Hi everybody! It’s my pleasure to welcome you to the last meeting of Bionic Man & Woman and also a great pleasure to introduce Dr. Arun Sharma who has been here with you in the UC School of Dentistry for a number of years. He wears an amazing number of hats. He serves as professor of prosthodontics. He’s the director of the prosthetic clinic. He also participates in the faculty practice. He serves as the prosthodontist for the craniofacial anomalies clinics serving children with malformed features on their faces and heads. He also is the current editor of the Journal of Pediatric Dentistry. I think that’s about it, but it’s an awful lot. Please join me in welcoming Dr. Sharma who is going to talk to us about implants.
Arun Sharma:
Thank you! What I’m going to be talking to you about is and I think I did this talk about five years ago. One of the gentlemen here reminded me, and I think it was about 2003. His question was, “What has changed since then?”, and fortunately, not too much. The good side of that is obviously what we have been doing has been pretty successful, and that’s what I’m going to share with you today and talk about a few things about where change is coming in how we accomplished some of the outcomes.
So, the topic that I’m going to talk about is replacing teeth, obviously, and what we are interested in using is titanium. It’s really important that we understand the difference between how teeth and titanium, though the objective of every patient is to actually have this tooth they’re going to chew with. It’s how this is anchored or connected to the underlying bone. It’s very different, and as we talk about it, I’ll show you how they differ and what we have to do in order to make up for that difference between teeth and implants.
If you look at an X-ray of a natural tooth and an X-ray of a dental implant, you can see it’s different. It’s really screw that’s made out of titanium placed in the jawbone, and then we connect a tooth to it which is what we would call a prosthesis.
What I want to try to do is, in the next hour or so, cover a few topics related to this. I’m going to talk about what happens when we lose teeth, what are its implications in terms of quality of life. Implants, what are the benefits of these implants? How do they benefit us? We’re going to talk about this word, osseointegration, which is really what has made implant dentistry predictable.
Implants were things that have been tried by people for thousands of years. If you go back to the Mayan culture, you will find they had bovine teeth that were removed and placed in human jaws, wired to adjacent teeth. The Egyptians had done same sorts of things. They’ve taken ivory, and they carved them into shapes of teeth. They were all ways of trying to replace teeth in a way, but none of them lasted a long enough period of time in how osseointegration has really brought about that change to where it’s predictable which is what we’re looking for.
I’m going share with you clinical applications, the type of patient scenarios that we actually use these implants in, and the benefits that we have with them. I’m also going to talk about failure because it’s not 100% successful, and we need to understand that. We need to understand why things fail and what happens when they do fail. These are the five basic areas that I’m going to cover.
Let’s talk about teeth. What happens when we lose teeth? These are typical examples of patients who show up in dental offices, and they are sometimes referred to as the dental cripple because they have lost all of their teeth in the upper jaw and they have just two teeth remaining in the lower jaw. They’ve got what is a prosthesis or a denture or plate that is sitting on the gums, and really that is not a very effective means of replacing the masticatory apparatus that all of us have.
When you have a denture that sits on gums, you’re taking soft tissue that’s going to be squished between two hard surfaces, between the bone on one side and the hard material that the dentures are made of, and the fact that these can move around. It’s very interesting that actually patients can do quite well with dentures or do as well with dentures as they do because you’re trying to keep this prosthesis up against gravity, and have it function through what’s going on.
Some patients tolerate this very well and some do not, and it’s very hard for us to be able to identify those patients who may not be good candidates for dentures. My grandparents had dentures, as I can remember when I was a little kid, the little glass in the bathroom with the pink stuff, and I was like, “I don’t know what the heck that is”. I didn’t know at that stage I would be a dentist be dealing with things like this, but it was something that most families didn’t even talk about. I mean, they were there.
I have some patients who have had dentures for so many years that their spouses still don’t know about it. When they come in to see me, they don’t want the spouse in the treatment room at the same time because they don’t want their spouse to actually look at them with their teeth out. It’s a very personal thing, and to still find that some people do very well with dentures is actually quite amazing.
What’s interesting also is that most patients, surprisingly, will do better with an upper denture than they will with a lower denture, and there are some interesting reasons for that. Partly, the upper denture is sitting on a larger surface area. It’s got the hard palate that’s completely covered so you’ve got a bigger foundation if you think of the snowshoe effect. You’ve got more surface area that you’re covering, and the stress from chewing is distributed over a much greater area.
