Resin strengthening of dental ceramics to prevent fracture of restorations in service

Missing or damaged tooth structure is routinely replaced by dental practitioners to prevent patients from experiencing pain, sensitivity and infection, in addition to restoring function and dental aesthetics. Tooth restoration may be performed directly in the mouth or indirectly by cementing a pre-fabricated restoration to the prepared tooth. Indirect techniques offer the dental operator greater control over the shape and form of the ultimate restoration and of the materials currently available, dental ceramics are most equipped to mimic tooth structure in shade, translucency and lustre. However, the major criticism levelled at dental ceramic restorations is their susceptibility to fracture in service and despite extensive engineering to increase the strength of these materials the data from clinical studies suggest the annual failure rate to be approximately 3-5%. Failure of dental restorations has high cost implications to both the patient and the relevant health authority both in terms of the cost of the revision dentistry and in terms of time required to attend appointments.Dental practitioners have a choice of different classes of cement materials available to use to secure dental ceramic restorations in the mouth. Of these, resin-based cements, which can adhesively bond to both the tooth and some dental ceramic materials, have been shown to reduce likelihood of fracture of the ceramic restoration in service. It is understood that the improved performance with these materials occurs because the resin-based cement interacts with the flaws on the surface of the ceramic from which a crack may propagate. However, the strengthening mechanism(s) is poorly understood thereby preventing the optimisation of the clinical techniques and the cementation materials required to exploit the available reinforcement. The proposed research aims to carefully characterise the strengthening mechanism and to begin to identify the material characteristics of the resin-based cement that are required to provide the most significant and durable reinforcement of dental ceramic restorations. Using these learnings, further efforts will be made to develop novel resin-coatings and processing routes that strengthen the dental ceramic and that may be applied prior to cementation. It is hoped that the outcomes of this study will be readily translatable into the provision of clinical protocols and development of optimised and/or novel materials that will reduce the incidence of premature fracture of dental ceramic restorations in service. The research is performed in close conjunction with clinical experts, industrial collaborators and international academic partners.

Patients are the main beneficiaries from this work, as clinicians will benefit from the targeting and elimination of key early failures of all-ceramic restorations by optimising adhesive cementation techniques and materials and therefore increasing confidence in and delivering higher survival rates for these aesthetic restorations.The lack of clinical confidence in the use of all-ceramic restorations in dentistry is primarily based on the high rate of failure in the first five years. It is estimated that for the 54,000 all-ceramic restorations placed under the National Health Service (NHS) in England and Wales each year an annual failure rate in the region of 3-5% is expected at best. The key early clinical failures of these restorations based on provisional data accounts for up to 30% of premature clinical failures. The current project investigates procedures whereby restoration failures can be reduced with appropriate cementation materials and procedures. Reducing the premature failure rate from 30 to 15% would result in increased restoration longevity providing a 3.75 million saving over a five year period to the relevant health authority in terms of material and labour costs. Wider significant economic implications to the United Kingdom relate to a reduction in the enforced absenteeism from the workplace by patients due to a need to receive revision dentistry following premature restoration failure. The development of innovative materials and processing routes will provide opportunity to enhance the clinical performance of all-ceramic restorations however, the successful implementation of operative techniques requires engagement with both clinicians and industry. To translate the findings of the proposed study into real oral healthcare benefits the researchers will engage the clinical community through the teaching curriculum within the host dental school and nationally via postgraduate Continuing Professional Development courses (including NHS funded Section 63 courses). As a clinical academic the applicant is an established dental educator and works closely with a network of Specialist qualified clinicians who regularly speak to clinical audiences both nationally and internationally. Manuscripts will be prepared for publication not only in peer-reviewed scientific journals but also in popular readership professional journals aimed at providing dental practitioners with evidence based clinical protocols. To ensure that patients who are the prime beneficiaries of this study have access to the information generated, efforts will be made to make available the key findings in appropriate open source media. Established links with industrial collaborators will enable dialogue regarding potential commercialisation of materials or processes resulting from the investigation. The applicant has developed collaborations with both industry and in academia. Such collaborations will provide expertise and facilities that will enhance the quality of the research and will be valuable in the dissemination and exploitation of the outcomes of the proposed research. The development of strong collaborative networks in a field where the UK possesses a competitive scientific and industrial base can only benefit UK competitiveness in this area. The host institution (The University of Birmingham) is well positioned to facilitate exploitation of the findings of the proposed study through support and enterprise services including the Medici programme which assists academics with the commercial and non-commercial development of their research and Alta Innovations, which is the institutions technology exploitation company. Finally the applicant as a clinical academic (training as a specialist in a field relevant to this proposal) has regular interaction through teaching and seminars with dental practitioners thus providing the capacity to disseminate the key outcomes widely.