Method and apparatus for sonic dental drilling

Claim 1

IN A SONIC DENTAL DRILL ASSEMBLY HAVING AN OSCILLATORY DRIVER AND DRILL-SHANK COUPLING MEANS SECURED THERETO FORMING, WITH A COUPLED-IN DRILL SHANK, A LONGITUDINAL STANDING WAVE SYSTEM: AN ANGLE DRILL SHANK COUPLED TO SAID COUPLING MEANS AND EXTENDING GENERALLY LONGITUDINALLY THEREFROM, AN ANGLE TIP ON SAID SHANK, SAID SHANK IS FORMED WITH A LONGITUDINAL CURVE, AND TERMINATES IN AN ENLARGED TIP HOLDER HEAD, SAID HEAD BEING FORMED WITH A BORE EXTENDING ANGULARLY OF SAID CURVED SHANK, AND WHEREIN SAID TIP COMPRISES A PIN REMOVABLY FITTED IN SAID ANGULAR BORE SAID SHANK HAVING A LENGTH TO UNDERGO LONGITUDINAL, SUBSTANTIALLY QUARTER WAVELENGTH STANDING WAVE ACTION AT A LONGITUDINAL WAVE RESONANT FREQUENCY OF THE ASSEMBLY WHEN SAID OSCILLATORY DRIVER IS OPERATED AT SAID RESONANT FREQUENCY, SAID SHANK AND ANGLE TIP BEING LATERALLY UNBALANCED, SO AS TO INDUCE A LATERAL WAVE COMPONENT IN SAID SHANK DERIVED FROM SAID LONGITUDINAL WAVE, AND SAID SHANK EMBODYING A PHYSICAL CONFORMATION WHICH TUNES SAID LATERAL WAVE TO A RESONANT FREQUENCY DIFFERING FROM THAT OF SAID LONGITUDINAL WAVE TO IMPART TO THE EXTREMITY OF SAID TIP AN ELLIPTICAL MOTION PATH, AND TO AN EXTENT HOLDING THE AMPLITUDE OF THE LATERAL COMPONENT OF MOTION TO A LESSER MAGNITUDE THAN THAT OF THE LONGITUDINAL COMPONENT OF MOTION, WHEREBY THE MAJOR AXIS OF THE ELLIPSE EXTENDS SUBSTANTIALLY NORMAL TO THE EXTREMITY THEREOF.