RCT Comparing Molar Two-and Three-unit RBBs – Interim Findings

Abstract

Objectives: Resin-bonded bridges (RBBs) are conservative prostheses requireing minimal tooth reduction. While two-unit cantilever (CL2) RBBs have been shown to be more successful than fixed-fixed counterparts, they are not recommended for molar-sized edentulous spans. This study reports the interim findings of a randomized-controlled trial comparing three-unit fixed-movable (FM3) and CL2 RBBs for molar-sized spans (8-10 mm). IRB-UW 14-233, Clinicaltrial.gov NCT02239718 Methods: Patients with one or more missing molars and meeting the inclusion/extrusion criteria were recruited and randomized (ratio 1:1) into CL2 (test) or FM3 (control) group. Patients were examined by independent assessors at baseline, 1-, 6-, 12- and 24-month after insertion of RBBs. Abutment teeth mobility were assessed by Periotest and abutment teeth movement were assessed by superimposition of pre- and postoperative digitized teeth. Patient satisfaction was evaluated by 14-items visual analogue scale after insertion of RBBs. Oral health-related quality of life was assessed using Oral Health Impact Factor (OHIP-49). Results: Fifty-one patients were reviewed and 63 RBBs were inserted with 29 CL2 and 34 FM3 RBBs. Fifty-three patients were reviewed at 1-month, 38 at 6-months, 29 at 12-month and five at 24-month. The majority of these prostheses were provided by undergraduate dental students. Two CL2 and one FM3 RBBs debonded resulting in retention rate of 93.1% and 97.1%. All were rebonded. Seven CL2 abutment teeth has increased in mobility while two of abutment teeth of FM3 increased. No tooth has moved greater than 0.5mm. The mean OHIP-49 scores of CL2 and FM3 groups were 33.1 and 38.2 respectively (p>0.05), whereas the general satisfaction of CL2 and FM3 were 84.1 and 90.1 respectively (p=0.049). No adverse outcomes were reported. Conclusions: The interim data show that CL2 RBBs can be successfully placed for molar spans with no observable complications. Longer term data will be collected. UGC-GRF no.17100314