<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT02239718</url>
  </required_header>
  <id_info>
    <org_study_id>17100314</org_study_id>
    <nct_id>NCT02239718</nct_id>
  </id_info>
  <brief_title>Novel Use of 2-unit Cantilever Resin-bonded Bridges for Replacing Missing Molar Teeth - a Randomized Clinical Trial</brief_title>
  <official_title>Novel Use of 2-unit Cantilever Resin-bonded Bridges for Replacing Missing Molar Teeth - a Randomized Clinical Trial</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>The University of Hong Kong</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
    <collaborator>
      <agency>Sun Yat-sen University</agency>
      <agency_class>Other</agency_class>
    </collaborator>
  </sponsors>
  <source>The University of Hong Kong</source>
  <oversight_info>
    <has_dmc>No</has_dmc>
  </oversight_info>
  <brief_summary>
    <textblock>
      Tooth replacement is a significant issue in the World and while dental implants and&#xD;
      conventional bridges have been used to replace missing teeth, dental implants are too&#xD;
      expensive for many and conventional dental bridges are destructive to supporting tooth&#xD;
      tissue.&#xD;
&#xD;
      Resin-bonded bridges (RBBs) are a conservative and cost effective replacement option that&#xD;
      involves minimal tooth preparation, leaving the majority of the tooth intact. They are&#xD;
      secured in place with an adhesive cement, which is bonded to the outer enamel layer. Clinical&#xD;
      audit of these prostheses at the University of Hong Kong shows two-unit RBBs to have some of&#xD;
      the highest success rates in the dental literature for the replacement of missing premolar&#xD;
      and incisor teeth. However, for the replacement of molar teeth, two-unit RBBs are not&#xD;
      performed, as established protocol and recognised texts contraindicate their use due to&#xD;
      concerns with tipping or drifting of supporting teeth. Replacement of a single missing molar&#xD;
      tooth can be with a three-unit, fixed-fixed (single-piece casting) or three-unit,&#xD;
      fixed-movable (two-part casting). However, the fixed-fixed option has a higher debond failure&#xD;
      rate than two-unit RBBs and therefore, at this centre, a modified, 3-unit fixed-movable&#xD;
      design is used. This two-part casting allows for minor, independent movements of the&#xD;
      supporting teeth and thereby aims to reduce stresses between them and, similarly, reduce&#xD;
      de-bonding forces. This has the potential for greater longevity and easier long-term&#xD;
      maintenance as if the major part of the bridge debonds it can be recemented.&#xD;
&#xD;
      The aim of this unique study is to compare 2-unit and 3-unit RBBs for the replacement of&#xD;
      single missing molar tooth in a randomized clinical trial. These two designs will be&#xD;
      clinically evaluated at 6 months , 1 year, 2 years and 3 years to observe the outcome&#xD;
      measures. The primary outcome will examine the success of the dental prostheses with respects&#xD;
      to the need of any clinical intervention to repair or remediate the RBB or supporting tooth.&#xD;
      Minor outcome measures will examine fatigue or damage to the prosthesis, changes in bone&#xD;
      support, pulpal or periodontal health or tooth mobility. Patient satisfaction and quality of&#xD;
      life evaluation of the dental prostheses will also be examined. Will 2-unit RBBs offer&#xD;
      patients a simpler, cheaper, and successful option over current designs? This has not been&#xD;
      previously reported.&#xD;
    </textblock>
  </brief_summary>
  <overall_status>Completed</overall_status>
  <start_date type="Actual">October 2014</start_date>
  <completion_date type="Actual">June 2019</completion_date>
  <primary_completion_date type="Actual">June 2019</primary_completion_date>
  <phase>N/A</phase>
  <study_type>Interventional</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <allocation>Randomized</allocation>
    <intervention_model>Parallel Assignment</intervention_model>
    <primary_purpose>Treatment</primary_purpose>
    <masking>None (Open Label)</masking>
  </study_design_info>
  <primary_outcome>
    <measure>Survival of bridges (RBB)</measure>
    <time_frame>Three years</time_frame>
    <description>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.&#xD;
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.&#xD;
If lost of the original bridge/abutment tooth (teeth) or complication dedicates the remake of the bridge, the bridge is regarded as failed.&#xD;
These will be presented in time to fail (survival) as well as time to complication/treatment (success) by Kaplan Meier curves.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Drifting of abutment teeth after insertion of the bridge</measure>
    <time_frame>Three years</time_frame>
    <description>Models will be taken after insertion/cementation of bridge (RBB) (baseline model) and at review appointments (see Time Frame).&#xD;
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.&#xD;
In potential tooth movement case, models will be scanned and superimposed for analysis of tooth movement (direction and magnitude of movement)</description>
  </primary_outcome>
  <secondary_outcome>
    <measure>Complications</measure>
    <time_frame>Three years</time_frame>
    <description>Complications related to the abutment teeth / prosthesis (RBB)&#xD;
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)&#xD;
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</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Abutment mobility</measure>
    <time_frame>Three years</time_frame>
    <description>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)</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Proximal contact tightness of the abutments</measure>
