COMPARISION OF CUTTING EFFICIENCY OF TUNGSTEN CARBIDE &DIAMOND BURS ON NICKEL CHROMIUM CASTING ALLOY
Even with the advances in materials and technologies in constructing crown and bridge, failure and the need to replace crown and bridge occurs all the time. When the conservative methods to remove the crown and bridge fail destructive disassembly of the prosthesis has to be carried out. Cutting through the crown with burs is time consuming and tiring.20 metal rods from a base metal alloy (Ni-Cr) rods were used for this study. The rods were divided into two groups .Group A was cut using SSW FG-271 tungsten carbide bur and Group B was cut using SF-11 diamond burs using a high speed hand piece for a constant time of 1 minute by a single operator. The cutting efficiency of each bur was evaluated corresponding to the weight loss.The amount of metal loss was 0.02±0.014 gms with diamond burs and 0.011±.007 gms with tungsten carbide burs.There was a statistically significant difference (<0.05) in the mean material loss between the different groups in independent sample t-test.Cutting efficiency was better with diamond burs.It depends on the diamond bur grit size and duration of the cutting procedure and many other factors. The cutting efficiency of the bur in zirconia and porcelain should also be considered while making the decision.