InfrapositionNCT07593131
Risk Factors Associated With Infraposition of Implant Supported Single Crowns in the Anterior Maxilla
An observational study of Infraposition and Estethics, run by Region Västerbotten at 2 sites in Sweden.
Trial summary
Losing a tooth in the front part of the upper jaw can affect both appearance and the ability to bite and chew. Treatment to replace missing teeth is therefore often required. Such treatment may be burdensome for the individual and can involve substantial costs for both the patient and society. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Infraposition, Estethics
- How many people
- 60 participants
- Where
- 2 sitesSweden
- Study dates
- 14 Dec 2021to 14 Dec 2036
- Phase
- Observational
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population consists of adult patients receiving implant-supported prosthodontic treatment at specialist departments of prosthodontics within the Public Dental Health Service in Sweden. Participants are recruited from the Department of Prosthodontics, Public Dental Health Service, Region Västerbotten, Umeå, and from the Department of Prosthodontics, Folktandvården Eastmaninstitutet, Stockholm.
Who may be able to join
- Patients over 18 years of age who had received an Implant Supported Single Crown in the anterior maxilla (canine to canine) were eligible for inclusion.
Who cannot join
None listed.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Sweden2 sites, 1 recruiting
- Terminated
Prosthodontic Departments at Folktandvården Eastmaninstitutet
Stockholm
- Recruiting
Department of Prosthodontics, Public Dental Health Service, Region Västerbotten
Umeå
Cecilia Turborn, DDS, +46702014173, cecilia.turborn@regionvasterbotten.se
Mattias Pettersson, DDS, PhD
About this study
Official title: Risk Factors Associated With Infraposition of Single-tooth Implants in the Anterior Maxilla
Losing a tooth in the front part of the upper jaw can affect both appearance and the ability to bite and chew. Treatment to replace missing teeth is therefore often required. Such treatment may be burdensome for the individual and can involve substantial costs for both the patient and society. A common treatment option is placement of a titanium screw (dental implant) in the jawbone. After a healing period, the implant is restored with a crown designed to resemble a natural tooth.
Replacement of missing teeth with dental implants in the anterior maxilla can be particularly challenging. Over time, the crown of an implant may appear shorter than the adjacent natural teeth. This occurs because natural teeth may continue to change position throughout adulthood, whereas dental implants remain fixed within the bone. As a result, the implant-supported crown may appear to sink relative to neighboring teeth, a phenomenon referred to as infraposition. The prevalence of infraposition and the factors contributing to its development are not yet fully understood.
Read more
The aim of this study is to determine the frequency and extent of infraposition and to identify potential contributing factors in individuals treated with a single implant-supported crown in the anterior maxilla. The study also aims to evaluate the aesthetic outcome after treatment from both the patient and the clinician perspective.
The study hypothesis is that infraposition occurs in a clinically relevant proportion of patients and that certain factors, such as age at implant placement or individual dental characteristics, may increase the likelihood of its occurrence. It is further hypothesized that infraposition of the implant-supported crown may influence aesthetic appearance and that these changes may be perceived differently by patients and dental professionals.
Through longitudinal follow-up and comparison of repeated digital scans, the study seeks to improve understanding of the occurrence of infraposition, its contributing factors, and its potential impact on the aesthetic outcome of implant-supported crowns over time.
Read the detailed description
This observational cohort study is based on long-term follow-up of patients treated with a single implant-supported crown in the anterior maxilla as part of routine clinical care. Participants are enrolled consecutively from the Departments of Oral Prosthodontics within the Public Dental Service in Region Västerbotten (Umeå) and Public Dental Service Stockholm AB. The study is based on repeated digital recordings of the dentition over time.
At the time of crown delivery, a digital impression is obtained using an intraoral scanner to create three-dimensional digital models of the dental arches and their spatial relationship. Additional digital impressions are obtained during scheduled follow-up visits at 1, 3, and 5 years after delivery, in accordance with routine implant follow-up clinical practice. An additional follow-up visit using the same procedures is performed at 10 years. Digital models obtained at different time points are superimposed and compared using proprietary software associated with the intraoral scanner. This enables measurement of positional changes of the adjacent teeth realtive to the implant-supported crown. Changes over time are recorded and used to assess the occurrence and degree of infraposition.
