An interventional study of Early first premolar extraction with observation and Early first premolar extraction with planned fixed orthodontic treatment in Crowding of Teeth, Malocclusion; Displaced Teeth and Malocclusion in Children, sponsored by Vastra Gotaland Region. Not yet recruiting. Open to participants aged 8 Years to 19 Years. Per ClinicalTrials.gov, last updated 2026-11-02.
Sponsored by Vastra Gotaland Region · Not applicable, Interventional, and Prevention
Dental crowding is the most common malocclusion affecting up to 45% of the population and represents one of the leading reasons for seeking orthodontic treatment. Severe crowding may have a negatively impact on oral health related quality of life particularly psychosocial well-being and self-perceived dental appearance.
In cases of severe crowding, extraction of four permanent teeth may be required to create sufficient space for proper alignment. Several treatment strategies are currently used, but there is a lack of scientific evidence regarding the optimal timing of tooth extraction and orthodontic treatment to achieve the best outcomes.
The trial compare 1) late first premolar extraction with fixed orthodontic treatment, (2) early first premolar extraction with planned fixed orthodontic treatment, and (3) early first premolar extraction followed by observation, with fixed treatment provided only if indicated. The study will evaluate treatment need, occlusal outcomes, spontaneous dental development, patient-reported outcomes, adverse effects, treatment efficiency, and cost-effectiveness.
Severe dental crowding in the mixed dentition is commonly managed by extraction of the first premolars followed by comprehensive fixed orthodontic treatment after eruption of the permanent dentition. Although this conventional approach is widely accepted, it is associated with prolonged treatment duration, extended exposure to fixed appliances, repeated clinical visits, treatment-related adverse effects, and substantial healthcare costs. An alternative strategy is early extraction of the first premolars during the mixed dentition, allowing spontaneous dental development before deciding whether comprehensive orthodontic treatment is necessary. Observational studies suggest that early extraction may reduce treatment need, shorten subsequent orthodontic treatment, and improve treatment efficiency without compromising dentofacial development. However, high-quality randomized controlled trials evaluating this treatment strategy are lacking.
The trial is designed to compare three treatment strategies for severe crowding in children with Angle Class I malocclusion: (1) early first premolar extraction followed by observation with fixed appliance treatment provided only if predefined criteria are fulfilled, (2) early first premolar extraction followed by planned fixed appliance treatment, and (3) conventional treatment with observation followed by first premolar extraction in the permanent dentition and fixed appliance therapy. The trial aims to determine which strategy provides the optimal balance between spontaneous dental development, orthodontic treatment need, treatment efficiency, patient-reported outcomes, adverse effects, and cost-effectiveness.
26 studies on the registry are indexed under Crowding; 11 are open to participants now.
This study's planned enrollment of 300 is above the median of 34 across 21 interventional studies indexed under Crowding.
Browse Crowding studies →Vastra Gotaland Region is the lead sponsor of 274 studies on the registry; 109 are open to participants now.
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Exclusion Criteria:
Participants allocated to the observation group will undergo extraction of the first premolars during the mixed dentition followed by observation. Comprehensive fixed orthodontic treatment will only be initiated if predefined criteria for orthodontic treatment are fulfilled after completion of the planned observation period.
Procedure: Early first premolar extraction with observation
Participants allocated to the early extraction group will undergo extraction of the first premolars during the mixed dentition followed by comprehensive fixed orthodontic treatment after eruption of the permanent dentition according to the study protocol.
Procedure: Early first premolar extraction with planned fixed orthodontic treatment
Participants allocated to the conventional treatment group will undergo observation during the mixed dentition followed by extraction of the first premolars and comprehensive fixed orthodontic treatment after eruption of the permanent dentition according to the study protocol.
Extraction of all first premolars during the mixed dentition stage, followed by observation without active orthodontic treatment. Comprehensive orthodontic treatment is offered at 18 years of age if orthodontic treatment need persists.
Extraction of all first premolars during the mixed dentition stage. No comprehensive orthodontic treatment is provided immediately after extraction. Orthodontic treatment with fixed appliance is initiated at the age of 14 years, when the permanent dentition is established.
