The in-vitro effect of two different concentrations of sodium hypochlorite on dentine hardness

الملخص EN

-Objective: To investigate the effect of two different concentrations of irrigant solutions of sodium hypochlorite (NaOCl) 2.25% and 5.25%, on dentine hardness.

Methods: Forty-eight extracted anterior and posterior teeth were decoronated and the roots were endodontically cleaned and shaped.

Each root was sectioned into cervical, middle and apical sections of 3mm thickness and mounted in an acrylic resin disc-shape mould.

After polishing the coronal surface of each section, microhardness was measured using a Wallace microhardness indentation tester at four locations 1mm away from the root canal lumen.

Specimens were allocated into two groups and then irrigated with either 5.25% or 2.25% sodium hypochlorite for one hour and microhardness was measured again.

Results: A statistically significant decrease (p<0.05) in dentine hardness in the root dentine as a whole and in every root section after application of the two different concentrations of sodium hypochlorite was observed.

There was no statistically significant (p>0.05) difference in the decrease of dentine hardness between the 5.25% and the 2.25% concentrations for the root as whole and in every root section.

Conclusion: Irrigation with 2.25% or 5.25% sodium hypochlorite significantly decreased root dentine microhardness.