Resin Bonded Bridges: Techniques for Success
Total Page：16
File Type：pdf, Size：1020Kb
Resin bonded bridges: IN BRIEF • Gain a contemporary understanding of the role of resin bonded bridges in PRACTICE techniques for success replacing missing teeth. • Learn how to improve survival and aesthetics of resin bonded bridges. K. A. Durey,1 P. J. Nixon,2 S. Robinson3 and M. F. W.-Y. Chan4 • A ‘quick reference’ summary of things to consider clinically and technically, to improve outcome. VERIFIABLE CPD PAPER Resin bonded bridges are a minimally invasive option for replacing missing teeth. Although they were first described over 30 years ago, evidence regarding their longevity remains limited and these restorations have developed an undeserved reputation for failure. This article provides a brief review of the literature regarding bridge success and continues to high- light aspects of case selection, bridge design and clinical procedure which may improve outcome. INTRODUCTION By using a RBB it is possible to provide a both general practice and hospital settings Resin bonded or resin retained bridges fixed replacement for missing teeth which reported that a high proportion of prac- (RBBs/RRBs) are minimally invasive fixed is essentially reversible and does not com- titioners used unfavourable techniques.8 prostheses which rely on composite resin promise the abutment tooth. This is espe- It seems reasonable to assume that with cements for retention. These restorations cially important for young patients who improved education and careful planning, were first described in the 1970s and since may be more likely to experience endo- outcome could be improved. this time they have evolved significantly. dontic complications as a result of exten- The aim of this article is to re-evaluate The first type of RBB was the Rochette sive tooth preparation. the role of RBBs in fixed prosthodontics Bridge, which relied on the retention Despite this recognised advantage, the and provide a guide for practitioners with generated by resin cement tags through role of RBBs as definitive restorations regard to case selection, bridge design and a characteristic perforated metal retainer.1 remains somewhat controversial due to a clinical techniques in order that successful However, longevity of this type of restora- lack of long term prospective data regard- outcomes may be achieved. tion was limited and in an effort to address ing success. The majority of information this, methods of altering the surface of is based on the results of longitudinal FACTORS AFFECTING SUCCESS the metal retainer to enhance microme- studies, many of which have been poorly Case selection chanical retention were developed.2 The controlled, used a variety of cements and term ‘Maryland Bridge’ resulted from the preparation techniques making it difficult i) Patient factors development of a type of electrochemi- to isolate factors affecting outcome.4 Restoration of missing teeth aims to cal etching at the University of Maryland. Recent systematic reviews have esti- improve oral function, aesthetics and More recently bridge retention has been mated the five-year survival rates for restore occlusal stability. However, inter- enhanced by the development of resin bridgework as 87.7% for resin bonded vention should be considered carefully as cements which bond chemically to both prostheses4 and just over 90% for con- in some cases it may be detrimental to the the tooth surface and the metal alloy. ventional bridges depending on design.5 remaining dentition.9-11 From a clinician’s perspective, the main Although these rates are lower than the General factors such as the health, age of advantage of RBBs is that, in compari- 94.5% success6 reported for implant the patient, their expectations, local factors son to conventional bridge preparations, retained single crowns over the same five related to dental health and the missing they are conservative of tooth structure.3 year follow up, resin bonded bridgework tooth itself need to be taken into account. has the advantages of being less invasive, For example in older patients with reduced requiring a shorter total treatment time manual dexterity it may be appropriate to 1*Specialist Registrar in Restorative Dentistry, 2,4Con- sultant in Restorative Dentistry, Leeds Dental Institute, and less financial commitment. accept a shortened dental arch rather than Clarendon Way, Leeds, LS2 9PU; 3Senior Lecturer in In contrast to these favourable esti- replacing a lost posterior unit. If a tooth Clinical Dentistry, University of Queensland, University 7 of Queensland, Turbot Street, Brisbane, Australia mations of RBB success, Hussey et al. must be replaced, a RBB may be preferable *Correspondence to: Dr Kathryn Durey reported high failure rates when they used to a removable partial denture (RPD) espe- Email: [email protected] the number of recement fees claimed to cially where there is a history of signifi- Refereed Paper gauge the success of RBBs in NHS gen- cant periodontal disease or dental caries.9 Accepted 16 June 2011 DOI: 10.1038/sj.bdj.2011.619 eral practice. Additionally, a recent study As they are minimally