A common misinterpretation by dentists that do not do all-ceramic restorations – or even CEREC for that matter – is how the restorations look on bitewing X-rays.

The first image shows a white "bar" at the interproximal, which is often times interpreted as a margin that is filled in with the resin cement or an open margin. 

But taking the X-ray from varying angles reveals a completely different story.

These images are self-explanatory; however, for those who are used to metal margins, which generally hide a great deal of information due to overlap, the following concise narrative properly depicts the situation.

The ceramic material is radiolucent, while the cement is opaque. When an image is taken that bisects the margin at a 90-degree angle, the overlap of the opaque material gives the illusion that there is an open margin filled with resin material.

I have this discussion with my Periodontist all the time. He calls and says "I think you need to redo this crown/onlay before the cement washes out.

Send him this link!