The effect of disinfectants on the properties of dental gypsum: 1. Mechanical properties

Abstract

Chemical disinfectants reduce the strength of dental gypsum when used as mixing water substitutes. Gum arabic and calcium hydroxide additives permit a lower liquid/powder ratio and can help offset this weakening.

The influence of postpouring time on the roughness, compressive strength, and diametric tensile strength of dental stone

“…The approved specimens were divided into 1-hour (n¼10), 24-hour (n¼10), and 7-day (n¼10) groups. 10,13 The 1-hour specimens were tested immediately, and the 24-hour and 7-day specimens were stored at 25 C AE2 C. The surface roughness of each specimen was measured on a central diametric line established by using digital calipers. A reading 2.5 mm in length was made with a surface roughness tester (SJ 201; Mitutoyo).…”

Effect of mixing methods on the physical properties of dental stones

“…Some used cylindrical specimens 40 mm in length  20 mm in diameter, [18][19][20] while others used cylinders of 12 mm in length  6 mm in diameter 16 or 10 mm in length  5 mm in diameter. 24 In the present study cylindrical stone specimens (25 mm in length  12.5 mm in diameter) were prepared. However, for the diametral tensile strength testing, previous investigators used varying geometrical specimen designs.…”

“…Some used flat cylindrical specimens 10 mm in diameter  3 mm in height, 16 while others used cylinders of equal diameter and height (5 mm  5 mm). 24 In a recent publication by Hersek et al 18 the same geometrical design used for compressive testing was used for diametral tensile strength testing (40 mm in height  20 mm in diameter). The present study followed the model set forth by Hersek et al 18 being the most recent.…”

The effect of disinfectants on the properties of dental gypsum, part 2: Surface properties

“…These additives can reduce the amount of liquid required for mixing and can help improve the properties of gypsum 6,7 . Part 1 of this research 8 used these additives before mixing dental stones with disinfectant solutions; the results showed acceptable strength properties of the set disinfected materials. These findings were significant when the 0.525% sodium hypochlorite or 0.1% povidone‐iodine solutions were used as mixing water substitutes, with reduced liquid/powder (L/P) ratios.…”

“…These findings were significant when the 0.525% sodium hypochlorite or 0.1% povidone‐iodine solutions were used as mixing water substitutes, with reduced liquid/powder (L/P) ratios. The present study is a continuation of part 1 8 and aims to evaluate the surface properties (hardness, roughness, and detail reproduction) of dental stones mixed with disinfectant solutions, and also to determine how adding gum arabic and calcium hydroxide affects these same properties.…”