What is the appropriate action when taking an impression with irreversible hydrocolloid?

Using the largest tray that fits comfortably is essential when taking an impression with irreversible hydrocolloid. This choice allows for proper coverage of all relevant areas of the dental arch, which is particularly important for capturing accurate detail, especially when working with impressions for full or partial dentures, or for orthodontic study models.

A larger tray helps accommodate the full arch and provides an even distribution of the material, ensuring that there is adequate space for the hydrocolloid to flow and capture the fine details of the teeth and surrounding structures. This reduces the risk of undercuts and ensures a complete impression.

Selecting a tight-fitting tray with a thin layer of material or ensuring the teeth are clean and thoroughly dry may not facilitate the best outcome. While cleanliness is indeed important, irreversible hydrocolloid performs better with a moist environment as it can help to minimize air entrapment and improve the accuracy of the impression. Additionally, removing the tray shortly after gelation can lead to distortion and inaccuracies, as the material needs adequate time to set fully to capture the desired detail.