Impact strength of teeth restored by fragment-bonding

The objective of this in vitro study was to investigate the impact strength of anterior teeth that have been fractured and restored by bonding with a dentin-bonding agent and a composite resin. Twenty sheep central incisors w ere divided into two groups, 10 in each. One group (intact teeth) served as the control and the teeth in the other group were fractured and then bonde d with a bonding agent and a low-viscous composite resin. The specimens wer e tested in a modified impact-testing machine (pendulum type). The mean imp act strength of the intact teeth was 30.6+/-2.16 KJ/m(2) and of the bonded teeth was 30.2+/-1.86 KJ/m(2). Statistics revealed that the two means were not significantly different. The results related well with the fracture str ength obtained by loading intact and bonded teeth at constant but low speed until fracture. It was concluded that bonding fragments to the remaining t ooth structure may restore the tooth to its original strength, measured at modest velocities of the applied force. In other words, reattaching the ori ginal coronal fragment of traumatised fractured anterior teeth restored wit h One-Step dentin bonding system and Eliteflo composite resin would withsta nd a second trauma to the same extent as intact teeth.