Structural analysis of strontium in human teeth treated with surface pre-reacted glass-ionomer filler eluate by using extended X-ray absorption fine structure analysis

Abstract

The bioactive effects of strontium released from surface pre-reacted glass-ionomer (S-PRG) fillers may aid in caries prevention. In this study, the local structure of strontium taken up by teeth was estimated by extended X-ray absorption fine structure analysis. Immersing teeth into S-PRG filler eluate increased the strontium content in enamel and dentin by more than 100 times. The local structure of strontium in enamel and dentin stored in distilled water was the same as that in synthetic strontium-containing hydroxyapatite (SrHAP). Moreover, the local structure of strontium in enamel and dentin after immersion in the S-PRG filler eluate was also similar to that of SrHAP. After immersion in the S-PRG filler eluate, strontium was suggested to be incorporated into the hydroxyapatite (HAP) of enamel and dentin at the calcium site in HAP.

Calcium Charge and Release of Conventional Glass-Ionomer Cement Containing Nanoporous Silica

“…In recent years, many studies of bioactive materials have been conducted [34,35,36]. The results of this study may be useful to the development of biomaterials.…”

Cutting-edge filler technologies to release bio-active components for restorative and preventive dentistry

“…Similar results have also been reported for other S-PRG fillercontaining materials such as orthodontic adhesives 83) , fissure sealants 84) , coating materials 54,85) , resinous vanishes 86) and denture base resins 87) . Uo et al 88) investigated the local structure of strontium taken up by teeth using X-ray absorption fine structure analysis, and revealed that the strontium content in enamel and dentin was 100 times greater after immersion in the eluate of S-PRG filler than before immersion. It is known that strontium enhances the acid resistance of teeth by converting hydroxyapatite to strontiumapatite 89,90) .…”

Time dependence of multi-ion absorption into human enamel from surface prereacted glass-ionomer (S-PRG) filler eluate

“…Sr K-edge XAFS spectra were measured on NW-10A beamlines at the Photon Factory of the High Energy Accelerator Research Organization (Tsukuba, Japan) by using the transmission method. Measurement and EXAFS analysis were described in the previous report 19) . Table 2 shows the time dependence of B, Na, Mg, Al, Zn, and Sr content in natural enamel and in enamels immersed in S-PRG eluate for various periods, up to 28 days; these time-dependence data are also plotted in however, it was also present in the enamel in high concentrations (7,000 ppm in approx.…”

“…In both cases, Sr and F penetration into dentin and enamel from the interface with the S-PRGcontaining material occurred for an extended period. Notably, Sr was reported to accumulate in the enamel and dentin for 3 months with S-PRG eluate immersion; this accumulated Sr was speculated to incorporated to the Ca site of HAP 19) . By using PIXE, Nakamura et al revealed Sr enrichment on the enamel surface after 40 min of contact with an S-PRG-containing experimental toothpaste 14) ; their report suggested that early Sr incorporation could occur in less than 1 h, and that the acid resistance of enamel was improved.…”