LOCAL EFFECT OF VARIOUS DRUGS ON THE DURATION OF INFILTRATION ANESTHESIA PRODUCED BY DENTAL ANESTHETIC SOLUTIONS

¹ Sterling-Winthrop Research Institute, Rensselaer, N. Y.

1. A series of experiments were carried out on guinea pigs to determine whether the duration of anesthesia produced by the injection of a dental anesthetic solution (Novocain 2.0 per cent; Ravocaine HCl, 0.4 per cent; and Levophed, 1:30,000) could be reduced by the local injection of various agents 20 minutes later. The solutions were injected either intradermally or subcutaneously and the degree and duration of anesthesia was determined by the technic of Bülbring and Wajda.

2. Sympatholytics like piperoxan HCl and 1205 I.S. were effective in reducing the duration of anesthesia produced by RNL, in concentrations as low as 0.025 per cent. Piperoxan was approximately 4 times as active as 1205 I.S.

3. Vasodilators like sodium nitrite (0.5 per cent), adenosine (0.2 per cent), adenosine-5-monophosphate (0.1 to 0.4 per cent) were effective when compared with saline injection.

4. Hyaluronidase (15 TR units per milliliter) was also effective.

5. Of all the compounds tested piperoxan was by far the most effective, showing indirectly the important role played by the vasoconstrictor in the duration of dental anesthesia. Sodium nitrite, adenosine, adenosine-5-monophosphate, and hyaluronidase acted synergistically when injected in mixed solutions with piperoxan.

6. Hyaluronidase increased the effect of a mixed solution of piperoxan and adenosine.

7. The most effective mixed solutions (piperoxan HCl, 0.05-0.2; adenosine, 0.2 per cent; and hyaluronidase, 15 TR units per milliliter) reduced the duration of intradermal anesthesia produced by RNL solution to 10 to 14 per cent of its expected value.