Final Peer Assessment Rating (PAR)
The primary analysis will compare the three randomized treatment strategies with respect to the final PAR score at 18 years of age, adjusted for baseline PAR score, according to the prespecified statistical analysis plan. PAR scores will be assessed on digital study models.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Spontaneous alignment of crowded teeth
Dental alignment assessed on digital study models using tooth size arch length discrepency (TSALD, mm) and Little's Irregularity Index (LII, mm)
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Spontaneus extraction space closure
Space closure closure assessed on digital study models using extent of space closure (mm).
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Sagittal skeletal relationship assessed by ANB Angle
Sagittal skeletal relationship asessed using ANB angle (degrees) on lateral cephalometric radiographs.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Sagittal skeletal relationship assessed by Wits appraisal
Sagittal skeletal relationship asessed using Wits appraisal (mm) on lateral cephalometric radiographs.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Change in jaw inclination (ML/NSL Angle)
Vertical skeletal relationship asessed using jaw the ML/NSL angle (degrees) on lateral cephalometric radiographs.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Facial height changes
Vertical skeletal relationship asessed using facial height (mm) measurements on lateral cephalometric radiographs.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Nasolabial angle changes
Soft-tissue relationships assessed using nasolabial angle (degrees) anon lateral cephalometric radiographs and profile photographs.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Lip positions relative to Rickett's estethic line
Soft-tissue relationships assessed as the distance from the upper and lower lips to Ricketts' estethic line (mm) on lateral cephalometric radiographs and profile photographs.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Tooth inclination changes on cephalometric radiographs
Tooth inclination assessed on lateral cephalometric radiographs using anagular measurments (degrees).
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Tooth movements on cephalometric radiographs
Tooth movements assessed on lateral cephalometric radiographs using linear measurments (mm).
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Change in objective treatment need assessed using the Index of Orthodontic Treatment Need (IOTN).
Orthodontic treatment need assessed using the Index of Orthodontic Treatment Need (IOTN). The scale ranges from Grade 1 (no treatment need) to Grade 5 (very great treatment need) with higher scores indicating greater orthodontic treatment need.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Change in objective treatment need assessed using the Index of Complexity, Outcome and Need (ICON).
Orthodontic treatment need assessed using the Index of Complexity, Outcome and Need (ICON). The scale ranges from \< 29 (easy) to \> 77 (very difficult), with higher scores indicating greater orthodontic treatment need and treatment complexity.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Change in objective treatment need assessed using the Dental Aesthetic Index (DAI
Orthodontic treatment need assessed using the Dental Aesthetic Index (DAI). The scale ranges from ≤ 25 (no or slight treatment need) to ≥ 36 (treatment mandatory), with higher scores indicating greater orthodontic treatment need and treatment complexity.
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Oral health-related quality of life (OHRQoL)
Oral health-related quality of life assessed using the Child Perceptions Questionnaire (CPQ11-14) Short Form. The scale ranges from 0 to 64, with higher scores indicating a greater negative impact on oral health-related quality of life.
Time frame: Baseline, Post-extraction (9-12 years of age), 14 years of age, 16 years of age, and 18 years of age (through study completion).
Self perceived orofacial aesthetics
Orofacial aesthetics assessed using the Orofacial Estethic Scale (OES). The scale ranges from 0 to 70, with higher scores indicating greater satisfaction with orofacial appearence.
Time frame: Baseline, Post-extraction (9-12 years of age), 14 years of age, 16 years of age, and 18 years of age (through study completion).
Health economic impact
Health economic impact assessed based on treatment duration, chair time, number of visits, healthcare resource utilization, and patient and family costs.
Time frame: From baseline to the end of active orthodontic treatment (approximately 16 years of age).
Change in white spot lesions
Changes in number of white spot lesions (early caries lesions) assessed on clinical photographs.
Time frame: 14 years of age, 16 years of age, and 18 years of age (through study completion).
Change in DeFS (Decayed, enamel included and Filled Tooth Surfaces)
Initial and manifest caries lesions assessed on bitewing radiographs using the DeFS index. Higher scores indicate greater caries experience.
Time frame: 14 years of age, 16 years of age, and 18 years of age (through study completion).
Change in root length
Extent of root resorptions assessed as change in root length (mm)on panoramic radiographs and periapical radiographs using linear measurements (mm).
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
No study locations are listed for this record.
Plan to share: No
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Start is estimated for Mar 2027; primary completion for Mar 2034, 84 months later.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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