Which dental material is most irritating to the pulp?

Zinc phosphate cement is considered the most irritating to the pulp among the options listed. This is primarily due to its acidic nature at the time of mixing. The acidity can lead to pulpal irritation if the cement comes into direct contact with the dental pulp or if there is insufficient insulating material or barrier between the cement and the pulp tissue.

Additionally, zinc phosphate cement has a lower pH than many other dental materials, which contributes to its potential to cause pulp sensitivity and irritation. In restorative dentistry, careful handling and application are essential when using this material to minimize any adverse reactions.

In contrast, materials such as glass ionomer and calcium hydroxide are often used for their biocompatibility and the ability to promote healing of the dental pulp. Zinc oxide eugenol also has soothing properties and is used in various applications for its palliative effects on the pulp. Thus, the characteristics of zinc phosphate cement clearly distinguish it as the most likely to cause irritation.