The influence of storage on dimensional changes in maxillary acrylic denture bases and the effect on tooth displacement.

This study investigated the influence of both room temperature storage and water storage on tooth displacement in complete dentures. Thirty maxillary dentures were manufactured and processed using 3 different curing cycles; long, short conventional and microwaved. Distances between fixed points on teeth were measured and the dentures stored at room temperature for 24 weeks. After storage, the distances were measured again and the dentures then stored in water at 37 degrees C for 24 weeks, when the distances were re-evaluated. Anteroposterior distances demonstrated contraction in all acrylic resins. Incisor-incisor (air = -8.5% and water = -7.0%) and molar-molar (room = -1.8% and water = -1.1%) distance changes were greater in the Onda-Cryl resin (p < 0.05), whereas the premolar-premolar (room = -2.2% and water = -1.7%) distance was higher in the QC-20 resin (p < 0.05).