Alaa M. Akmal, Yousreya A. Shalaby And Amir S. Azer,

ABSTRACT
Background: The Accuracy Of The Marginal Adaptation Of A Crown Margin To The Abutment Is A Trigger That Influences The Survival And Efficiency Of Fixed Prosthodontics. Inaccurate Marginal Adaptation Is Potentially Detrimental To The Tooth And The Supporting Periodontal Structures. These Days Improved Vision Is Essential In All Dental Fields Enhancing Precision And Perfection.
Objectives: To Evaluate The Effect Of Two Different Magnification Approaches On The Marginal Fit Of CAD/CAM Monolithic Lithium Disilicate Glass Ceramic Crowns.

Materials and Methods: In-vitro Study Using 24 Upper Right Cuspid Typodont Teeth; Divided Into Three Groups According To Tooth Preparation Approach (n=8). Group I (control Group) Teeth Preparation Without Magnification (control Group), Group II Teeth Preparation Using The Dental Loupes With 3.5x Magnification And Group III Preparation Using The Dental Operating Microscope (DOM) Under Magnification Of 16x. Optical Impressions Were Taken Through Scanning By Sirona InEOS X5 Extra-oral Scanner Where Full Anatomical Crowns Were Structured, Processed, Sintered And Glazed. CBCT Was Utilized To Evaluate The Marginal Gapes Before And After Cementation/aging.

Results: Marginal Gaps Were Significantly Increased After Cementation And Aging In All Groups Yet Still Within The Acceptable Marginal Gap Range. Group III Showed The Least Marginal Gap Followed By Group II & Group I Respectively.

Conclusions: Magnification Devices Are Highly Recommended As A Major Assistant In The Daily Dental Work. Operating Microscopy OM Is A Significant Supplement To The Armamentarium Of Present-day Dentistry. It Helps Set The Bar Of Excellence And Flawlessness At The Highest Level Including All Dental Fields.