Aim: To compare the anaesthetic efficacy of mandibular second premolar infiltration (SP) with that of mandibular first molar infiltration (FM) in inducing pulpal anaesthesia in the mandibular first molar. To further investigate the mechanisms of action that underlie mandibular infiltration, gender-related differences in the anaesthetic efficacy were also assessed. Methodology: A total of 29 adult subjects randomly received two sets of SP and FM injections using one cartridge (1.7 mL) of 4% articaine and 1 : 100 000 adrenaline at two separate appointments. The responses of the teeth were assessed using an electronic pulp tester over a 30-min period. A comparison of the anaesthetic success between the SP and FM infiltration routes was analysed using the McNemar's test. Gender-related differences in the anaesthetic success of infiltration routes were assessed using the Fisher's exact test. Results: For the second premolar and the first and second molar teeth, the success rates of SP were 72.4%, 62.1% and 48.3%, whereas the success rates of FM were 75.9%, 51.7% and 55.1%, respectively. There were no significant differences between the success rates of SP and FM or between the rates obtained for each tooth. Significant gender-related differences were observed for the second premolar (P < 0.01) and the first molar (P < 0.05) using FM. However, a significant difference was observed only for the second premolar using SP (P < 0.05). Conclusions: The differences in the injection sites did not affect the anaesthetic success rates for the mandibular second premolar and molar teeth. However, articaine buccal infiltration produced a higher anaesthetic success rate in the second premolar and first molar teeth of Korean female patients.
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