Anesthetic efficacy and heart rate effects of the intraosseous injection of 3% mepivacaine after an inferior alveolar nerve block

Objective. The purpose of this study was to determine the anesthetic effica cy and heart rate effects of an intraosseous injection of 3% mepivacaine af ter an inferior alveolar nerve block. Study design. Through use of a repeated-measures design, each of 48 subject s randomly received 2 combinations of injections at 2 separate appointments . The combinations were (1) an interior alveolar nerve block (with 1.8 mL o f 3% mepivacaine) + intraosseous injection with 1.8 mL of 3% mepivacaine an d (2) an inferior alveolar nerve (with 1.8 mt of 3% mepivacaine) + mock int raosseous injection. The first molar was blindly pulp tested at 2-minute cy cles for 60 minutes postinjection. Anesthesia was considered successful wit h 2 consecutive 80 readings. Heart rate (pulse rate) was measured with a pu lse oximeter. Results. All subjects had lip numbness with both of the inferior alveolar n erve + intraosseous techniques. Anesthetic success for the first molar was significantly increased for 30 minutes with intraosseous injection of mepiv acaine in comparison with the interior alveolar nerve block alone (mock int raosseous injection). Subjects receiving the intraosseous injection of mepi vacaine experienced minimal increases in heart rate. Conclusions. The intraosseous injection of 1.8 mt of 3% mepivacaine, when u sed to augment an inferior alveolar nerve block, significantly increased an esthetic success for 30 minutes in the first molar. The 3% mepivacaine had a minimal effect on heart rare and would be useful in patients with contrai ndications to epinephrine use.