At each follow-up visit, participants undergo standard clinical and radiographic evaluation of the implant-supported crown, including assessment of peri-implant soft tissues, marginal bone levels, implant stability, occlusion, and oral hygiene conditions. Radiographic imaging follows standardized regional clinical guidelines and is identical to that used in routine implant follow-up.
Data collected for analysis include demographic variables, sex, age at implant placement, medical history and medications, lower anterior face height, pre-prosthetic orthodontic treatment, cause of tooth loss, smile line, type of temporary restoration, implant type (bone-level or tissue-level), implant manufacturer, augmentation procedures, implant position, restoration type (screw-retained or cement-retained), use of a temporary implant-supported single crown, and occlusion or articulation on the implant-supported single crown.
The aesthetic outcome of the implant-supported crown is assessed using both objective and subjective evaluation methods. Objective evaluation is based on standardized clinical and digital criteria derived from three-dimensional models and clinical examinations. Subjective evaluation includes patient-reported assessments of aesthetic satisfaction using a questionnaire.
Follow-up time points are recorded for all participants. Data are collected using a predefined protocol to ensure standardized documentation across study sites. Source data are obtained from clinical dental records and digital scan files. All data are handled in accordance with national patient data legislation and the General Data Protection Regulation (GDPR).
Statistical analyses are planned to explore correlations between infraposition and patient-related, anatomical, and treatment-related factors, as well as correlations between infraposition, marginal bone level changes, and aesthetic evaluations over time.
- Conditions
- Infraposition, Estethics
- Keywords
- Dental Implants, Esthetics, Dental, Dental Impression Technique, Imaging, three dimensional, Positional change, Infraposition
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Adults (≥18) with a single implant-supported crown in the anterior maxilla (canine-canine). | Not described |
What is being measured
The primary outcome is the main question the study is designed to answer.
Infraposition
Outcome Measure 1 Title: Frequency of Infraposition of Implant-Supported Single Crowns Description: Proportion of patients with infraposition of an implant-supported single crown relative to adjacent teeth in the anterior maxilla after crown delivery.
Unit of Measure: Percentage (%) of patients
Outcome Measure 2 Title: Extent of Infraposition of Implant-Supported Single Crowns Description: Displacement of adjacent teeth relative to implant-supported single crown in the anterior maxilla after crown delivery.
Unit of Measure: Millimeters (mm)
Outcome Measure 3 Title: Correlation between Extent of Infraposition and Contributing Factors Description: Correlation of infraposition extent (mm) with sex, age at implant placement, medical history/medication, facial height, orthodontic treatment, cause of tooth loss, smile line, temporary restoration, implant and restoration characteristics, augmentation procedures, implant position, and occlusion/articulation.
Unit of Measure: Millimeters(mm)
Measured: From enrollment until the end of the study, 10 years after the last study participant is recruited.
Secondary outcomes (1)
Aesthetic evaluation
To evaluate aesthetic outcomes at baseline and follow-up using both subjective and objective evaluation methods.
Secondary Outcome Measure 1 Title: Patient-Reported Aesthetic Outcome Description: Patient-reported aesthetic satisfaction with implant-supported single crowns.
Unit: VAS (0-100 mm) and ordinal scale (1-4) Tool: Patient questionnaire using a visual analogue scale and a four-level satisfaction scale
Secondary Outcome Measure 2 Title: Clinician-Reported Aesthetic Outcome Description: Clinician-reported aesthetic evaluation of implant-supported single crowns.
Unit: VAS (0-100 mm) and ordinal scale (1-4) Tool: Clinician assessment using VAS and a four-level ordinal scale
Secondary Outcome Measure 3 Title: Objective Aesthetic Outcome (PES and WES) Description: Objective evaluation of peri-implant soft-tissue and crown-related aesthetics of implant-supported single crowns.
