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Effect of Early Versus Late Premolar Extraction on Orthodontic Tooth Movement

2026年8月15日 更新者:Shanzay Khan、Shifa College of Dentistry

Effect of Early vs Late Premolar Extraction on the Rate of Orthodontic Tooth Movement: A Randomized Controlled Trial

The goal of this randomized controlled trial is to evaluate whether the timing of premolar extraction affects the rate of orthodontic space closure during en-masse anterior retraction. The study will also assess gingival cleft formation, mesial movement of the upper first molars, ease and duration of premolar extraction, and patient-reported pain and anxiety.

The main question it aims to answer is:

Does early versus late premolar extraction affect the rate of orthodontic space closure?

Researchers will compare two groups of patients. In the early extraction group the maxillary first premolars will be extracted before or within one week of start of fixed orthodontic treatment. In the late extraction group, the premolars will be extracted after alignment and immediately before the start of space closure.

Participants will:

  • Receive fixed orthodontic treatment and bilateral extraction of the maxillary first premolars.
  • Be randomly assigned to either the early-extraction or late-extraction group.
  • Undergo orthodontic alignment followed by en-masse anterior retraction.
  • Have dental impressions/digital models obtained at the start of retraction and at 3 and 6 months to measure orthodontic tooth movement and space closure.
  • Be assessed for gingival clefts and mesial movement of the upper first molars.
  • Have the ease and duration of their premolar extraction recorded and report their pain and anxiety associated with the extraction procedure.

研究概览

详细说明

This randomized controlled trial will evaluate the effect of early versus late maxillary first premolar extraction on the rate of orthodontic space closure during en-masse anterior retraction. A total of 26 participants aged 13 to 25 years requiring bilateral maxillary first premolar extractions as part of their orthodontic treatment will be randomly allocated in a 1:1 ratio to an early-extraction or late-extraction group.

In the early-extraction group, the maxillary first premolars will be extracted before or within one week of fixed appliance placement. Participants will subsequently undergo leveling and alignment, and en-masse anterior retraction will begin after stabilization on a 0.019 × 0.025-inch stainless steel archwire. In the late-extraction group, leveling and alignment will be completed first using the same archwire sequence. The maxillary first premolars will then be extracted immediately before initiation of en-masse anterior retraction. Thus, space closure will occur through relatively healed extraction sites in the early-extraction group and relatively fresh extraction sites in the late-extraction group.

Orthodontic space closure will be assessed at baseline and at 3 and 6 months after initiation of retraction. Secondary assessments will include mesial movement of the maxillary first molars, incidence and severity of gingival clefts, ease and duration of premolar extraction, and patient-reported pain and anxiety. Digital models will be used to assess orthodontic tooth movement, while gingival clefts will be evaluated clinically.

研究类型

介入性

注册 (估计的)

26

阶段

  • 不适用

联系人和位置

本节提供了进行研究的人员的详细联系信息,以及有关进行该研究的地点的信息。

学习联系方式

学习地点

参与标准

研究人员寻找符合特定描述的人,称为资格标准。这些标准的一些例子是一个人的一般健康状况或先前的治疗。

资格标准

适合学习的年龄

  • 孩子
  • 成人

接受健康志愿者

不

描述

Inclusion Criteria:

  1. Age 13-25 years
  2. No prior orthodontic treatment
  3. Overjet 4-8 mm
  4. Symmetric dental arches with mild to moderate crowding requiring bilateral first premolar extractions.
  5. Probing depth less than 4 mm on all teeth

Exclusion Criteria:

  1. History of dental trauma
  2. Poor oral hygiene
  3. Syndromic patients
  4. Systemic diseases or medications affecting bone metabolism

学习计划

本节提供研究计划的详细信息,包括研究的设计方式和研究的衡量标准。

研究是如何设计的?

设计细节

  • 主要用途:治疗
  • 分配:随机化
  • 介入模型:并行分配
  • 屏蔽:单身的

武器和干预

参与者组/臂
干预/治疗
有源比较器:Healed Socket Group (Control Group)
Maxillary first premolars will be extracted before or within one week of fixed orthodontic appliance placement. Participants will subsequetly undergo leveling and alignment followed by en-masse anterior retraction after stabilization on a 0.019 x 0.025-inch stainless steel archwire.
Bilateral extraction of the maxillary first premolars will be performed prior to or within one week of fixed orthodontic appliance placement, allowing the extraction sockets to heal during leveling and alignment before commencement of en-masse anterior retraction.
实验性的:Unhealed Socket Group (Intervention Group)
Maxillary first premolars will be extracted after the participant has completed leveling and alignment, and has been stabilizad on a 0.019 x 0.025-inch stainless steel archwire for one month. This will be followed immediately by en-masse anterior retraction.
Bilateral extraction of the maxillary first premolars will be performed after completion of leveling and alignment and one month of stabilization on a 0.019 × 0.025-inch stainless steel archwire, immediately before commencement of en-masse anterior retraction.

