- What is the clinical evidence on the longevity of all-ceramic/porcelain crowns?
- What is the clinical evidence on the longevity of different types of all-ceramic/porcelain crowns compared with other types of all-ceramic/porcelain crowns?
- What is the clinical evidence on the longevity of ceramic/porcelain-fused-to-metal crowns?
- What is the clinical evidence on the longevity of all-ceramic/porcelain crowns compared with ceramic/porcelain-fused-to-metal crowns?
- What is the long-term (eight years and longer) cost-effectiveness of all-ceramic/porcelain crowns compared with ceramic/porcelain-fused-to-metal crowns?
- What are the evidence-based guidelines regarding the use of all-ceramic/porcelain crowns or ceramic/porcelain-fused-to-metal crowns?
Two systematic reviews were identified, both of which analysed tooth-supported, all-ceramic materials. They showed high survival rates between evaluated all-ceramic materials (5 year survival ranging from 84.5% to 97.6%). Other clinical studies examining all-ceramic crowns included materials such as yttrium oxide partially stabilized zirconia crowns (Y-TZP), lithium disilicate crowns, and layered zirconia crowns. The survival rates varied from 92% and 98.5% at 5 years to a 15 year survival rate of 81.9%. The results of one randomized controlled trial (RCT) suggested that there is no difference in survival rates between porcelain-fused-to-metal (PFM) crowns and all-ceramic crowns. Survival rates over 5 years in this comparative study were 97.44% for PFM crowns and 97.73% for zirconia pressed crowns. PFM crowns had a mean 7 year survival rate of 69.2%.Complications appeared to be uncommon in most studies. The most common complications were chipping, fractures, endodontic complications, secondary caries, root fracture, and periapical lesions. Based on the available evidence, both PFM crowns and all-ceramic crowns appear to be safe interventions, with similarly low complication rates between the two materials.There were many limitations to this evidence, including a lack of comparative studies, a variety of materials and techniques used in manufacturing the crowns, and a lack of Canadian-based studies. Individuals with parafunctional habits including bruxism were also excluded from many studies, which also limited generalizability of the results. Although a large number of studies were identified examining the survival of crowns, the evidence is inconclusive as to whether one material is superior to another, as there is a distinct lack of comparative evidence, a lack of randomized trials, and a lack of studies with long-term follow-up. No systematic reviews were identified that included or compared PFM crowns to all-ceramic crowns, and the included RCT did not detect any significant differences between the two materials. The included systematic reviews also did not perform quality appraisal on included primary studies, thus the quality of the conclusions cannot be determined. Additionally, no relevant evidence-based guidelines or economics publications were identified regarding the use of all-ceramic/porcelain crowns or porcelain fused to metal crowns, therefore, these research questions could not be addressed in this report. This is a limitation that should be considered, as it is unknown whether the materials used in crowns differ in cost-effectiveness