Unit: PES and WES scores (0-10) Tool: Clinician assessment using PES and WES
Measured: From enrollment until the end of the study, 10 years after the last study participant is recruited.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 May 2026
- Study start14 Dec 2021
- Primary completion14 Dec 2036 (estimated)
- Study completion14 Dec 2036 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for InfrapositionStudies of the same condition, open and under way.
- 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
- Observational
- Observational model
- Cohort
- Time perspective
- Other
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Region Västerbotten
- Sponsor type
- Other government
- Collaborators
- Umeå University
- Responsible party
- Sponsor
- Investigators
- Mattias Pettersson, DDS, PhD, Principal investigator, Division of Prosthetic Dentistry, Department of Odontology, Faculty of Medicine, Umeå Uni-versity, Umeå, Sweden
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07593131
- Sponsor's protocol ID
- EPN Dnr 2021-00133
- Status last verified
- May 2026
- First submitted
- 4 May 2026
- Last updated
- 18 May 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 18 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Risk Factors Associated With Infraposition of Single-tooth Implants in the Anterior Maxilla
- ClinicalTrials.gov ID
- NCT07593131
- Acronym / sponsor ID
- EPN Dnr 2021-00133
- Conditions
- Infraposition, Estethics
- Keywords
- Dental Implants, Esthetics, Dental, Dental Impression Technique, Imaging, three dimensional, Positional change, Infraposition
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Region VästerbottenOther government
- Collaborators
- Umeå University
- Study start
- 14 Dec 2021 (actual)
- Primary completion
- 14 Dec 2036 (estimated)
- Study completion
- 14 Dec 2036 (estimated)
- First posted
- 18 May 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.
Losing a tooth in the front part of the upper jaw can affect both appearance and the ability to bite and chew. Treatment to replace missing teeth is therefore often required. Such treatment may be burdensome for the individual and can involve substantial costs for both the patient and society. A common treatment option is placement of a titanium screw (dental implant) in the jawbone. After a healing period, the implant is restored with a crown designed to resemble a natural tooth.
Replacement of missing teeth with dental implants in the anterior maxilla can be particularly challenging. Over time, the crown of an implant may appear shorter than the adjacent natural teeth. This occurs because natural teeth may continue to change position throughout adulthood, whereas dental implants remain fixed within the bone. As a result, the implant-supported crown may appear to sink relative to neighboring teeth, a phenomenon referred to as infraposition. The prevalence of infraposition and the factors contributing to its development are not yet fully understood.
The aim of this study is to determine the frequency and extent of infraposition and to identify potential contributing factors in individuals treated with a single implant-supported crown in the anterior maxilla. The study also aims to evaluate the aesthetic outcome after treatment from both the patient and the clinician perspective.
The study hypothesis is that infraposition occurs in a clinically relevant proportion of patients and that certain factors, such as age at implant placement or individual dental characteristics, may increase the likelihood of its occurrence. It is further hypothesized that infraposition of the implant-supported crown may influence aesthetic appearance and that these changes may be perceived differently by patients and dental professionals.
Through longitudinal follow-up and comparison of repeated digital scans, the study seeks to improve understanding of the occurrence of infraposition, its contributing factors, and its potential impact on the aesthetic outcome of implant-supported crowns over time.
Detailed description
This observational cohort study is based on long-term follow-up of patients treated with a single implant-supported crown in the anterior maxilla as part of routine clinical care. Participants are enrolled consecutively from the Departments of Oral Prosthodontics within the Public Dental Service in Region Västerbotten (Umeå) and Public Dental Service Stockholm AB. The study is based on repeated digital recordings of the dentition over time.
At the time of crown delivery, a digital impression is obtained using an intraoral scanner to create three-dimensional digital models of the dental arches and their spatial relationship. Additional digital impressions are obtained during scheduled follow-up visits at 1, 3, and 5 years after delivery, in accordance with routine implant follow-up clinical practice. An additional follow-up visit using the same procedures is performed at 10 years. Digital models obtained at different time points are superimposed and compared using proprietary software associated with the intraoral scanner. This enables measurement of positional changes of the adjacent teeth realtive to the implant-supported crown. Changes over time are recorded and used to assess the occurrence and degree of infraposition.
