[Influence of positive pressure on gypsum bonded investments].

Abstract

The work aims to investigate the influence of positive pressure to initial and final setting time, as well as the volume variation in course of the pressure carried out gypsum-bonded investment found at Dental Commerce. Seventy-six test samples were obtained, being five of them through conventional investing technique and seventy-one through technique by pressure. Gillmore needles were employed for determining the setting time, meanwhile for volumetric variation a mathematic formula had been applied. According to results, it was concluded that the use of positive pressure affected the initial and the final setting time and the volume after set.