Evaluation of marginal gap of Ni-Cr copings made with conventional and accelerated casting techniques.

Context: Conventional casting techniques following the manufacturers' recommendations are time consuming. Accelerated casting techniques have been reported, but their accuracy with base metal alloys has not been adequately studied. Aim: We measured the vertical marginal gap of nickel-chromium copings made by conventional and accelerated casting techniques and determined the clinical acceptability of the cast copings in this study. Settings and Design: Experimental design, in vitro study, lab settings. Materials and Methods: Ten copings each were cast by conventional and accelerated casting techniques. All copings were identical, only their mold preparation schedules differed. Microscopic measurements were recorded at ×80 magnification on the perpendicular to the axial wall at four predetermined sites. The marginal gap values were evaluated by paired t test. Results: The mean marginal gap by conventional technique (34.02 μm) is approximately 10 μm lesser than that of accelerated casting technique (44.62 μm). As the P value is less than 0.0001, there is highly significant difference between the two techniques with regard to vertical marginal gap. Conclusion: The accelerated casting technique is time saving and the marginal gap measured was within the clinically acceptable limits and could be an alternative to time-consuming conventional techniques.

Flexible resins in the rehabilitation of maxillectomy patient.

Surgical resection is an established and common method for treatment of maxillofacial tumors. Such intervening surgery in this region may involve the destruction of antral, nasal, or orbital contents and jaws. Normally, the end result is a defect which may affect speech, swallowing, mastication and facial appearance. Prosthodontic restoration of functions and facial form is an excellent method in the replacement of missing parts and restoration of contour. Pertinent research in materials, designs and methods have resulted in whole array of possible prosthess that can be provided to meet specific patient needs. This case report describes the fabrication of definitive obturator prosthesis made of flexible acrylic resin on a chrome cobalt base.