Kareem Talaat Ahmed, Hanaa I. Sallam And Rasha N. Sami,

ABSTRACT


Aim: The Aim Of The Study Was To Evaluate Vertical Marginal Gap Distance And Internal Adaptation Between Lithium Disilicate Superstructures And Lithium Disilicate Hybrid Abutments Constructed By CAD/CAM Technique And Heat Pressing Technique.

Materials and Methods: 14 Dummy Implants Were Placed In Epoxy Resin Blocks By The Aid Of A Paralleling Device Then Titanium Bases Were Screwed To The Dummy Implants. The Samples Were Randomly Assigned Into Two Study Groups (n=7 Each) According To The Construction Technique; Group I : Lithium Disilicate (e.max CAD) Hybrid Abutments And Superstructures Constructed By CAD /CAM Technique, Group II: Lithium Disilicate (e-max Press) Hybrid Abutments And Superstructures Constructed By Heat Pressing Technique. The Produced Ceramic Abutments Of Both Groups Were Cemented Onto Their Corresponding Titanium Bases Using Adhesive Resin Cement. All Superstructures Were Designed As Monolithic Upper First Premolar, Half Of Which Were Constructed By The CAD/CAM Technique And The Other Half By The Heat Pressing Technique. Vertical Marginal Gap Distance Measurements Between Each Abutment And Its Corresponding Superstructure Were Recorded At 36 Points (9 Points /surface) Using Digital Microscope. Internal Adaptation Was Measured Using Silicon Replica Technique. Data Were Collected, Tabulated And Statistically Analyzed Using Student T-test (P ? 0.05).

Results: The Heat Pressing Group Showed A Statistically Significant Lower Marginal Gap Distance Between Hybrid Abutments And Superstructures Than The CAD/CAM Group. On The Other Hand, Samples Of The CAD/CAM Group Showed Statistically Significant Higher Internal Adaptation Between Hybrid Abutments And Superstructures Than Samples Of The Heat Pressing Group. Conclusion: Vertical Marginal Gap Distance And Internal Adaptation Between Lithium Disilicate Implant Superstructures And Lithium Disilicate Hybrid Abutments Were Significantly Affected By Their Construction Technique. Heat Pressing Construction Technique Improved The Vertical Marginal Gap Distance While CAD/CAM Technique Improved The Internal Adaptationbetween Lithium Disilicate Implant Superstructures And Lithium Disilicate Hybrid Abutments.