A slow release calcium delivery system for the study of reparative dentine formation

Abstract

Several liquid, semi-solid and solid delivery systems were formulated and tested to devise a method of reproducibly administering accurate micro-doses of calcium into a 700 microns diameter cavity in a rat maxillary incisor tooth, in the absence of hydroxyl ions. Development of this delivery system was necessary to facilitate studies of the mechanisms of pulpal repair and odontoblast differentiation. The principal requirements for the delivery system were that it should be easily administered into a small pulp exposure in the rat incisor and that a greater than 1000-fold range in calcium ion concentrations could be incorporated and delivered for a period of 2-3 days, preferably in an acidic environment to minimize the effect of non-specific nucleation under alkaline conditions. Poly- (ethylene) glycol microspheres were found to be an ideal vehicle. Under the in vitro dissolution conditions used, complete release of all calcium salts occurred within 12-15 hours, except for the very water-insoluble calcium stearate. It was anticipated that the release of calcium ions would be significantly more prolonged in vivo because of the physical constraints of the prepared cavity as well as the restricted access to fluid flow.

Mineral Trioxide Aggregate with or without Calcium Chloride in Pulpotomy

“…We found in the literature a number of hypotheses on the biochemical mechanisms responsible for migration, differentiation, and cell proliferation, as well as formation of mineralized tissue (25,28,29). Calcium ions might cross the cell membrane by depolarization or activation of membrane-bound calcium channels (30). In vivo, when great amounts of calcium ions are available, it could activate adenosine triphosphate, which plays a significant role in the mineralization process (31).…”

Effect of mineral trioxide aggregate on proliferation of cultured human dental pulp cells

“…The calcium hydroxide separates into calcium and hydroxide ions, resulting in increased pH and calcium ion release. Calcium ions may cross the cell membrane by depolarization or activation of membrane-bound calcium channels, therefore, it is likely that this ion would play a greater role in the reparative process than would the hydroxyl ion (Hunter et al 1998). Calcium ions are necessary for the differentiation and mineralization of pulp cells (Schröder 1985).…”

Sustained release of calcium hydroxide from poly(dl-lactide-co-glycolide) acid microspheres for apexification

“…[6][7][8]. Hunter et al manufactured calcium citrate loaded poly(ethyleneglycol)-MS within a range size of 180-2000 lm releasing Ca 2?…”

“…Hunter et al manufactured calcium citrate loaded poly(ethyleneglycol)-MS within a range size of 180-2000 lm releasing Ca 2? for 3-4 days but for pulp capping [6,7]. For apexification, Strom et al produced alginate-based MS loaded with Ca(OH) 2 to promote long term release of Ca 2?…”