So I tried a new bonding agent last week. One of the Scottsdale Center employees broke a 12-year-old porcelain onlay. What better place to use the CEREC! We numbed him up and prepped the remaining tooth structure away for a conservative onlay prep.

Once I imaged with the CEREC and designed with the 4.0 software, we milled out the molar only with e.max, my go-to material for all molars. Once it came time to bond, we decided to use XTR from Kerr; in fact the cerecdoctors.com mentors all got a sample of XTR and NX3 and are involved in a little internal study to test it out.

Here is what Kerr says about XTR: It's a self-etching bonding agent with bond strengths in the 30-50 mpa range (depending on what study you look at). The interesting thing is that Kerr claims that XTR does not lead to sensitivity. Being an avid fan of Gluma, I decided to see if this was, in fact, the case. XTR seals the tubules (similar to Gluma) and helps combat post-operative sensitivity.

So we followed the protocol: Brush the primer, air dry, brush the adhesive, air dry, apply cement and seat restoration. Cleanup with the NX3 cement was easy and the restoration was bonded in place. The true test came a few days later when I saw the patient for follow up. How was the sensitivity? None, he stated. None whatsoever.

It's one patient but I think it was a good indication that XTR might work as advertised. I'll have to use it more and see what the result is with other patients but so far it's performed nicely in the cementation of an onlay.

i alreay use xtr since june 2011. I only use the sample. Not the bottle because the sample, we always have the same concentration without evaporation. The post operative sensitivity with that products doesnot exist. I have absolute no sensitiivity with that product. I change all the old composite, cerec onlay, cerec inlay, crown that other dentist made and my own mine because, yes i got a lot of sensitivity in the past, and after i change it and used xtr, there is anymore sensitivity. This products is amazing!!!!!! I realy recommand it to every dentist with sensitivity products. We test the bonds strengths and we got 28 MPa on the dentin.