Factors affecting the viscosity of sodium hypochlorite and their effect on irrigant flow

Abstract

Dynamic viscosity increased with sodium hypochlorite and surfactant concentration but decreased with temperature. Under clinical conditions, all viscosities measured led to laminar flow. The transition between laminar and turbulent flow may be reached by modifying different parameters at the same time: increasing flow rate and temperature whilst decreasing irrigant viscosity by adding surfactants with a high value of critical micellar concentration.

Penetration of Sodium Hypochlorite Modified with Surfactants into Root Canal Dentin

“…Adding a surfactant at high concentration larger than CMC increases irrigant viscosity. Moreover, dynamic viscosity of NaOCl solutions statistically increased with NaOCl concentration (from 0.6 to 9.6%) but decreased with increased temperature (from 22 to 37 °C) (20). This well-known phenomenon may be explained by thermal agitation of the molecules which move more easily at 37 °C than at 22 °C (22) and could explain the increase in penetration depth recorded for Chlor-Xtra versus <6% NaOCl at 37 °C and 45 °C with 2 min exposure time.…”

“…Few data are available concerning the modification of irrigant viscosity through surfactant addition. Viscosity of a fluid is a measure of its resistance to flow under an applied force and has a direct influence on the nature of irrigant flow (20). Bukiet et al (20) showed that mean viscosity (μ) (mPa s) of 2.4% NaOCl mixed with different concentrations of Triton X 100 at 37 °C, generally increased with the concentration of surfactant.…”

The effect of sodium hypochlorite concentration and irrigation needle extension on biofilm removal from a simulated root canal model

“…It has been reported that irrigant penetration increased by increasing its temperature, or adding a surfactant that lowers its surface tension (15). Irrigant agitation has been recommended to improve the irrigant penetration and mixing within the root canal system (9).…”

Effect of sodium hypochlorite irrigation with or without surfactants on the bond strength of an epoxy-based sealer to dentin

“…Root canal irrigants are used to remove debris, bacteria, and toxic products from the root canal system that remain untouched even after root canal preparation [1][2][3][4]. Sodium hypochlorite (NaOCl) is recommended as the primary irrigant because of its broad antibacterial activity and ability to dissolve organic tissues, such as pulp tissue, collagen fibers, and bacterial biofilm [1,3,5].…”

“…As another possible means of improving the effectiveness of irrigants, surface-active agents, also called surface modifiers or surfactants, have been added to antibacterial solutions to reduce their surface tension, thereby achieving a better adaptation to dentin and deeper penetration into the dentinal tubules or lateral canals [2,4,10]. Stojicic et al [11] found that NaOCl with added surfactant was more effective in necrotic soft tissue dissolution than NaOCl with unaltered surface tension.…”