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In another approach to the problem of aspiration before injection of local anesthetics, a new self aspirating plunger was designed. It is composed of similar materials currently in use. Its action is simply the elastic return of a temporarily stretched diaphragm in the center of the plunger. A gentle pressure and release will cause aspiration. No harpoon is used; therefore the cartridge can be more quickly loaded and changed. No special syringe is needed.Stanley C. Harris has said, "one of the most insidious dangers in therapeutics is the complacency which develops when undesirable reactions are infrequent. With local anesthesia, this complacency is intensified by the knowledge that local anesthetics are given intravenously by intention in certain medical procedures. However, when this procedure is employed, the patient is hospitalized, in an operating room with emergency equipment and drugs instantly available."(1)Dentists are aware of the possible consequences of intravascular injection of local anesthetics and know that these can range from lack of anesthesia to an unplesant experience or to a rare lethal one.(2-3) Case histories of complications of intravascular injection appear regularly in the literature. The presence of the anesthetic in the blood can easily be demonstrated.(4)