The effect of surfactant addition to EDTA on microhardness of root dentin

The aim of this study was to investigate the effect of different concentrations of cetrimide with or without 5% EDTA solution on the microhardness of human root dentin in vitro.

Twenty-five recently extracted single-rooted human teeth were selected. The roots were split longitudinally into 2 parts. The specimens were randomly divided into the following 5 groups and were treated with 5% EDTA, 5% EDTA + 0.25% cetrimide, 5% EDTA + 0.50% cetrimide, 0.25% cetrimide, and 0.50% cetrimide immediately after the initial baseline microhardness measurements. A standardized volume of 50 mL of each solution was used for 1 minute. The reference microhardness values of untreated specimens were initially measured with a Vickers indenter under a 50-g load and a 10-second dwell time at the midroot level of the root dentin. Post-treatment microhardness values were obtained in the same manner as the initial ones. The decrease in microhardness was calculated as a percentage. Data were analyzed statistically by 1-way analysis of variance (P = .05) and the post hoc Tukey test for multiple comparisons at the same level of significance.

All solutions significantly decreased the microhardness of root dentin (P < .05). Although there was no significant difference among the solutions (P > .05), the specimens in the EDTA + 0.50% cetrimide solution group showed the highest change in microhardness. The plain EDTA and plain 0.50% cetrimide groups had similar values.

The use of surfactants higher than 0.25% in concentration is questionable for clinical conditions.