Evaluation of the diffusion of calcium hydroxide-based medicaments through the dentinal tubules and apical foramen: A mass spectrometry study.

This mass spectrometry study investigated the diffusion of hydroxyl and calcium ions from a calcium hydroxide intracanal medicament (Pulpdent®) when used alone or mixed in equal parts with a steroid-antibiotic paste (Ledermix®). The pH (using pH meter) and calcium ion concentration (using inductively coupled plasma-mass spectrometry) of the diffused medicaments were assessed using endodontically prepared human extracted teeth with either a sealed or a patent apex, at time intervals of 1, 3, 8, 24, and 168 h. A one-way ANOVA was used to explore differences between and within groups, with Tukey-Kramer/Games-Howell posttests. In both situations tested, Pulpdent® showed greater release of both calcium and hydroxyl ions than when mixed in equal parts with Ledermix®. Greater initial release of both ions occurred in roots with a patent apex, but by 1 week there was no significant difference between the two. If a 50:50 combination of Pulpdent® paste and Ledermix® paste is used, there is a lower release of calcium ions and hydroxyl ions than using Pulpdent® paste alone. With both Pulpdent® paste alone and Pulpdent® paste mixed equally with Ledermix® paste, the major pathway for movement of hydroxyl ions and calcium ions is diffusion through the dentine of the root, with the apex playing only a minor role.