Amr Ali , Adel El Tannir And Maha Ahmed Taymour,
ABSTRACT
Systems Imply None Or Minimal Influence Of The Dental Laboratory Technician. However, It Is Not Clear Wether Metal Ceramic Restorations Produced By CAD/CAM Systems Show Comparable Adaptation To Those Produced By The Dental Laboratory Technician.
Purpose: This Study Evaluated And Compared The Marginal Gap And Internal Adaptation Of Metal Copings Produced By Four Techniques: Conventional Waxing Technique (CW), Milled Metal Technique (MM), Milled Wax Technique Followed By Conventional Casting (MW1), Milled Wax Technique With Margination Followed By Conventional Casting (MW2)
Materials and Methods: A Master Metal Die Of A Maxillary First Molar Prepared With Chamfer Finish Line Was Produced, Forty Stone Dies Were Poured From Impressions Of The Master Die And Were Randomly Assigned To Each Of The Study Groups (n=10), Metal Copings Were Then Fabricated According To The Study Groups (CW, MM, MW1, MW2). The Metal Copings Were Seated On The Master Metal Die And Held In Place By A Spring Holding Device And The Vertical Marginal Gap Was Measured By A Stereomicroscope Under 10x Magnification At 40 Predetermined Points For Each Specimen. The Internal Gap Was Measured Using The Replica Technique At 7 Predetermined Points For Each Specimen. One Way ANOVA Was Used To Compare Between The Four Groups Followed By Tukey Post Hock Test.
Results: The Least Marginal Gap Was Recorded By The MW2 (47.5 � 3.7�m) With Significant Difference (P<0.05) To The CW (55 � 5.4�m) And MM (60.5 � 7�m Groups) While There Was No Significant Difference With MW1 (50.3 � 5�m). The Internal Gap Results Showed No Significant Difference (P>0.05) Between The Studied Groups With The Least Gap Recorded By MM Group
(127 � 42�m). All Results Were Within The Clinically Acceptable Range.
Conclusion: CAD/CAM Can Be Used In The Production Of Metal Copings As An Efficient, Time Saving And Aseptic Alternative To Conventional Casting As It Produces Copings With Clinically Acceptable Marginal And Internal Adaptation Values.
