RCT comparing molar two and three-unit RBBs – interim findings

Abstract

Objectives: Two-unit cantilevered (CL2) resin-bonded bridges (RBBs) should be considered as the standard of care for replacing single- anterior and premolar teeth compared to three-unit fixed-fixed designs. However, for missing molars the use of CL2 designs goes against previous principles of prosthodontic bridge design. The aim of this paper is to report the interim findings of a randomized-controlled trial (Clinicaltrial.gov NCT02239718) comparing RBBs of FM3 and CL2 designs for molar-sized spans (8-10 mm). Methods: Patients with one or more missing molars that fulfilled the inclusion/extrusion criteria (IRB: UW14-233) 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’s satisfaction and oral health-related quality of life were evaluated by 14-item questionnaire and OHIP-49 respectively. Results: Seventy-six patients were enrolled and 95 RBBs were randomized into 45 CL2 and 50 FM3 designs. Fifty-three patients were reviewed at 1-month, 35 at 6-months, 26 at 12-month and one at 24-month. The majority of the prostheses were provided by undergraduate dental students. Two CL2 and one FM3 RBBs debonded resulting in retention rate of 95.6% and 98.0%. They were all rebonded. Two CL2 abutment teeth has increased in mobility while three abutment teeth of FM3 increased. No tooth has moved greater than 0.5mm. Patient reported outcome evaluation were good and no adverse outcomes were reported. Conclusions: The interim data show that CL2 RBBs can be successfully placed for single molar spans with no observable complications. Longer term data will be collected. Grant UGC: 17100314