Missing TeethNCT02239718
Novel Use of 2-unit Cantilever Resin-bonded Bridges for Replacing Missing Molar Teeth - a Randomized Clinical Trial
A study testing 2-unit cantilevered resin bonded bridge and 3-unit fixed movable resin bonded bridge in people with Missing Teeth, run by The University of Hong Kong at 2 sites in China.
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Missing Teeth
- What is being tested?
- 2-unit cantilevered resin bonded bridge and 3-unit fixed movable resin bonded bridge
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 78 participants
- Where
- 2 sitesChina
- Study dates
- Oct 2014to Jun 2019
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.)
- 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
- 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
- The patient will have a minimum of 12 occluding pairs of teeth (24 teeth in total)
- have a natural dentition opposing the planned RBB
- More than 30% bone support on the tooth abutment(s)
Show all 10Show fewer
- Patients will agree to being randomly assigned to one of the two treatment groups, a 2-unit bridge or 3-unit fixed movable bridge
- 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
- The patient is over 18 years old
- The patient is in sound dental health, ie no active caries and controlled periodontal disease
Who cannot join
- Patients with active tooth decay
- Patients with uncontrolled periodontal disease. RBB abutment with a probing depth greater than 5mm and bleeding on probing
- Patients with teeth missing opposite to the planned RBB
- Abutment tooth mobility of 2 or greater (Millers classification)
- Patients with a known allergy to the dental alloy used to make the RBB, ie. Ni/Cr
- Patients with debilitating illnesses or complicating medical conditions
- Non-vital or root treated abutment teeth
Trial locations and contacts
2 sites in 1 country.
China2 sites
Department of Prosthodontics, Guanghua School of Stomatology & Affiliated Hospital of Stomatology, Sun Yat-sen University
Guangzhou, Guangdong
Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong
Hong Kong, Guangdong
About this study
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
- Being tested
- 2-unit cantilevered resin bonded bridge, 3-unit fixed movable resin bonded bridge
- Keywords
- Resin bonded bridges, Clinical trial, Prospective, Survival, Oral health related quality of life
- Medical subject headings
- Anodontia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
2-unit cantilevered resin bonded bridgeProcedure or surgery
Use one tooth as abutment tooth to replace one adjacent missing tooth
3-unit fixed movable resin bonded bridgeProcedure or surgery
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).
| Study group | Role | What they receive |
|---|---|---|
| 2-unit cantilevered resin bonded bridge | Experimental | Use one tooth as abutment tooth to replace one adjacent missing tooth Receives: Procedure: 2-unit cantilevered resin bonded bridge |
| 3-unit fixed movable resin bonded bridge | Active comparator | 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). Receives: Procedure: 3-unit fixed movable resin bonded bridge |
What is being measured
The primary outcome is the main question the study is designed to answer.
Survival of bridges (RBB)
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.
Measured: Three years
Drifting of abutment teeth after insertion of the bridge
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)
Measured: Three years
Secondary outcomes (4)
Complications
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
Measured: Three years
Abutment mobility
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)
Measured: Three years
Proximal contact tightness of the abutments
Measured with passing a dental floss and digital tension gauge on metal matrix band
Measured: Three years
Oral Health related Quality of Life
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.
Measured: Three years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Sep 2014 (estimated)
- Study startOct 2014
- Primary completionJun 2019
- Study completionJun 2019
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (8)Papers the sponsor has linked to this study.
- Other trials for Missing TeethStudies of the same condition, open and under way.
- More trials run by The University of Hong KongThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 78 participants (actual)
Sponsor and investigators
- Lead sponsor
- The University of Hong Kong
- Sponsor type
- University, hospital or other
- Collaborators
- Sun Yat-sen University
- Responsible party
- Principal investigator, Dr Michael G. Botelho, The University of Hong Kong
- Investigators
- Michael G Botelho, BDS MSc PhD, Study chair, Oral Rehabilitation, Faculty of Dentistry, The University of Hong KongEdward CM Lo, BDS MDS PhD, Study director, Dental Public Health, Faculty of Dentistry, The University of Hong KongYan Wang, BDS MDS PhD, Study director, Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen UniversityWalter YH Lam, BDS MDS, Principal investigator, Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02239718
- Sponsor's protocol ID
- 17100314
- Status last verified
- Aug 2020
- First submitted
- 4 Sep 2014
- Last updated
- 18 Aug 2020
- Results posted
- No
- Data monitoring committee
- No
Publications
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.
