Survival of Zircona- and Metal-supported bridges - A Systematic Review

Several clinical studies with data up to 5 years reported on a high prevalence of chipping of the ceramic veneer material of zirconia-supported fixed partial dentures (FPD) which is higher when the data are compared to metal-supported FPDs. On the other hand the fracture of the framework was a rare event to date. The question are: (1) Do zirconia-supported FPDs really chip more often than metal-supported FPDs or (2) If this is true may the higher chipping rate be due to the fact that the investigators are more attentive and register every small chip which in fact does not hamper function and aesthetics of the restoration ? It seems overdue to systematically analyse clinical studies related to zirconia-supported FPDs and compare the data with clinical studies on metal-supported restorations. For that purpose the medical/dental database provided by PubMed as well as published abstracts of scientific meetings will be searched for clinical studies on zirconia- and metal supported FPDs. The inclusion criteria are: (1) prospective clinical trial of at least 2 years, (2) report on technical failures like fracture of the framework and/or chipping of the veneer material and its extent, (3) replacement of FPD due to fracture/chipping.