One of the challenges with onlay preparations is dealing with undercuts. Â Our choices are to either prep away the undercut, leave the undercut and allow the lab or CEREC to block it out, or to manually block out the undercut at time of preparation.
Early in my career I chose the path of letting the lab do it.  This worked most of the time but sometimes didn’t work.  This lack of predictability led me to simply prep away the undercut.  This over preparation went against the point of onlays – being conservative.
Today I am blocking out the undercuts at the time of preparation. Â This can serve several purposes. Â First and foremost it allows me to maintain being conservative. Â Secondly, it allows me to choose a restorative material to protect and support the tooth.
Specifically, I am referring to using a biologically active restorative material for deep preparations.
This patient came to our office for an only on tooth #3. Â As you can see after removal of the alloy restoration there was recurrent decay.
In this case the decay is removed and care is taken to not widen the preparation form.
Now a biologically active restorative material (Calcimol – VOCO Dental) is placed to insulate the pulp and block out the undercut.
The preparation is then completed.
Whether working with a lab or using CEREC – this is a great technique to be conservative and help prevent a adverse pulpal response.
Hope you enjoy!
