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

Summary

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.

Conditions

• Missing Teeth

Interventions

PROCEDURE

2-unit cantilevered resin bonded bridge

Use one tooth as abutment tooth to replace one adjacent missing tooth

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).

Sponsors & Collaborators

• Sun Yat-sen University

  collaborator OTHER

• The University of Hong Kong

  lead OTHER

Principal Investigators

• Michael G Botelho, BDS MSc PhD · Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong

• Edward CM Lo, BDS MDS PhD · Dental Public Health, Faculty of Dentistry, The University of Hong Kong

• Yan Wang, BDS MDS PhD · Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University

• Walter YH Lam, BDS MDS · Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2014-10-31

Primary Completion

2019-06-30

Completion

2019-06-30

Countries

• China

Study Locations