Abstract
Objective. The reinforcement effect of polymer-grade montmorillonite (PGV and PGN nanoclay) on Fuji-IX glass ionomer cement was investigated. Materials and Method. PGV and PGV nanoclays (2.0 wt%) were dispersed in the liquid portion of Fuji-IX. Fourier-transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC) were used to quantify acid-base reaction and the liquid portion of GIC. The mechanical properties (CS, DTS, FS, and E f) of cements (n = 20) were measured at 1 hour, 1 day, and 1 month. The microstructure was examined by cryo-SEM and TEM. Results. FTIR shows that the setting reaction involves the neutralisation of PAA by the glass powder which was linked with the formation of calcium and aluminium salt-complexes. The experimental GICs (C-V and C-N) exhibited mechanical properties in compliance to ISO standard requirement have higher values than Fuji-IX cement. There was no significant correlation of mechanical properties was found between C-V and C-N. The average Mw of Fuji-IX was 15,700 and the refractive index chromatogram peak area was 33,800. TEM observation confirmed that nanoclays were mostly exfoliated and dispersed in the matrix of GIC. Conclusion. The reinforcement of nanoclays in GICs may potentially produce cements with better mechanical properties without compromising the nature of polyacid neutralisation.
Highlights
Since the discovery of glass ionomer cement (GIC) by Wilson and Kent [1] the family of GICs have evolved into a diverse group of dental materials that include direct restoratives, luting cements, liners, bases, atraumatic restoratives, and pit and fissure sealants [2]
The mean results of diametral-tensile strength (DTS) of the cements formed after dispersion of nanoclay at three storage intervals do not show any significant difference (P > 0.05) compared to Fuji-IX GP (F-IX) when data was analysed by one-way Analysis of variance (ANOVA) and post hoc Tukey’s test
The cements stored for 1 month have higher DTS than cement stored for 1 day (P < 0.01)
Summary
Since the discovery of glass ionomer cement (GIC) by Wilson and Kent [1] the family of GICs have evolved into a diverse group of dental materials that include direct restoratives, luting cements, liners, bases, atraumatic restoratives, and pit and fissure sealants [2]. They are available as conventional and resin-modified products. The properties of a conventional GIC are influenced by the glass-powder and chemical composition of the polymer liquid. Various modifications and the developments of glasspowder and polymer liquid have been introduced to improve the mechanical properties of GICs by altering the chemistry [5]
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