At each follow-up visit, participants undergo standard clinical and radiographic evaluation of the implant-supported crown, including assessment of peri-implant soft tissues, marginal bone levels, implant stability, occlusion, and oral hygiene conditions. Radiographic imaging follows standardized regional clinical guidelines and is identical to that used in routine implant follow-up.
Data collected for analysis include demographic variables, sex, age at implant placement, medical history and medications, lower anterior face height, pre-prosthetic orthodontic treatment, cause of tooth loss, smile line, type of temporary restoration, implant type (bone-level or tissue-level), implant manufacturer, augmentation procedures, implant position, restoration type (screw-retained or cement-retained), use of a temporary implant-supported single crown, and occlusion or articulation on the implant-supported single crown.
The aesthetic outcome of the implant-supported crown is assessed using both objective and subjective evaluation methods. Objective evaluation is based on standardized clinical and digital criteria derived from three-dimensional models and clinical examinations. Subjective evaluation includes patient-reported assessments of aesthetic satisfaction using a questionnaire.
Follow-up time points are recorded for all participants. Data are collected using a predefined protocol to ensure standardized documentation across study sites. Source data are obtained from clinical dental records and digital scan files. All data are handled in accordance with national patient data legislation and the General Data Protection Regulation (GDPR).
Statistical analyses are planned to explore correlations between infraposition and patient-related, anatomical, and treatment-related factors, as well as correlations between infraposition, marginal bone level changes, and aesthetic evaluations over time.
Study design
- Observational model
- Cohort
- Time perspective
- Other
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Adults (≥18) with a single implant-supported crown in the anterior maxilla (canine-canine). | – | – |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consists of adult patients receiving implant-supported prosthodontic treatment at specialist departments of prosthodontics within the Public Dental Health Service in Sweden. Participants are recruited from the Department of Prosthodontics, Public Dental Health Service, Region Västerbotten, Umeå, and from the Department of Prosthodontics, Folktandvården Eastmaninstitutet, Stockholm.
Key inclusion criteria (1 listed)
- Patients over 18 years of age who had received an Implant Supported Single Crown in the anterior maxilla (canine to canine) were eligible for inclusion.
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Infraposition
Time frame: From enrollment until the end of the study, 10 years after the last study participant is recruited.
Outcome Measure 1 Title: Frequency of Infraposition of Implant-Supported Single Crowns Description: Proportion of patients with infraposition of an implant-supported single crown relative to adjacent teeth in the anterior maxilla after crown delivery. Unit of Measure: Percentage (%) of patients Outcome Measure 2 Title: Extent of Infraposition of Implant-Supported Single Crowns Description: Displacement of adjacent teeth relative to implant-supported single crown in the anterior maxilla after crown delivery. Unit of Measure: Millimeters (mm) Outcome Measure 3 Title: Correlation between Extent of Infraposition and Contributing Factors Description: Correlation of infraposition extent (mm) with sex, age at implant placement, medical history/medication, facial height, orthodontic treatment, cause of tooth loss, smile line, temporary restoration, implant and restoration characteristics, augmentation procedures, implant position, and occlusion/articulation. Unit of Measure: Millimeters(mm)
1 secondary outcome
Aesthetic evaluation
Time frame: From enrollment until the end of the study, 10 years after the last study participant is recruited.
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 18 May 2026.
- Individual participant dataSharing planned: No
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.
Mattias Pettersson, DDS, PhD principal investigator
Division of Prosthetic Dentistry, Department of Odontology, Faculty of Medicine, Umeå Uni-versity, Umeå, Sweden
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Infraposition and Estethics, run by Region Västerbotten at 2 sites in Sweden.
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 1 inclusion and 0 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: looking for participants now, as of the sponsor's last update on 18 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Sweden. Whether a site is taking part right now should be confirmed with that site. See every site.
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 Cecilia Turborn, DDS (+46702104173, cecilia.turborn@regionvasterbotten.se), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Infraposition (time frame: From enrollment until the end of the study, 10 years after the last study participant is recruited.). 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 18 May 2026.