Chlorhexidine Debris extrusion Endovac Humans In Vitro Techniques Random Allocation Reciprocating files Root Canal Irrigants Root Canal Preparation Saline Solution Sodium Hypochlorite Sodium hypochlorite Therapeutic Irrigation Tooth Apex administration and dosage biomedical and dental materials chlorhexidine evaluation study human hypochlorite sodium in vitro study lavage metabolism procedures randomization root canal preparation tooth apex