Apical and radial pH diffusion through root dentin from five modern intracanal medicaments: a twelve-week evaluation of alkaline dynamics

OBJECTIVE: This ex vivo study characterized the temporal and spatial behavior of hydroxyl ion diffusion through root dentin from five contemporary intracanal medicaments over 12 weeks, with emphasis on vehicle composition and apical diffusion beyond the medicament terminus. METHODS: Sixty-six extracted single-rooted human teeth were prepared using the ProTaper Ultimate rotary system to an F3 finishing file. Specimens were randomly allocated to five medicament groups: purified water, propylene glycol, methylcellulose in water, silicone oil, or calcium silicate. Standardized cavities were prepared at inner dentin, outer dentin, and two apical sites approximately 3 mm and 6 mm beyond the medicament terminus. Remaining dentin thickness between the canal lumen and each cavity was recorded. pH was measured at weeks 1, 2, 4, 8, 10, and 12 using a calibrated micro pH electrode. RESULTS: Significant main effects were observed for medicament, week, and location (all p < 0.001). Hydroxyl ion diffusion exhibited clear spatial attenuation (Inner > Outer > Proximal ≥ Distal) across all active groups. Low-viscosity aqueous vehicles produced the highest and most sustained alkalinization. Apical diffusion beyond the medicament was limited to approximately 3 mm. The calcium silicate-based medicament did not produce significant dentin alkalinization at any time point. CONCLUSIONS: Vehicle composition significantly influences both the magnitude and temporal dynamics of dentin alkalinization. Complete medicament delivery to working length is critical, as passive diffusion does not compensate for incomplete placement.

Author dc:creator

• Hefnawi, Badr

Advisors dc:contributor.advisor

• Giordano, Russell, II
• Hsu, Tun-Yi

• Dentistry
• Alkaline dynamics
• Calcium hydroxide
• Hydroxyl ion diffusion
• Intracanal medicaments
• pH

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/2144/53240

OAI identifier oai:identifier

oai:open.bu.edu:2144/53240