effect of different curing methods on the bond strength of heat-cured soft lining material and heat-cured acrylic resin: a comparative study

One of the serious defects of soft lining materials is their poor adhesion base. So, in this study the effect of different curing methods on the bond strength of heat cured acrylic resin and heat cured acrylic soft liner was investigated. Sixty specimens were prepared, thirty for shear test, and thirty for tensile test and eash of them was subdivided equally into three groups according to different curing methods, microwave oven, conventional curing bath and domestic pressure cooker [P.C] Half of the specimens were stored in distilled water for 2 days and the remainder for 30 days. The force required for failure by separation of soft liner was measured using Lloxd universal testing machine at cross heat speed 22mm/min. The results of this investigation showed that the highest bonding strength was obtained when using domestic P.C. either after 2 days or after 30 days storage in distilled water. While the bond strength of soft lining material cured by conventional curing bath and microwave oven was less than cured by domestic P.C, also there was a reduction of this bond strength after 30 days of storage in distilled water. The microwave group showed the least value of bond strength. There was no significant difference between the bond strength of the microwave group and conventional group after 2 days of storage while there was significant difference between them after 30 days of storage

Effect of record base stabilization on mandibular centric position

Ten completely edentulous patients were selected to investigate the effect of record base stabilization on mandibular centric position. Zinc oxide euginol impression paste, light body rubber base impression material, tissue conditioner, and denture adhesive were used as stabilization materials for the record bases. The mandibular centric position was graphically traced using intra-oral tracer. The results of this study revealed that, record base stabilization is essential for accurate recording of mandibular centric position whatever the stabilization material used. It also revealed that, denture adhesive is a simply highly effective record base stabilization material