Effects of porous-hydroxyapatite incorporated into glass-ionomer sealants

Abstract

The purpose of the present study was to evaluate the mechanical and chemical properties of a novel glass ionomer cement for use as a pit and fissure sealant containing a porous hydroxyapatite, namely, apatite ionomer cement (AIC). Control sealant samples were used Fuji III (GIC-S). The experiment sealant samples (AIC-S) consisted of porous spherical hydroxyapatite (HApS) particles added at 28 wt% to GIC-S powder. The GIC-S and AIC-S samples were evaluated through mechanical strength measurements, scanning electron microscopy observations, energy dispersive X-ray spectroscopy analysis, fluoride ion release tests, and antibacterial tests. The flexural strength of the AIC-S was significantly higher than that of GIC-S for each period, 1 h, 24 h and 1 year. The fluoride release dose for AIC-S was consistently higher than that for GIC-S. In addition, the antibacterial properties of AIC-S were superior to those of GIC-S. The novel AIC-S may be a more suitable sealant material for pits and fissures with intact and/or infected enamel.

Influence of Porous Spherical-Shaped Hydroxyapatite on Mechanical Strength and Bioactive Function of Conventional Glass Ionomer Cement

“…The AIC specimens in our previous studies [20,21,22,23,24] were made by reducing GIC powder and adding HAp powder instead. Because fluoride is contained in the GIC glass powder, it was not clear why the AIC had superior fluoride release properties in spite of a decrease in the amount of GIC powder.…”

“…Arita et al demonstrated that porous HAp made by grinding HAp with columnar crystal shapes using an automatic ball mill is suitable for use in dental restorative AIC formulations [21]. In our study, a commercial porous HAp (HApS) was selected because of its low cost, and because it can produce an AIC with applications as a restorative and sealing material [23,24]. However, an AIC including this spherical, porous HApS has not yet been compared with materials made with HAp powders with other morphologies.…”

“…These data suggest that there is no benefit in adding reinforcing materials that do not undergo chemical reactions with the GIC. In addition, the HApS particles are breakable and can therefore disperse into the matrix layer [24]. It has also been shown that HAp can act as a drug delivery carrier due to its superior adsorptive properties [30,31].…”

“…Each specimen was subsequently attached to a cotton thread and immersed in 18 mL of deionized water at 37 °C. Refer to our previous studies [21,23,24], the period of measurement was decided for five days. During these trials, each disc was removed from the water and washed with 2 mL of deionized water over the immersion water every 24 h for five days, such that the 2 mL wash water was combined with the original 18 mL water.…”

“…Porous, spherical HAp particles were found to be the most effective in this regard [23]. This novel material, which we term apatite ionomer cement (AIC), has also exhibited high antibacterial activity [24]. …”