What is a potential issue with zinc oxide impression material?

Zinc oxide impression material can indeed cause irritation to the mucosa, which is a potential issue when using this material in dental procedures. This irritation may arise due to the powdery nature of zinc oxide, which can be abrasive and irritating when it comes into contact with sensitive oral tissues. Additionally, some individuals may have allergic reactions to components in the material, further contributing to mucosal discomfort.

The other options describe characteristics that do not accurately reflect issues commonly associated with zinc oxide impression material. It is not classified as a thermoplastic material, nor does it typically cause excessive bleeding, which is more associated with other types of dental procedures or materials. The setting time of zinc oxide impression material is generally controlled and not classified as "quick," allowing for a more manageable working time for clinicians. Thus, the issue of mucosal irritation stands out as a key concern with this material.