Clinical Tips 5: Vonlay after RCT

Posterior teeth that received a root canal therapy will need a cuspal coverage restoration to prevent them from being fractured. The biting forces we distribute on our teeth are so strong, we need to ensure that those forces are directed down the entire root of the tooth – not just one part – after a root canal. This is also true for teeth that are already fractured, better force distribution helps to ensure a long lasting tooth! A cuspal coverage restoration means we cover up the cusps – and they come in two forms. Onlays, and crowns. Crowns are more typical, onlays are a great way to save remaining tooth structure. The old joke is that you ‘only get so many crown preps out of a tooth’ and by doing an onlay, we have saved some crowns for the future!

We start with a rubber dam here, to protect the cheeks and tongue from the handpiece and to ensure if we use any sort of bond or adhesives, they stay dry for ideal bond strengths.

Next, we prep the occlusal of the tooth for the onlay. We make sure we have smooth tooth structure, and sufficient reduction to have enough room for our ceramic to be nice and strong.

Next, we prep the buccal, or cheek facing surface, for the veneer portion of our restoration. We are careful to only take down as much tooth structure as is necessary for esthetics.

After we scan, design, and mill the restoration using our CEREC technology (more on that later) we then have to prepare the restoration for bonding. We do that with HF acid, and it results in a nice frosty appearance of the ceramic. That means its ready for bonding to our resin cement.

Next, we try in the restoration. Looks great!!

Finally, we bond the restoration in with a resin cement. The resin bonds tightly to the tooth, then tightly to the ceramic for a permanent bond! The ceramic gets its strength from the tooth, and the tooth gets its strength from the ceramic. It is a match meant to be! The resin cement we use is Panavia V5 SA, which is self priming and self etching and very easy to use and clean up! We then clean up the excess, polish the finish lines, and fully cure the cement. Looking great! This tooth should be protected against fractures, and still has ‘life’ left in it in the event it needs a crown in the future!