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

Completed

Conditions

Intervention / Treatment

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

Interventional

Enrollment (Actual)

39

Phase

  • 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 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

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
Intervention / Treatment
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

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

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

Medical University of Graz

Investigators

  • 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)

March 4, 2021

Primary Completion (Actual)

November 13, 2025

Study Completion (Actual)

November 13, 2025

Study Registration Dates

First Submitted

January 12, 2021

First Submitted That Met QC Criteria

January 12, 2021

First Posted (Actual)

January 13, 2021

Study Record Updates

Last Update Posted (Actual)

January 27, 2026

Last Update Submitted That Met QC Criteria

January 26, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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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