Comparison of two ultrasonic instruments for post removal.

The relative performance of two different ultrasonic units commonly used clinically for post removal was evaluated using tips designed specifically for post vibration. Twenty-four extracted maxillary and mandibular cuspids with crowns removed at the labial cementoenamel junction were treated endodontically. Post spaces were made 10 mm into the roots before cementing a 16 mm #5 (0.