Objectives: to study the porosity and water absorption of experimental fluorinated-MTA (Mineral Trioxide Aggregate) cements. Methods: Experimental calcium-silicate MTA cements (WTC-Ba, FTC-Ba, F10TC-Ba) containing tri- and dicalcium-silicate, tricalcium-aluminate, calcium sulphate, (sodium fluoride only in F-cements) and barium sulphate were prepared. Porosity measurements (total porosity, pore size distribution and pores interconnection) were performed (at 1 and 21 days) on dry cylindrical samples (6mm height; 6mm diameter) in two conditions (relative humidity RH 95±5% or simulated body fluid DMEM, Dulbecco's Modified Eagle Medium). Total porosity was evaluated using the Archimedes principle by Hg immersion of the samples (indirect method). Micro-porosity (<6 nanometers) was derived by BET method trough the N2 adsorption (indirect method) on the entire specific surface area (SSA). Open porosity/pores interconnection (0.003-350 microns) was calculated by MIP (mercury intrusion porosimetry) i.e. differential mercury intrusion volume related to the applied pressure. Water absorption (swelling behaviour) i.e. the percentage change in original weight loss was evaluated in deionized water at 37°C using cylindrical samples (6mm-height, 6mm-diameter). Results: pores diameter (Fig.1-3) and water absorption (Fig.4) are increased by the presence of fluoride. The presence of sodium fluoride increase the pore diameter of cements immersed in DMEM for 1 day and mainly for 21 days (Fig.2). Porosity is affected by the environmental conditions (higher in DMEM) (Fig.3) and curing time (always reduced with time) (Fig.1). Conclusions: the immersion in simulated body fluid increase the porosity of MTA cements. A correlation between porosity and water absorption exists. Calcium-silicate cements may be fluorine-doped to obtain tailored materials with designed porosity, useful to produce bone grafts or scaffolds.
Macro- and micro-porosity and water absorption of fluoride-doped MTA cements
GANDOLFI, MARIA GIOVANNA;PRATI, CARLO
2010
Abstract
Objectives: to study the porosity and water absorption of experimental fluorinated-MTA (Mineral Trioxide Aggregate) cements. Methods: Experimental calcium-silicate MTA cements (WTC-Ba, FTC-Ba, F10TC-Ba) containing tri- and dicalcium-silicate, tricalcium-aluminate, calcium sulphate, (sodium fluoride only in F-cements) and barium sulphate were prepared. Porosity measurements (total porosity, pore size distribution and pores interconnection) were performed (at 1 and 21 days) on dry cylindrical samples (6mm height; 6mm diameter) in two conditions (relative humidity RH 95±5% or simulated body fluid DMEM, Dulbecco's Modified Eagle Medium). Total porosity was evaluated using the Archimedes principle by Hg immersion of the samples (indirect method). Micro-porosity (<6 nanometers) was derived by BET method trough the N2 adsorption (indirect method) on the entire specific surface area (SSA). Open porosity/pores interconnection (0.003-350 microns) was calculated by MIP (mercury intrusion porosimetry) i.e. differential mercury intrusion volume related to the applied pressure. Water absorption (swelling behaviour) i.e. the percentage change in original weight loss was evaluated in deionized water at 37°C using cylindrical samples (6mm-height, 6mm-diameter). Results: pores diameter (Fig.1-3) and water absorption (Fig.4) are increased by the presence of fluoride. The presence of sodium fluoride increase the pore diameter of cements immersed in DMEM for 1 day and mainly for 21 days (Fig.2). Porosity is affected by the environmental conditions (higher in DMEM) (Fig.3) and curing time (always reduced with time) (Fig.1). Conclusions: the immersion in simulated body fluid increase the porosity of MTA cements. A correlation between porosity and water absorption exists. Calcium-silicate cements may be fluorine-doped to obtain tailored materials with designed porosity, useful to produce bone grafts or scaffolds.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
