Novel Use of 2-unit Cantilever Resin-bonded Bridges for Replacing Missing Molar Teeth - a Randomized Clinical Trial

August 14, 2020 updated by: Dr Michael G. Botelho, The University of Hong Kong

Tooth replacement is a significant issue in the World and while dental implants and conventional bridges have been used to replace missing teeth, dental implants are too expensive for many and conventional dental bridges are destructive to supporting tooth tissue.

Resin-bonded bridges (RBBs) are a conservative and cost effective replacement option that involves minimal tooth preparation, leaving the majority of the tooth intact. They are secured in place with an adhesive cement, which is bonded to the outer enamel layer. Clinical audit of these prostheses at the University of Hong Kong shows two-unit RBBs to have some of the highest success rates in the dental literature for the replacement of missing premolar and incisor teeth. However, for the replacement of molar teeth, two-unit RBBs are not performed, as established protocol and recognised texts contraindicate their use due to concerns with tipping or drifting of supporting teeth. Replacement of a single missing molar tooth can be with a three-unit, fixed-fixed (single-piece casting) or three-unit, fixed-movable (two-part casting). However, the fixed-fixed option has a higher debond failure rate than two-unit RBBs and therefore, at this centre, a modified, 3-unit fixed-movable design is used. This two-part casting allows for minor, independent movements of the supporting teeth and thereby aims to reduce stresses between them and, similarly, reduce de-bonding forces. This has the potential for greater longevity and easier long-term maintenance as if the major part of the bridge debonds it can be recemented.

The aim of this unique study is to compare 2-unit and 3-unit RBBs for the replacement of single missing molar tooth in a randomized clinical trial. These two designs will be clinically evaluated at 6 months , 1 year, 2 years and 3 years to observe the outcome measures. The primary outcome will examine the success of the dental prostheses with respects to the need of any clinical intervention to repair or remediate the RBB or supporting tooth. Minor outcome measures will examine fatigue or damage to the prosthesis, changes in bone support, pulpal or periodontal health or tooth mobility. Patient satisfaction and quality of life evaluation of the dental prostheses will also be examined. Will 2-unit RBBs offer patients a simpler, cheaper, and successful option over current designs? This has not been previously reported.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

78

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

  • China
    • Guangdong
      • GuangZhou, Guangdong, China
        • Department of Prosthodontics, Guanghua School of Stomatology & Affiliated Hospital of Stomatology, Sun Yat-sen University
      • Hong Kong, Guangdong, China
        • Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong

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

16 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. A missing molar tooth that ranges in length from 8-10 mm as judged by the pre-treatment study model. (No more than one per quadrant, if more than one, then different designs will be used in the same mouth.)
  2. The patient has been informed of the various treatment options (dental implants, partial dentures, conventional fixed prosthodontics and no treatment) and if the patient has chosen the RBB as their preferred treatment option, they will be invited to participate in the study
  3. The patient is available to attend for clinical examination at 6 monthly interviews for a period up to 36 months from the start of the study
  4. The patient will have a minimum of 12 occluding pairs of teeth (24 teeth in total)
  5. have a natural dentition opposing the planned RBB
  6. More than 30% bone support on the tooth abutment(s)
  7. Patients will agree to being randomly assigned to one of the two treatment groups, a 2-unit bridge or 3-unit fixed movable bridge
  8. The patient will have been informed on the nature of the study and be required to sign a consent form agreeing to undertake treatment in the study
  9. The patient is over 18 years old
  10. The patient is in sound dental health, ie no active caries and controlled periodontal disease

Exclusion Criteria:

  1. Patients with active tooth decay
  2. Patients with uncontrolled periodontal disease. RBB abutment with a probing depth greater than 5mm and bleeding on probing
  3. Patients with teeth missing opposite to the planned RBB
  4. Abutment tooth mobility of 2 or greater (Millers classification)
  5. Patients with a known allergy to the dental alloy used to make the RBB, ie. Ni/Cr
  6. Patients with debilitating illnesses or complicating medical conditions
  7. Non-vital or root treated abutment teeth

