ABSTRACT
INTRODUCTION: To study the effect of various sprue designs on the properties of base metal alloy castings. The base metal alloys are extensively used for their excellent properties such as an increase in hardness, high melting range, high elastic modulus, its compatibility with ceramic material and low cost. However, to improve the properties of the base metal alloys is an ongoing research leading to various modifications in their fabrication procedure - which include sprue designs and their mode of attachment to the wax pattern. AIMS AND OBJECTIVES: Study compared the effect of three sprue designs viz. conical sprue, cylindrical sprue and bottleneck sprue on the properties of mass and microhardness of base metal alloy castings. MATERIALS AND METHODS: A prefabricated wax mesh pattern was selected for the fabrication of the alloy test samples in the study. The cylindrical sprue design was connected to the mesh pattern with a straight attachment. The bottleneck sprue design was connected to the mesh pattern with a constricted attachment. The conical sprue design was connected to the mesh pattern with a flared attachment. In this manner, ten samples for each of the three different sprue designs were prepared. RESULTS: The obtained value for mass and microhardness were subjected to statistical analysis. ANOVA test was performed to determine the difference between the sprue designs. CONCLUSION: The bottleneck sprue, conical sprue, and cylindrical sprue designs did not exert any apparent influence on the mass and microhardness.
ABSTRACT
PURPOSE OF THE STUDY: The aim of this study was to evaluate clinically the performance of composite resin used to restore midline diastema between the maxillary and mandibular central incisors. METHODOLOGY: Direct composite restorations were done for 45 patients with midline diastema between the maxillary and mandibular central incisors. Standard protocols were followed for the placement of composite resin for the diastema closure, and recall visits were made for every 6 months for a period of 60 months for evaluation of the success of these restorations made. Qualified dental personnel examined the restorations made. RESULTS: Clinical evaluations were done after the restorations had been in place for an average of 6 months. Results indicate that none of the restorations were totally lost, and resulting in a 91% overall retention rate for the period of 60 months. About 62% of the restorations made had no noticeable color difference with that of the adjacent tooth, and gingival health indicated 73% of the sample was without any signs of inflammation. CONCLUSIONS: Composites restored for diastemas exhibit satisfactory survival rates placed with recommended placement protocols and without occlusal loading.
