Abstract: A vibratory device having a drive circuit for providing a highly regulated drive voltage/current to the vibrator. A DC voltage is derived from line voltage. A DC-to-DC converter steps up the voltage to at least the desired voltage for vibration. The stepped up DC voltage is provided to the vibratory coils through a path containing a switch. The switch is controlled by an oscillator which turns the switch on and off at a desired vibration frequency so as to provide an alternating current through the coil for generating the vibratory force.

Abstract: A system of treating teeth or associated tooth structure by the use of abrasive-laden fluid stream provides fluid at high pressure to a manifold with selectively operable valves delivers fluid at a selected pressure to a device for mixing the fluid with abrasive and delivers the air/abrasive mix to a hand-held device for application of an abrasive-laden stream to a tooth or associated tooth structure. Priming air at a relatively low pressure pressurizes the air abrasive device. A flow path for pure air bypasses the air/abrasive device. A selective control allows the operator to deliver a stream of air or air and abrasive to the tooth or associated tooth structure as desired. Preferably the fluid pressure is controlled by a manually-operable servo valve system. Upon termination of a treatment with the air abrasive mix, the pure air is diverted through a purge line to purge the system downstream from the abrasive device of excess abrasive particles.

Abstract: Treating teeth or associated tooth structure by the use of an abrasive-laden fluid stream which provides fluid at high pressure to a manifold with selectively operable valves, delivers fluid at a selected pressure to a mixer for fluid and abrasive and delivers the mix to a handpiece for application of abrasive-laden air to a tooth or tooth structure. Low pressure priming air pressurizes the air abrasive device. A path for pure air bypasses the air/abrasive device. A control allows for delivery of air or air and abrasive as desired. Fluid pressure is controlled by a manually-operable servo system. Following treatment with the air/abrasive, a purge line purges the system downstream from the abrasive device of excess abrasive particles. A vacuum removes abrasive particles and debris from the patient's mouth. The abrasive delivery device may include a hand-held nozzle having fluid ports operable by the fingers of the operator to control system functions.

Abstract: An attended messaging system having an audio message recording and playback device connected in series between a telephone base unit and a telephone receiver handset or headset. The recording and playback device includes a solid-state audio memory chip for storing a message and pairs of operational amplifiers connecting the memory chip of the recoding and playback device with the telephone base unit and with the speaker and microphone of the telephone receiver handset or headset in a differential circuit of audio signal channels. The recording and playback device is manually-actuable by means of buttons or switches to operate in a recording mode, in which a message spoken into the handset or headset microphone is stored in the audio memory chip, or in a playback mode, in which the previously recorded message is communicated through the telephone base unit and telephone line to a designated remote telephone station with which audio communication has been established by the telephone base unit.