When taking a polysulfide impression for a cast crown, why are custom trays generally favored over stock trays, except for which of the following reasons?

Show Answers

Custom trays help ensure even shrinkage of the impression materialUsing custom trays reduces the amount of impression material neededStock trays often lack adequate flange lengthImpressions made with custom trays are simpler to extract from the oral cavity

Explanation

Custom trays offer advantages such as promoting uniform material contraction, requiring less impression material, and providing proper flange extension. However, impressions made with custom trays are not necessarily easier to remove from the mouth compared to those made with stock trays.