Developing evidence-based decision making for tooth replacement in partially dentate patients

Abstract

Objectives:This study aimed to evaluate the effectiveness of different tooth replacement strategies in adult patients with shortened dental arches, including survival rates of prosthodontic interventions, risk of tooth loss and impact on oral-health related quality of life (OHRQoL); to determine the most appropriate tooth replacement strategies in adult patients with 10 or less functional mandibular;and to compare success and survival rates of functionally orientated treatment according to the principles of the shortened dental arch using resin bonded bridgework, with conventional treatment using removable partial dentures. Methods:A systematic review of randomised and non-randomised controlled trials was conducted to evaluate studies of the effectiveness of different tooth replacement strategies in adult patients with shortened dental arches. A protocol was registered with the International Register of Systematic Reviews, and the review was conducted in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). A modified Delphi analysis was used to develop consensus from experts in Restorative Dentistry on the most appropriate tooth replacement strategies in adult patients with shortened dental arches. Ethical approval of the protocol was granted by the Joint Research Ethics Committee, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, and a two-round internet based Delphi consensus process was used. Survival analysis of data from a randomised controlled clinical trial was conducted, to compare success and survival rates of functionally orientated treatment according the principles of the shortened dental arch (SDA) using resin bonded bridgework (RBB), with conventional treatment using removable partial dentures (RPD), after 36 months. Results: The systematic review search strategy identified 112 potentially relevant publications; 22 from Medline (OVID), 54 from EMBASE (OVID), 35 from CENTRAL, one from the authors’ knowledge of the subject area, and none from Open SIGLE. Following screening, ten articles were eligible for inclusion in the systematic review.Of these, four were analyses of different outcomes from a multi centre randomized controlled trial in Germany, whilst one study was the pilot phase for this trial. Two further randomized controlled trials were included from the United Kingdom and Republic of Ireland. The remaining articles were reports of prospective cohort studies from Denmark and the Netherlands. Twenty invited participants completed at least one round of the online modified Delphi survey.All participants had at least ten years post-graduate experience, with the median time from graduation twenty-two years (inter-quartile range 12.5 – 27.5 years). There was consensus amongst study participants on the appropriateness of thirty-seven tooth replacement strategies (37%) across ten clinical scenarios of tooth loss in the mandible. Of these, thirteen were considered appropriate (13%) and twenty-four were considered inappropriate (24%). After 36 months, 89 participants completed the randomised controlled clinical trial. As part of the study a total of 89 RPDs and 120 RBBs were constructed. For the RBBs, 113 (94.3%) were judged as successful with a further 7 (5.8%) having survived after one episode of recementing. In comparison, 65 RPDs were judged to have been successful (73.0%) with a further 10 (11.2%) having survived. A total of 14 RPDs (15.7%) were no longer in use and were considered as unsuccessful. Cumulative survival analysis demonstrated that the success rate for the resin bonded bridges was significantly better than the removable partial dentures (p=0.005). Conclusions:From the systematic review conducted, there is currently insufficient evidence to recommend one tooth replacement strategy over another in adult patients with reduced dentitions. There is a need for further research as there are insufficient numbers of good quality randomised controlled trials currently available.Participants in the modified Delphi analysis agreed that no tooth replacement was appropriate in elderly patients (> 65 years old) with existing functional shortened dental arches (absence of molar teeth). They also agreed that provision of removable partial dentures and conventional bridgework wasnot appropriate in this clinical scenario. Where patients are missing premolar and molar teeth, dental implant supported crowns or bridgework was considered appropriate with consensus, regardless of age. The cumulative survival rate for resin bonded bridges used as part of functionally orientated treatment (SDA group) was significantly better than removable partial dentures for partially dentate older adults (p=0.005), after 36 months. The cumulative survival rate for upper removable partial dentures was significantly better than lower removable partial dentures in partially dentate older adults, particularly in Kennedy Class I cases.