What factor most affects the working time of polysulfide impression materials?

The working time of polysulfide impression materials is most significantly influenced by room temperature. Polysulfide pastes undergo a polymerization reaction that is affected by temperature; as the temperature rises, the curing process accelerates, leading to a shorter working time. Conversely, lower temperatures slow down the chemical reaction, extending the working time available for the clinician to manipulate the material before it sets.

Humidity levels may have some impact on the overall performance and setting characteristics of impression materials, but the direct and most substantial influence comes from temperature. The type of tray used and the thickness of the material applied can also affect the impression-taking process, but they do not primarily dictate the working time. Thus, understanding the significance of temperature in the context of polysulfide materials is crucial for clinical practice.