Volume 6 Issue 1 (January - February), 2020

Original Articles

Assessment of marginal gap of complete crowns made by using wet and dry ceramic ring liners - a comparative study
Ramandeep Singh, Sunny Sharma

Backgrounds: Indirect restorations constitute a major part of dental restoration. The accuracy of casting is subject to material volumetric changes occurring due to shrinkage of wax and alloys. Hence; the present study was conducted for assessing marginal gap of complete crowns made by using wet and dry ceramic ring liners – a comparative study. Materials & methods: A total of 30 stone dies duplicated from a brass master die mimicking a prepared premolar tooth were included. A counter die with dimensions 1mm larger than the master die was made for making wax patterns of uniform dimensions. A custom tray of autopolymerising acrylic resin and polyvinyl siloxane impression material was used for duplicating brass master die. Thirty stone dies were prepared in this manner and were divided into groups of fifteen each as follows: Group A – Castings made by using dry ceramic ring liner and Group B – Castings made by using wet ceramic ring liner. Wax patterns were made on stone dies. The casting procedure was performed by using an induction casting machine. Nickel chromium alloy was used to fabricate the castings. The castings were seated on the stone die with finger pressure. Assessment of marginal gap was done using scanning electron microscope. Results: Mean marginal gap among the specimens of Group A and Group B was found to be 59.3µm and 152.3µm respectively. Significant results were obtained while comparing the mean marginal gap among the specimens of both the study groups. Conclusion: Crowns made by using dry ceramic ring liners show significantly less marginal gap in comparison to wet ceramic ring liners. Key words: Marginal Gap, Complete crown

 
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