Pilot study of the effects of three bonding systems on the torsional resistance of a titanium-reinforced composite core

Abstract

Statement of problem. There are no studies analyzing the effects of a bonding agent on torsional resistance for a titanium-reinforced core material bonded with a multistep bonding system. Purpose. This pilot study investigated the effects of multistep bonding agents on torsional resistance of a titanium-reinforced composite core material (Ti-Core core material). Material and methods. A total of 40 recently extracted human molars with their crowns removed were placed into acrylic resin blocks and divided into 4 groups of 10 specimens. Only multistep bonding systems were used (AllBond-2, ScotchBond Multi-Purpose, Tenure A&B, and the control without bonding agent). Specimens were prepared according to manufacturer’s instructions. The control group was etched with a 37.5% phosphate acid. All cores were fabricated with Ti-Core titanium core material with No. 1 hard copper bands as the matrix. Ti-Core core material was applied and allowed to cure for 1 hour, then the cores were placed in 100% humidity (water) for 1 week. Test specimens were placed in a special jig and a clockwise torsional force applied. Torsional force was measured on a Lebow 1102-200 torque transducer and recorded on a Hewlett Packard 7015B X-Y recorder in inch × ounce then converted into Newton-meter. One-way analysis of variance (ANOVA) was used to test for statistical significance ( P <.05). Results. Torsional values (Newton-meter) were AllBond-2, 0.1980, ScotchBond Multi-Purpose, 0.1890, Tenure A&B, 0.2142; the control group recorded a value of zero. Statistical analysis revealed that bonding systems did not differ from one another. Conclusion. Use of a bonding agent increased the core’s resistance to torsional forces. Lack of a bonding agent dramatically reduced the resistance to torque. (J Prosthet Dent 1999;82:277-80.)