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

NCT ID: NCT02239718

Last Updated: 2020-08-18

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

78 participants

Study Classification

INTERVENTIONAL

Study Start Date

2014-10-31

Study Completion Date

2019-06-30

Brief Summary

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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.

Detailed Description

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Conditions

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Missing Teeth

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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2-unit cantilevered resin bonded bridge

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

Group Type EXPERIMENTAL

2-unit cantilevered resin bonded bridge

Intervention Type PROCEDURE

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

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).

Group Type ACTIVE_COMPARATOR

3-unit fixed movable resin bonded bridge

Intervention Type PROCEDURE

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).

Interventions

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2-unit cantilevered resin bonded bridge

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

Intervention Type 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).

Intervention Type PROCEDURE

Eligibility Criteria

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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
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Sun Yat-sen University

OTHER

Sponsor Role collaborator

The University of Hong Kong

OTHER

Sponsor Role lead

Responsible Party

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Dr Michael G. Botelho

Clinical Associate Professor

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Michael G Botelho, BDS MSc PhD

Role: STUDY_CHAIR

Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong

Edward CM Lo, BDS MDS PhD

Role: STUDY_DIRECTOR

Dental Public Health, Faculty of Dentistry, The University of Hong Kong

Yan Wang, BDS MDS PhD

Role: STUDY_DIRECTOR

Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University

Walter YH Lam, BDS MDS

Role: PRINCIPAL_INVESTIGATOR

Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong

Locations

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Department of Prosthodontics, Guanghua School of Stomatology & Affiliated Hospital of Stomatology, Sun Yat-sen University

Guangzhou, Guangdong, China

Site Status

Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong

Hong Kong, Guangdong, China

Site Status

Countries

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China

References

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Botelho MG, Ma X, Cheung GJ, Law RK, Tai MT, Lam WY. Long-term clinical evaluation of 211 two-unit cantilevered resin-bonded fixed partial dentures. J Dent. 2014 Jul;42(7):778-84. doi: 10.1016/j.jdent.2014.02.004. Epub 2014 Mar 28.

Reference Type BACKGROUND
PMID: 24685984 (View on PubMed)

Lam WY, Botelho MG, McGrath CP. Longevity of implant crowns and 2-unit cantilevered resin-bonded bridges. Clin Oral Implants Res. 2013 Dec;24(12):1369-74. doi: 10.1111/clr.12034. Epub 2012 Oct 2.

Reference Type BACKGROUND
PMID: 23025467 (View on PubMed)

Botelho MG, Leung KC, Ng H, Chan K. A retrospective clinical evaluation of two-unit cantilevered resin-bonded fixed partial dentures. J Am Dent Assoc. 2006 Jun;137(6):783-8. doi: 10.14219/jada.archive.2006.0290.

Reference Type BACKGROUND
PMID: 16803807 (View on PubMed)

Botelho MG, Dyson JE. Long-span, fixed-movable, resin-bonded fixed partial dentures: a retrospective, preliminary clinical investigation. Int J Prosthodont. 2005 Sep-Oct;18(5):371-6.

Reference Type BACKGROUND
PMID: 16220800 (View on PubMed)

Botelho MG. Improved design of long-span resin-bonded fixed partial dentures: three case reports. Quintessence Int. 2003 Mar;34(3):167-71.

Reference Type BACKGROUND
PMID: 12731596 (View on PubMed)

Botelho MG. Inhibitory effects on selected oral bacteria of antibacterial agents incorporated in a glass ionomer cement. Caries Res. 2003 Mar-Apr;37(2):108-14. doi: 10.1159/000069019.

Reference Type BACKGROUND
PMID: 12652048 (View on PubMed)

Botelho MG, Nor LC, Kwong HW, Kuen BS. Two-unit cantilevered resin-bonded fixed partial dentures--a retrospective, preliminary clinical investigation. Int J Prosthodont. 2000 Jan-Feb;13(1):25-8.

Reference Type BACKGROUND
PMID: 11203604 (View on PubMed)

Botelho MG, Yon MJY, Mak KCK, Lam WYH. A randomised controlled trial of two-unit cantilevered or three-unit fixed-movable resin-bonded fixed partial dentures replacing missing molars. J Dent. 2020 Dec;103:103519. doi: 10.1016/j.jdent.2020.103519. Epub 2020 Nov 2.

Reference Type DERIVED
PMID: 33152408 (View on PubMed)

Other Identifiers

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17100314

Identifier Type: -

Identifier Source: org_study_id

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