Biomechanical properties of splint materials while curing

Many studies have evaluated splint strength at maturity with multiple splint materials, methods, and configurations but none have analyzed splints as they cure. The purpose of this study is to evaluate the properties of different splint materials immediately following activation and as they mature. Splints were dipped for three seconds in two temperatures of water and an additional group of fiberglass with no water was tested as well. Splint weight was taken as an additional measurement to assure homogenous groups. All splints were tested in three-point bending at a constant displacement. The generalized linear model (GLM) including all time frames showed differences in yield load and ultimate loads after three minutes. All ultimate loads occurred at greater than 20° of angulation. Plaster had a much lower displacement at its yield load at all times after 3 min. Plaster had a higher stiffness at 1° of angulation at all time points after six minutes. The GLM that excluded the three-day time showed that the higher temperature increased initial stiffness in the splints at three and six minutes. Fiberglass has a higher yield point and ultimate load when compared to plaster. However, these loads were measured at significant splint angulation for the fiberglass, suggesting that plaster is acting as a true splint. Fiberglass is stronger and faster to cure than plaster. In situations where the surgeon desires the strongest splint, fiberglass may be preferable. However, the initial stiffness of plaster is superior to fiberglass.