研究衡量的是什么?

主要结果指标

结果测量
措施说明
大体时间
Rate of Orthodontic Space Closure Measured on Digital 3D Dental Models
大体时间:Baseline (T0), 3 months (T1), and 6 months (T2) after initiation of en-masse anterior retraction
Intraoral scans will be obtained to generate digital 3D dental models at baseline (T0), 3 months (T1), and 6 months (T2) after initiation of en-masse anterior retraction. The extraction space will be measured in millimeters as the linear distance between the highest convexity on the mesial surface of the maxillary second premolar and the distal surface of the maxillary canine. The rate of space closure will be calculated as the reduction in extraction-space width over the corresponding observation period and expressed in millimeters per month (mm/month).
Baseline (T0), 3 months (T1), and 6 months (T2) after initiation of en-masse anterior retraction

次要结果测量

结果测量
措施说明
大体时间
Incidence and Severity of Gingival Clefts Assessed Clinically Using a Periodontal Probe
大体时间:Baseline (T0), 3 months (T1), and 6 months (T2) after initiation of en-masse anterior retraction
Gingival clefts will be assessed clinically using a periodontal probe.The presence, severity (depth and width in mm), and type (buccal, lingual, or through-and-through) of gingival clefts will be recorded. Cleft severity will be assessed by measuring depth and width in millimeters. Depth will be measured perpendicular to the occlusal plane, and the width will be measured parallel to the occlusal plane from the buccal and lingual aspect, with the greater of the two measurements recorded as the cleft width.
Baseline (T0), 3 months (T1), and 6 months (T2) after initiation of en-masse anterior retraction
Linear Mesial Movement of Maxillary First Molars Measured on Digital Models
大体时间:Baseline (T0), 3 months (T1), and 6 months (T2) after initiation of en-masse anterior retraction
Measurements will be performed on digital dental models obtained by intraoral scanning. Linear mesial movement of the maxillary first molars will be measured in millimeters. Perpendicular reference lines to the mid-palatal suture will be constructed through the mesial contact point of the maxillary first molar and the medial end of the third palatal rugae. The distance between these reference lines will be measured in millimeters. The change in this distance from baseline (T0) to 3 months (T1) and from baseline to 6 months (T2) will represent linear mesial movement.
Baseline (T0), 3 months (T1), and 6 months (T2) after initiation of en-masse anterior retraction
Ease of Maxillary First Premolar Extraction Assessed by Surgeon-Rated 4-Point Likert Scale and Extraction Duration
大体时间:Periprocedural
Surgeon-perceived ease of extraction will be assessed using a 4-point Likert scale: 1 = very easy, 2 = easy, 3 = difficult, and 4 = very difficult, with higher scores indicating greater extraction difficulty. Extraction duration will also be recorded from the time the forceps are clamped onto the tooth until the tooth is completely removed from the socket.
Periprocedural
Patient-Reported Pain and Dental Anxiety Associated With Premolar Extraction
大体时间:Dental anxiety immediately before extraction; pain immediately following extraction.
Pain will be assessed using a 0-10 Visual Analogue Scale, where 0 represents no pain and 10 represents the worst pain. Dental anxiety will be assessed using a 5-item questionnaire, with each item rated from 1 (not anxious) to 5 (extremely anxious), giving a total score of 5-25. Higher scores indicate greater pain or anxiety.
Dental anxiety immediately before extraction; pain immediately following extraction.

合作者和调查者

在这里您可以找到参与这项研究的人员和组织。

研究记录日期

这些日期跟踪向 ClinicalTrials.gov 提交研究记录和摘要结果的进度。研究记录和报告的结果由国家医学图书馆 (NLM) 审查,以确保它们在发布到公共网站之前符合特定的质量控制标准。

研究主要日期

学习开始 (实际的)

2026年7月22日

初级完成 (估计的)

2028年1月1日

研究完成 (估计的)

2028年6月1日

研究注册日期

首次提交

2026年8月12日

首先提交符合 QC 标准的

2026年8月15日

首次发布 (实际的)

2026年8月19日

研究记录更新

最后更新发布 (实际的)

2026年8月19日

上次提交的符合 QC 标准的更新

2026年8月15日

最后验证

2026年7月1日

更多信息

与本研究相关的术语

药物和器械信息、研究文件

研究美国 FDA 监管的药品

不

研究美国 FDA 监管的设备产品

不

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