Whether we’re talking about teeth or implants , occlusion can be a tricky thing. Adding to the complexity, neither teeth nor implants behave exactly the same way - both of them have things that can make them easier to deal with in some ways, but can be more complex in others. In this article, I will cover some of these key differences and how they impact you and your patients.
Decreasing Occlusion Confusion
Obviously, one of the biggest differences is the fact that teeth have periodontal ligaments while implants do not. This fact greatly impacts the way we need to plan our cases. One of the greatest things about having a PDL is the fact that it works as somewhat of a shock absorber; this is a huge plus for teeth.
I like to think that the difference this makes in regard to teeth with PDL and implants without a PDL is this: teeth are like wooden posts in firm soil while implants are like metal poles in concrete. If we think of the two this way and then envision hitting them with a baseball bat, the results are going to be vastly different. The same, albeit on a smaller scale, can be said for the results with excessive occlusal forces.
One of the other big things is the fact that teeth can be moved positionally, while implants cannot. However, when it comes to implants, they are "where they are" and you do not have to worry about them drifting. Of course, "they are where they are," and you cannot move them if needed or desired. The pros and cons of positional movement are exactly the opposite when it comes to teeth.
So what does all this mean for us and our patients? For starters, while it used to be thought that we should make the occlusion on our implants slightly lighter than on natural teeth, we have to realize that when our implants oppose natural teeth, those teeth are going to move. Even if we start with a slightly lighter occlusion on the implant it will not last in most cases since the opposing tooth or teeth will move.
Next, when we have teeth opposing teeth, we will have more "give" or shock absorption. This means that we will have less chipping and fracture risk. When thinking about teeth opposing implants, we will have less "give" and, as a result, a higher risk of chipping and fracture. Lastly, implants against implants will have zero "give" except for any slight flex that is present in the restorative materials you selected for your case.
John R. Carson, DDS, PC, Spear Visiting Faculty and Contributing Author http://www.johncarsondds.com