Fady A. Issa, Hesham Katamish And Tarek Salah Morsi,

ABSTRACT
The Purpose Of This Study Was To Evaluate The Performance Of New Hybrid-ceramics As Anterior And Posterior Implant Supported Abutments Under Cyclic Loading As A One-piece Hybrid Abutment And Measure Their Fracture Resistance. 20 Implant Analogues Were Embedded In Acrylic Resin Blocks. Titanium Base Was Placed And Scanned. Samples Were Designed As Upper Central Incisors And Upper First Premolars Using Exocad Software For CAD/CAM Milling Using VITA ENAMIC Blocks. All Abutments Were Permanently Cemented To Titanium Base Using Resin Cement. All Samples Were Subjected To Cyclic Fatigue Loading Followed By Fracture Resistance Testing Of Surviving Specimens. Posterior One-piece Hybrid Abutment Samples Showed Higher Survival Rate Than Posterior One-piece Abutments During Cyclic Loading. The Mean Fracture Loads Of The One-piece Hybrid Abutments Both Anterior & Posterior Were 304 N And 417.6 N Respectively. Fractographic Analysis Confirmed That Crack Originated From The Occlusal Surface (under The Indenter) And Spread To Restoration Margins, Which Lead To Clean Bulk Fracture Of The Samples.