Effect of bench-delay after flask cooling on the posterior teeth movement in maxillary complete dentures

Abstract

The aim of this investigation was to verify the influence of bench-delay on posterior teeth shift after denture storage in water at temperature of 37ºC, when the flask was cooled in curing water bath. Ten maxillary complete dentures were constructed with Clássico heat-cured acrylic resin using the conventional method of packing in metallic flasks. Metallic reference pins were placed in the labial cusp of the first pre-molars (PM), and mesiolabial cusp of the second molars (M). The acrylic resin was polymerized twelve hours after final flask closure in a water bath cycle at 74ºC for 9 hours. The flasks were removed from the thermo-polymerizing unit after watercooling, and remained stored on the bench for 3 hours. After deflasking and finishing, the dentures were stored in water at temperature of 37ºC for periods of one week, one month, and three months. After deflasking and storage period tested, the PM-PM (pre-molar to pre-molar), M-M (molar to molar), LPM-LM (left pre-molar to left molar) and RPM-RM (right pre-molar to right molar) distances were measured with a STM Olympus microscope, with an accuracy of 0.0005mm. Collected data were submitted to ANOVA and Tukey´s test (5%). No statistically significant difference was noted in the posterior teeth shift in all distances, when the deflasking period was compared with the periods of water storage.