Effect of investment mass on distortion of MOD wax patterns

Flaring of proximal walls of years, but not examined. In this experiment, the mass of investment peripheral to the wax patterns was varied by use of casting rings of the same lengths but of different diameters. Thirty castings were made individually, ten from each ring of 28 mm, 48 mm, and 60 mm diameter. The castings were cemented to their parent dies, sectioned mesiodistally, and the cement spaces at specific sites measured. Flaring angles were calculated for the proximal walls and were found to be inversely proportional to the diameters of the casting rings, and, thus, to the peripheral mass of investment. Further studies to detail the fluid mechanics of investments and to predict wax pattern behavior are warranted.