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

✍ Scribed by K. Wakasa; M. Yamaki

• Publisher: Springer
• Year: 1995
• Tongue: English
• Weight: 267 KB
• Volume: 6
• Category: Article
• ISSN: 0957-4530
• DOI: 10.1007/bf00123373

✦ Synopsis

Titanium crowns were cast using experimental magnesia-based investment mixed with hydrolysed sol. Ten types of hydrolysed sol were used, adding a catalyst to each sol whether the setting (hardening) of the magnesia investment powder appeared within 3 h after mixing. A penetration test using a Vicat needle to measure needle depth as setting was carried out after mixing of the investment powder, showed that the penetration depth decreased gradually with increasing holding time at room temperature. Setting time was shown to be more or less than 3 h or dependent on the gelation. The total magnitude of expansion (setting + thermal) ranged from 0.5 to 0.9% using the selected mixtures. Titanium cast crowns were made in the range 0.02-1.3 mm (occlusal) and 0.03-1.5 mm (cervical), depending on the expansion value of the particular magnesia-based investments mixed with the hydrolysed sols.