Each tube was sealed in a flask containing 7.5 mL of distilled water. The pH was measured (PH 30 Sensor Corning; Corning Inc., New York, NY, USA) with a pH meter at 3, 24, 72, and 168 h of spatulation ...

Twenty specimens (n=10) were made and, since the same test specimen was used for the different storage times, variables such as water/powder ratio, hand spatulation time, etc, were excluded. Photos ...