Comparison of Marginal Gap Using E4D Design and Conventional Cast Metal Copings

Objective. The purpose of this study was to evaluate if there was a significant difference on vertical marginal gap with metal copings fabricated by two different techniques. Background. The reduction of the marginal gap between a crown and tooth abutment is an important goal in Fixed Prosthodontics. Smaller gap produce less gingival irritation and decrease cement washout, improving the clinical outcome and longevity of the restoration. Methods. From a master die, eight impressions were made using PVS material. These 8 impressions were poured twice each in type IV die stone to produce 16 samples. The techniques used to fabricate the metal copings were: A wax pattern coping and a CAD/CAM milled plastic coping. The dies were numbered from 1 to 8 and marked A for the 1st pour group and B for the 2nd pour group. Groups 1 and 2 were organized as follows: Group 1 (CAD/CAM) included the first four samples of group A and the last four samples of Group B. Group 2 (WAX) included the last four samples of Group A and the first four samples of group B. The sixteen samples were sent to a dental laboratory for fabrication of metal copings produced by these two different techniques. Results. Mean separation for all four sides of the 16 copings were recorded. Significant differences found by Side (p < 0.05) and Coping (p < 0.05). Conclusion. The Wax technique resulted in a smaller vertical marginal gap (μm) than the CAD/CAM technique. Grants. Grant from NSU-HPD supported this project.