[Relationship between the infiltration arts and penetration depth of molten glass into aluminum oxide matrix].

Objective: To explore the influences of infiltration time and temperature on the penetration depth of GI-II glass into alumina matrices, thus providing a theoretical basis for facilitating the clinical fabrication of all-ceramic restorations.

Methods: After preparing cuboid alumina specimens 7 x 7 x 5 mm3 in size, we carried out the infiltration firing procedure at 1100 degrees C for six different time duration (30, 60, 90, 120, 150, 180 minutes), and at five different temperatures (1060, 1080, 1100, 1120, 1140 degrees C) for 1 hour each. The penetration depth of glass into the alumina matrices was measured under a stereoscope with magnification of 10 times.

Results: The infiltration time duration and penetration depth were not linearly but exponentially related for both Vita and GI-II materials (r = 0.9886 for Vita and r = 0.9932 for GI-II). The regression equations were as follows: d2 = 0.1122t - 0.4955 (Vita) and d2 = 0.1638t + 0.5873 (GI-II). The temperature and depth were not linearly related either, with increased penetration speed under higher temperatures for GI-II material; the tendency for Vita material was just the opposite.

Conclusion: At an infiltration temperature of 1100 degrees C, the molten infiltration time duration of GI-II glass could be reduced to 1 hour for copings and 3 hours for anterior bridge substructures due to its better infiltration ability.