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Complications: Inflammatory Reactions, Mechanical ComplicationsNCT04707716

Implant Supported Single Crowns With Different Retention Modes

A study testing conometric concept Acuris system, screw retention and cementation in people with Complications: Inflammatory Reactions, Mechanical Complications, run by Medical University of Graz at 1 site in Austria.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

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… Read more about this study

Who is it for?
Ages 18 to 99 yearsHealthy volunteers can take part
What is being tested?
conometric concept Acuris system, screw retention and cementation
Could I receive a placebo?
No, everyone receives an active treatment
How many people
39 participants
Where
1 siteAustria
Study dates
4 Mar 2021to 13 Nov 2025
Phase
Interventional
Are there results?
None posted in the registry

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 to 99 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • 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.

Who cannot join

  • 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

Trial locations and contacts

1 site in 1 country.

Austria1 site

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

    Graz, 8010

Other trials in Austria

About this study

Official title: 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.

Read the 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.

Being tested
conometric concept Acuris system, screw retention, cementation
Keywords
MMP-8, marginal bone level, conometric concept - Acuris, crown retention, all-ceramic crown

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • conometric concept Acuris systemOther

    implant crown retention type using friction only

  • screw retentionOther

    screw retained implant crown

  • cementationOther

    cement retained implant crown

Study groups in NCT04707716
Study groupRoleWhat they receive
conometric concept (Acuris system)Experimentalsingle implant crown retention using friction only
Receives: Other: conometric concept Acuris system
screw retentionActive comparatorscrew retained implant Crown fixation
Receives: Other: screw retention
cementationActive comparatorcement retained implant Crown fixation
Receives: Other: cementation

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change of marginal bone level

    assessed by single tooth x-ray; in mm

    Measured: at baseline, 4 months after implant placement and 3, 6 and 12 months after restoration

  2. Change of matrix metalloproteinase 8 level

    biomarker for Inflammation of peri-implant disease; in ng/ml

    Measured: 4 months after implant placement, 3, 6 and 12 months after integration of the implant crown

Secondary outcomes (12)

  1. Change of probing depth (PD)

    using a periodontal probe; in mm

    Measured: at baseline, 4, 7, 10, 16 months after implantation

  2. Number of occurrences of chipping

    visual check

    Measured: measured after integration of implant crown 3, 6 and 12 months after restoration

  3. soft tissue maintenance

    Papilla Index (Jemt T, 1997), the index ranges from 0 to 4, while 2 and 3 indicate physiological outcome

    Measured: measured 4 months after implant placement and 3, 6 and 12 months after restoration

  4. technician satisfaction

    evaluated using an individual questionnaire

    Measured: measured 12 months after restoration

  5. dentist satisfaction

    evaluated using an individual questionnaire

    Measured: measured 12 months after restoration

  6. patient satisfaction

    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: measured at baseline, 3 and 12 months after restoration

  7. Plaque Index (PI)

    in percent

    Measured: at baseline, 4, 7, 10 and 16 months after implantation

  8. Bleeding on Probing (BOP)

    in percent

    Measured: at baseline, 4, 7, 10 and 16 months after implantation

  9. Patient satisfaction concerning the implant crown

    evaluated using an individual questionnaire

    Measured: measured 12 months after restoration

  10. Number of occurrences of fractures

    visual check

    Measured: measured after integration of implant crown 3, 6 and 12 months after restoration

  11. Number of occurrences of screw loosening

    visual check

    Measured: measured after integration of implant crown 3, 6 and 12 months after restoration

  12. Number of occurrences of crown loosening

    visual check

    Measured: measured after integration of implant crown 3, 6 and 12 months after restoration

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted13 Jan 2021
  2. Study start4 Mar 2021
  3. Primary completion13 Nov 2025
  4. Study completion13 Nov 2025

Resources

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
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
39 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04707716
Sponsor's protocol ID
32-578 ex 19/20
Status last verified
Jan 2026
First submitted
12 Jan 2021
Last updated
27 Jan 2026
Results posted
No
FDA-regulated drug
No
FDA-regulated device
No

Publications

  • DeCarlo AA, Grenett HE, Harber GJ, Windsor LJ, Bodden MK, Birkedal-Hansen B, Birkedal-Hansen H. Induction of matrix metalloproteinases and a collagen-degrading phenotype in fibroblasts and epithelial cells by secreted Porphyromonas gingivalis proteinase. J Periodontal Res. 1998 Oct;33(7):408-20. doi: 10.1111/j.1600-0765.1998.tb02337.x.

    PubMed 9842506

  • Jemt T. Regeneration of gingival papillae after single-implant treatment. Int J Periodontics Restorative Dent. 1997 Aug;17(4):326-33.

    PubMed 9497723

  • Kraus RD, Epprecht A, Hammerle CHF, Sailer I, Thoma DS. Cemented vs screw-retained zirconia-based single implant reconstructions: A 3-year prospective randomized controlled clinical trial. Clin Implant Dent Relat Res. 2019 Aug;21(4):578-585. doi: 10.1111/cid.12735. Epub 2019 Mar 12.

