Abstract：
To evaluate the effect of friction vs frictionless mechanics on the rate of anterior segment retraction (ASR) in patients with bimaxillary protrusion.
Thirty females (18.3 ± 3.7 years) with bimaxillary protrusion were randomly allocated into the friction group, using elastomeric power chains, and the frictionless group, using T-loop springs for ASR. Eligibility criteria included absence of skeletal discrepancies and any systemic diseases or medications, among others. Randomization in a 1:1 ratio was generated by Microsoft Excel. Opaque sealed envelopes were sequentially numbered for allocation concealment. Only blinding of the outcome assessor was applicable. Activations were done every 4 weeks until completion of ASR. The primary outcome was the rate of ASR measured on digital models. Anchorage loss, molar rotation, and pain experienced were also assessed.
Two patients were lost to follow-up. The rate of ASR was 0.68 ± 0.18 mm/mo in the friction group vs 0.88 ± 0.27 mm/mo in the frictionless group, with no significant difference. A significant difference in anchorage loss of 1.63 mm and molar rotation of 7.06° was observed, being higher in the frictionless group. A comparable pain experience associated with both mechanics was reported.
No difference in the rate of ASR or pain experience was observed between friction and frictionless mechanics. However, extra anchorage measures should be considered when using frictionless mechanics as greater anchorage loss and molar rotations are anticipated.
Thirty females (18.3 ± 3.7 years) with bimaxillary protrusion were randomly allocated into the friction group, using elastomeric power chains, and the frictionless group, using T-loop springs for ASR. Eligibility criteria included absence of skeletal discrepancies and any systemic diseases or medications, among others. Randomization in a 1:1 ratio was generated by Microsoft Excel. Opaque sealed envelopes were sequentially numbered for allocation concealment. Only blinding of the outcome assessor was applicable. Activations were done every 4 weeks until completion of ASR. The primary outcome was the rate of ASR measured on digital models. Anchorage loss, molar rotation, and pain experienced were also assessed.
Two patients were lost to follow-up. The rate of ASR was 0.68 ± 0.18 mm/mo in the friction group vs 0.88 ± 0.27 mm/mo in the frictionless group, with no significant difference. A significant difference in anchorage loss of 1.63 mm and molar rotation of 7.06° was observed, being higher in the frictionless group. A comparable pain experience associated with both mechanics was reported.
No difference in the rate of ASR or pain experience was observed between friction and frictionless mechanics. However, extra anchorage measures should be considered when using frictionless mechanics as greater anchorage loss and molar rotations are anticipated.
摘要：
评价摩擦与无摩擦力学对双颌前突患者眼前节退缩率(ASR)的影响。
将30名女性（18.3±3.7岁）双颌前突随机分配到摩擦组，使用弹性动力链，和无摩擦组，使用T型弹簧ASR。合格标准包括没有骨骼差异和任何全身性疾病或药物，在其他人中。通过MicrosoftExcel产生1:1比例的随机化。不透明的密封信封按顺序编号以进行分配隐藏。只有结果评估者的盲法才适用。每4周进行激活,直到完成ASR。主要结果是在数字模型上测量的ASR率。失去锚地,磨牙旋转,还评估了经历的疼痛。
两名患者失访。摩擦组为0.68±0.18mm/mo,无摩擦组为0.88±0.27mm/mo,没有显著差异。观察到1.63mm的锚固损失和7.06°的磨牙旋转的显着差异，在无摩擦组中较高。报告了与两种力学相关的可比疼痛经历。
在摩擦和无摩擦力学之间没有观察到ASR或疼痛体验率的差异。然而,当使用无摩擦力学时，应考虑额外的锚固措施，因为预计会有更大的锚固损失和磨牙旋转。
将30名女性（18.3±3.7岁）双颌前突随机分配到摩擦组，使用弹性动力链，和无摩擦组，使用T型弹簧ASR。合格标准包括没有骨骼差异和任何全身性疾病或药物，在其他人中。通过MicrosoftExcel产生1:1比例的随机化。不透明的密封信封按顺序编号以进行分配隐藏。只有结果评估者的盲法才适用。每4周进行激活,直到完成ASR。主要结果是在数字模型上测量的ASR率。失去锚地,磨牙旋转,还评估了经历的疼痛。
两名患者失访。摩擦组为0.68±0.18mm/mo,无摩擦组为0.88±0.27mm/mo,没有显著差异。观察到1.63mm的锚固损失和7.06°的磨牙旋转的显着差异，在无摩擦组中较高。报告了与两种力学相关的可比疼痛经历。
在摩擦和无摩擦力学之间没有观察到ASR或疼痛体验率的差异。然而,当使用无摩擦力学时，应考虑额外的锚固措施，因为预计会有更大的锚固损失和磨牙旋转。
