Modified direct relining method produces an accurate adaptation of denture

The purpose of this study was to examine if a modified direct relining method could result in excellent denture adaptation compared to a conventional method. Direct relining was done using heat-polymerized acrylic resin base on a maxillary cast with two times of three seconds of cooling using dichloro-difluoro-methane coolant. Discrepancy between cast and intaglio surface at residual ridge and center of palate was measured at 12 minutes after mixing of resin (Time 0) and at 24 hours or seven days after water immersion (36 degrees C). At Time 0 (with three seconds of cooling), the discrepancy at ridge (0.39 +/- 0.27) and palate (0.66 +/- 0.31) was significantly lower compared to that of control (ridge = 0.93 +/- 0.51; palate = 1.14 +/- 0.13, P < 0.05); and the same observations occurred at 24 hours and seven days too. On intaglio side (with three seconds of cooling), the peak temperature was 5 degrees C lower than that of control and it occurred at a delay of about 60 seconds. Based on the results of this study, we therefore suggested that this delayed and lowered temperature served to improve the adaptability of denture base.