An RCT of molar two- and three-unit RBBs – initial findings

Objectives: The aim of this randomized controlled trial (RCT) is to compare the clinical performance of three-unit fixed-movable (FM3) and two-unit cantilever (CL2) resin-bonded bridges (RBBs) for molar-sized spans (8-10 mm).
Methods: This study was registered with Clinicaltrial.gov (NCT02239718) and ethical approval was obtained. Patients with at least one missing molar and who met the inclusion/exclusion criteria were recruited and randomized (ratio 1:1) into CL2 and FM3 groups. Patients were clinically examined before and at 1, 6, 12 months after cementation of RBBs. Abutment teeth mobility and tightness of proximal contacts were recorded by Periotest and digital gauge respectively. Patient’s satisfaction with the RBB was recorded by visual analogue scale.


Results: So far 57 patients were enrolled and 72 RBBs were inserted, 32 were CL2 and 40 were FM3. One-month, 6-month and 12-month examinations were conducted on 37, 28 and 5 subjects, respectively. The majority these RBBs were provided by students or junior dentists (38.9%). Two CL2 and one FM3 RBBs were debonded, resulting in retention rates of 93.8% and 97.5% for the groups respectively. The presence of proximal contacts inferred no abutment tooth had drifted. Patients in both groups were satisfied with their RBBs. No adverse outcomes were reported.
Conclusions: These initial findings demonstrate that CL2 RBBs are successful for molar spans with no observable drifting of abutment teeth. Longer term and more comprehensive data will be collected.