The effect of intracanal medication variations on microhardness of simulated immature root dentin

The effect of different medicaments and irrigation solutions on root dentin microhardness (MH) was evaluated depending on time. After initial measurements, MH of 60 maxillary incisors (n = 15 per group) was measured after 3 steps: irrigation with 2.5% sodium hypochlorite, exposure to medicaments [triple antibiotic (TAP) or calcium hydroxide (CH) pastes, 1 week or 1 month)] and final irrigation [20 mL of 17% EDTA or 20 mL 1% phytic acid (PA)]. The percentage of MH reduction was calculated. Data were analysed statistically at P < 0.05. Treatments caused a significant decrease in MH values compared to baseline and pre-measurements (P < 0.05). TAP significantly reduced the MH values of the samples over time (P < 0.05). Removal of TAP after 1 month with PA resulted in a significant reduction in MH compared to removing TAP after 1 week and CH removing after 1 month (P < 0.05). Considering the chemical preparation steps, the most hazardous effect on MH was observed after the first irrigation.