Inconclusive results were reported about the cleaning and disinfection accomplished by the two irrigation methods .
There is insufficient evidence to cl aim general superiority of any one of these methods .
The aim of this study was to systematic ally review and critically analyse the published data on the treatment outcome ( primary outcome ) and on the  cleaning and disinfection of root canals  ( secondary outcomes ) achieved by negative pressure irrigation as compared to syringe irrigation .
Effect of apical preparation size and preparation taper on irrigant volume delivered by using negative pressure irrigation system.
INTRODUCTION The purpose of this investigation was to determine the effect that apical preparation size and preparation taper had on the volume of irrigant delivered to the working length of a root canal preparation in a clinical ly relevant amount of time . METHODS Forty intact human single-rooted teeth were r and omly distributed into 2 separate phases . The first phase aim ed to determine the smaller apical size that will allow more volume of irrigant at working length . All sample s had the same taper and were sequentially instrumented to sizes of 30.06 , 35.06 , 40.06 , and 45.06 . The second phase aim ed to determine the taper that will allow more volume of irrigant at working length . Teeth were sequentially instrumented to 40.02 , 40.04 , 40.06 , and 40.08 . All sample s were irrigated by using the micro-cannula , and the volume of sodium hypochlorite suctioned at working length under negative pressure was measured during a period of 30 seconds by using a custom recovery device . RESULTS An increase in size from ISO # 35 to ISO # 40 result ed in a percentage gain of approximately 44 % in mean irrigant volume , whereas an increase in size from ISO # 40 to ISO # 45 result ed in a percentage gain of approximately 4 % . An increase in taper from 0.02 through 0.08 result ed in percentage gains of approximately 74 % , 5.4 % , and 2.4 % increase , respectively . CONCLUSIONS The data demonstrated that an increase in apical preparation size and taper result ed in a statistically significant increase in the volume of irrigant . In addition , an apical enlargement to ISO # 40 with a 0.04 taper will allow for tooth structure preservation and maximum volume of irrigation at the apical third when using the apical negative pressure irrigation system
Inconclusive results were reported about the cleaning and disinfection accomplished by the two irrigation methods .
There is insufficient evidence to cl aim general superiority of any one of these methods .
The aim of this study was to systematic ally review and critically analyse the published data on the treatment outcome ( primary outcome ) and on the  cleaning and disinfection of root canals  ( secondary outcomes ) achieved by negative pressure irrigation as compared to syringe irrigation .