What is Fit Checker and why use it?

Most porcelain fused to metal and full metal crowns are still made using the lost wax technique. Probably because of this sometimes castings fit too tight. While wax can easily spring microscopic undercuts, metal castings can't and can cause a crown to bind, prematurely on high spots on a prep.

I can still remember a dental school instructor telling me that crown either fit or don't fit and there is really no point in doing much adjusting internally in order to make them fit. I have found this advice to be often not true, since I routinely and repeatedly apply GC Fit Checker to the inside of my crowns when trying them in.

Fit Checker is a quick setting silicone film that can be applied to the inside of a crown immediately prior to seating it. Once set (60 seconds after mixing), it will show a dentist the film thickness of the material inside a seated crown. Often I find that by abrading small drag marks seen in internal aspect of the crowns, I can get them to seat more fully. A fully seated casting will have a better marginal seal and when using a traditional dental cement, it will have less "wash out" of the cement.

While occasionally my crowns fit without any internal adjustments, most require several applications of Fit Checker and micro abrasions with a slow speed round bur,in order for me to be satisfied with the fit. Although many of my colleagues report no need to  use Fit Checker, I am addicted to it and would be lost without it.

About the author: Lawrence Spindel DDS is a dentist in New York City, who has has maintained  a general and cosmetic dental practice for over thirty years.