    <time_frame>Three years</time_frame>
    <description>Measured with passing a dental floss and digital tension gauge on metal matrix band</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Oral Health related Quality of Life</measure>
    <time_frame>Three years</time_frame>
    <description>Measured by Oral Health Impact Profile 49 (OHIP) and 14-item satisfaction (Visual Analogue Scale VAS)&#xD;
OHIP will involve pre-operative (before treatment) as well as peri-operative (after tooth preparation and before RBB cementation) time frame.</description>
  </secondary_outcome>
  <number_of_arms>2</number_of_arms>
  <enrollment type="Actual">78</enrollment>
  <condition>Missing Teeth</condition>
  <arm_group>
    <arm_group_label>2-unit cantilevered resin bonded bridge</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>Use one tooth as abutment tooth to replace one adjacent missing tooth</description>
  </arm_group>
  <arm_group>
    <arm_group_label>3-unit fixed movable resin bonded bridge</arm_group_label>
    <arm_group_type>Active Comparator</arm_group_type>
    <description>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).</description>
  </arm_group>
  <intervention>
    <intervention_type>Procedure</intervention_type>
    <intervention_name>2-unit cantilevered resin bonded bridge</intervention_name>
    <description>Use one tooth as abutment tooth to replace one adjacent missing tooth</description>
    <arm_group_label>2-unit cantilevered resin bonded bridge</arm_group_label>
  </intervention>
  <intervention>
    <intervention_type>Procedure</intervention_type>
    <intervention_name>3-unit fixed movable resin bonded bridge</intervention_name>
    <description>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).</description>
    <arm_group_label>3-unit fixed movable resin bonded bridge</arm_group_label>
  </intervention>
  <eligibility>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          1. A missing molar tooth that ranges in length from 8-10 mm as judged by the&#xD;
             pre-treatment study model. (No more than one per quadrant, if more than one, then&#xD;
             different designs will be used in the same mouth.)&#xD;
&#xD;
          2. The patient has been informed of the various treatment options (dental implants,&#xD;
             partial dentures, conventional fixed prosthodontics and no treatment) and if the&#xD;
             patient has chosen the RBB as their preferred treatment option, they will be invited&#xD;
             to participate in the study&#xD;
&#xD;
          3. The patient is available to attend for clinical examination at 6 monthly interviews&#xD;
             for a period up to 36 months from the start of the study&#xD;
&#xD;
          4. The patient will have a minimum of 12 occluding pairs of teeth (24 teeth in total)&#xD;
&#xD;
          5. have a natural dentition opposing the planned RBB&#xD;
&#xD;
          6. More than 30% bone support on the tooth abutment(s)&#xD;
&#xD;
          7. Patients will agree to being randomly assigned to one of the two treatment groups, a&#xD;
             2-unit bridge or 3-unit fixed movable bridge&#xD;
&#xD;
          8. The patient will have been informed on the nature of the study and be required to sign&#xD;
             a consent form agreeing to undertake treatment in the study&#xD;
&#xD;
          9. The patient is over 18 years old&#xD;
&#xD;
         10. The patient is in sound dental health, ie no active caries and controlled periodontal&#xD;
             disease&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          1. Patients with active tooth decay&#xD;
&#xD;
          2. Patients with uncontrolled periodontal disease. RBB abutment with a probing depth&#xD;
             greater than 5mm and bleeding on probing&#xD;
&#xD;
          3. Patients with teeth missing opposite to the planned RBB&#xD;
&#xD;
          4. Abutment tooth mobility of 2 or greater (Millers classification)&#xD;
&#xD;
          5. Patients with a known allergy to the dental alloy used to make the RBB, ie. Ni/Cr&#xD;
&#xD;
          6. Patients with debilitating illnesses or complicating medical conditions&#xD;
&#xD;
          7. Non-vital or root treated abutment teeth&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>18 Years</minimum_age>
    <maximum_age>N/A</maximum_age>
    <healthy_volunteers>No</healthy_volunteers>
  </eligibility>
  <overall_official>
    <last_name>Michael G Botelho, BDS MSc PhD</last_name>
    <role>Study Chair</role>
    <affiliation>Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong</affiliation>
  </overall_official>
  <overall_official>
    <last_name>Edward CM Lo, BDS MDS PhD</last_name>
    <role>Study Director</role>
    <affiliation>Dental Public Health, Faculty of Dentistry, The University of Hong Kong</affiliation>
  </overall_official>
  <overall_official>
    <last_name>Yan Wang, BDS MDS PhD</last_name>
    <role>Study Director</role>
    <affiliation>Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University</affiliation>
  </overall_official>
  <overall_official>
    <last_name>Walter YH Lam, BDS MDS</last_name>
    <role>Principal Investigator</role>
    <affiliation>Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong</affiliation>
  </overall_official>
  <location>
    <facility>
      <name>Department of Prosthodontics, Guanghua School of Stomatology &amp; Affiliated Hospital of Stomatology, Sun Yat-sen University</name>
      <address>
        <city>GuangZhou</city>
        <state>Guangdong</state>
        <country>China</country>
      </address>
    </facility>
  </location>
  <location>
    <facility>
      <name>Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong</name>
      <address>
