The bending strength of acrylic resin samples repaired under pressure.

The bending strength of heat-cured resin samples was found to be 49% higher than that of autopolymerizing resin samples cured under room conditions. Curing the latter resin in a pressure vessel at 32psi and 30 degrees C increased its strength by 4.5%. For this reason and because a less porous material is obtained, pressure-curing may be employed with advantage for the preparation of various appliances from S.C. resin. The effect of pressure-curing in increasing the strength of the repaired samples was not significant. It would also appear that pressure affects the porosity of small quantities of repair material less than when appliances are made from S.C. resins only. The increase in strength achieved by pressure-curing repairs, in which only small quantities of S.C. resin are used, is therefore questionable.