Abstract: A method for cutting with a tool comprises rotating the tool in a first direction. Then, at a predetermined moment, quit rotating the tool and allow the tool to coast in the first direction. While the tool coasts, a parameter is determined that represents drag experienced by the tool as the tool coasts. If the determined parameter does not exceed a predetermined limit then the tool is rotated in the first direction. If the determined parameter exceeds the predetermined limit, then the tool is rotated in another direction opposite the first direction. The predetermined moment when the tool begins to coast may be any desired moment, such as when the tool rotates through a specific distance or for a specific period of time.

Abstract: An apparatus that indicates a proximity of a dental instrument in a tooth's root canal to the canal's apical foramen while using the dental instrument to perform a dental/medical procedure. The apparatus includes a signal generator that provides divider signal across a first node and a third node, and a reference impedance coupled between the first node and a second node. The second node and third node include configuration for electrically coupling between a tip of the dental instrument and an electrode coupled with a body tissue of the patient, a stimulation signal being defined across the second node and the third node. The apparatus also includes a microprocessor operable to compare the stimulation signal and the divider signal, and generate a proximity signal in response to the comparison, and a proximity indicator that indicates the proximity of the dental instrument to the apical foramen in response to the proximity signal.

Abstract: An endodontic obturator includes a body and a disposable cartridge containing gutta percha that is couplable with the body. By containing the gutta percha in a disposable cartridge, a dentist or other medical technician does not have to clean the body or other components of the obturator, thus reducing the amount of time required to clean the obturator after use. The obturator also includes a heater operable to heat the gutta percha in the disposable cartridge and a thermal barrier operable to resist the flow of heat from the heater to the rest of the body. In addition, the obturator includes a mechanism operable to generate pressure in the disposable cartridge to dispense the gutta percha. With the thermal barrier, a portion of the obturator's body that a dentist or other medical technician might hold while injecting gutta percha into a patient's tooth may be kept relatively cool.

Abstract: An apical foramen locator that a dental or medical practitioner can use to quickly and accurately identify the location of a patient's apical foramen during a dental/medical procedure is provided. The apical foramen locator determines the location of the apical foramen relative to a tool inserted into the patient's tooth by sensing an impedance—typically the voltage across two electrodes—and a stimulus voltage, and retrieving from an impedance map apical foramen location data that corresponds to the sensed impedance. The apical foramen locator can include a power circuit operable to apply a stimulus voltage across two electrodes and a reference resistor, an impedance-sensing circuit operable to read the stimulus voltage, a first voltage across the electrodes and a second voltage across the reference resistor and a processing component operable to derive first and second voltage indices from the stimulus, first and second voltages.

Abstract: An apparatus that indicates a proximity of a dental instrument in a tooth's root canal to the canal's apical foramen while using the dental instrument to perform a dental/medical procedure. The apparatus includes a signal generator that provides divider signal across a first node and a third node, and a reference impedance coupled between the first node and a second node. The second node and third node include configuration for electrically coupling between a tip of the dental instrument and an electrode coupled with a body tissue of the patient, a stimulation signal being defined across the second node and the third node. The apparatus also includes a microprocessor operable to compare the stimulation signal and the divider signal, and generate a proximity signal in response to the comparison, and a proximity indicator that indicates the proximity of the dental instrument to the apical foramen in response to the proximity signal.