Abstract: A dental prophylaxis angle includes a body, a drive gear and a driven gear. The body has a sleeve with an open rear end, a neck, a head, a first axial bore, and a second axial bore. The first axial bore is located in the neck, and the second axial bore is located in the head. The first and second axial bores communicate with each other at an intersection. A channel extends through the body from the base of the neck to the open rear end. The drive gear is adapted to be inserted into said body through said head. The drive gear includes a gear, an intermediate portion and a shaft. The shaft extends rotatably from the open rear end of the sleeve, through the first bore, and into the second bore. The intermediate portion further includes an angled leading edge. The drive gear defines a circumferential groove between said gear and said intermediate portion. The driven gear is rotatably mounted in the head and operatively connected to the drive gear. The body further includes a lip extending into the channel.

Abstract: A high-speed medical/dental handpiece includes a handle, which carries air, water, and light to a disposable cartridge which is received on the sleeve. The cartridge includes a head portion and a sleeve portion. The cartridge head defines a chamber having an upper and lower portions each of which receives a bobbin shaped sleeve bearing, and a central portion which receives a turbine. The bearings each form annular channels with their respective chambers. The cartridge includes water and air passages which direct water to the turbine so that the turbine is driven by an air/water mixture. Water is also directed to the upper bearing and grooves in the lower bearing chamber allow water to enter the annular channel around the lower bearing. Axial passages in the bearings enable water to pass from the annular chamber to the bit to contact the bit shaft. The air and water in the chamber are exhausted through the bit opening in the bottom of the head as well as through a plurality of exhaust ports in the head.