Effect of the Abutment-Prosthesis Connection on Marginal Bone Loss and Gingival Sealing Around Dental Implants

May 9, 2026 updated by: Miguel Padial-Molina, Universidad de Granada

In dental implant restoration, available literature demonstrates the advantage of using tall abutments, with a change of diameter with respect to the implant and a conical internal connection in the abutment-implant gap. However, for multiple restorations, the abutment-prosthesis connection has not been studied in detail. The "multi-unit" systems, both standard and brand specific, have either a flat or butt joint or an cone. In any case, both are external connection systems. Recently, an internal-type abutment-prosthesis connection system has been developed. Although it is proving its usefulness in single restorations, its use in multiple restorations compared to traditional systems has not been studied.

Therefore, taking into account all of the above, the present study has the overall objective of analyzing marginal bone loss (MBL) and adaptation of soft tissues by comparing a multiple prosthesis system of the "external, flat" type versus an external system of the "internal, conical" type.

Study Overview

Status

Suspended

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

40

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

  • Spain
    • Granada
      • Granada, Granada, Spain, 18071
        • Universidad de Granada

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion criteria:

  • Kennedy class I or II (unilateral or bilateral free end) or III (posterior intermediate edentulous section) mandibular requiring 2 implants to restore at least 2 molars, 2 molars and 1 premolar, or 2 premolars and 1 molar.
  • Possibility of placing a transgingival abutment at least 2 mm high.

Exclusion criteria:

  • Need for simultaneous bone augmentation.
  • Heavy smokers (>10 cigarettes/day).
  • Uncontrolled type 1 or 2 diabetes (HgA1c>8).
  • Known autoimmune or inflammatory disease.
  • Serious blood disorders, such as hemophilia or leukemia.
  • Local or systemic infection that may compromise normal healing (e.g., extensive periapical pathology).
  • Liver or kidney dysfunction/failure.
  • Currently receiving cancer treatment or within 18 months from completion of radio- or chemotherapy.
  • Long-term history of oral bisphosphonates use (i.e., 10 years or more).
  • History of intravenous bisphosphonates.
  • Long-term (>3 months) history of antibiotics or drugs known to alter the inflammation and/or immunological system 3 months before inclusion.
  • Severe osseous diseases (e.g., Paget disease of bone).
  • Pregnant women or nursing mothers.
  • Not able or not willing to follow instructions related to the study procedures.

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: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Connect®
Restoration of multiple implants with a Connect® abutment between the implant and the prosthesis.
Device: Connect®
Restoration of multiple implants with a Connect® abutment between the implant and the prosthesis.
Active Comparator: Multi-unit
Restoration of multiple implants with a conventional multi-unit abutment between the implant and the prosthesis.
Device: Multi-unit
Restoration of multiple implants with a conventional multi-unit abutment between the implant and the prosthesis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Marginal bone level
Time Frame: 1 year
Peri-implant marginal bone level measured by standardized periapical radiography
1 year

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Peri-implant microbiome
Time Frame: 1 year
Relative abundance of microbial species in the peri-implant sulcus evaluated by next-generation sequencing methods
1 year
Peri-implant inflammation
Time Frame: 1 year
Concentration of pro-inflammatory markers in the peri-implant sulcus evaluated by multiplex techniques methods
1 year

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Soft-tissue volume
Time Frame: 1 year
Three-dimensional volume of the soft tissue around the implants
1 year

Collaborators and Investigators

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

Sponsor

Universidad de Granada

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)

July 10, 2023

Primary Completion (Estimated)

May 1, 2026

Study Completion (Estimated)

July 1, 2026

Study Registration Dates

First Submitted

May 20, 2023

First Submitted That Met QC Criteria

May 20, 2023

First Posted (Actual)

May 31, 2023

Study Record Updates

Last Update Posted (Actual)

May 12, 2026

Last Update Submitted That Met QC Criteria

May 9, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2622CEIH2022

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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