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

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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.