        <city>Hong Kong</city>
        <state>Guangdong</state>
        <country>China</country>
      </address>
    </facility>
  </location>
  <location_countries>
    <country>China</country>
  </location_countries>
  <reference>
    <citation>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.</citation>
    <PMID>24685984</PMID>
  </reference>
  <reference>
    <citation>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.</citation>
    <PMID>23025467</PMID>
  </reference>
  <reference>
    <citation>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.</citation>
    <PMID>16803807</PMID>
  </reference>
  <reference>
    <citation>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.</citation>
    <PMID>16220800</PMID>
  </reference>
  <reference>
    <citation>Botelho MG. Improved design of long-span resin-bonded fixed partial dentures: three case reports. Quintessence Int. 2003 Mar;34(3):167-71.</citation>
    <PMID>12731596</PMID>
  </reference>
  <reference>
    <citation>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.</citation>
    <PMID>12652048</PMID>
  </reference>
  <reference>
    <citation>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.</citation>
    <PMID>11203604</PMID>
  </reference>
  <verification_date>August 2020</verification_date>
  <study_first_submitted>September 4, 2014</study_first_submitted>
  <study_first_submitted_qc>September 11, 2014</study_first_submitted_qc>
  <study_first_posted type="Estimate">September 15, 2014</study_first_posted>
  <last_update_submitted>August 14, 2020</last_update_submitted>
  <last_update_submitted_qc>August 14, 2020</last_update_submitted_qc>
  <last_update_posted type="Actual">August 18, 2020</last_update_posted>
  <responsible_party>
    <responsible_party_type>Principal Investigator</responsible_party_type>
    <investigator_affiliation>The University of Hong Kong</investigator_affiliation>
    <investigator_full_name>Dr Michael G. Botelho</investigator_full_name>
    <investigator_title>Clinical Associate Professor</investigator_title>
  </responsible_party>
  <keyword>Resin bonded bridges</keyword>
  <keyword>Clinical trial</keyword>
  <keyword>Prospective</keyword>
  <keyword>Survival</keyword>
  <keyword>Oral health related quality of life</keyword>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Tooth Loss</mesh_term>
    <mesh_term>Anodontia</mesh_term>
  </condition_browse>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT02239718
org study id: 17100314
nct id: NCT02239718
lead sponsor: 
collaborator: 
has dmc: No
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.
allocation: Randomized
intervention model: Parallel Assignment
primary purpose: Treatment
masking: None (Open Label)
measure: Survival of bridges (RBB)
time frame: Three years
description: 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.
measure: Drifting of abutment teeth after insertion of the bridge
time frame: Three years
description: 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)
measure: Complications
time frame: Three years
description: 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
measure: Abutment mobility
time frame: Three years
description: 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)
measure: Proximal contact tightness of the abutments
time frame: Three years
description: Measured with passing a dental floss and digital tension gauge on metal matrix band
measure: Oral Health related Quality of Life
time frame: Three years
description: 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.
arm group label: 2-unit cantilevered resin bonded bridge
arm group type: Experimental
description: Use one tooth as abutment tooth to replace one adjacent missing tooth
arm group label: 3-unit fixed movable resin bonded bridge
arm group type: Active Comparator
description: 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
intervention name: 2-unit cantilevered resin bonded bridge
description: Use one tooth as abutment tooth to replace one adjacent missing tooth
arm group label: 2-unit cantilevered resin bonded bridge
intervention type: Procedure
intervention name: 3-unit fixed movable resin bonded bridge
description: 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).
arm group label: 3-unit fixed movable resin bonded bridge
criteria: 
gender: All
minimum age: 18 Years
maximum age: N/A
healthy volunteers: No
last name: Michael G Botelho, BDS MSc PhD
role: Study Chair
affiliation: Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong
last name: Edward CM Lo, BDS MDS PhD
role: Study Director
affiliation: Dental Public Health, Faculty of Dentistry, The University of Hong Kong
last name: Yan Wang, BDS MDS PhD
role: Study Director
affiliation: Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University
last name: Walter YH Lam, BDS MDS
role: Principal Investigator
affiliation: Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong
facility: 
facility: 
country: China
citation: 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.
PMID: 24685984
citation: 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.
PMID: 23025467
citation: 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.
PMID: 16803807
citation: 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.
PMID: 16220800
citation: Botelho MG. Improved design of long-span resin-bonded fixed partial dentures: three case reports. Quintessence Int. 2003 Mar;34(3):167-71.
PMID: 12731596
citation: 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.
PMID: 12652048
citation: 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.
PMID: 11203604
responsible party type: Principal Investigator
investigator affiliation: The University of Hong Kong
investigator full name: Dr Michael G. Botelho
investigator title: Clinical Associate Professor
mesh term: Tooth Loss
mesh term: Anodontia