Systematic analysis of mineral trioxide aggregate using a model cement system

Mineral trioxide aggregate (MTA) is a Portland cement-based material in use in dentistry for over 20 years. Although originally developed as a root canal reparative material, multiple applications have since been found for the cement. Commercial MTA is expensive, and for research, its composition cannot be changed/modified. This investigation endeavored to create and validate an affordable MTA model cement system for future research into the material, and use the model created to analyse the cement with view to further understanding it and improving its properties. An MTA-like model system was established and setting times, compressive strength, relative porosity, apparent and specific densities and radiopacity were measures used to assess cement samples made. Sample storage time, composition, alternative radiopacifiers, material consistency and handling, and the effect of powder-to-liquid ratio (PLR) were all investigated, utilising the model system. 5 wt% Plaster of Paris content was found to provide optimal material characteristics, with Bi2O3 the most effective radiopacifier, requiring a minimum proportion of 20 wt% for adequate radiopacity to meet the required standard. A higher PLR (4.0 – 4.5 g/ml) than recommended for commercial MTA was found to be best for cement workability and material properties, including radiopacity