Effect of package weight on the total amount of die stone used annually in a dental school

Purpose This study compared the total amount of Type IV dental stone (die stone) used annually by dental students when they were supplied with either 70‐g or 140‐g preweighed packages of die stone. Materials and Methods In September 1994, all the bulk containers of die stone were removed from the student dental clinic and laboratories and replaced by 70‐g preweighed packages of die stone (Silky‐Rock; Whip Mix, Louisville, KY). At the end of August 1998, all 70‐g packages of die stone were removed from the student dental clinic and laboratories. The average annual number of 70‐g packages of preweighed die stone used by the students from 1994 to 1998 was calculated. From September 1998 to the end of August 1999, only 140‐g preweighed packages of die stone (Silky‐Rock) were supplied to the students. The number of the 140‐g packages of preweighed die stone and total weight used by students during this period were calculated and compared with the average annual number of 70‐g preweighed packages of die stone used during the 1994–1998 period. Results From September 1994 to August 1998, the students used an annual average of 4060 ± SD 250 of the 70‐g packages (284.2 ± 17.5 kg per annum). From September 1998 to August 1999, the students used 3360 of the 140‐g packages (470.4 kg). Conclusions Although the students used in total 700 fewer of the 140‐g die stone packages per annum than the annual average number of 70‐g packages, they used 186.2 kg (65.5%) more die stone when supplied with the 140‐g packages.