Comparative evaluation of diametral tensile strength of phosphate-bonded investment (ringless) material by using air-drying method, conventional hot air oven, microwave oven, and combination of microwave and conventional oven: An study.

This study evaluated and compared the diametral tensile strength (DTS) of phosphate-bonded investment (PBI) material (ringless) used in removable cast partial denture fabrication.Comparative - study.The PBI material, Wirovest used in this study was subjected to four different drying methods. A total of 80 specimens were prepared in a cylindrical form; 20 specimens were air dried for 2 h, 20 specimens were dried in a conventional oven at 230°C for 1 h, 20 specimens were dried in microwave oven at 600 W for 10 min, and remaining 20 specimens were dried first in microwave oven and then in conventional oven. The dried specimens were tested at 2-h interval for diametral compression at a crosshead speed of 0.5 cm/min.Pairwise analysis.The microwave drying technique and drying by combination method resulted in greater DTS, respectively.Within the limitation of this study, PBI specimens dried in microwave oven at 600W for 10 min increased the diametral strength and are also a time-saving procedure.