Yasmin Hefnawy, Jylan Fouad El-Guindy And Lamyaa Khair Allah,

ABSTRACT
The Aim Of This Study: Was To Measure The Fracture Resistance In Endodontically Treated Teeth Restored With Lithium Disilicate Crowns Retained With Fiber Posts And Core Compared To VITASUPRINITY And CERASMART Endocrowns. Statement Of The Problem: The Risks That Increased The Potential Of Tooth Fracture After Endodontic Treatment, The Risks Included Loss Of Tooth Structure, Post Canal Preparation, Post Selection. Endocrowns Were Revealed To Fail More When Fixed To Premolars. The Influence Of Different Crown Material On Fracture Resistance Of Ceramic Crowns Placed On Endodontically Treated Maxillary Premolars Has Not Been Clearly Established. RESEARCH QUESTION: In Endodontically Treated Maxillary Premolars Will Teeth Requiring (VITASUPRINITY) And Hybrid Ceramics (CERASMART) Endo Crowns Provide Better Fracture Resistance Compared To Lithium Disilicate Ceramic Crowns Retained With Glass Fiber Posts? Hypothesis: 1. Endo-crowns Will Have More Fracture Resistance Than Lithium Disilicate Crowns Retained With Fiber Postsand Composite Core. 2. Endocrowns Restoration Made Of VITASUPRINITY Material Would Show More Fracture Resistance Than Endocrowns Made Of Hybrid Ceramics CERASMART. Conclusion: 1. Both VITASUPRINITY And CERASMART Endocrowns Are As Promising As Fiber Post And Composite Core Supported IPS E.max CAD Crowns. 2.Favourable Mode Of Fracture Of VITASUPRINITY, CERASMART Endocrowns And Fiber Post And Composite Core Supported IPS E.max CAD Crowns Since The Fracture Was Mostly Above CEJ ?repairable?. 3. All Fracture Resistance Loads Obtained Were Far Beyond The Maximum Masticatory Forces, Which Can Withstand The Maximum Intraoral Masticatory Forces In The Maxillary Premolar Region.