What effect does oil or water have on impressions for treatment casts?

Using oil or water on impressions for treatment casts typically decreases the quality of the final cast. This is primarily because the presence of oil or an excessive amount of water can interfere with the set of the impression material or the material used to create the cast.

When oil is introduced, it acts as a barrier that can prevent impression materials from adhering properly. This can lead to incomplete or inaccurate impressions, ultimately compromising the precision of the treatment cast. Similarly, while water can be an essential component in the mixing of some impression materials, too much water can dilute the material. This dilution can reduce the viscosity and strength of the impression, leading to distortions and inaccuracies in the final cast.

In contrast, maintaining a clean, dry environment during the impression process is essential for achieving high-quality casts. This ensures proper detail capture and adherence, which are crucial for creating effective treatment casts that fit well and function as intended.