(PR120) In Vitro pH Changes Comparing Calcium Hydroxide and Bioceramic Intracanal Medicament in Simulated Root Surface Resorption Defects

External inflammatory root resorption (EIRR) may occur after trauma due to root damage and pulpal infection, resulting in hard tissue loss. Standard treatment involves root canal therapy using calcium hydroxide (CH) as an intracanal medicament to elevate pH in peripheral dentin. This study compared the effectiveness of CH and a new bioceramic intracanal medicament in raising pH in a simulated EIRR model. Fifty-four extracted human teeth were decoronated to a standard length and grouped by similar dentin thickness using CBCT. The teeth were divided into three groups (n=18/group). Following root canal preparation with a standardized protocol, external root surface defects were created with a #6 round bur and the canals were filled according to their respective group: saline (control), CH (Ultracal XS), and bioceramic (EndoSequence BC Temp). pH levels at the defect site were measured after 5 hours, 1 day, and 7 days, with additional measurements planned at 14, 21, 28, 49, 84 days. Data were analyzed using ANOVA and Tukey’s test (p < 0.05). Time dependent pH changes occurred within and between the experimental groups and the control groups. A statistically significant interaction was observed between groups and time, indicating that pH levels varied between groups over time. The bioceramic and saline groups showed a decrease in pH over time, whereas the CH group maintained a more constant pH level (P=.0000001). Compared to saline and the bioceramic, calcium hydroxide was the most effective medicament in maintaining an elevated pH over time.