Also, it’s on a jaw that’s actually not moving. Anything that’s attached to the lower jaw—the lower jaw is the moving part of the mechanism. The upper jaw stays stable. So, you’ve got to have teeth attached to the lower jaw, and they need to be able to move together which is quite a challenge.
The fact that you have a tongue, which could be very active in some people, and every time you talk, you swallow, and you chew, your tongue moves. The chance of this denture that’s staying in close proximity to the tongue is going to be dislodged and food’s going to get underneath it. So, it tends to be much more uncomfortable.
The other part of it that’s pretty interesting is that we know when people lose their teeth, there is a decrease in their ability to chew. That varies on many factors like when the teeth were lost and what their experience was in terms of were the teeth lost at one time an completely replaced versus you’ve lost one tooth or two teeth and you had a smaller bridge and it’s gradually increased in size, you learn to adapt.
It’s also easier for younger people to accept dentures than it is for somebody who’s older because adaptation’s just much more difficult, and you’ve gotten used to having your own teeth for such a long period of time that it’s not easy to get used to something new in your mouth.
We do know from a number of studies that dentures, the best case scenario, are only about 20% as efficient as natural teeth. So, there is a significant drop in somebody’s ability to chew, and when you think about that, it then restricts the diet. There are some papers that talk about the other health issues that come up with that because you’re eating softer foods. You’re not chewing your food as well. You’re probably avoiding certain things like lettuce and salads. You’re probably eating more processed foods that are high in sodium. There’re issues that are related to the fact that people’s diets change when the masticatory efficiency goes down.
There’s a comfort issue when you lose teeth because you are dealing with an artificial substance, something that was not really meant to be there. It’s been designed by us. The interesting part of all this is that in prosthesis or any artificial device that’s made, dentures still are way more efficient when you compare them to natural teeth versus losing a leg or losing an arm or losing an eye. When you talk about those prosthesis, what do they give back in terms of what the original was? Teeth, or dentures, are far superior in spite of them only being about 20%.
There’s a psychological component, just like I mentioned earlier, where we have patients whose spouses have never really seen them without the teeth in their mouth, and they just don’t want to be in that position that anybody should know that teeth are missing. So, there is a psychological component for people wanting to hang on even to that one last tooth like the patient I showed you in the last screen who had two teeth in the lower jaw and did not want to lose them because there was an attachment to having these teeth for a long period of time.
When they come to people like me, we look at them and say, “Well what is the purpose of these teeth? They’re not really doing anything. They’re not helping you.” In fact, sometimes, it could be a hindrance in us providing the prostheses that’s going to work well. It’s not easy to walk people into sacrificing a tooth where that tooth, by itself, is okay, but in the big picture, it’s really not doing much in terms of benefitting the patient.
So, we see another patient now who’s coming in who has no teeth left in their jaw at all, and what you’re looking at is the upper jaw and lower jaw. This is an X-ray. It’s called panorex. Many of you may have had it. You stand in this machine, and it swings around your head. It gives you a very good global view of what’s going on with the jaw. What you’re seeing here is the sinus cavity. This is the lower jaw, tongue space back here. We’re using this to look to see if any teeth are left behind, any roots are left behind, how much bone somebody has because we know when teeth are lost, the bone continue to shrink overtime. It’s not going to stay the way it is.
We also know that this bone loss is an ongoing process. The gums and the bone that were there, were there to support teeth. When the teeth are lost, that bone and gum has lost their purpose, and they will slowly shrink away. So, if you look at children who were born with no teeth, they don’t have the bone and the gum to start with because there were no teeth that were formed, and therefore, they’re down to what we call basal bone or just the skeletal part of it. There’s none of that alveolus or alveolar part that holds the teeth.
We also know that the lower jaw bone shrinks or loses its bone at about three times the rate of the upper jaw bone. There’s been studies that have gone on for over 25 years that have followed these patients which is significant to us because it’s the lower jaw that’s always more problematic for patients with dentures. Therefore, if we know they’re going to keep losing bone at a much more rapid rate, we want to be able to intervene and do something that maybe we can do something to stop that process or at least slow it down to be able to maintain it over a long period of time.
