Fayrouz Abdel Hassieb, Ashraf Hassan Mokhtar And Tamer Abd El Rehim Hamza,

ABSTRACT
Statement Of The Problem: Fracture Resistance Is Essential For The Long-term Success Of Endocrown Restorations. Recently The Use Of Hybrid Ceramics Had Been Used For Endocrown Fabrication Yet The Studies Comparing Their Fracture Resistance Are Limited. The Purpose Of This In Vitro Study: Was To Compare Fracture Resistance Of Recently Introduced Hybrid Ceramic And Lithium Disilicate Endocrown Restorations Cemented With Two Bonding Approaches.

Materials and Methods: Twenty Extracted Human Maxillary First Molars Were Divided Into Two Equal Groups Of Ten Teeth According To Ceramic Material Used Each Group: Group (E): Ten Teeth Were Prepared To Receive E-max Endocrowns. Group (V): Ten Teeth Were Prepared To Receive Vita-Enamic Endocrowns. Each Group Was Further Subdivided Into Two Groups (n=5) According To Bonding Approach: Sub Group (1) N=5: Endocrowns Cemented With Self-adhesive Rein Cement (Rely-X Unicem). Sub Group (2) N=5: Endocrowns Cemented With Self-etch Adhesive (Futurabond DC 8th Generation) And Self-adhesive Resin Cement (Rely-X Unicem). After Standardized Preparation Of All Samples Fracture Resistance Was Tested Using Universal Testing Machine.

Results: Showed That Ceramic Type Had A Statistically Significant Effect On Mean Fracture Resistance. Cementation Technique And The Interaction Between The Two Variables Had Non-statistically Significant Effect On Mean Fracture Resistance. Since The Interaction Between The Variables Is Non-statistically Significant, So The Variables Are Independent From Each Other.

Conclusions: 1) Lithium-disilicate Endocrowns Showed Higher Fracture Resistance Than Hybrid Ceramics Endocrowns. 2) Futurabond DC In Combination With Rely-X Unicem Increased The Fracture Resistance Of Hybrid Ceramic Endocrowns Approximating Their Performance To Lithium-disilicate Endocrowns.