Mohamed T. Kamal, Cherif A. Mohsen And Raessa M.Mohammed,

ABSTRACT
Objective The Purpose Of This Study Was To Assess Retention And Microleakage Of Endocrown Constructed Of Two Different Materials Namely IPS E.max And Hybrid Ceramic Compared To Conventional Endo/post/crown Technique.

Materials and Methods: Forty Mandibular Endodontically Treated Molars Will Be Classified Into 2 Groups According Technique Of Restoration. Group I (involving 20 Endodontically Treated Molars Restored With Post, Core And Crowns, Group II (involving 20 Endodontically Treated Molars Restored With Endocrowns). Then Each Group Will Be Divided Into 2 Subgroups (10 Samples For Each Group) According To Material Of Construction Of Crown And Endocrown Into Subgroup I (IPS E-max Press Crown And Vita Enamic Crown) And Subgroup II (IPS E-max Press Endocrown And Vita Enamic Endocrown). Then Sub Group Will Be Divided Into Sub Classes (5 Samples For Each) According To Type Of Test (retention And Microleakage). Specimens Which Will Have Being Tested For Retention ,mounted In A Universal Testing Machine And Will Be Subjected To Tensile Load At A Crosshead Of 5 Mm/min The Load Required For Debonding Was Recorded In Newton. While For Microleakage Test, The Samples Were Immersed Into 0.5 % Methylene Blue (M.B) Solution For 24 Hours At Room Temperature In An Incubator At 37�C Then They Were Sectioned In B-L Direction By Isomet And Dye Penetration Depth Was Measured Using Nikon MA 10 Followed By Image Analysis Using Computer Software. The Data Was Collected For Microleakage (dye Penetration), Tabulated And Statistically Analyzed. Result: It Was Found That The The Highest Retention Mean Value Was Recorded For Vita Enamic Conventional Crown (479.5+_38.4) While The Lowest Retention Mean Value Was Recorded For Vita Enamic Endocrown Which Recorded (85.7�14.7). The Difference Between Groups Was Statistically Significant As Indicated By Two Way ANOVA Test (F=44.9, P Value = <0.001 < 0.05) Besides, It Was Found That The Highest Microleakage Mean Value Was Recorded For Vita Enamic Conventional Crown (915.9�40.7) While The Lowest Microleakage Mean Value Was Recorded For E-max Endocrown Preparation Design Which Recorded (395.2�42.2). The Difference Between Groups Was Statistically Significant As Indicated By Two Way ANOVA Test (F= 5.26, P Value = <0.036< 0.05) Conclusion 1- Bond Strength To All Ceramic Is Influenced By Amount Of Tooth Structure Involved In Cementation And What?s Structure It Bonded As Vita Enamic Conventional Crown Retained By Post And Composite Core Is The Most Retentive Restoration. 2- Microleakage Under Restoration Affected By Impression Techniques, Processing Technology As Pressing Technique Is Less Micro Gab And Microleakage Than Milling Technique.