In vitro apical pressure created by 2 irrigation needles and a multisonic system in mandibular molars

OBJECTIVES: The aim of this study was to evaluate the apical pressure generated by 2 endodontic irrigation needles and the GentleWave system in mandibular molars. MATERIALS AND METHODS: The mesial and distal root canals of 12 mandibular molars were irrigated with a 30-gauge close-end needle or with a 30-gauge open-end needle. Procedures were performed in the mesial and distal canals. The GentleWave procedure and irrigation at 1 mm from the apex in the distal roots using an open-end needle were used, respectively, as negative and positive controls. The apical pressure was measured using a data acquisition pressure setup. Apical pressure exerted by the different needles in the 2 different canal types was statistically compared using 2-way analysis of variance. RESULTS: Significant differences were found in the apical pressure for both needles and the canal type. The lowest values were obtained with close-end needles and in mesial canals. Negative apical pressure values were obtained using GentleWave. CONCLUSIONS: The needle and the canal type influenced the apical pressure. The GentleWave procedure produced negative apical pressure.