Abstract: A prophy angle having a single improved snap-in mounting shaft having an enlarged snap-through outer boss portion that is discontinuous in circumference for retaining the prophy cup rotor in permanent position and isolating the rotor from frictionally engaging other parts other than through the gearing except under stress, a press fit drive shaft retention locking sleeve that frictionally engages the housing when pressed into locking position, a reduction of the surface contact of the drive shaft with the inside of the housing by introducing vanes in contact with the housing wall rather than a continuous cylinder contact, and a closed vent hole with a hub on the drive shaft.

Abstract: A method for the making of a tooth mold which includes the steps of scanning the surface of a model of a tooth to obtain data on the three-dimensional surface locations of the model, processing the data in a CAD/CAM computer, and using the processed data to fabricate a tooth mold. The scanning step involves subjecting a rotating tooth model to radiant energy from a laser beam, receiving and translating reflections of the radiant energy into electronic signals, and digitizing the signals into data of the three-dimensional surface locations of the tooth model. The processing step involves translating the data, editing the data, creating a three-dimensional surface pattern of the tooth model, evaluating the surface pattern by visual analysis and comparison to known geometric values of the tooth model, and creating a tooth path program.