Seal integrity of hollow-bulb obturators

Five techniques using various materials were evaluated for their ability to produce a watertight seal between obturator and lid. Leakage was determined by an increase in sample weight above that attributed to sorption and by visualization of water inside the clear acrylic resin samples. A watertight seal was obtained for some samples in each of the test groups. Only the two-flask technique sealed with heat-processed acrylic resin produced a watertight seal in all samples. It was determined that pressure up to 30 psi for 1 hour does not rupture a sealed hollow bulb and immersion under pressure is required to detect leakage of a bulb in a short period of time.