Apical Negative Pressure: Safety, Efficacy and Efficiency

Abstract

The objective of dentistry is to prevent oral disease and retain the natural dentition, hopefully for the lifetime of the patient. The objective of endodontic treatment is to prevent and/or treat apical periodontitis. In order for an endodontic irrigant delivery system to be mechanically effective and satisfy the objective of endodontics, it must reach the apical terminus, create a current along the root canal wall and have the ability to remove debris, tissue and bacterial contaminants. Currently, the irrigant of choice to achieve this objective is full-strength sodium hypochlorite (NaOCl). During endodontic irrigation, the organic component of pulpal tissue consumes NaOCl rapidly as the reaction of hydrolysis occurs forming water and releasing ammonia and carbon dioxide as the by-products. In very short order, a column of gas develops at the apical one third of the root canal (apical vapour lock). The conundrum that the clinician faces is to safely and effectively deliver the irrigants to the apical terminus, break the apical vapour lock and allow constant exchange of irrigant and thereby continual hydrolysis of pulpal tissue by the NaOCl, without the risk of apical extrusion. This chapter will outline the scientific evidence surrounding apical negative pressure as a safe and reliable method to deliver irrigants to the apical terminus, thereby satisfying the objectives of endodontic treatment.