PubMed 24685984Lam 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.
PubMed 23025467Botelho 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.
PubMed 16803807Botelho 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.
PubMed 16220800Botelho MG. Improved design of long-span resin-bonded fixed partial dentures: three case reports. Quintessence Int. 2003 Mar;34(3):167-71.
PubMed 12731596Botelho 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.
PubMed 12652048Botelho 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.
PubMed 11203604Botelho 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.
PubMed 33152408
Study at a glance
From the registry record, last updated by the sponsor on 18 Aug 2020. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Novel Use of 2-unit Cantilever Resin-bonded Bridges for Replacing Missing Molar Teeth - a Randomized Clinical Trial
- ClinicalTrials.gov ID
- NCT02239718
- Acronym / sponsor ID
- 17100314
- Conditions
- Missing Teeth
- Keywords
- Resin bonded bridges, Clinical trial, Prospective, Survival, Oral health related quality of life
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 78 participants (actual)
- Lead sponsor
- The University of Hong KongUniversity, hospital or other
- Collaborators
- Sun Yat-sen University
- Study start
- Oct 2014 (actual)
- Primary completion
- Jun 2019 (actual)
- Study completion
- Jun 2019 (actual)
- First posted
- 15 Sep 2014 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| 2-unit cantilevered resin bonded bridge | Experimental | Procedure: 2-unit cantilevered resin bonded bridgeUse one tooth as abutment tooth to replace one adjacent missing tooth |
| 3-unit fixed movable resin bonded bridge | Active comparator | Procedure: 3-unit fixed movable resin bonded bridgeUse 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). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- 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.)
- 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
- 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
- The patient will have a minimum of 12 occluding pairs of teeth (24 teeth in total)
- have a natural dentition opposing the planned RBB
Key exclusion criteria (7 listed)
- Patients with active tooth decay
- Patients with uncontrolled periodontal disease. RBB abutment with a probing depth greater than 5mm and bleeding on probing
- Patients with teeth missing opposite to the planned RBB
- Abutment tooth mobility of 2 or greater (Millers classification)
- Patients with a known allergy to the dental alloy used to make the RBB, ie. Ni/Cr
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 2-unit cantilevered resin bonded bridgeUse one tooth as abutment tooth to replace one adjacent missing tooth | Procedure or surgery | 2-unit cantilevered resin bonded bridge |
| 3-unit fixed movable resin bonded bridgeUse 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 or surgery | 3-unit fixed movable resin bonded bridge |
Primary outcome
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.
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)
4 secondary outcomes
Complications
Time frame: Three years
Abutment mobility
Time frame: Three years
Proximal contact tightness of the abutments
Time frame: Three years
Oral Health related Quality of Life
Time frame: Three years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Aug 2020.
- Background: PubMed 24685984Botelho 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.
- Background: PubMed 23025467Lam 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.
- Background: PubMed 16803807Botelho 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.
- Background: PubMed 16220800Botelho 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.
- Background: PubMed 12731596Botelho MG. Improved design of long-span resin-bonded fixed partial dentures: three case reports. Quintessence Int. 2003 Mar;34(3):167-71.
- Background: PubMed 12652048Botelho 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.
- Background: PubMed 11203604Botelho 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.
- Derived from this study: PubMed 33152408Botelho 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Michael G Botelho, BDS MSc PhD study chair
Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong
Edward CM Lo, BDS MDS PhD study director
Dental Public Health, Faculty of Dentistry, The University of Hong Kong
Yan Wang, BDS MDS PhD study director
Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing 2-unit cantilevered resin bonded bridge and 3-unit fixed movable resin bonded bridge in people with Missing Teeth, run by The University of Hong Kong at 2 sites in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Aug 2020. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Survival of bridges (RBB) (time frame: Three years). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT02239718, which also lists 8 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Aug 2020.