The effect of Mg 2+ incorporation into the glass phase of zinc-based glass polyalkenoate cements

Incorporating Germanium Oxide into the Glass Phase of Novel Zinc/Magnesium-Based GPCs Designed for Bone Void Filling: Evaluating Their Physical and Mechanical Properties

“…This shift suggests increased glass stability, which may be attributed to the formation of BO groups, which likely exists as Si–O–Ge groups are formed in the glass, agreeing with the network connectivity calculation. As expected the increase of BO requires increased energy to melt the glass [ 32 ], therefore, T m increased from 1055 °C to 1139 °C with increasing Ge content up to 8 mol %. This was assumed to be due to the increasing ratio of BO:NBO when increasing the concentration of a former element (Ge).…”

“…TK16 with 6.5 mol % GeO 2 was found to have a longer setting time compared to TK10 with 0 mol % GeO 2 and a shorter T s than the TK17 (7 mol % GeO 2 ) and TK18 (8 mol % GeO 2 ) ( Figure 11 ). This may be due to TK16 having a higher percentage of NBOs compared to TK17 and TK18, which results in a greater cross-linking of the PAA and increased of the iGPCs [ 32 ]. No significant difference ( p 0.05 ) was found in and between TK16 and TK17 cements.…”

“…Three glasses were produced containing germanium oxide (GeO 2 ) using the control glass TK10 (SiO 2 -CaO-ZnO-MgO) [ 32 ] while substituting zinc oxide (ZnO) with GeO 2 up to 8 mol % (TK16, TK17 and TK18) as shown in Table 1 . GPCs made with glasses in this series that contained less than 6.5 mol % GeO 2 were not injectable.…”

“…The network connectivity (NC) of the glasses was calculated using Equation (1), considering the molar compositions of the glasses ( Table 1 ), where Si 4+ and Ge 4+ were considered network formers [ 10 , 32 , 33 ], each contributing four bridging oxygens (BO) to the glass network [ 34 ]. Zn 2+ and Mg 2+ behave as network intermediates and have previously been identified as acting primarily as network modifiers in similar glasses; each of these elements contribute 2 non-bridging oxygen (NBO) to the glass network [ 32 , 35 ]. where, NC = Network Connectivity; BO = Bridging Oxygens; NBO = Non-Bridging Oxygens.…”

“…An STM United Tensile Tester (United Testing Systems, Inc., Huntington Beach, CA, USA) fitted with a ±2 kN load cell at a crosshead speed of 1 mm min −1 was used to test the cement samples ( n = 5). Moulds (4 mm Ø × 6 mm height) according to ISO9917 [ 38 ], were filled using a disposable 10 mL syringe with a 16-gauge needle (injection technique) to excess with freshly mixed cement then covered with acetate sheet [ 32 ]. After 1 h of incubation at 37 °C the samples were de-moulded and then incubated in DDI water (37 °C) for 1, 7 and 30 days.…”