Assessment of In Vitro Shock Absorption Behavior of Implant Supported Crowns Using Different Crown Materials and Luting Conditions -An in vitro study-

Abstract

This in vitro study was designed to evaluate force absorption capacity of implant-supported crowns made of different restorative materials and connected to zirconia hybrid abutments with different luting agents. Materials and Methods: premolar crowns were milled of different computer-aided design/computer-aided manufacture materials (n = 21 crowns per material): zirconia, polyether ether ketone, and VITA Enamic. Crowns were mounted on titanium implant replicas with zirconia hybrid abutments using different luting agents: uncemented, temporarily cemented and adhesively bonded. As a reference, one implant replica was tested without a crown. Force absorptions of the different combinations of crown materials and luting agents were determined by applying an increasing force (0 to 200 N) on the occlusal crown surface and measuring the resulting force below the implant by a digital force gauge. Mean curves of applied and resulting forces up to 200 N were determined, and slopes were calculated. Statistical analysis was performed (Two-way MANOVA proved that there was a significant effect of interaction between different materials and different luting conditions). Significant (P≤.005) differences in the applied and resulting forces were found between the crown materials that were uncemented, temporarily cemented, and adhesively bonded. Materials with higher moduli of elasticity (zirconia) showed steeper slopes of the force curves and lower shock-absorbing capacity. The results of the time factor showed that crowns of Zirconia groups reached the maximum forces (200N) more rapidly than Resin based materials [PEEK, VITA Enamic] but were more influenced by the effect of luting agents ad showed better results with adhesive cementation. The damping effects of resin-based materials [PEEK, VITA Enamic] were higher in general and combination with all cementation and luting modes. VITA Enamic showed slightly better shock absorbing capacity with adhesive cementation than temporary cementation, PEEK showed the highest shock absorbing capacity regardless of cementation mode.