Which occurs when an alginate impression is stored in water or a very wet paper towel?

When an alginate impression is stored in water or a very wet paper towel, imbibition occurs. This is the process where hydrophilic materials like alginate absorb water, leading to an increase in size due to the influx of moisture. Alginate impressions are made from a hydrocolloid material that can readily take up water, which can alter their dimensions and potentially affect the quality of any subsequent casts or models made from these impressions.

In the context of dental practices, understanding imbibition is crucial for managing the handling and storage of impressions. If alginate impressions absorb too much water, they may distort, which can compromise the accuracy of the dental models produced from them, leading to potential issues in fitting dental appliances or restorations.

The other terms do not apply to the scenario described. Syneresis refers to the expulsion of water from a gel, typically resulting in shrinkage. Hydrocolloid is a general term for substances that can form a gel with water, but it doesn’t describe the specific reaction to being stored in water. Polymerization refers to a chemical process that transforms monomers into a polymer, which is not relevant to the wet storage of alginate impressions. Thus, imbibition is the correct term for the