    PubMed 30861635

  • Lekholm U, Adell R, Lindhe J, Branemark PI, Eriksson B, Rockler B, Lindvall AM, Yoneyama T. Marginal tissue reactions at osseointegrated titanium fixtures. (II) A cross-sectional retrospective study. Int J Oral Maxillofac Surg. 1986 Feb;15(1):53-61. doi: 10.1016/s0300-9785(86)80011-4.

    PubMed 3083006

  • Lemos CA, de Souza Batista VE, Almeida DA, Santiago Junior JF, Verri FR, Pellizzer EP. Evaluation of cement-retained versus screw-retained implant-supported restorations for marginal bone loss: A systematic review and meta-analysis. J Prosthet Dent. 2016 Apr;115(4):419-27. doi: 10.1016/j.prosdent.2015.08.026. Epub 2015 Nov 14.

    PubMed 26589441

  • Lorenzoni M, Pertl C, Wegscheider W, Keil C, Penkner K, Polansky R, Bratschko RO. Retrospective analysis of Frialit-2 implants in the augmented sinus. Int J Periodontics Restorative Dent. 2000 Jun;20(3):255-67.

    PubMed 11203567

  • Ma J, Kitti U, Teronen O, Sorsa T, Husa V, Laine P, Ronka H, Salo T, Lindqvist C, Konttinen YT. Collagenases in different categories of peri-implant vertical bone loss. J Dent Res. 2000 Nov;79(11):1870-3. doi: 10.1177/00220345000790110901.

    PubMed 11145357

  • Meissen R, Mintcheva M, Netuschil L. Matrix metalloproteinase-8 levels in peri-implant sulcus fluid adjacent to titanium and zirconium nitride surfaces. Int J Periodontics Restorative Dent. 2014 Jan-Feb;34(1):91-5. doi: 10.11607/prd.1504.

    PubMed 24396843

  • Penarrocha-Oltra D, Monreal-Bello A, Penarrocha-Diago M, Alonso-Perez-Barquero J, Botticelli D, Canullo L. Microbial Colonization of the Peri-Implant Sulcus and Implant Connection of Implants Restored With Cemented Versus Screw-Retained Superstructures: A Cross-Sectional Study. J Periodontol. 2016 Sep;87(9):1002-11. doi: 10.1902/jop.2016.160017. Epub 2016 May 6.

    PubMed 27153291

  • Sailer I, Muhlemann S, Zwahlen M, Hammerle CH, Schneider D. Cemented and screw-retained implant reconstructions: a systematic review of the survival and complication rates. Clin Oral Implants Res. 2012 Oct;23 Suppl 6:163-201. doi: 10.1111/j.1600-0501.2012.02538.x.

    PubMed 23062142

  • Sorsa T, Tjaderhane L, Konttinen YT, Lauhio A, Salo T, Lee HM, Golub LM, Brown DL, Mantyla P. Matrix metalloproteinases: contribution to pathogenesis, diagnosis and treatment of periodontal inflammation. Ann Med. 2006;38(5):306-21. doi: 10.1080/07853890600800103.

    PubMed 16938801

  • Sorsa T, Hernandez M, Leppilahti J, Munjal S, Netuschil L, Mantyla P. Detection of gingival crevicular fluid MMP-8 levels with different laboratory and chair-side methods. Oral Dis. 2010 Jan;16(1):39-45. doi: 10.1111/j.1601-0825.2009.01603.x. Epub 2009 Jul 8.

    PubMed 19627514

  • Teughels W, Van Assche N, Sliepen I, Quirynen M. Effect of material characteristics and/or surface topography on biofilm development. Clin Oral Implants Res. 2006 Oct;17 Suppl 2:68-81. doi: 10.1111/j.1600-0501.2006.01353.x.

    PubMed 16968383

  • Thoma DS, Sailer I, Muhlemann S, Gil A, Jung RE, Hammerle CHF. Randomized controlled clinical study of veneered zirconia abutments for single implant crowns: Clinical, histological, and microbiological outcomes. Clin Implant Dent Relat Res. 2018 Dec;20(6):988-996. doi: 10.1111/cid.12674. Epub 2018 Oct 17.

    PubMed 30328283

  • Vindasiute E, Puisys A, Maslova N, Linkeviciene L, Peciuliene V, Linkevicius T. Clinical Factors Influencing Removal of the Cement Excess in Implant-Supported Restorations. Clin Implant Dent Relat Res. 2015 Aug;17(4):771-8. doi: 10.1111/cid.12170. Epub 2013 Nov 14.

    PubMed 24224895

Questions about this trial

What is this clinical trial studying?

A study testing conometric concept Acuris system, screw retention and cementation in people with Complications: Inflammatory Reactions, Mechanical Complications, run by Medical University of Graz at 1 site in Austria.

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 6 inclusion and 8 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: finished, as of the sponsor's last update on 27 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Austria. 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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change of marginal bone level (time frame: at baseline, 4 months after implant placement and 3, 6 and 12 months after restoration). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04707716, which also lists 15 linked publications.

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 27 Jan 2026.

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