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 .
In Vivo Intracanal Temperature Evolution during Endodontic Treatment after the Injection of Room Temperature or Preheated Sodium Hypochlorite.
INTRODUCTION Heating a sodium hypochlorite solution improves its effectiveness . The aim of this study was to measure the in vivo temperature changes of sodium hypochlorite solutions that were initially preheated to 66 ° C or at room temperature inside root canals during routine irrigation . METHODS Thirty-five root canals were prepared to ISO size 40 with 4 % taper . A type K ( nickel-chromium-nickel ) thermocouple microprobe ( Testo NV , Ternat , Belgium ) was positioned within 3 mm of the working length to measure the temperature at 1-second intervals . In each canal , 2 test protocol s were evaluated in a r and omized order with 3 % sodium hypochlorite solutions : ( 1 ) preheated to 66 ° C and ( 2 ) at room temperature . The temperature measurements began 5 seconds before the 25 seconds of irrigant injections and continued for 240 seconds . This result ed in 270 data points for each protocol . RESULTS The temperature of the irrigant at room temperature increased from the initial intracanal temperature after injection of 20.7 ° C ( ±1.2 ° C ) to 30.9 ° C ( ±1.3 ° C ) in 10 seconds and to 35 ° C ( ±0.9 ° C ) after 240 seconds . The temperature of the preheated to 66 ° C solution decreased from 56.4 ° C ( ±2.7 ° C ) to 45.4 ° C ( ±3.0 ° C ) after 5 seconds , reached 37 ° C ( ±0.9 ° C ) after 60 seconds , and reached 35.7 ° C ( ±0.8 ° C ) after 240 seconds . CONCLUSIONS The original temperatures of the sodium hypochlorite solutions were buffered inside the root canal and tended to rapidly evolve to equilibrium . The findings of this study contribute to an improved underst and ing of the thermodynamic behaviors of irrigant solutions inside root canals in vivo
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 .