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: 2-unit cantilevered resin bonded bridge
Use one tooth as abutment tooth to replace one adjacent missing tooth
Procedure: 2-unit cantilevered resin bonded bridge
Use one tooth as abutment tooth to replace one adjacent missing tooth
Active Comparator: 3-unit fixed movable resin bonded bridge
Use teeth from both side of the missing tooth space to replace a tooth. The prosthesis is cast in two piece and connected with a fixed-movable joint (semi-precision, allow degree of movement).
Procedure: 3-unit fixed movable resin bonded bridge
Use teeth from both side of the missing tooth space to replace a tooth. The prosthesis is cast in two piece and connected with a fixed-movable joint (semi-precision, allow degree of movement).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Survival of bridges (RBB)
Time Frame: Three years

Clinically whether the bridge is in subject's mouth. Any complication(s) and associated treatment(s) will be recorded. In case where there is absence of complication/treatment, this bridge is regarded as success.

If complication occur and/or treatment (apart from routine periodontal maintenance) is required but the original bridge is still in the mouth, this bridge is regarded as survival.

If lost of the original bridge/abutment tooth (teeth) or complication dedicates the remake of the bridge, the bridge is regarded as failed.

These will be presented in time to fail (survival) as well as time to complication/treatment (success) by Kaplan Meier curves.
Three years
Drifting of abutment teeth after insertion of the bridge
Time Frame: Three years

Models will be taken after insertion/cementation of bridge (RBB) (baseline model) and at review appointments (see Time Frame).

Vacuum suck down will be made on the baseline model and fitted in subject's mouth during review appointments to screen for any potential tooth movement.

In potential tooth movement case, models will be scanned and superimposed for analysis of tooth movement (direction and magnitude of movement)
Three years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Complications
Time Frame: Three years

Complications related to the abutment teeth / prosthesis (RBB)

This is measured from review examinations as well as from patient history (any treatment of the RBB by the third parties other than the study centres)

Review examination will look for: debonding, fracture of framework, fracture of veneer material, caries occurring related to retainer on the abutments, extraction related to periodontal disease or root fracture resulting in loss of the entire reconstruction, abutment endodontic or apical radiolucency, probing depth greater than 5mm
Three years
Abutment mobility
Time Frame: Three years
Tested by two handles of mirror (Grade 0, I, II, III) and periotest (Grade 0: -8 to +9; I: 10 to 19; II: 20 to 29; III: 30-50)
Three years
Proximal contact tightness of the abutments
Time Frame: Three years
Measured with passing a dental floss and digital tension gauge on metal matrix band
Three years
Oral Health related Quality of Life
Time Frame: Three years

Measured by Oral Health Impact Profile 49 (OHIP) and 14-item satisfaction (Visual Analogue Scale VAS)

OHIP will involve pre-operative (before treatment) as well as peri-operative (after tooth preparation and before RBB cementation) time frame.
Three years

Collaborators and Investigators

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

Sponsor

The University of Hong Kong

Collaborators

Sun Yat-sen University

Investigators

  • Study Chair: Michael G Botelho, BDS MSc PhD, Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong
  • Study Director: Edward CM Lo, BDS MDS PhD, Dental Public Health, Faculty of Dentistry, The University of Hong Kong
  • Study Director: Yan Wang, BDS MDS PhD, Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University
  • Principal Investigator: Walter YH Lam, BDS MDS, Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong

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)

October 1, 2014

Primary Completion (Actual)

June 1, 2019

Study Completion (Actual)

June 1, 2019

Study Registration Dates

First Submitted

September 4, 2014

First Submitted That Met QC Criteria

September 11, 2014

First Posted (Estimate)

September 15, 2014

Study Record Updates

Last Update Posted (Actual)

August 18, 2020

Last Update Submitted That Met QC Criteria

August 14, 2020

Last Verified

August 1, 2020

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 17100314

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.

Clinical Trials on Missing Teeth

Clinical Trials on 2-unit cantilevered resin bonded bridge

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Cameroon

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

3
Subscribe