Under the conditions of these in vitro leakage studies , it is concluded that smear layer removal improves the fluid-tight seal of the root canal system whereas other factors such as the obturation technique or the sealer , did not produce significant effects
The purpose of this systematic review was to determine whether smear layer removal reduces leakage of obturated human teeth in vitro .
Effect of precurving endosonic files on the amount of debris and smear layer remaining in curved root canals.
Endosonic files are prone to constraint ; this reduces their efficiency , particularly in the apical third and in curved root canals . Precurving the file may reduce constraint , thereby improving the file 's ability to debride . This investigation was undertaken to compare both straight and precurved endosonic files as to debris and smear layer removal .  Thirty-six curved root canals were r and omly allocated into six groups . Each group was prepared using a step-down technique , then instrumented with either a straight or precurved endosonic file of size 15 , 20 , or 25 . The tooth roots were split and examined under the scanning electron microscope . Blind examinations were made for debris and smear layer removal and evaluation scores were analyzed using a log linear approach . The root canals instrumented with the precurved files had a significantly lower debris score than those prepared with straight files . Precurving did not affect smear layer removal . In conclusion , precurving of files decreased the amount of debris but did not affect smear layer removal
Under the conditions of these in vitro leakage studies , it is concluded that smear layer removal improves the fluid-tight seal of the root canal system whereas other factors such as the obturation technique or the sealer , did not produce significant effects
The purpose of this systematic review was to determine whether smear layer removal reduces leakage of obturated human teeth in vitro .