pH Stability of Calcium Hydroxide Preparations in a Simulated Acidic Environment

Background Calcium hydroxide (Ca(OH)₂) is a widely used intracanal medicament in endodontics, prized for its high pH, which provides antibacterial effects and promotes healing. However, its efficacy is challenged by the acidic pH of purulent exudates in infected root canals. This study aimed to evaluate the pH stability of three calcium hydroxide preparations—BC Temp (bioceramic-based), UltraCal XSTM, and mixed Ca(OH)₂ powder with saline—in simulated acidic and neutral environments. Materials and Methods 30 decoronated, single-rooted premolars were prepared using rotary files. The canals were treated with sodium 5.5% hypochlorite (NaOCl- ) and 17% ethylenediaminetetraacetic acid (EDTA), dried, and filled with one of the three calcium hydroxide formulations. Samples were suspended in test tubes containing either a neutral (pH 7.0) or acidic (pH 5.0) buffer solution, maintained at 37°C and 100% humidity for 10 days. Intracanal pH was recorded daily using a calibrated probe. Statistical analysis was performed using linear mixed-effects regression with a Bonferroni adjusted p value of 0.0167 Results BC Temp: Demonstrated superior pH stability, maintaining a pH >9.5 in the acidic environment, which is critical for antimicrobial efficacy. UltraCal XS: Showed a decrease in pH from 8.6 to 8.0 under acidic conditions. Hand-Mixed Ca(OH)₂: Experienced a similar pH drop, from 8.7 to 8.4. The pH of BC Temp was significantly higher than the other preparations under acidic conditions, likely due to its bioceramic composition, which allows for controlled ion release and interaction with dentinal tubules. Conclusions The study finds that the acidic environment reduces the pH of traditional calcium hydroxide formulations, potentially compromising their antimicrobial efficacy. BC Temp's sustained high pH highlights its suitability for challenging clinical scenarios involving persistent infection or acidic environments. The findings support the integration of bioceramic technology into calcium hydroxide formulations for improved performance.