sealed envelopes for allocation concealment. Retraction started in all patients following first premolars extraction using miniscrews as a source of indirect anchorage. Activation was done on a monthly basis until complete retraction of anterior segment. The rate of retraction, amount of anchorage loss, the dental, and soft tissue changes were analyzed on digital models and lateral cephalograms taken before retraction and after space closure.
METHODS: The outcome assessor was blinded through data concealment during assessment.
RESULTS: Two patients were lost to follow up, so 30 patients completed the trial. The rate of anterior segment retraction was 0.88 ± 0.66 mm/month in the frictionless group compared to 0.72 ± 0.36 mm/month in the friction group which was statistically significant. Anchorage loss of 1.18 ± 0.72 mm in the friction group compared to 1.29 ± 0.55 mm in the frictionless group with no significant difference. Comparable dental and soft tissue changes following en-masse retraction were reported in both groups, with no statistically significant difference.
UNASSIGNED: one patient complained of soft tissue swelling following miniscrew insertion, but the swelling disappeared after one week of using mouth wash.
CONCLUSIONS: The study focused only on the maxillary arch.
CONCLUSIONS: Both mechanics have successfully achieved the required treatment objectives in patients with bimaxillary dentoalveolar protrusion. Frictionless group showed a faster rate of retraction than the friction group, which was statistically but not clinically significant.
BACKGROUND: Clinicaltrials.gov with the identifier NCT03261024.
OBJECTIVE: To compare the efficiency of friction and frictionless mechanics during en-masse retraction of maxillary anterior teeth in adult patients with bimaxillary dentoalveolar protrusion.
METHODS: Two-arm parallel group, single-center randomized clinical trial.
METHODS: Thirty-two adult patients with bimaxillary protrusion were recruited and randomly allocated to two different retraction mechanics. A friction group, using NiTi coil springs and a frictionless group using closing T-loops for en-masse retraction. Randomization in a 1:1 ratio was generated by Microsoft Excel. The randomization numbers were secured in opaque sealed envelopes for allocation concealment. Retraction started in all patients following first premolars extraction using miniscrews as a source of indirect anchorage. Activation was done on a monthly basis until complete retraction of anterior segment. The rate of retraction, amount of anchorage loss, the dental, and soft tissue changes were analyzed on digital models and lateral cephalograms taken before retraction and after space closure.
METHODS: The outcome assessor was blinded through data concealment during assessment.
RESULTS: Two patients were lost to follow up, so 30 patients completed the trial. The rate of anterior segment retraction was 0.88 ± 0.66 mm/month in the frictionless group compared to 0.72 ± 0.36 mm/month in the friction group which was statistically significant. Anchorage loss of 1.18 ± 0.72 mm in the friction group compared to 1.29 ± 0.55 mm in the frictionless group with no significant difference. Comparable dental and soft tissue changes following en-masse retraction were reported in both groups, with no statistically significant difference.
UNASSIGNED: one patient complained of soft tissue swelling following miniscrew insertion, but the swelling disappeared after one week of using mouth wash.
CONCLUSIONS: The study focused only on the maxillary arch.
CONCLUSIONS: Both mechanics have successfully achieved the required treatment objectives in patients with bimaxillary dentoalveolar protrusion. Frictionless group showed a faster rate of retraction than the friction group, which was statistically but not clinically significant.
BACKGROUND: Clinicaltrials.gov with the identifier NCT03261024.
摘要：
背景：在正畸治疗过程中，拔牙空间闭合是一个具有挑战性的阶段，不仅影响整个治疗持续时间，而且影响整个治疗结果。
目的：比较成人双颌牙槽突突患者上颌前牙整体缩回过程中摩擦和无摩擦力学的效率。
方法：双臂平行组，单中心随机临床试验。
方法：招募了32例成年双颌前突患者，并随机分配到两种不同的牵拉力学中。一个摩擦组，使用NiTi螺旋弹簧和无摩擦组，使用闭合T形圈进行整体回缩。通过MicrosoftExcel产生1:1比例的随机化。将随机化编号固定在不透明的密封信封中，以进行分配隐藏。首次使用小支抗作为间接锚固源的前磨牙拔除后，所有患者都开始缩回。每月进行一次激活，直到眼前段完全缩回。退缩的速度,锚固损失金额，牙齿,在回缩前和空间闭合后采集的数字模型和外侧头颅图分析软组织变化。
方法：结果评估者在评估期间通过数据隐藏而蒙蔽。
结果：两名患者失访，所以30名患者完成了试验。无摩擦组前段回缩率为0.88±0.66mm/月，摩擦组为0.72±0.36mm/月，差异有统计学意义。摩擦组的支抗损失为1.18±0.72mm，与无摩擦组的1.29±0.55mm无明显差异。两组均报告了整体回缩后的牙齿和软组织变化，差异无统计学意义。
■一名患者主诉微型机组插入后软组织肿胀，但是使用漱口水一周后肿胀消失了。
结论：本研究仅集中于上颌弓。
结论：两种机制都成功地实现了双颌牙槽突突患者所需的治疗目标。无摩擦组比摩擦组有更快的回缩速度，具有统计学意义，但无临床意义。
背景：Clinicaltrials.gov，标识符为NCT03261024。
目的：比较成人双颌牙槽突突患者上颌前牙整体缩回过程中摩擦和无摩擦力学的效率。
方法：双臂平行组，单中心随机临床试验。
方法：招募了32例成年双颌前突患者，并随机分配到两种不同的牵拉力学中。一个摩擦组，使用NiTi螺旋弹簧和无摩擦组，使用闭合T形圈进行整体回缩。通过MicrosoftExcel产生1:1比例的随机化。将随机化编号固定在不透明的密封信封中，以进行分配隐藏。首次使用小支抗作为间接锚固源的前磨牙拔除后，所有患者都开始缩回。每月进行一次激活，直到眼前段完全缩回。退缩的速度,锚固损失金额，牙齿,在回缩前和空间闭合后采集的数字模型和外侧头颅图分析软组织变化。
方法：结果评估者在评估期间通过数据隐藏而蒙蔽。
结果：两名患者失访，所以30名患者完成了试验。无摩擦组前段回缩率为0.88±0.66mm/月，摩擦组为0.72±0.36mm/月，差异有统计学意义。摩擦组的支抗损失为1.18±0.72mm，与无摩擦组的1.29±0.55mm无明显差异。两组均报告了整体回缩后的牙齿和软组织变化，差异无统计学意义。
■一名患者主诉微型机组插入后软组织肿胀，但是使用漱口水一周后肿胀消失了。
结论：本研究仅集中于上颌弓。
结论：两种机制都成功地实现了双颌牙槽突突患者所需的治疗目标。无摩擦组比摩擦组有更快的回缩速度，具有统计学意义，但无临床意义。
背景：Clinicaltrials.gov，标识符为NCT03261024。
