Which material is a bioactive calcium silicate liner commonly used after selective caries removal?

• A. MTA.
• B. Zinc oxide eugenol.
• C. Glass ionomer cement.
• D. Calcium hydroxide.

Answer: (A)

Calcium-silicate liners used after selective caries removal aim to promote pulpal healing by releasing calcium ions and forming a durable seal at the dentin interface. The material that fits this description is mineral trioxide aggregate, a calcium silicate cement that sets in moist conditions and is known for its bioactivity. It encourages dentin bridge formation and provides a reliable seal, which is why it’s favored in conservative approaches. Zinc oxide eugenol lacks bioactivity and can interfere with bonding to some restorative materials. Glass ionomer cement is biocompatible and fluoride-releasing but is not a calcium silicate and does not offer the same level of dentinogenic stimulation. Calcium hydroxide is indeed bioactive and promotes dentin formation, but it is not a calcium silicate cement and has different properties and longevity concerns. Thus, MTA best fits the description of a bioactive calcium silicate liner after selective caries removal.