IADR Abstract Archives
Properties of Industrial Gypsum Compared to Designated Dental Gypsum Products
Objectives: Industrial gypsum is significantly more economical than proprietary dental stone. However, the composition of each is advertised as ISO Type III stone. Additionally, the literature discusses using an ISO Type II gypsum for mounting casts. Despite this, ISO Types I, II, and III stones are available for this purpose. The objective of this research was to determine if an industrial stone would perform as well as a designated dental stone in terms of properties and to determine which of Types I-III stones would be most appropriate for mounting casts.
Methods: For diagnostic stones, Type III Buff Stone (Prince Mineral, Houston, TX) was compared to the designated dental Microstone (WhipMix, Louisville, KY). For mounting stones, ISO Type III Mounting Stone (WhipMix) was compared to Type II Mounting Plaster (WhipMix) and Type I Laboratory Plaster (WhipMix). The diagnostic stones were tested for reproduction of detail, expansion, and compression (n=5), while the mounting stones were tested for expansion and compression using ISO 6873 as a guide.
Results: Microstone consistently reproduced a 50µm wide line; Buff Stone was only able to consistently reproduce a 75µm wide line. Microstone’s expansion matched the product description of 0.12%; Buff Stone expanded 0.20%. Microstone had a significantly (p<0.01) greater compressive strength (26.7 vs 15.2 MPa). When comparing the mounting stones, there was little difference in terms of expansion for the three mounting stones. Compressive strengths significantly (p<0.01) increased with type (I,II,III): 6.2, 15.9, 23.5MPa, respectively. Given the cost savings, the Type II stone may have adequate properties to be used for mounting casts.
Conclusions: The designated dental Microstone outperformed the industrial Buff Stone in reproduction of detail, expansion, and compression strength, making it a more appropriate product for dental use. Additionally, Type II Mounting Plaster performed adequately to meet the requirements of a mounting stone.
Methods: For diagnostic stones, Type III Buff Stone (Prince Mineral, Houston, TX) was compared to the designated dental Microstone (WhipMix, Louisville, KY). For mounting stones, ISO Type III Mounting Stone (WhipMix) was compared to Type II Mounting Plaster (WhipMix) and Type I Laboratory Plaster (WhipMix). The diagnostic stones were tested for reproduction of detail, expansion, and compression (n=5), while the mounting stones were tested for expansion and compression using ISO 6873 as a guide.
Results: Microstone consistently reproduced a 50µm wide line; Buff Stone was only able to consistently reproduce a 75µm wide line. Microstone’s expansion matched the product description of 0.12%; Buff Stone expanded 0.20%. Microstone had a significantly (p<0.01) greater compressive strength (26.7 vs 15.2 MPa). When comparing the mounting stones, there was little difference in terms of expansion for the three mounting stones. Compressive strengths significantly (p<0.01) increased with type (I,II,III): 6.2, 15.9, 23.5MPa, respectively. Given the cost savings, the Type II stone may have adequate properties to be used for mounting casts.
Conclusions: The designated dental Microstone outperformed the industrial Buff Stone in reproduction of detail, expansion, and compression strength, making it a more appropriate product for dental use. Additionally, Type II Mounting Plaster performed adequately to meet the requirements of a mounting stone.