Comparison of Inferior Alveolar Nerve Block Anesthesia Using Direct and Indirect Techniques in terms of Blood Aspiration Probability

This prospective double-blinded clinical trial study aimed to compare the direct and indirect techniques of inferior alveolar nerve block (IANB) anesthesia regarding positive aspiration and success rate.   This study included all 250 healthy patients who were referred to the Oral and Maxillofacial Surgery Department, Mashhad Dental School, Mashhad, Iran, for lower teeth extraction. The patients were randomly assigned to two groups. In total, 126 patients were subjected to IANB by a direct technique, and an indirect technique was utilized to perform IANB on the others. The primary and secondary outcomes were positive aspiration and anesthetic success, respectively. The data were statistically analyzed with SPSS software (version 19) using the Chi-square test. The positive aspiration rates were 23 (18.3%) and 7 (5.6%) in the direct and indirect groups, respectively, which was statistically significant (P=0.002). The incidence rates of positive aspiration on the right and left sides were 13 (11%) and 17 (12.9%), respectively, which had no significant difference (P=0.651). Moreover, the success rates of direct and indirect techniques were 106 (84.1%) and 93 (75%) respectively, which was not statistically significant. It is worth mentioning that the success rates were similar on the right (79.7%) and left (79.5%) sides.   According to the established results, the indirect technique of IANB has a significantly less positive aspiration rate, compared to the direct technique. This advantage is especially valuable in high-risk patients undergoing inadvertent intravascular injection of an anesthetic drug, which can lead to catastrophic complications.