Patent ID: 8777615

Claim:
A dental prophylaxis device comprising: a handpiece having a body; a removable hollow shell surrounding said body; an electric motor mounted inside said body; said electric motor coupled to an output shaft; said output shaft comprising a driving shaft part and an output gear, said output gear having a substantially vertical surface comprising formations on said surface; and a prophy angle removably coupled to said handpiece and said hollow shell and comprising an axial bore having a driven shaft; said driven shaft including a shaft part having two ends, one end ending in a driven gear part and the other end having a prophy cup attached thereon for rotation thereto, said shaft part comprising formations; wherein said electric motor couples to the driven shaft of the prophy angle via the formations on said output gear and the shaft part, said formations on said output gear and the shaft part comprising complementary formations for easy detachment and accurate attachment of the output and driven shafts, and wherein the shell includes a first aperture for inserting the handpiece body into the shell and a second aperture for receiving the output shaft therethrough when the prophy angle is removed from the body, wherein the shell further includes a plurality of circumferentially arranged snap fit arms extending therefrom that include protrusions thereon that are received in a corresponding groove defined in the handpiece, and wherein the snap fit arms extend from the shell into the axial bore of the prophy angle.