Ahmad Ghahremanloo - Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
Mohsen Movahedzadeh - Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
Abdollah Javan Rashid - (M.Sc. of Biostatistics) Dental Schools, Mashhad University of Medical Sciences, Mashhad, Iran

Introduction: Marginal fit is a key factor for long term clinical success through any dental restorations. Poor marginal adaptation causes cement dissolution. This can lead to dental caries, gingival irritation, periodontal diseases, and finally treatment failure. The aim of this study was measurement and comparison of marginal gap quantities in metal ceramic and all ceramic dental restorations fabricated by various methods. Methods & Materials: A total of 60 complete crowns in 6 groups (n=10) were fabricated as. Follows: Group A: Conventional metal-ceramic collarless restorations. Group B: Metal-ceramic collarless restorations with CAD/CAM wax copings and porcelain layering. Group C: Metal-ceramic collarless restorations with Ceramill Sintron metal copings and porcelain layering. Group D: All ceramic e-max. Press (lithium disilicate) restorations. Group E: All ceramic restorations with CAD/CAM zirconia copings and porcelain layering. Group F: All ceramic CAD/CAM translucent zirconia (Zolid). Replica technique and optical microscope (60 x magnifications) used to gap measurement. Mann whitney and kruskal-wallis tests used to analyze the data. Results: The lowest mean marginal gap seen in group C (29.12) and the highest mean marginal gap seen in group E(78.19)The mean marginal adaptation was better in metal ceramic restorations than all ceramic restorations and the difference was significant (P˂0.001). Conclusion: According to our study, marginal gap of metal ceramic and all ceramic restorations was clinically acceptable (less than 120 microns).    

Marginal gap, marginal adaptation, metal ceramic, all ceramic