pH changes and calcium ion diffusion from calcium hydroxide dressing materials through root dentin

Area of Science:

• Endodontics
• Dental Materials Science
• Biomineralization

Background:

• Calcium hydroxide (CH) is widely used in endodontics for its antimicrobial and regenerative properties.
• Understanding the diffusion characteristics of CH components, calcium ions (Ca2+) and hydroxyl ions (OH-), through root dentin is crucial for optimizing treatment outcomes.
• External root resorption requires effective management, and the choice of intracanal dressing material significantly impacts therapeutic efficacy.

Purpose of the Study:

• To investigate and compare the diffusion properties of Ca2+ and OH- through root dentin using various calcium hydroxide (CH) dressing materials.
• To evaluate the impact of different CH formulations on the pH and Ca2+ concentration in the surrounding medium over time.
• To determine the suitability of different CH materials for treating external root resorption based on their diffusion characteristics.

Main Methods:

• Twenty-eight single-rooted teeth underwent instrumentation, external defect creation, and smear layer removal with 17% EDTA.
• Teeth were sealed, and baseline Ca2+ and pH levels in saline were recorded for 3 days.
• Teeth were then filled with one of four CH materials: DT Temporary Dressing CH, CH powder with saline, TempCanal, or CH points.
• Ca2+ concentrations and pH were measured in the surrounding saline at multiple time points up to 28 days.

Main Results:

• Nonsetting CH pastes demonstrated a gradual release of Ca2+ into the surrounding medium.
• CH points did not show a significant increase in Ca2+ concentration.
• None of the tested CH materials induced a sustained increase in the pH of the surrounding medium during the study period.

Conclusions:

• Nonsetting calcium hydroxide pastes facilitate the diffusion of Ca2+ through root dentin without significantly altering the pH of the surrounding environment.
• The diffusion pattern observed suggests that nonsetting CH pastes may be more advantageous than CH points for managing external root resorption.
• Further research into the long-term effects and clinical efficacy of these CH materials in treating root resorption is warranted.