What Went Wrong In Onlay Cementation?
July 9, 2016 at 1:29 am #5034
Pt had large amalgam and fractured the disto lingual cusp on 19. I did an onlay prep preserving the buccal and mesial unaffected tooth structure. Onlay was cemented and a month later, when patient returned I was horrified to see darkness on the mesial of the tooth, not at the margin but from within. The emax onlay fit well so something went wrong in the cementation. This is what we did.
Tooth surface after prep:
SE Protect and SE Bond
Then Scan and design
After trying in:
HF etch 20 sec
Rinse and dry
Monobond 60 sec. Air dry
Rinse surface of prep
Rely X unicem2
Full cure light and wait 5min
Remove packing cord after cleaning up cement.
Any ideas as to what could have happened?
Any thoughts would be much appreciated.July 9, 2016 at 12:51 pm #10170
Did you use a hemostatic agent? You’ll see this with the ferrous containing agents. Stick with the alumina agents like viscostat clear of traxident.July 9, 2016 at 3:24 pm #10171
might as well use bubble gum, Unicem 2 is not successful for onlays. Also dark from within is probably from ferric sulfate like mike said.July 9, 2016 at 8:02 pm #10172
Yep, unicem has about the same brand strength as RMGI. Sounds like your protocol is maybe it bit too complicated too. My current protocol:
Clean and boost 10 second scrub (apex dental, prep cleaner, removes oils and debris)
Etch 15 sec
Adhese, scrub the prep 20 seconds, air thin, cure
Variolink esthetic, flash cure 1 second 4 corners of the restoration, peel the excess off, floss, and cure
Same treatment of the restoration as the poster.
I get the idea of sealing the dentin, but for a one visit restoration I don’t think you get much benefit for all the effort. Plus more things that could go sideways. Anecdotally I see almost zero post op endo issues since going to same day 7 years ago. A couple of weeks with a leaky temp, sure the IDS is a good thing. An hour or so of dentin exposure, especially if you clean the prep and bond doesn’t seem to be an issue at all.
Bonding is one of the toughest bits of the learning curve!July 9, 2016 at 9:56 pm #10173
You are right about all the steps, time consuming and eventually frustrating since I didn’t get the optimal result.
Definitely sounds like the viscostat and cord caused the shadowing.
Does the shadowing mean the bond is compromised and I should replace the onlay or is it an esthetic issue?
Thanks for sharing your protocol,
Variolink esthetic for all restoratios? inlay, only full crown?July 9, 2016 at 10:14 pm #10174
Always best to keep things simple and predictable imho. Cord is fine, I always use a double cord technique, leave the primary cord in until I cement, helps prevent any cement from going sub-g. Just avoid any ferrous agents on the cord. Yes I’d replace the restoration, the bond is compromised and it’ll probably leak. I do use Variolink now for everything, crowns to veneers. Really nice resin cement, easy to clean up.July 10, 2016 at 4:28 am #10175
We use Unicem II for all our full coverage restorations, but not in combination with IDS, and not with partial coverage restorations. I consider it a strong cement but not a bond. (i.e. I need mechanical/geometric retention) While it does lack the high bond strength of a tradition resin cement, it has fantastic fatigue management which in my opinion is a valid consideration when choosing a luting/bonding agent. Our protocol is to use air-abrasion immediately before cementing, to homogenize the dentin and remove any contaminates from hemostatics- especially when we use those that contain iron.
I did IDS for several years, but have since switched to air-abrasion, followed by a SE system at the time of seating, (single visit) which is much simpler and seems to have the same benefits of bonding to fresh dentin. I’ve seen the dark grey under restorations too and it sucks, but so far I don’t think we’ve had a restoration grey out from ferric sulfate with Unicem after air-abrading.
I’m a little confused where you saw the grey. Did you do a 19DOL onlay and see grey between the occlusal portion of the onlay and the medial-occlual portion of the tooth?July 11, 2016 at 8:06 pm #10176
Dr. Martin I love that you use air-abrasion. It’s not for me but it is very good. I bet your success with Unicem, and your lack of dark staining from ferric sulfate is due to your use of air-abrasion which both cleans and creates a high energy rough surface in which the unicem can bond. It is not really fair to compare unicem with air-abrasion to just unicem alone as the air-abrasion step is creating addition micromecahnical adhesion. Unicem alone does little to create a durable bond to dentin. If you are doing traditional preparations with retention and resistance form and have thick ceramic it does not matter, you can use bubble gum. However, If you are doing a lot of occlusal veneers, onlays and crown lays Unicem will be the death of your practice. I need a bond that is going to last, a tenacious bond. For the past 7 years I have been using Optibond XTR/NX3 , many other systems exist. I also like Variolink esthetic with Adhese Universal.July 12, 2016 at 1:30 am #10177
I used Optibond Fl for years (IDS) and wanted to like XTR but it was too smelly. (I get dizzy after 2 beers) We had a $200 Danville Prep-Start for the occasional ‘no drill’ sealants, but it wasnt until we plumbed the restorative ops with $2200 Prepstart units, that it made air-abrasion doable at every bonding instance. The Prepstart allows very controlled delivery without filling the pt’s mouth with sand. (They are hooked to the foot petal and we have a activation switch on our delivery unit.) Mechanically removing the smear layer, in conjunction with a SE adhesive (Bisco), allowed my total-etch brain to make the jump to selective etch. For partial coverage, we use 27 micron/40psi AlO2, 15s 37% enamel etch, Bisco SE, and warm Z-100 composite. I like the composite for 1-2 units, but is is a hassle with larger cases, then it’s 3M veneer. I did like the one tube on NX3 I tried…
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