silicon and soda-lime

In this study, different glasses were investigated to improve reusable investments. Borosilicate glass (BSG) powder and soda-lime glass (SLG) powder were prepared by milling broken beakers and microscope slides, respectively, and used in experimental investments (I-BSG, I-SLG) by blending glass powder (10 wt%) with cristobalite (90 wt%). Some properties and casting fits were evaluated with commercial gypsum-bonded investment as the control. Both BSG and SLG were mainly composed of Si, but SLG had a large Ca content. The glass transition temperatures were approximately 800°C (BSG) and 700°C (SLG). Experimental investments with heating showed the significantly (p<0.05) higher expansion than that of the control. The compressive strength of I-SLG was higher than that of I-BSG, and increased with temperature. The MOD inlay obtained from I-SLG had a significantly smaller gap than that from I-BSG, and was comparable to the control. These results suggest SLG could be applied clinically as a reusable dental investment.

Topics: Boron Compounds; Calcium; Calcium Compounds; Calcium Sulfate; Compressive Strength; Dental Casting Investment; Dental Casting Technique; Dental Marginal Adaptation; Differential Thermal Analysis; Equipment Reuse; Glass; Gold Alloys; Hot Temperature; Humans; Inlays; Materials Testing; Oxides; Palladium; Silicates; Silicon; Silicon Dioxide; Silver; Sodium Hydroxide; Spectrometry, X-Ray Emission; Stress, Mechanical; Surface Properties; Transition Temperature