Thermal behavior of casting investment during setting

Abstract

The aim of this study was to examine the thermal reactions of silica-sol liquids for mixing investment powders using differential thermal analysis (DTA) and also the setting behaviour of the mixed powders using differential scanning calorimetry (DSC). The silica-sol liquids showed the appearance of vapourization (around 100 degrees C as a peak temperature) and combustion (200-300 degrees C) in DTA measurement. Mixed silica-sol investment exhibited the setting behaviour with an exotherm in the DSC measurement representing that greater peak time, setting time and heat in mixed investment than with gypsum-bonded investment.

Dental magnesia-based investments for cast titanium crown: setting and fitness

“…The complete crown wax pattern fabricated on a stainless steel die was invested in phosphate-bonded investments including alumina [15,16]. Resulting crown margins ranged from 0.0128 to 0_0498 mm.…”

“…The fit of a cast crown was evaluated by the clearance between the margins of the crown and duplicated stone models at occlusal and cervical sites [15,16]. The values were measured using the longitudinally cut die.…”

“…Each sol in Table I was accelerated by 10% aqueous ammonium carbonate giving a sol-to-aqueous ammonium carbonate ratio of 16/1 [15]. The total expansion was defined as the sum of setting and thermal expansions, according to a previous report [15].…”

Dental castable glass ceramics: ceramming treatment and colour property

“…The liquid-to-powder ratio was 0.34 using a liquid mixture of A (16 ml) and B liquids (1 ml). The CQ mould was placed in a burnout furnace heated to 910°C with a hold time of 30 rain (Jelenko AccuTherm II 500, J. Morita Co, Tokyo) immediately after setting to make the setting expansion 0% (the total expansion of the mould was considered to be the thermal expansion when heated to 910 °C; 2.1%) [11].…”