Bident

> In addition to superior bipolar coagulation, the Bident Bipolar System introduces a new modality to tissue management -- bipolar cutting. The bipolar cutting system operates in quite a different manner from the familiar monopolar cutting of the present machines. While both monopolar and bipolar cutting are done with an approximately one megahertz sine wave, in monopolar cutting the power is presented to a fine tipped active electrode at a very high voltage with the return to a proportionately large indifferent or ground plate. This voltage dropped precipitously when the active electrode was brought into a firm contact with tissue or used in a bloody field or under irrigation. Customarily, for the fastest monopolar cutting, the power was turned on before the electrode contacted the tissue. A spark then jumped to the tissue as the electrode approached, the impedance remained high, and tile tissue was vaporized just prior to the contact of the electrode, so maintaining the high voltage necessary for this type of cutting.

Monopolar voltages of well over 2500 volts were applied at the electrode with powers of several hundred watts or more available. Even with the power levels turned down, the initial voltage was still very high and though it shunted down as the tissue was touched, a considerable total current, distributed roughly in a geometric cone from the active electrode to the ground plate was distributed in adjacent tissues. The most conductive path to the ground had the highest current density. This, of course, means current flowpasses through main trunks of blood vessels, whose branches are being cut or coagulated, through neural structures as well as muscle and bone. There is a considerable amount of current and heat at distances of even 1 to 2 cm from even a small point of tissue contact. For this reason the use of monopolar coagulation has been restricted, particularly for work around fillings, crowns or implants.

The Bident Bipolar Cutting system was designed on the basis that there would be no spark and that the instruments would cut while in contact with the tissue whether dry or under irrigation. No indifferent plate is used. The voltage was kept quite low and the extremely low impedance of the generator minimized the voltage drop from open circuit to full load. Accordingly, this technique provides for cutting not based on vaporization by an advancing spark, but rather by a true molecular resonance by the sine wave cutting current dividing the tissue without sparking, thermal damage or current spread. Since all the current passes only between the two tips of the Bident instruments and not to a return pad, there is no current or heat spread to adjacent areas. The device may be used with total safety in all tissues as well as directly on bone and around crowns, fillings and metallic implants without the risk of necrosis.



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			> In addition to superior bipolar coagulation, the Bident Bipolar System introduces a new modality to tissue management -- bipolar cutting. The bipolar cutting system operates in quite a different manner from the familiar monopolar cutting of the present machines. While both monopolar and bipolar cutting are done with an approximately one megahertz sine wave, in monopolar cutting the power is presented to a fine tipped active electrode at a very high voltage with the return to a proportionately large indifferent or ground plate. This voltage dropped precipitously when the active electrode was brought into a firm contact with tissue or used in a bloody field or under irrigation. Customarily, for the fastest monopolar cutting, the power was turned on before the electrode contacted the tissue. A spark then jumped to the tissue as the electrode approached, the impedance remained high, and tile tissue was vaporized just prior to the contact of the electrode, so maintaining the high voltage necessary for this type of cutting. Monopolar voltages of well over 2500 volts were applied at the electrode with powers of several hundred watts or more available. Even with the power levels turned down, the initial voltage was still very high and though it shunted down as the tissue was touched, a considerable total current, distributed roughly in a geometric cone from the active electrode to the ground plate was distributed in adjacent tissues. The most conductive path to the ground had the highest current density. This, of course, means current flowpasses through main trunks of blood vessels, whose branches are being cut or coagulated, through neural structures as well as muscle and bone. There is a considerable amount of current and heat at distances of even 1 to 2 cm from even a small point of tissue contact. For this reason the use of monopolar coagulation has been restricted, particularly for work around fillings, crowns or implants. The Bident Bipolar Cutting system was designed on the basis that there would be no spark and that the instruments would cut while in contact with the tissue whether dry or under irrigation. No indifferent plate is used. The voltage was kept quite low and the extremely low impedance of the generator minimized the voltage drop from open circuit to full load. Accordingly, this technique provides for cutting not based on vaporization by an advancing spark, but rather by a true molecular resonance by the sine wave cutting current dividing the tissue without sparking, thermal damage or current spread. Since all the current passes only between the two tips of the Bident instruments and not to a return pad, there is no current or heat spread to adjacent areas. The device may be used with total safety in all tissues as well as directly on bone and around crowns, fillings and metallic implants without the risk of necrosis.