Since we are also supposed to be treating teeth, I thought that there would be an interest in the changes going on with regards to periodontics and restorative dentistry and how this might be changing in small but important ways the methodology of the blending of these two important day to day concepts. For the benefit of our patients.

I realize that there is mostly comments on this journal regarding implants, but implants are only one part of the process. Unless a patient is completely edentulous, there are teeth in the mouth as well as placed implants. One of the complaints from general dentists to periodontists is that the focus has changed from saving teeth to removal and placing implants.

With this in mind, I think it is important to remain interested primarily in sound periodontal concepts and particularly, perio/restorative concepts for without this in the front of our brains, our patients will suffer the consequences. "Advanced Clinical Dentistry" means just that, and implants are only one small part. Periodontal Prosthesis is in my mind, what was developed at University of Pennsylvania by Dr. Morton Amsterdam, et.al., and subsequent "sister" schools at Boston and Seattle. But these principals are very important to be used whenever needed whether it be one tooth or the whole mouth. This is what we now call "Interdisciplinary Dentistry" or similar titles. Really, what this means is to complete a complete diagnosis and treat the identified condition using all aspects of dentistry required for the most effective and long term result.

So, with the techniques present that allow bonding to dentin with a degree that will survive fracture tests such as mentioned in the first post, the need for retention form in preparation is not important like it used to be. No 2mm ferrule needed, and full coverage crowns no longer NEED to be included in treatment planning for retention (one may choose them for other necessary reasons, but not for retention). This changes the way we see designs of crown lengthening surgery (CLS).

No 2mm ferrule, no need for 5mm of tooth structure above the bone. No cement (bonding instead) so no wash out of cement, no 50 micron gap, no microenvironment for bacteria, so does the effect on biologic width change? Well, since most of the studies on BW violation focus on bacterial invasion secondary to this inherent gap, then the negative effect on BW is reduced if the bonding is sound.

With the lack of need for the 2mm ferrule and therefore less ostectomy needed in the CLS procedure, the less it needs to ramp to adjacent teeth and therefore the less CLS effects the adjacent teeth and the more focused on the local area one can be. Now, if you include the concepts in platform switching to teeth, you can minimize the CLS area of inclusion even more... since BW is not a vertical measurement.

Interesting, huh? So lets not forget about what we are really supposed to be about to our patients: A saviour of teeth, so to speak.

Any comments? I would sure welcome some if any are interested. Food for thought anyway!

Hey Arroyodds... finally someone responds! Thanks!..

As for the crown lengthening, I was not indicating the lack of need for CLS, I was positioning a question regarding how a bonded restoration, bonded completely, might change the thinking a little given that this type of margin interface between a restoration and the tooth. Let us say it is completely sealed. No marginal gap for bacterial invasion, etc. Since the majority of studies regarding BW invasion and inflammation focus on the bacteria being the main etiology and this type of a margin would not encourage that, might this also make a difference in tissue response? I know of no study that had focused on this factor. I will say that 99% of the time I provide CLS. However, I have over the last year, on several geriatric patients, placed margins near the bone with no CLS. Interesting, up to 1 year later, there is no inflammation or pain or bleeding with probing. I can always go back and provide the CLS if needed, but I have found this very interesting. I do not promote this, but it is food for thought. We have done this with Geristore in the past with success. I have even provided tissue grafts over these on rare occasions with success as well and not probable beyond normal.

As for the restorative materials, this is open for discussion, but I use the Immediate Dentin Sealing (IDS) technique using Optibond FL (see studies by Pascal Magne, et.al). In experimental studies, in 185,000 cycles of artificial chewing on endodontically treated teeth restored with no posts and evaluating all the usual porcelains including Emax and MZ100 blocks, 100% of the porcelains failed, including Emax. NONE of the failures were at the bond to the dentin, ALL of them broke the tooth, not the bond to the dentin. This is very significant. Even more surprising, 75% of the MZ100 blocks survived without fracture. This is also very significant. All of these restorations including the porcelain were luted with warm Z100 composite.

I do not like the usual composite cements.. too much resin, too little filler. They, in my experience, ALWAYS wash out at the occlusal margins and look terrible later on. These cements are also not as homogenous with color of the tooth as Z100 is. The Z100 do not wash out and keep their marginal integrity. If you are looking for long term restorations on a par with gold over many years, it seems it would be best to use what is shown to be the strongest in all aspects. Emax, of which I do a lot due to insurance considerations, is not as strong as the MZ100 blocks. The technique with these type of restorations can also look more like a tooth than the porcelains can if done with this in mind. They can be so tooth like, you can hardly tell that it is a restoration.

The IDS technique is very "technique sensitive". According to research by Pascal, the highest bond strength to dentin was achieved in the middle 90s and the materials since then have been going down in strength. Not that success cannot be achieved with these materials but they are NOT nearly as strong as the IDS method according the studies done by Magne. I have never seen a restoration cemented with the common resin (composite) cements that were not washed out at the occlusal margins a year or two (or less).

While there seems to be a very high success rate with Emax material, the research shows that this material is not as supportive under stress than ZM100 is. Will this make a difference over a long period of time? Well, the research seems to indicate that this would be the case. We do not have the long term evaluations on these materials so the stronger should be better I would think. Certainly in the dentin bond. There are those that say that you can't bond to dentin. This is clearly not true. But the technique for the strongest is sensitive and has a learning curve, takes a bit more time, but for my patients it is worth it. I hate failures!

Comments?

Thanks for the info Richard. I have not been to this meeting, so I looked up the info. Found quite a few Google responses for "AAIP"

Here is the website for the meeting:
http://aaipusa.com/Meetings.php

Looks pretty good. Not sure if I can make it to this year's meeting as my patient schedule is alreay full for that week. However, now that I know about the meeting, perhaps I can make it next year.

Thanks again!