Mandibular Molar Infiltration Anesthesia: Is It Mental?

Introduction: Supplemental buccal infiltration in the mandibular first molar region has been shown to improve the success of an inferior alveolar nerve block not only in the first molar but also in the premolar and lateral incisor teeth, so this technique appears to be producing some regional nerve block. This might occur by entry of solution into the mandibular canal via the mental foramen rather than by direct diffusion through the buccal cortex. One way of testing this hypothesis would be to compare buccal and lingual infiltrations in the mandibular first molar region, the latter technique foregoing entry through the mental foramen as a mechanism. Objectives: The objective of this study was to compare the pulpal responses of mandibular teeth after a buccal or lingual infiltration in the mandibular first molar region of 4% articaine with 1:100,000 epinephrine. Methods: Twenty volunteers received 1.8mls of the local anesthetic buccally or lingually to the mandibular first molar in a randomised fashion. Responses of ipsilateral first molar, first premolar and lateral incisor teeth were assessed using an electronic pulp tester every 4 minutes post injection for a period of 47 minutes. Numbers of no responses to the maximum stimulation from the pulp tester were recorded for each tooth with each technique (maximum possible number = 240 per tooth). Data were analysed by McNemar's test. Results: Significantly more episodes of no response to maximum stimulation were recorded after the buccal compared to the lingual infiltration for each tooth (molars 141 vs 23; premolars 180 vs 37; lateral incisors 80 vs 35 respectively [p < 0.001 for each tooth]). Conclusions: Buccal infiltration is significantly more effective than lingual infiltration in the molar region for pulpal anesthesia of molar, premolar and lateral incisors. Diffusion via the mental foramen may be the mechanism of this method