Apical diffusion of calcium hydroxide in an in vitro model

Area of Science:

• Endodontics
• Dental Materials Science
• Biomaterials

Background:

• Intracanal medicaments are crucial in endodontic treatment to manage infection and inflammation.
• Calcium hydroxide (Ca(OH)2) is a widely used intracanal medicament due to its antimicrobial and tissue-healing properties.
• The efficacy of Ca(OH)2 may be influenced by its diffusion characteristics within the root canal system and periapical tissues.

Purpose of the Study:

• To develop and utilize an in vitro agar model to investigate the diffusion of calcium hydroxide (Ca(OH)2) medicaments.
• To assess the impact of varying viscosity and apical foramen size on Ca(OH)2 diffusion and resulting pH.
• To understand how medicament properties influence potential effects on periapical tissues.

Main Methods:

• An in vitro agar model was created using brain heart infusion agar and a calcium-reactive dye.
• Simulated root canals (pipette tips) with varying apical foramen sizes were used.
• Three Ca(OH)2 medicaments of different viscosities were tested, and calcium and hydroxyl ion concentrations were measured over 24 hours.

Main Results:

• Calcium (Ca) concentration and pH in the agar increased significantly with larger apical foramen sizes.
• A 10% Ca(OH)2 solution demonstrated higher Ca diffusion and pH compared to Pulpdent or a Ca(OH)2 paste.
• Medicament viscosity and vehicle properties demonstrably affected Ca(OH)2 diffusion.

Conclusions:

• The physical properties of the vehicle used for Ca(OH)2 medicaments play a significant role in their diffusion capabilities.
• Larger apical foramina facilitate greater diffusion of Ca(OH)2 and associated ions.
• Optimizing medicament formulation and considering canal anatomy are important for maximizing therapeutic effects in periapical tissues.