What is the safest way to clean up the cement found inside a porcelain crown?

This question was submitted by a general dentist: A patient comes in with a full porcelain crown which has come off. The tooth is sound and there is resin cement inside the crown. What’s the safest way to clean up the cement from inside that crown?

Dr. Alan Kilistoff, from the  University of Alberta, provided the following initial response in an interview recorded with Dr. John. O’Keefe. A summary of the interview is provided followed by the complete audio interview (7 minutes)

• Historically, the safest way would have been to sandblast out the interior of the crown; however, this is not feasible anymore due to increasing concerns about infection control. 
• Using a new sharp round bur (perhaps #8) with slow speed, you should be able to remove the cement. 
• However, there is a need to know why the crown fell off in the first place and if there is a fracture or a start of a fracture in the crown in which case it is likely to fail again soon after re-cementation?

Is it necessary to remove all the cement? 

• Yes for bonding purposes. 
• Cement residue might inhibit the flow of new cement which is necessary to ensure that the new material occupies the whole space between the crown and the remaining tooth structure.

Any particular concerns when using the bur to remove the residual cement? 

• You have to be careful not to concentrate forces and break the porcelain crown. 

Do you have any particular question on this topic? Do you have any comments or suggestions? Email us at oasisdiscussions@cda-adc.ca

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