Investigation of Biofilm Formation on Temporary push-on Rings of Implant Crowns

August 10, 2026 updated by: University Hospital, Basel, Switzerland

Temporary push-on Rings of Antimicrobial Alloys for Transmucosal Implant Abutment Systems: a Randomized Clinical Study on Early and Mature Biofilm Formation

This in-vivo study investigates early (48h), mature (2 weeks) and long-term (3 months) biofilm formation and composition on temporary push-on cones (exchangeable conical rings) made of noble-alloy-based materials (Pagalinor, PA) in comparison to Titanium-6Aluminum-7Niobium alloy (TAN) presently used in the transmucosal portion of dental implant abutments.

Study Overview

Status

Status

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

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

Oral biofilm (dental plaque) consists of bacteria and their metabolic products as well as saliva components and food residues. It is recognizable as a tough and structured coating on teeth and artificial surfaces within the oral cavity. Plaque development is a physiological process that begins immediately after cleaning of the oral surface. If the biofilm is not removed by daily oral hygiene, it continues to mature while changing the structure and its microbial composition.

Implant restorations comprise the osseous implant portion predominantly manufactured from titanium alloys, the transmucosal implant portion (in most implant systems as a separate abutment), and the clinical crown, which is in most systems extraorally cemented on an abutment and screw-retained onto the implant. According to current knowledge, microbial colonization of the implant abutment surface plays a significant role in the aetiology of peri-implantitis.

This study investigates the antibacterial potential of a temporary push-on cone (conical ring) that could reduce the risk of bacterial related peri-implant diseases due to decreased biofilm susceptibility, compared to current available transmucosal materials, in the short- and long-run. The test material Pagalinor®2 (PA) is an established material in dental medicine and has proven to accumulate least biofilm in an in-vivo biofilm sampling model using removable splints. The control material consists of the current transmucosal implant abutment material Titanium-6Aluminum- 7Niobium alloy (TAN). The push-on rings are designed for repeated application along the transmucosal implant abutment portion with high precision fit and will allow biofilm sampling in the natural implant environment. Profound insight into the native homeostasis of biofilm formation will be obtained and therefore enhance the knowledge about long-term tissue response.

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 (Estimated)

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.
33

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

  • Switzerland
      • Basel, Switzerland, 4058
        • Recruiting
        • UZB (University Center for Dental Medicine Basel)
        • Contact:
        • Contact:
        • Principal Investigator:
          • Nicola U. Zitzmann, Prof. Dr.
        • Principal Investigator:
          • Lucia K. Zaugg, Dr. med. dent.

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 and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Informed Consent signed by the subject
  • Presence of one or more bone level titanium implant prior to insertion of the final restoration
  • No systemic illness
  • No heavy smoking (smoking <10 cigarettes/day)
  • No pregnancy
  • No active periodontitis (probing pocket depth ≤4 mm)
  • No pharmacological treatment or antibiotic therapy during or up to three months before the study

Exclusion Criteria:

  • Systemic illness (e.g. Diabetes)
  • Heavy smoking (smoking >10 cigarettes/day)
  • Known or suspected non-compliance, drug or alcohol abuse
  • Pregnancy
  • Active periodontitis (probing pocket depth >4 mm)
  • Pharmacological treatment or antibiotic therapy during or up to three months before the study

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: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

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: Pagalinor®2 (PA) test arm
All patients will wear both the test and control ring material for a within-subject comparison. Ideally, biofilm sampling can be performed in a split mouth design (randomly allocated materials within subjects) with one patient having two implants for placing the test and the control material at the same time. In addition, patients providing one implant, will receive test and control push-on rings in a randomly assigned order, so that both materials are assessed in a consecutive manner.
Device: Rings made of PA (test)
Rings made of PA (test) 0.2mm in thickness are pushed on the conical titanium base (abutment) of implant crowns and are removed and replaced after 48h, 2 weeks and 3 months for quantification of the bacterial biofilm. Test rings are applied in a split-mouth design provided that 2 implants are present (total of 4 months study period), or one after the other when only 1 implant is present (total of 8 months study period).
Active Comparator: Titanium-6Aluminum- 7Niobium alloy (TAN) control arm
All patients will wear both the test and control ring material for a within-subject comparison. Ideally, biofilm sampling can be performed in a split mouth design (randomly allocated materials within subjects) with one patient having two implants for placing the test and the control material at the same time. In addition, patients providing one implant, will receive test and control push-on rings in a randomly assigned order, so that both materials are assessed in a consecutive manner.
Device: Rings made of TAN (control)
Rings made of TAN (control) 0.2mm in thickness are pushed on the conical titanium base (abutment) of implant crowns and are removed and replaced after 48h, 2 weeks and 3 months for quantification of the bacterial biofilm. Control rings are applied in a split-mouth design provided that 2 implants are present (total of 4 months study period), or one after the other when only 1 implant is present (total of 8 months study period).

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 in total bacterial load formed on the removable rings of each material
Time Frame: at 48 hours after ring placement, 2 weeks after ring placement and 3 months after ring placement
Quantification of the bacterial load formed on the removable rings of each material by quantitative real-time PCR (qPCR) using primers specific to highly conserved regions of bacterial 16S rRNA genes.
at 48 hours after ring placement, 2 weeks after ring placement and 3 months after ring placement

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 in bacterial composition (taxonomic diversity) between different materials at various time points by using metagenomic sequencing analysis
Time Frame: at baseline, 2 weeks after ring placement and 10 weeks after ring placement
To assess differences in bacterial composition (taxonomic diversity) between different materials at various time points by Illumina MiSeq sequencing. The taxonomy of each 16S rRNA gene sequence will be analyzed by Ribosomal Database Project (RDP) Classifier (http://rdp.cme.msu.edu/) against the SILVA (SSU123) 16S rRNA database using a confidence threshold of 70%.
at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in probing pocket depth (PPD) in mm
Time Frame: at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in probing pocket depth (PPD) to investigate the inflammatory tissue response
at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in bleeding on probing (BoP)
Time Frame: at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Recording bleeding on probing (BoP) to investigate the inflammatory tissue response
at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in noninvasive laser doppler flowmetry
Time Frame: at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in noninvasive laser doppler flowmetry to to measure the blood flow of mucosa next to the ring
at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in the cells of the peri-implant soft tissue
Time Frame: at 2 weeks after ring placement
To investigate the attachment of peri-implant soft tissues to implant materials, fibroblasts and junctional epithelial cells markers will be analysed using real-time quantitative PCR (RT-qPCR).
at 2 weeks after ring placement

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.
University Hospital, Basel, Switzerland

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
ITI International Team for Implantology, Switzerland

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: Nicola U. Zitzmann, Prof. Dr., University Center for Dental Medicine Basel

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.
January 11, 2022

Primary Completion (Estimated)

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.
December 31, 2026

Study Completion (Estimated)

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.
December 31, 2026

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).
November 3, 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.
November 16, 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.
November 17, 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.
August 11, 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.
August 10, 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.
August 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.
  • 2021-D0061; ex21Zitzmann

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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