Effects of relining on long-term marginal stability of provisional crowns

Provisional resins crowns are commonly placed to protect prepared teeth, but the marginal adaptation of interim crowns has always been a problem. These experiments examined the effects of thermocycling and occlusal loading on relined and unrelined polymethyl methacrylate resin transitional crowns. Three groups of interim crowns were made on a cast metal die tooth preparation; unrelined, relined correction, and paint-on correction. After thermocycling and occlusal loading of the specimens, the change in mean marginal gap was significantly greater for the unrelined group. Axial changes were greatest for relined group and least for the unrelined group. These results suggested that relining of polymethyl methacrylate interim crowns can be useful to prevent increases in marginal gap width during extended intraoral periods.