Esraa Hashem, Ghada I. Shehab And Hanaa I. Sallam,

ABSTRACT
Purpose. The Purpose Of This Study Was To Assess The Vertical Marginal Gap Distance Of The IPS E.max Ceramic Copings As Affected By Finish Line Steepness And Construction Technique. Material And Methods. Fifty Four IPS E.max Ceramic Copings Were Fabricated With 2 Different Construction Techniques On Two Nickel Chromium Dies With 2 Different Finish Line Steepnesses (1 And 3 Mm). Copings Were Divided According To Their Construction Technique Into Two Main Groups: Group I : Machinable All Ceramic Copings And Group II : Heat Pressed All Ceramic Copings. Each Group Was Further Subdivided Into Two Subgroups According To Different Finish Line Steepness: Subgroup 1: 1-mm Finish Line Steepness And Subgroup 2 : 3-mm Finish Line Steepness. The Vertical Marginal Gap Distance Was Measured Using A Stereomicroscope, And Data Were Statistically Analyzed Using 2-way ANOVA Followed By Pair- Wise Tukey�s Post-hoc Tests. Results. IPS E.max Ceramic Copings Constructed By CAD/CAM Technology With 3 Mm Finish Line Steepness Recorded The Highest Statistically Significant Vertical Marginal Gap Distance Mean Value (111.01 � 8.05�m), While Copings Constructed By Heat Pressed Technique With 1 Mm Finish Line Steepness Recorded The Lowest Statistically Significant Vertical Marginal Gap Distance Mean Value (26.06 � 3.9 �m) Among The Tested Groups . Pair-wise Tukey�s Post-hoc Test Showed That There Was No Statistically Significant Difference Between Copings Constructed By Heat Pressed Technique With 1 Mm And 3 Mm Finish Line Steepness (P=0.329). Conclusion. Increasing The Finish Line Steepness Significantly Increases The Vertical Marginal Gap Distance Especially With CAD/CAM Construction Technique. The Construction Technique Significantly Affected The Vertical Marginal Gap Distance Of IPS Emax Ceramic Copings, With The Superiority Of The Heat Pressing Technique. Clinical Implications. IPS E.max Press Is More Reliable Than IPS E.max CAD For Preparations And Restorations Of Teeth With Increased Degree Of Finish Line Steepness.