What can I say about bond failure under porcelain veneers? That it is aggravating to both patient and dentist? Of course.
That it’s the last thing the dentist wants to accept and believe? That too.
That sensitivity could go away in time? Well, that depends upon the kind of sensitivity. Painful sensitivity to cold that goes away in seconds may be short lived and could be expected to improve on its own in a few days to a week or so.
Sensitivity to biting pressure? That’s worth a careful look at occlusion, but if the restorations aren’t exposed to excessive occlusal pressure upon normal closing or in excursive movements, then it it’s time to consider something more troublesome.
A dentist who had placed six upper anterior veneers referred her patient to me to evaluate TMJ health and occlusion because her patient had persistent pain and sensitivity in all six of those teeth.
The dentist stated that the veneers were done to replace six veneers that had been done 14 years before and that some of those older veneers had marginal leakage that resulted in caries under those restorations—a couple of them quite deep.
The dentist stated that after the caries were removed she placed a glass ionomer liner in the deepest areas. Then acrylic provisional veneers were placed.
The patient complained of pressure sensitivity while the temporaries were in place, but the dentist felt that the sensitivity would be relieved when bonding the final porcelain veneers.
It was not. The dentist adjusted the bite on the veneers over several appointments hoping to relieve the pain. After a few weeks she referred her patient to an endodontist and also to a prosthodontist.
The endodontist found that the pulps responded normally to testing and therefore he did not recommend endodontic therapy.
The prosthodontist’s opinion was that there was a failure of the dentin bond and that the veneers should be removed, the dentin etched, desensitized with Gluma, sealed, temporaries placed and new veneers done.
(Do not pass GO; pay $200.)
Well, instead of doing that, the dentist referred to me for occlusal analysis and TMJ exam. She even sent me nice face-bow mounted models.
Indeed there are occlusal issues including lack of canine guidance, major working side interferences on both sides, and an overall unbalanced occlusion with much harder occlusal force on the right vs. the left side posterior teeth.
(I could quibble about even placing final veneers on anterior teeth when the posterior occlusion is so obviously compromised, but for our purposes today, let’s let that be. I do wonder though: what would John Kois do?)
However, there was occlusal contact on only one of the veneers–the right canine–in C.O., and no contact on any of the anterior teeth in right and left function.
So occlusion appears to play no role in the sensitivity.
TMJs appear normal on joint imaging and there is smooth joint function and full normal range of motion.
I did not see models of the preparations, although that may not have been terribly instructive. I have to agree with the prosthodontist on this one: I think there is a failure of the bonding procedure especially as it regards dentin bonding.
Perhaps the father of adhesion dentistry in the United States, Ray Bertolotti, could comment on the possible reasons for that failure better than I can but I didn’t call Dr. Bertolotti for comment, so here’s my 2 cents.
Deep caries under the previous veneers, nearly resulting in pulp exposures according to the dentist, is certainly a reason for caution. Was the dentin sealed with excellent moisture control particularly at the margins? Many experts recommend using retraction cord at this stage. Some authorities still advise the use of rubber dam for bonding and sealing but with newer materials that step is called for less often. Still, I do wonder about those very deep carious lesions. How well were they sealed? Was there possibly contamination with saliva or even fluid from the gingival sulcus?
I found all six of the veneered teeth to be so sensitive that even light finger pressure on the facial surface of any of them created quite a bit of pain.
According to Pascal Magne, PhD, DMD, chair of the department of esthetic dentistry at the University of Southern California, a partial (I take that to mean incomplete) bonding of the dentin will result in sensitivity or total failure of the bond. He recommends etching and sealing the freshly cut dentin surface before temporization, indeed even before impressions. Failure to do so could compromise the success of bonding when it comes time to place the final veneers.
I talked with an endodontist about this particular case and he stated that he sees sensitivity caused by faulty bonding procedures more often than one would think. Patients referred to him for root canal treatment are happy not to need endodontic therapy, but the referring dentist still needs to re-do the bonded restorations. The endodontist recommended removal of veneers from the two most sensitive teeth, desensitizing and sealing of dentin, followed with new temporaries. If the sensitivity does not go away at that stage, then root canal treatment will probably be needed.
“Veneer treatments frequently fail because of certain protocols (steps) not being followed or the allotted time frames for completing each step shortened.” ~ Dr. Ira Koeppel
Total etch bonding has been around a long time. Back in the early-to-mid eighties, when the concept was just gaining acceptance, Dr. Gordon Christianson was asked, “What’s the best material for dentin bonding?” And he answered, “A one-half round bur!”
We quickly came a long way from those old days, and bonding procedures continue to be simplified and improved. We’re now up to generation 7 with self etching primers but that is fodder for considerable debate in dentistry with many still preferring a total etch three-bottle system for bonding veneers. And yet some of the old precautions must still be observed. Careful cleansing, desensitizing, and reasonable moisture control are all still critical.
I spoke with the patient a week or so after I saw her to find out if the dentist had arranged to see her to discuss re-doing the veneers. She said that had not happened yet. I urged her to stay in touch. I would like to know that her problem is being handled.
That night I had the strangest dream. In the dream, the patient was in my office, seated in my dental chair. A good friend and dental colleague was with me and we were looking at her veneers together, discussing her case. Suddenly, all six anterior teeth morphed, as if in a Salvadore Dali painting, into a loudly crying baby with a soiled diaper. I undid the safety pins, removed the messy diaper and started cleaning up the baby’s bottom with some kind of disinfecting hypoallergenic baby wipes. The baby calmed down and smiled, apparently quite happy.
Gee whiz! I wonder what that dream could mean?