Endodontic re-instrumentation enhances hydroxyl ion diffusion through radicular dentine

Area of Science:

• Endodontics
• Dental Materials Science
• Biomaterials

Background:

• Calcium hydroxide (CH) is a common intracanal medicament.
• Its efficacy relies on hydroxyl ion release and diffusion.
• Understanding diffusion before and after retreatment is crucial for endodontic success.

Purpose of the Study:

• To evaluate hydroxyl ion diffusion from CH paste.
• Assess diffusion before root canal filling.
• Assess diffusion after root canal retreatment.

Main Methods:

• 60 root canals were prepared and treated for smear layer removal.
• CH paste was placed, and pH was measured over 28 days (pH1).
• Canals were filled with various sealers, retreated, refilled with CH, and pH measured again (pH2).

Main Results:

• pH measurements increased significantly over time for both pH1 and pH2.
• Post-retreatment pH measurements (pH2) were significantly higher than pre-filling measurements (pH1).
• This indicates enhanced ionic diffusion after retreatment.

Conclusions:

• Hydroxyl ions from CH paste diffuse through dentinal tubules.
• Root canal retreatment can re-establish dentine permeability to ionic diffusion.
• Increased time positively influences the diffusion of hydroxyl ions.