The evaluation of the mechanical characteristics of the synthesized glass-ionomer cements (GICs): the effect of hydroxyapatite and fluorapatite nanoparticles and glass powders

Incorporation of Nanomaterials in Glass Ionomer Cements—Recent Developments and Future Perspectives: A Narrative Review

“…Best results: HAP 7.5% (H = 112.17 VHN), 35FHAP 5% (H = 81.23 VHN), 65FHAP 7.5% (H = 80.5 VHN), 95FHAP 5% (H = 81.23 VHN), control 48.94 VHN HAP [ 86 ] Obtained by co-precipitation, hexagonal, 80–150 nm GC Fuji I ® (type I) 1, 2, 4, 6, 8% AM in GIC at different powder/liquid ratios, evaluation of FS, μSBS Addition of AM led to the increase in mechanical properties and adhesion potential. Best results at 6% HAP, 3:1 powder/liquid ratio: FS = 30.97 MPa (control 11.65 MPa), μSBS = 0.97 MPa (control 0.39 MPa) HAP [ 87 ] Commercially available, <200 nm SDI Riva Self Cure GIC (type I) 1, 3, 5, 8, 10% AM in GIC, evaluation of fluoride release, CS, antibacterial effect (against S. mutans ) Addition of HAP increased release up to 8% HAP (0.36 μg/mm 2 ), while CS increased for 3–10% HAP (147.12–149.72 MPa), IZ (best results at 8% HAP) ~8.5 mm HAP [ 88 ] Obtained by co-precipitation, 24 nm GC Fuji II GP ® (type II ii ) 5, 8% in GIC, evaluation of CS, DTS, H, ST, WT Addition of HAP increased mechanical properties: ST = 150/153 s (control 187), WT = 110/108 (control 125), CS ~70/70 (control ~65 MPa), DTS ~9.5/11 (control ~8 MPa), H = 69.3/75.4 (control = 65.3 VHN) FAP [ 88 ] Obtained by co-precipitation, 30 nm Addition of FAP increased mechanical properties: ST = 138/135 s (control 187), WT = 98/95 (control 125), CS = ~72/72 (control ~65 MPa), DTS ~11/12 (control ~8 MPa), H = 74.2/77.3 (control = 65.3 VHN) HAP [ 89 ] Commercially available GC Fuji II GP ® (type II ii ) 25% AM in GIC, evaluation of microleakage at enamel and dentin/cementum interface Microleakage of occlusal margin was significantly lower than that of gingival margin …”

“…The surface hardness of the GIC was found to increase upon the addition of HAP derived from chicken egg shells (significantly for 7 and 9% HAP concentrations) [ 84 ], while in other works an optimum concentration was proposed for both HAP and fluorhydroxyapatite (with different degrees of fluoridation) after which the surface hardness starts to decrease [ 85 ]; addition of nano-HAP to luting GIC to improve the flexural strength and shear bond strength was also found to have an optimum concentration (6%, at a powder/liquid ratio of 3/1) [ 86 ], while the use of a commercial nano-HAP product led to an increase in the mechanical and antimicrobial properties—as well as of the fluoride ion-release capacity—up to an optimum of 8% HAP [ 87 ]. Comparing different types of nano-apatitic materials (hydroxyapatite and fluorapatite- FAP), Barandehfard et al [ 88 , 90 ] obtained superior results in terms of mechanical properties, as well setting and working times, for FAP; this is probably due to the lower solubility rate of FAP (better for 8% FAP compared with 5% FAP). Both apatitic materials presented, however, superior results at both concentrations when compared with the classic GIC used as control [ 88 , 90 ].…”

“…Comparing different types of nano-apatitic materials (hydroxyapatite and fluorapatite- FAP), Barandehfard et al [ 88 , 90 ] obtained superior results in terms of mechanical properties, as well setting and working times, for FAP; this is probably due to the lower solubility rate of FAP (better for 8% FAP compared with 5% FAP). Both apatitic materials presented, however, superior results at both concentrations when compared with the classic GIC used as control [ 88 , 90 ].…”

Polymeric Dental Nanomaterials: Antimicrobial Action

“…Apart from their antimicrobial action, inorganic nanoparticles are able to improve the integrity of the hybrid layer at the resin–dentin interface [ 34 , 35 ], inhibit enamel demineralization [ 36 ] and formation of white spot lesions [ 37 , 38 ] during orthodontic treatment, increase the compressive strength [ 39 , 40 ] and microhardness [ 41 ] of restorations based on glass ionomer cement, and reduce polymerization shrinkage of light-curing dental composites [ 42 ] and the surface roughness of dentures [ 43 , 44 ] and implants [ 45 ] ( Supplementary Materials, Table S4 ).…”

“…Ag NPs and TiO 2 NPs occupy voids in the GIC, acting as additional contact points between the binder and glass particles. This increases the compressive strength [ 39 , 81 ], flexural strength, and Vickers microhardness of the composites and the micro-shear bond strength to dentin [ 82 ].…”