This study examined the influence of thickness on changes (lin ear dimensions, warpage, and water uptake) in a denture base resin following two processing methods (heat polymerization and microwave activation). Changes were influenced by both processing method and thickness. These findings suggested that the processing method and denture base resin thickness are important factors in the dimensional change of acrylic resin dentures, and that the overall dimensional denture base changes are the result of localized changes.