Implant Supported Single Crowns With Different Retention Modes

January 26, 2026 updated by: Medical University of Graz

Implant Supported Single Crowns With Different Retention Modes - Effects on Peri-implant Tissue: A Prospective Randomized Controlled Clinical Trial

This study aims to examine the inflammatory response mediated by MMP-8 (Matrix metalloproteinase-8 ) level in peri-implant sulcus fluid adjacent to screw-retained, cemented or using the Acuris-system fixed single implant crowns as well as changing of the marginal bone level within the first year after implant restoration. Furthermore periodontal parameters, patient satisfaction and possible occurring biological or technical complications will be evaluated.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

After giving their written consent volunteers will be screened and eligible subjects will be randomized to three different groups. In group 1 Acuris® is used as fixation type; in group 2 screw retention, and in group 3 cementation is used. After 3 months of submerged healing the dental implants will be restored with all ceramic single implant crowns, fixed by using the randomized fixation mode. Follow-up visits till one year after implant restoration will be performed. At least 11 study visits during 16 months will be conducted.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
39

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Austria
      • Graz, Austria, 8010
        • Medical University of Graz, Department of Dental Medicine and Oral Health, Division of Oral Surgery and Orthodontics

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 99 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • capability of giving an informed consent
  • good health as defined by the subjects medical history (no contraindications as described in the exclusion criteria below)
  • age 18 to 99 years
  • Good periodontal status: BOP < 20%, PI < 30%, no PD > 4mm
  • No heavy smokers (< 10 cigarettes/day)
  • at least 1 missing tooth in the premolar and molar region (with at least a mesial neighboring tooth/implant showing adequate hard- and soft tissue situation without the need of crestal hard- or soft tissue augmentation) either in the maxilla or in the mandible requiring implant therapy for reconstruction, requiring sinus floor augmentation or not.

Exclusion Criteria

  • Insufficient bone volume for implant placement requiring GBR (guided bone regeneration) procedure in crestal area.
  • Heavy Smokers (>10 cigarettes/day)
  • Medication with a contraindication for implant therapy (especially antiresorptive therapy, ongoing or recently completed local radiotherapy, systematic diseases, ongoing immunosuppressive therapy, functional disorders like Bruxism).
  • Skeletal immaturity.
  • Any active malignancy or ongoing treatment for malignancy.
  • An active infection (e.g. caries, gingivitis, periodontitis) at or in the neighboring area of the operative site.
  • Pregnancy
  • unable or unwilling to return for follow-up visits for a period of at least 16 months

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: conometric concept (Acuris system)
single implant crown retention using friction only
Other: conometric concept Acuris system
implant crown retention type using friction only
Active Comparator: screw retention
screw retained implant Crown fixation
Other: screw retention
screw retained implant crown
Active Comparator: cementation
cement retained implant Crown fixation
Other: cementation
cement retained implant crown

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change of marginal bone level
Time Frame: at baseline, 4 months after implant placement and 3, 6 and 12 months after restoration
assessed by single tooth x-ray; in mm
at baseline, 4 months after implant placement and 3, 6 and 12 months after restoration
Change of matrix metalloproteinase 8 level
Time Frame: 4 months after implant placement, 3, 6 and 12 months after integration of the implant crown
biomarker for Inflammation of peri-implant disease; in ng/ml
4 months after implant placement, 3, 6 and 12 months after integration of the implant crown

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change of probing depth (PD)
Time Frame: at baseline, 4, 7, 10, 16 months after implantation
using a periodontal probe; in mm
at baseline, 4, 7, 10, 16 months after implantation
Number of occurrences of chipping
Time Frame: measured after integration of implant crown 3, 6 and 12 months after restoration
visual check
measured after integration of implant crown 3, 6 and 12 months after restoration
soft tissue maintenance
Time Frame: measured 4 months after implant placement and 3, 6 and 12 months after restoration
Papilla Index (Jemt T, 1997), the index ranges from 0 to 4, while 2 and 3 indicate physiological outcome
measured 4 months after implant placement and 3, 6 and 12 months after restoration
technician satisfaction
Time Frame: measured 12 months after restoration
evaluated using an individual questionnaire
measured 12 months after restoration
dentist satisfaction
Time Frame: measured 12 months after restoration
evaluated using an individual questionnaire
measured 12 months after restoration
patient satisfaction
Time Frame: measured at baseline, 3 and 12 months after restoration
evaluated using OHIP-G 14 questionnaire. The following dimensions are captured by the OHIP-G 14: functional Limitation (e.g., "pronouncing any words because of problems with your teeth, mouth, dentures, or jaw?") and physical Pain (e.g., "Have you had painful aching in your mouth"). 14 questions are raised, which are answered using a rating scale from 0 (never) to 4 (very often).
measured at baseline, 3 and 12 months after restoration
Plaque Index (PI)
Time Frame: at baseline, 4, 7, 10 and 16 months after implantation
in percent
at baseline, 4, 7, 10 and 16 months after implantation
Bleeding on Probing (BOP)
Time Frame: at baseline, 4, 7, 10 and 16 months after implantation
in percent
at baseline, 4, 7, 10 and 16 months after implantation
Patient satisfaction concerning the implant crown
Time Frame: measured 12 months after restoration
evaluated using an individual questionnaire
measured 12 months after restoration
Number of occurrences of fractures
Time Frame: measured after integration of implant crown 3, 6 and 12 months after restoration
visual check
measured after integration of implant crown 3, 6 and 12 months after restoration
Number of occurrences of screw loosening
Time Frame: measured after integration of implant crown 3, 6 and 12 months after restoration
visual check
measured after integration of implant crown 3, 6 and 12 months after restoration
Number of occurrences of crown loosening
Time Frame: measured after integration of implant crown 3, 6 and 12 months after restoration
visual check
measured after integration of implant crown 3, 6 and 12 months after restoration

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Medical University of Graz

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Norbert Jakse, UnivProfDDr, Department of Dental Medicine and Oral Health

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 4, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 13, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 13, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 12, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 12, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 13, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 26, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 32-578 ex 19/20

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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