Crowding of TeethcSPACENCT07911176
Timing, Trajectories and Prediction in Severe Dental Crowding: The Create SPACE (cSPACE)
A study testing Early first premolar extraction with observation and Early first premolar extraction with planned fixed orthodontic treatment in people with Crowding of Teeth and Malocclusion; Displaced Teeth, run by Vastra Gotaland Region.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 8 to 19 years
- Conditions the study is for
- Crowding of Teeth, Malocclusion; Displaced Teeth, Malocclusion in Children
- What is being tested?
- Early first premolar extraction with observation and Early first premolar extraction with planned fixed orthodontic treatment
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 300 participants
- Where
- No sites listed yet
- Study dates
- 1 Mar 2027to 1 Mar 2036
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 8 to 19 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Children aged approximately 10-12 years in the mixed dentition (DS2- DS3)
- Angle Class I malocclusion with no indication for orthognathic treatment
- Severe maxillary crowding with ≥6 mm maxillary arch-length discrepancy
- Mandibular crowding requiring orthodontic treatment
- Permanent first molars and incisors erupted
- Permanent first premolars present and considered suitable for extraction according to the study protocol
- Considered suitable for orthodontic treatment involving extraction of the first premolars
- Written informed consent from parent(s) or legal guardian(s) and assent from the child, when appropriate
Who cannot join
- Previous orthodontic treatment, including extraction of permanent teeth
- Primary tooth extractions performed for orthodontic purposes
- Craniofacial syndromes or cleft lip and/or palate
- Congenitally missing permanent teeth (excluding third molars and second molars) affecting treatment planning
- Supernumerary teeth requiring alternative treatment
- Systemic disease or medication affecting bone metabolism or orthodontic tooth movement
Show all 9Show fewer
- Severe dental anomalies requiring individualized treatment outside the study protocol
- Untreated dental disease or poor oral health preventing orthodontic treatment
- Inability or unwillingness to comply with the study protocol or follow-up schedule
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Timing, Trajectories and Prediction in Severe Dental Crowding: The Create SPACE (cSPACE) Multicenter Randomized Controlled Trial.
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.
Read the detailed description
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.
- Being tested
- Early first premolar extraction with observation, Early first premolar extraction with planned fixed orthodontic treatment
- Keywords
- crowding, premolar extraction
- Medical subject headings
- Crowding, Malocclusion
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Early first premolar extraction with observationProcedure or surgery
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.
Early first premolar extraction with planned fixed orthodontic treatmentProcedure or surgery
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.
| Study group | Role | What they receive |
|---|---|---|
| Early extraction with observation | Experimental | 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. Receives: Procedure: Early first premolar extraction with observation |
| Early extraction with planned fixed orthodontic treatment | Experimental | 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. Receives: Procedure: Early first premolar extraction with planned fixed orthodontic treatment |
| Conventional treatment | No intervention | 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Secondary outcomes (16)
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)
Measured: 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).
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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).
Measured: 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).
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: From baseline to the end of active orthodontic treatment (approximately 16 years of age).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Nov 2026
- Study start1 Mar 2027 (estimated)
- Primary completion1 Mar 2034 (estimated)
- Study completion1 Mar 2036 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Crowding of TeethStudies of the same condition, open and under way.
- More trials run by Vastra Gotaland RegionThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 300 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Vastra Gotaland Region
- Sponsor type
- Other government
- Collaborators
- Region Östergötland, Region Jönköping County, Region Halland, Region Jämtland Härjedalen, Västra Götalandsregionen, Linkoeping University
- Responsible party
- Principal investigator, Anna Westerlund, Vastra Gotaland Region
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07911176
- Sponsor's protocol ID
- cSPACE
- Acronym
- cSPACE
- Status last verified
- Oct 2026
- First submitted
- 2 Oct 2026
- Last updated
- 2 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Timing, Trajectories and Prediction in Severe Dental Crowding: The Create SPACE (cSPACE) Multicenter Randomized Controlled Trial.
- ClinicalTrials.gov ID
- NCT07911176
- Acronym / sponsor ID
- cSPACE / cSPACE
- Keywords
- crowding, premolar extraction
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 300 participants (estimated)
- Lead sponsor
- Vastra Gotaland RegionOther government
- Collaborators
- Region Östergötland, Region Jönköping County, Region Halland, Region Jämtland Härjedalen, Västra Götalandsregionen, Linkoeping University
- Study start
- 1 Mar 2027 (estimated)
- Primary completion
- 1 Mar 2034 (estimated)
- Study completion
- 1 Mar 2036 (estimated)
- First posted
- 2 Nov 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Early extraction with observation | Experimental | Procedure: Early first premolar extraction with observationParticipants 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. |
| Early extraction with planned fixed orthodontic treatment | Experimental | Procedure: Early first premolar extraction with planned fixed orthodontic treatmentParticipants 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. |
| Conventional treatment | No intervention | –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. |
Who may qualify
- Ages
- 8 to 19 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (8 listed)
- Children aged approximately 10-12 years in the mixed dentition (DS2- DS3)
- Angle Class I malocclusion with no indication for orthognathic treatment
- Severe maxillary crowding with ≥6 mm maxillary arch-length discrepancy
- Mandibular crowding requiring orthodontic treatment
- Permanent first molars and incisors erupted
Key exclusion criteria (9 listed)
- Previous orthodontic treatment, including extraction of permanent teeth
- Primary tooth extractions performed for orthodontic purposes
- Craniofacial syndromes or cleft lip and/or palate
- Congenitally missing permanent teeth (excluding third molars and second molars) affecting treatment planning
- Supernumerary teeth requiring alternative treatment
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Early first premolar extraction with observationExtraction 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. | Procedure or surgery | Early extraction with observation |
| Early first premolar extraction with planned fixed orthodontic treatmentExtraction 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. | Procedure or surgery | Early extraction with planned fixed orthodontic treatment |
Primary outcome
Final Peer Assessment Rating (PAR)
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
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.
16 secondary outcomes
Spontaneous alignment of crowded teeth
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Spontaneus extraction space closure
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
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
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)
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Facial height changes
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Nasolabial angle changes
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
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
Time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).
Tooth movements on cephalometric radiographs
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).
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).
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
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)
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
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
Time frame: From baseline to the end of active orthodontic treatment (approximately 16 years of age).
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Nov 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
A study testing Early first premolar extraction with observation and Early first premolar extraction with planned fixed orthodontic treatment in people with Crowding of Teeth and Malocclusion; Displaced Teeth, run by Vastra Gotaland Region.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 2 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Anna Westerlund, Prof (+46703171213, anna.westerlund@odontologi.gu.se), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Final Peer Assessment Rating (PAR) (time frame: Baseline, 14 years of age, 16 years of age, and 18 years of age (through study completion).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Nov 2026.