Vital Pulp Tissue Response to Sodium Hypochlorite

By Rosenfeld EF, James GA, Burch BS

Date: 01/1978
Journal: JOE


  • Purpose: to evaluate the solvent action of 5.25% NaOCl on vital human pulp tissue that had not been disturbed by instrumentation.
  • N=42 vital premolars, 2 control, 40 experimental group.
  • Materials/Methods:

  • G1:10 teeth: access, irrigation with 5.25% NaOCl , 5ml for 15 min. 10 teeth: irrigated with saline
  • G2: 10 teeth, access instrumentation to size 40 in max, 60 in mand 5mm away from apex. Irrigation with 5.25% NaOCl , 10 teeth irrigation with saline. In both groups dentin shelf/ledge was created as reference point during microscopic evaluation. Teeth closed with cotton and cavit and extracted within 45 min
  • Fixed. Stained and viewed under light microscope by 2 blinded independent examiners
  • Most highlighted Results:
  • damage from the operative procedure Concavity (pulpal surface)was seen in tooth accessed with no irrigation (fig1).
  • Predentin was not removed in instrumented and non-instrumented saline group. In contrast ,NaOCl removed predentin.
  • Non-instrumented/ NaOCl : digestive, nonspecific effect, minimal effects on deeper pulpal tissue .pulp level was higher in teeth small canals compared to wide. Pulp level varied from 0.5 -3.0 mm below the cut surface, with a mean level of 1.7 mm.
  • Instrumented / saline: some residual tissue remained in canal walls.
  • Instrumented/NaOCl: residual tissue was removed from the canal walls, only lateral canals adjacent to the main canal were affected. In 50% of this group the content of the dentinal tubules was digested.

Clinical significance:

NaOCl has non-selective effect on both necrotic and vital tissue. And it should be supplemented with instrumentation. Result suggest relation between width of the canal and depth of penetration.