What material is typically used to prevent the irritation of the pulp when using IRM?

Calcium hydroxide is commonly used to prevent pulp irritation when using Intermediate Restorative Material (IRM). It is a material known for its alkaline properties, which helps to neutralize acids and provides a soothing effect on the pulp tissue. When applied as a lining under restorative materials, calcium hydroxide serves as a protective barrier that can encourage healing and reduce sensitivity in the dental pulp after procedures like cavity preparation.

The effectiveness of calcium hydroxide is largely due to its ability to stimulate the production of secondary dentin, which further protects the pulp and aids in the repair process. This property is essential in dental procedures where there is a risk of pulp exposure or irritation, making calcium hydroxide the ideal choice in this context.

Other materials listed, such as sodium fluoride, alcohol-based primers, and composite resins, serve different functions in dental treatments but do not have the specific pulp-protective characteristics that calcium hydroxide possesses when used with IRM. Sodium fluoride is typically used for its anticariogenic properties; alcohol-based primers are intended for bonding purposes; and composite resin is primarily a restorative material, not a pulp-protective layer.