PMMA Open Margin Problem

[bdental2013]

Using PMMA in a preliminary impression to make a temporary crown on tooth 30, I find that due to the small amount of shrinkage I often have to add to the margin and then trim. This can be time consuming. Any advice out there on how to get the margin right the first time, or speed up the remarginating?

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[sgv]

What are you using for the impression material? I like to use a triple tray with impression material. Your problem might also be poor impression capture of the anatomy or subgingival margins in your crown prep. If the PMMA isn't adhering to the crown, I would reduce the problematic portion of the margin with a bur to add bulk and then bead a drop of PMMA onto the margin before the crown is seated. I make sure that there's a little excess bulging out before I take an explorer, positioned parallel to the long axis of the tooth, and ride along the interface between root and crown.

 

[bdental2013]

Using a putty matrix for the impression. I'll try adding the drop of PMMA and using an explorer to scrape the excess, thanks for the tip!