Bonding soft reline materials to base metals

In the past it has been difficult to treat soft tissue changes occurring beneath metal frameworks of removable partial dentures or complete dentures using soft reline materials. The main difficulty has been in getting the resilient materials to adhere to the metal. This research investigates the use of microabrading with and without a universal resin bonding system in achieving a clinically useful bond between two soft reline materials and a commonly used base-metal alloy.

120 disks, 1 inch in diameter, were cast in Ticonium (CPM Industries, Albany, NY). The surface of the disks was finished to a high polish and then evenly microabraded. Four test groups of 15 pairs of disks were established, with two groups receiving Coe-Soft (Coe Laboratories, Chicago, IL) and two groups receiving Soft Oryl (Teledyne Getz, Elk Grove Village, IL). One group of each reline material had the microabraded surfaces on each disk treated with All Bond 2. Then, 1.2 mm of reline material was placed between each set of disks and allowed to cure. The disks were placed on an Instron machine and a tensile force was applied until bond failure occurred.

All four groups showed significant bond strengths, with the Soft Oryl groups showing statistically significant higher bond strengths. In both reline material groupings, the groups with only microabrading showed slightly higher bond strengths.

Soft reline materials can be made to adhere to base-metal alloys used in removable prosthodontics with clinically acceptable strengths using microabrading with or without the use of a resin bonding system.