EVALUATION OF MARGINAL FIT AND INTERAL FIT OF METAL COPINGS FABRICATED BY THREE DIFFERENT TECHNIQUES- AN IN VITRO STUDY

Abstract

Statement of problem: An optimal marginal and internal fit plays an important role in the longevity of a restoration. Increased marginal gaps can cause bacterial and biofilm adherence. Also, poor internal fit can lead to decreased retention and resistance form. There are various techniques available for the fabrication of restorations. All these techniques have their own pros and cons. In regards to these problems, the present study was conducted to find out whether the manufacturing technique has any influence on the marginal and internal fit of copings. Aim: The aim of this study was to evaluate and compare the internal and marginal fit of Co-Cr copings fabricated by three different techniques namely, conventional lost wax technique, 3D resin printing technique and CAD/CAM milling technique. Materials and methods: A stainless steel master model and a custom tray were fabricated. Totally 30 impressions were made and poured with die stone to obtain 30 die specimens. The specimens were grouped into three groups. Group 1- conventional lost wax technique, group 2- 3D resin printing technique and group 3- CAD/CAM milling technique. Co-Cr copings were fabricated using the respective technique. For evaluating the internal fit, weighing technique was followed. The cross-sectional technique was followed to assess the marginal fit. Results: There was statistically significant difference between the different groups in terms of internal and marginal fit. The CAD/CAM milling technique showed better marginal and internal fit compared to the other two techniques. The 3D resin printing technique showed better results than the conventional technique but was not statistically significant. Conclusion: Within the limitations of this present study, the results drawn suggests the use of CAD/ CAM milling technique and the 3D resin printing technique for fabricating restorations in routine dental practice.