Effects of Root Canal Irrigants on the Smear Layer of Root Canal Wall

Abstract

Abstract : Root canal irrigants, smear layer removal agents and/or fluorides were applied to the smear layers that were produced after filing of human root canal walls’. Permeability was studied by the dye penetration test. Surface structure of root canal dentin was examined by scanning electron microscope (SEM).

 The following results were obtained :

 1) In root canal irrigants, NaClO was ineffective to remove the smear layer, however, Tubulicid Plus, EDTA and EDTA-NaClO-H₂O₂ were effective to remove smear layer on the SEM observation. All irrigants except Tubulicid Plus enhanced dye penetration.

 2) In smear layer removal agents, Dentin Conditioner, Tubulicid Blue and Tubulicid Red were ineffective to remove the smear layer on the SEM observation. Tubulicid Blue enhanced dye penetration, however, Dentin Conditioner and Tubulicid Red reduced it.

 3) Application of SnF₂ or Dentin Conditioner with SnF₂ to the smear layer did not remove it. Dentin Conditioner with SnF₂ was most effective to reduce dye penetration, however, dye penetration was not reduced by SnF₂.

 Therefore, considering the three dimensional obturation after root canal preparation, irrigation of EDTA-NaClO-H₂O₂ is useful for clinical procedure. On the other hand, Dentin Conditioner with SnF₂ is useful for dentin-chips filling method.