An interventional study of Early Maxillary First Premolar Extraction and Late Maxillary First Premolar Extraction in Malocclusion Class II and Malocclusion, Angle Class I, sponsored by Shifa College of Dentistry. Recruiting at 1 site in Pakistan. Open to participants aged 13 Years to 25 Years. Per ClinicalTrials.gov, last updated 2026-08-19.
Sponsored by Shifa College of Dentistry · Not applicable, Interventional, and Treatment
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:
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.
35 studies on the registry are indexed under Malocclusion, Angle Class I; 10 are open to participants now.
This study's planned enrollment of 26 is below the median of 32 across 31 interventional studies indexed under Malocclusion, Angle Class I.
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Exclusion Criteria:
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.
Procedure: Early Maxillary First Premolar Extraction
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.
Procedure: Late Maxillary First Premolar Extraction
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.
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.
Rate of Orthodontic Space Closure Measured on Digital 3D Dental Models
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).
Time frame: Baseline (T0), 3 months (T1), and 6 months (T2) after initiation of en-masse anterior retraction
Incidence and Severity of Gingival Clefts Assessed Clinically Using a Periodontal Probe
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.
Time frame: 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
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.
Time frame: 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
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.
Time frame: Periprocedural
Patient-Reported Pain and Dental Anxiety Associated With Premolar 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.
Time frame: Dental anxiety immediately before extraction; pain immediately following extraction.
Started Jul 2026 (actual). Primary completion is estimated for Jan 2028, 18 months after the start.
Of 23 interventional studies with no phase under Malocclusion, Angle Class I, half reached primary completion within 21 months of starting (the median), counting those still running; a quarter within 15 and three quarters within 24. This study's planned 18 months is below that.
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Shifa College of Dentistry