(PR067) Assessment of Intracanal Calcium Hydroxide pH Stability in Simulated-Inflammatory Conditions

Objective: There are several pre-mixed formulations of Calcium hydroxide preparations as intracanal dressing. More recently, BC Temp^TM, a bioceramic particle containing Ca(OH)_₂ preparation with prolonged release of hydroxyl ions (OH-) to neutralize the acidic environment arising from periapical inflammatory changes, might have superior clinical benefits. This study evaluates pH changes in intracanal medicaments (BC Temp Brasseler/UltraCal^TM XS Ultradent/hand-mixed Ca(OH)_₂) with a simulated inflammatory environment.

Methods: Thirty decorated single-root-teeth were prepared to size 35/.04, using simulated clinical/standard irrigation protocols (NaOCl/EDTA), and were randomly assigned to three groups (n=5) BC Temp Brasseler/UltraCal XS Ultradent/hand-mixed Ca(OH)_₂. Each group is assigned to 2 pH buffer solutions (pH 5 or 7). Root-canals were filled with respective Ca(OH)_₂ preparations and suspended in a test tube containing 1 of the 2 conditions. Later, they were placed on a rocker in an incubator with simulated oral conditions (100% humidity and 37°C). Intracanal pH measurements were recorded daily for 10 days. Data was analyzed using a linear mixed-effects regression model/Wilcoxon (p < 0.05).

Results: There were no significant (p>.05) changes in BC Temp group in both conditions. However, fresh-mixed Ca(OH)_₂ (p=0.006) and UltraCal (p=0.003) groups had significantly reduced pH in acidic conditions over 10 days.

Conclusion: BC Temp demonstrated superior pH stability compared to both UltraCal and fresh-mixed Ca(OH)_₂ preparation, possibly due to inclusion of bioceramic particles in formulation. Further studies (in vivo) are needed to explore the clinical benefits of adding bioceramic particles in calcium hydroxide pastes and associated physical properties/mechanisms involved in the extended-release of calcium and hydroxyl ions.