Patent ID: 7618409

Claim:
A method for a practitioner to administer a controlled injection of a dental anesthetic drug into intraligamentary tissue of a subject, the method comprising: providing a drive unit for supplying the drug at at least one flow rate; providing a handpiece for being held by the practitioner, the handpiece being connected to the drive unit by a flexible tube for receiving the drug, the handpiece carrying an injection needle to be inserted into the subject near the intraligamentary tissue of the subject, the injection needle having a tip for passing the drug to the subject at an instantaneous and at an absolute pressure that is at the tip of the injection needle, and that varies due to a placement of the needle tip in the subject, there being a minimum threshold pressure of about 200 to 500 psi and an absolute pressure which is desired for administering the drug to the intraligamentary tissue; operating the drive unit for supplying the dental anesthetic drug to the injection needle at a selected flow rate; having the practitioner hold the handpiece; having the practitioner move the handpiece without moving the drive unit, to insert the tip of the needle into the subject at a location near the intraligamentary tissue of the subject for passing the drug to the subject near the intraligamentary tissue at the instantaneous and absolute pressure that is at the tip of the needle and that varies in real-time as a function of the intraligamentary tissue and a placement of the tip of the needle, the practitioner continuing to move the tip of the needle in the subject to seek the intraligamentary tissue; sensing or calculating the instantaneous pressure on a real-time basis; supplying a perceptible auditory ascending signal to the practitioner that indicates when the instantaneous pressure is rising toward the minimum threshold pressure, for guiding movement of the placement of the tip of the needle by the practitioner at least until the minimum threshold pressure has been reached; supplying a perceptible auditory specific signal to the practitioner that indicates when the instantaneous pressure has reached the minimum threshold pressure which indicates that the practitioner has moved the tip of the needle into the intraligamentary tissue; after the perceptible auditory specific signal is supplied, having the practitioner maintain the tip of the needle in the intraligamentary tissue for supplying a selected dosage of the drug to the intraligamentary tissue at the selected flow rate; and notifying the practitioner by a perceptible auditory signal when the instantaneous pressure declines or fluctuates before reaching the minimum threshold pressure.