invasive, RBBs can ©British Dental Journal 2011; 211: 113-118 of RBB designs employed by dentists in also provide a temporary option for young BRITISH DENTAL JOURNAL VOLUME 211 NO. 3 AUG 13 2011 113 © 2011 Macmillan Publishers Limited. All rights reserved. PRACTICE patients who have suffered the early loss of an anterior tooth. This situation would otherwise condemn the patient to years of denture wear until growth has ceased and an implant or definitive bridge can be considered. RBBs have the advantages of taking minimal clinical time12 and rarely requiring anaesthetic, therefore they may be appro- a b priate for patients who are apprehensive of dental treatment or unable to commit to more involved treatment involving mul- tiple appointments. However, the patient should still be dentally motivated and caries and periodontal disease should be under control before embarking on fixed prosthodontics. In addition, managing c d expectations with regard to aesthetic out- Fig. 1 a) Older patient with a history of successfully treated periodontal disease and come and longevity should be considered dissatisfaction with partial denture. b) Remaining teeth lingually tilted with increased an important part of treatment planning.13 mobility. c) Provision of multiple (5) cantilever RBBs mimicking root exposure and staining of If expectations are unrealistic, patient sat- natural teeth. d) Note novel bucco-occlusal retaining wing used on lingually tilted molar tooth isfaction with the final result is likely to be low. there has been significant tooth wear. to have undergone some resorption and ii) Abutment tooth selection Additionally, the alignment or angulation have reduced length however, they may When selecting abutment teeth, investi- of teeth may affect the degree to which a also be ankylosed and so are well placed gations should be carried out to ensure retainer can be extended. Crowding may to act as abutments. endodontic and periodontal health. reduce access and rotations may mean that Periodontal support should be assessed full wraparound is difficult to achieve. An iii) Occlusal features considering bone levels and root configu- unconventional approach may be neces- When planning for RBBs, a detailed assess- ration. Although a history of periodontal sary, for example in Figure 1, where a ment of both static and dynamic occlusal disease and reduced bone support does buccal retaining wing has been used on a relationships is crucial to optimise success. not exclude bridgework (Fig. 1), the use lingually tilted molar in an effort to avoid A wax up on articulated casts gives a valu- of abutments with active periodontal dis- the undercut lingual area that proved dif- able view from the palatal aspect aiding ease should be avoided as increased func- ficult to access. the assessment of the amount of interoc- tional loading may increase the rate of If periodontal support and coronal con- clusal space available for the retainer periodontal destruction.14 dition are favourable, any teeth, including wings and pontics.13 It is important that Coronally, there should be sufficient retained deciduous teeth,15 can act as abut- the pontic is not involved in guidance dur- enamel available for bonding. The denti- ments over an appropriate span. Deciduous ing mandibular excursive movements.16 If tions of hypodontia patients are frequently molars can make particularly good abut- this is unachievable, guidance should be associated with a degree of microdontia ments as they are multirooted and have a shared with other natural teeth. reducing the amount of tooth structure large coronal surface area which allows If there is insufficient space for an aes- available. Surface area may also be com- full extension of the retainer wing. The thetic pontic, adjustment of opposing teeth promised if teeth are restored or where roots of retained deciduous teeth are likely could be considered. Alternatively space Fig. 2 Hypodontia case demonstrating two cantilever RBBs to replace UL 3 and ULE. Note the extent of coverage of metal retainers, characterisation of porcelain work and ovate style pontic to achieve good aesthetics 114 BRITISH DENTAL JOURNAL VOLUME 211 NO. 3 AUG 13 2011 © 2011 Macmillan Publishers Limited. All rights reserved. PRACTICE may be gained with localised anterior be maintained separately to restorative composite build ups to adjust guidance treatment, either with removable ortho- patterns or by cementing the restoration dontic retainers or orthodontic bonded at an increased OVD on the retainer.17 wire retainers. If a fixed-fixed design is With both of these options the occlusion required, contact in excursive movements would then be allowed to re-establish over and intercuspation should be on the a period of months through passive erup- retainer only.19 tion.18 Cementing restorations high does not appear to increase the risk of abut- i) Retainer wing coverage ment teeth proclining or the restoration The surface area covered by an RBB retainer Fig. 3 Upper central incisor following lengthening of clinical crown height using 19 debonding, however, the authors suggest has been shown to affect retention.