In-vitro measurement of apically extruded irrigant in primary molars

This study investigated the weights of irrigant extruded apically through extracted primary molar teeth. The aim was to compare the weight of canal irrigant (isotonic sodium chloride solution) extruded through the root canal using either a syringe fitted with a 27-gauge needle or an endosonic unit. Root canals were divided randomly into five groups of 15 discrete canals. The area of each apical foramen was recorded prior to the use of the irrigant. For each irrigation technique the maximum depth of penetration of the needle tip/file was either 2-3 mm or 6-7 mm from the apical foramen. In four groups the crowns of the teeth were in a mandibular position, in the fifth group the teeth were inverted to simulate maxillary teeth. The results showed that irrigant was extruded using both methods. There was significantly less extrusion of irrigant when the endosonic unit was used (P<0.01). There was no statistically significant relationship between foramen area and amount of extruded irrigant (P>0.05). There was no significant extrusion of irrigant in teeth with closed apices when either of the two methods was used (P>0.05).