# The Effects of Sodium Dichloroisocyanurate and Calcium Hydroxide as Intracanal Medicaments on Microhardness and Fracture Resistance of Dentin: An In Vitro Study

## TL;DR

This study found that long-term use of sodium dichloroisocyanurate and calcium hydroxide as root canal medicaments can weaken tooth dentin over time.

## Contribution

The study provides new evidence on the long-term effects of two common intracanal medicaments on dentin properties.

## Key findings

- Short-term use of NaDCC and CH did not significantly affect dentin microhardness.
- Prolonged use of NaDCC significantly reduced dentin microhardness and fracture resistance.
- After 3 months, both NaDCC and CH showed reduced dentin microhardness compared to the control group.

## Abstract

The aim of this study was to evaluate the effect of sodium dicholoroisocyanurate (NaDCC) as intracanal medicament on the dentin microhardness and fracture resistance of teeth compared to calcium hydroxide (CH).

Root canals of mandibular premolars (n = 153) were instrumented and randomized into two treatment groups and an untreated control group (n = 51). Treatment groups received either NaDCC or CH. After 1 week, 1 month, or 3 months, 17 teeth were randomly selected from each group, and two root cylinders were obtained: one for fracture resistance and the other for microhardness test. Two‐way ANOVA, one‐way ANOVA, and Tukey post hoc tests were used for statistical analysis.

The microhardness and fracture resistance in the control and CH groups were not affected by time (p > 0.05). However, NaDCC caused significant decreases in dentin microhardness after 1 month and 3 months (p < 0.001) as well as in fracture resistance (p < 0.05) after 1 month. The groups comparison at each time point showed no significant differences in microhardness and fracture resistance after 1 week (p > 0.05). However, after 1 month, a significant reduction in microhardness and fracture resistance was detected for NaDCC and in the fracture resistance for CH (p < 0.05). After 3 months, compared to the control group, lower microhardness in NaDCC and CH groups and lower fracture resistance in CH group were detected (p < 0.05).

Short‐term application of NaDCC and CH did not adversely affect dentin microhardness. However, prolonged use reduced dentin microhardness, and both medicaments significantly decreased fracture resistance compared with the control group. Limiting the duration of intracanal medicament application is therefore recommended.