A STUDY ON EFFICIENCY OF ROOT CANAL IRRIGATION IN AN EXPERIMENTAL ROOT CANAL MODEL WITH LATERAL CANALS

Abstract

Aim: The aim of this study was to improve root canal irrigation by intracanal aspiration technique (IAT), which was designed to minimize extrusion of irrigant from the apical foramen, by using different types of aspiration needles. Materials and Methods: A model which had two lateral canals at the coronal 1/3 and apical 1/3, was irrigated with only injection flow, or injection and aspiration flow for 50 sec at flow rate 0.2 ml/sec. A side-vented needle was used for injection, and aspiration was performed with a side-vented or iNP needle that had one hole at the pointed end, and a thinner tip. Injection and aspiration needles were inserted to a point 3 mm from the root canal orifice (point U) or the apical foramen (point L). In Experiment 1, the percentage of calcium hydroxide paste (CP) remaining in the root canal and lateral canals after irrigation was measured in each method. The x-ray contrast image of the remaining CP in the model was acquired with a digital CCD sensor. The contrast ratio of the root canal and lateral canal areas was calculated. In Experiment 2, extrusion of 0.2% methylene blue (MB) from the apical foramen after irrigation was measured in each method. The amount of MB extrusion was quantified by absorbance. Results: Experiment 1: The remaining CP in the root canal was the least when IAT irrigation was aspirated by an iNP needle at point L. In lateral canals, the remaining CP observed depended on the insertion point of the injection needle. Experiment 2: IAT irrigation aspirated point L group showed the least amount of MB extrusion compared with other groups. Conclusion: The aspiration needle for IAT should be inserted more apically. Furthermore, aspiration using an iNP needle enables more efficient cleaning compared with side-vented needle in IAT.