Cerec has played a huge role in my dental career of 11 years. Over the years not only has cerec made me a better dentist but has also made me a more conservative dentist. Because of the ease of same day dentistry I can practice a wide range of conservative indirect restorations on posterior teeth like inlays and Onlays without the hassle of having to predictably temporize them.
However I feel one kind of preparation is underutilized by most Cerec dentists. I call that kind of preparation a Crownlay. I define a crownlay as a preparation that has complete cuspal reduction with margins being high and dry and in most cases above the height of contour. This kind of a preparation can be utilized in most cases where large failing restorations like composite and amalgam are being restored. Most dentists prepare such teeth for complete coverage crowns and there is nothing wrong in doing so. However with the CADCAM technology available today where we can cement our restorations same day we don’t have to worry about temporization which could be extremely difficult and unpredictable for non retentive restorations.
So what I do is remove old restorative material , preserve as much enamel as possible and keep the margins high and dry. I find such margins are easy to scan and marginate.
Also keeping the margins high and dry and on enamel helps with better bond strength. Supra gingival margins long term helps in maintaining better gingival health compared to sub gingival margins. By using high transluceny ( HT) blocks one can easily camouflage the margins and make them disappear when bonded to margins that are supra gingival.
So to sum it up here are the benefits of crownlays over crowns:
More conservative Preps.
Easier to scan and marginate.
Better bond strengths.
Healthier gingiva long term.

If you haven’t utilized Crownlays for your patients give it a try. It makes for a more conservative and longer lasting restoration for your patients.
Keep Cerecing.

Pre- Op image of failing amalgam restoration

Crownlay Prep focused on conserving enamel

Crownlay bonded in place

Crownlay on #20. The margins are above the height of contour. Cerasmart HT block used here.

6 year Recall on #31 Crownlay. Vita Mark 2 used here.