The effect of residual calcium hydroxide on the accuracy of a contemporary electronic apex locator

A selection of abstracts of clinically relevant papers from other journals. The abstracts on this page have been chosen and edited by John R. Radford.

Abstract

Calcium hydroxide intracanal dressing compromise the accuracy of an electronic apex locator.

Main

Usun Y, Uzun O et al. Acta Odontol Scand 2014; 10.3109/00016357.2014.961027

A 'more than one' visit approach, with the use of a calcium hydroxide dressing, is associated with an 'improved microbiological status of the root canal system'. The authors argue that confirmation of the root canal working length may be required at each appointment. In this study, the root canals of 56 extracted upper central incisor teeth were prepared using ProTaper to size F3 file. The working length was determined using an electronic apex locator (Root ZX Mini). The canals were filled with calcium hydroxide (DiaPaste^™), at the working length. After 10 days storage, calcium hydroxide was removed at the working length, 2 mm short of the working length, and 4 mm short of the working length. Residual calcium hydroxide was confirmed using radiography. Control teeth were left empty. The mean working length, determined by the electronic apex locator, was significantly less (but by only 1 mm) when 4 mm of calcium hydroxide was left in the canal.