The constitution, physical properties and biocompatibility of modified accelerated cement

Objectives. The aim of this study was to determine constitution and physical properties of a prototype material based on Portland cement and assess biocompatibility compared with glass-ionomer cement by evaluating cell morphology. Materials and methods. Analysis of the material was performed using energy dispersive analysis (EDAX) and X-ray diffraction (XRD) analysis. Compressive strength and the effect of changing the mixing and curing conditions on the compressive strength of the materials were evaluated. Dimensional stability was evaluated by measuring water uptake of the materials. Biocompatibility was assessed at I and 28 days using a cell-culture technique and semi-quantitative cell morphological evaluation was performed by SEM. Results. Analysis of the material showed that it was primarily composed of tricalcium silicate and dicalcium silicate. The compressive strength of the prototype cement and variants was comparable to Ketac Molar (47.98 N mm(-2) after 1 day, P > 0.05). Vacuum mixing did not improve the compressive strength of the prototype cements at any age. Wet curing was detrimental to the neat cement at 1 day (35.98 N mm(-2), P = 0.011) and 7 days (44.08 N mm(-2), P = 0.025). The filler-replaced cement prototypes were more stable and less susceptible to changes in compressive strength by varying the curing method (P > 0.05). The prototype material took up more water (0.9%) than glass-ionomer cement (1.7%) with P=0 after 1 day. Curing at 100% humidity resulted in a net loss of weight for all the materials tested. The test materials were less biocompatible than glass-ionomer cement at 1 day but their biocompatibility improved as the material aged. Conclusions. The constitution of the prototype material was broadly similar to that of mineral trioxide aggregate. The prototype cement could be a potential dental restorative material as its compressive strength compared well to an established restorative material. However, the material did not support cell growth, with biocompatibility being similar to that of glass-ionomer cement. (C) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved