Computer-controlled delivery versus syringe delivery of local anesthetic injections for therapeutic scaling and root planing

Background. The authors conducted a study to compare administration of local anesthetic using a computer-controlled delivery device with an aspirating syringe for therapeutic scaling and root planing. The anterior middle superior alveolar, or AMSA, injection was compared with other maxillary injections. Methods. Twenty healthy adults with moderate periodontal disease participated in this single-blind crossover study. Subjects were evaluated by a trained examiner and were treated by experienced dental hygienists. Subjects provided written and verbal pain ratings via a visual analog scale, or VAS, and a verbal rating scale, or VRS. AMSA injections were compared with syringe-delivered injections-greater palatine, or GP, and nasopalatine, or NP, blocks, and anterior superior alveolar and middle superior alveolar injections-in maxillary quadrants. Bleeding and changes in attachment were evaluated after one month. Results. VAS and VRS scores for AMSA were significantly lower for computer-controlled delivery when compared with NP injections and combined maxillary injections (VAS scores) and with GP and combined maxillary injections (VRS scores). Mean injection times were similar for both groups. Mean gains in attachment were equal, 0.19 millimeters for quadrants anesthetized using computer-controlled injections and 0.22 mm for syringe injections. Conclusions. Subjects reported having less pain with GP and NP injections delivered using the computer-controlled device, and total injection time was similar to that required for syringe injections. Both techniques provided adequate anesthesia for therapeutic scaling and root planing. Clinical Implications. The two anesthetic delivery techniques were therapeutically equivalent for mandibular injections, and the AMSA injection has clinically significant advantages for maxillary injections.