A handpiece tip having a set of longitudinally vibrating piezoelectric elements. To obtain oscillatory or torsional movement, a deep, spiral groove is cut on the exterior of the tip shaft. The groove translates longitudinal vibrations into oscillatory or torsional vibrations, and does not require the...http://www.google.de/patents/US20010011176?utm_source=gb-gplus-sharePatent US20010011176 - Torsional ultrasound tip
