Wednesday, February 22, 2012

Ferrule Effect

Hey all,

First I wanted to address my last blog. I was angry and I might have sounded a bit harsh to corporate dentists. I might have brushed them all in the same stroke.

I thought there were some great comments, here is one:

First, let me say that I think your blog is great dentists both young and old. But I find your latest post a bit disturbing. I have worked for a group practice and private and if you are naive enough to think that over treating is just occurring in the multiple-doctor practices then you are sadly mistaken. I like you agree that far to often than we'd like we see patient coming in for second opinions with what can only be described as "aggressive" treatments. But I feel safe in saying that just because a private practice doesn't have a "CFO" managing daily production doesn't mean that they don't have daily financial goals. I feel it does it disservice to the dental profession to group "all" the dentists that practice a group setting as over treating and just-concerned-about-the-money people. It would be equivalent to saying after one bad experience to McDonalds that "all" McDonalds have bad service. To make a generalized statement about group practices is simply unfair. Again, let me state that I agree with you concern over dentists that over treat. But please be more conscious about generalizing all group practices and consequently all dentists that work in a group practice in the same boat.

I have to say I totally agree with this person. I think over treatment is a common problem, industry-wide, and I don't think all corporate dentists or multi-dentist facilities are bad.

I apologize for my curtness and I appreciate his/her comment. I will be more conscientious about my words. Again, I am sorry for being somewhat of a jerk.

I was doing a bridge on an 88-year-old woman on teeth 5-8. She is frail, but #6 was broken down below the level of the bone and it had to be done. Two days earlier I had done a huge filling on #8. I decided that there was too much filling on this tooth and it wasn't going to last, so I was just going to add it to the bridge. I prepped it with 5 and 7.

While we were making the temp, the filling broke off in the temp. I had to go out and tell the husband that I needed to do a root canal and post and core to fix this tooth. He agreed, so we reappointed and let them go.

Today, I did the root canal and post and core, and then I went to prep the tooth to add it to the bridge. The tooth was basically at gum level. As I was prepping this tooth, I started to think about the ferrule.

I remember talking about this ferrule effect in the first CE course I took right out of dental school with John Kois. John Kim describes it as this:

“This is something that's often confused. The ferrule is the ring of metal that goes along the gingival margin of a crown or a core buildup. It's not a ring of tooth structure. The tooth structure is removed in order to place a ferrule. The theory is that a ferrule will help distribute lateral forces and prevent fracture after you do a post and core.”

I think I remember the ideal is 2mm. Well, I have to be totally honest with you. I have never considered the ferrule. If the tooth has 2mm of good tooth structure, great. If it doesn't, I don't change my treatment one bit. I have never sent anyone for crown lengthening to get a ferrule.

I have never seen anything fail and said, "Damn, I should have sent her for perio surgery," or, "Why are all my post and cores failing?" They just don't fail.

Today, I was prepping and I saw the tooth margin. But I was prepping my core material and this didn’t bother me one bit. There was some tooth that I was prepping, but it surely wasn’t 2mm all the way around. It might have been 2mm in about 25% of the prep.

It is weird. I know the theory. I know what the books say. But I also know that this tooth is going to be okay. I know this patient is 88. I know that they are from Boston (their son is a great patient of mine) and are only here until April. And I know that this is going to add about 10 weeks before I can finalize this (the time doesn't bother me - I was just thinking).

I just did it. I packed my cord. I took my awesome impression and made another awesome temp. And in two weeks, I will cement this crown and not think about it anymore.

And I am writing this thinking, "I wonder if you guys are going to nail me to the wall on this one." You know I try hard to do things right. You know that I care and that I watch my stuff coming back. If anything fails within 5 years, I am doing it again for free. And if any crowns fails before 8 years, I usually do it again for free or for a significantly reduce the fee. But this is not the topic for today.

Do you consider the ferrule effect? Do you stop what you are doing and send someone over for crown lengthening? Do you think less of me? Be easy on me.

Have a great Wednesday.


Anonymous said...

With all due respect- You had a blog about corporate dentists overtreating. And now you write about treatment planning a bridge for a patient who is 88 years old without paying close attention to well documented research on the ferrule effect. If your standards are higher than corporate dentists, then adhere to them. One might view your approach as deliberately taking a chance without a ferrule. What about providing the patient with an option of crown lengthening and if they refuse, then proceed comfortably? Just a thought...

Anonymous said...

Yes John, I do stop and either send the patient for a crown lengthening or to an orthodontist for an extrusion. I have enough seen crowns placed by other practitioners without sufficient sound tooth structure for the crown to attach to believe this is necessary.

Anonymous said...

I appreciate the fact that some dentists have ethics and some do not. However, I really don't think you should shy away from the"corporate culture" that exists in chain dentistry. The reality is these dentists have big brother encouraging them to produce in a manner that does not exist with someone who is a sole proprietorship. Heck even taking too many low paying PPO's may create an environment where the money needs to be made back somehow. Once again, third parties influencing the doctor/patient relationship. I hope you have not shied away from trying to educate the public about corporate greed when it comes to dentistry. They are not in the game to help their fellow man, that should not be news to anyone.

Jenn and Steven said...

I think ferrule is important, but it depends on what tooth we are talking about, what the patient's occlusion is like, etc. etc. The truth of the matter is that in this day and age, if a tooth is going to need crown lengthening, endo, post and core and a crown, it might be more predictable to do an implant -- again, depending on the patient, the tooth and various circumstances. In my own mouth, I would take an implant before I would take endo, post/core, crown lengthening, and a crown.

Anonymous said...

John I am you friend from dental school. But either you have not done enough crown and bridge to see cases fail or you are the greatest or luckiest dentist ever. Without a ferrule and crown lengthening on a case that really needs it there is a 50-75% chance it will fail. The lateral forces and laws of physics always win in the end.

Anonymous said...

A patient is seated in the chair as you sneak into into the op. Regardless of what is on your instrument tray, all your eyes will see is the crown that has come out with the post and core still neatly attached to it. You nervously rifle through the chart to see when it was placed. Once you realize that it is in fact not your crown, then, and only then, do you exchange pleasantries with the patient.

Ferrule effect and "Dry Clean Only" are the only 2 rules that I obey in life. Preop if I don't see ferrule, it gets a crown lengthening at perio. This happens only a handful of times a year as normally you can dig down to get it at prep time. But I've been burned on it and have seen others suffer the same fate when it is overlooked or taken too cavalierly.

Just my $0.02 here but to avoid costly redo's, ferrule effect should be in every successful dentist's mind before and during a crown prep. G in BC

Anonymous said...

You asked for comments but not all comments are published. Yes I do stop and send a pt over to the periodontist for crown lengthening if need. Just leave a temp on.

Kallie said...

I loved reading all the positive feedback to your AGD Impact article! You are setting a great example to younger dentists that not everything needs a crown!


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