Biomechanics of prefabricated zirconium oxide and glass fiber posts in vitro: a systematic literature review

Aim: As aesthetic needs keep rising, conventional metal – ceramic coronal restorations are being replaced by full – ceramic crowns. Such restorations oblige dental professionals to choose tooth – colored zirconium oxide or glass fiber posts in order to achieve an overall aesthetic result. Both post systems have similar aesthetic but different mechanical properties. The purpose of this study is to characterize the in vitro biomechanics of prefabricated zirconium oxide posts and compare them with glass fiber posts. Material and methods: Rewieving process was in line with PRISMA guidelines. Using previously established keywords literature search was performed in four electronic databases („Cochrane Library “, „Medline“, „Pubmed“, „Wiley“). All publications, which were written in English and were comparing zirconium oxide and glass – fiber posts in vitro were accepted to this literature review. Results: After initial search 208 articles were identified by titles. Then, after selection process, 12 articles were accepted for qualitive analysis. All accepted articles were divided into two groups – in vitro studies, which used extracted human teeth (6 articles) and studies which performed finite element analysis (6 articles). After methodological comparison, in in vitro group failure loads and modes were compared. In finite element analysis group stress distribution was compared. Conclusions: Prefabricated zirconium oxide posts have high modulus of elasticity, which causes strain accumulation in a post itself that leads to non-restorable fractures in vitro. Meanwhile glass – fiber posts tend to have more homogeneous strain transmission to the dentin of the root