How soon after taking an impression should it be poured up to prevent distortion?

The most accurate time frame for pouring up an impression, particularly to prevent distortion, is typically within one hour after the impression has been taken. When an impression is made, the material used can begin to change, particularly if it is a thermoplastic or a material that is affected by moisture and temperature.

If the impression is not poured within this time frame, the likelihood of distortion increases. This is due to various factors, including the material's tendency to absorb moisture from the air, which can alter its shape, or changes in temperature that could affect the impression's dimensional stability.

Pouring the impression promptly ensures that the model captures the detailed anatomy and is vital for the accuracy of any subsequent dental work such as crowns, bridges, or dentures. While some materials may allow for slightly longer times before pouring without significant risk of distortion, sticking to the one-hour guideline helps ensure the best results.