Some implant dentists are concerned that the use of dental implants will lead to widespread TMJ among the older population. The concern is that because dental implants don’t have the same cushioning mechanism as natural teeth they will lead to more stressful chewing, causing wear and damage to the temporomandibular joints that results in dysfunction.
Although poorly fitting dental implants can — like any restoration — result in bite problems, there is no reason why dental implants have to lead to TMJ.
Bite Soft: How Your Teeth Are Cushioned
Although we think of our teeth as being hard structures that are firmly anchored in the jawbone, this view isn’t completely accurate. Instead, our teeth actually have several cushioning mechanisms built in.
First, teeth aren’t as hard as you think, and that’s a good thing. The outer enamel is very hard and brittle, but it surrounds two inner layers that are softer and more flexible: the dentin and tooth pulp. This internal cushioning allows the tooth to flex when you bite down, reducing the risk that your tooth will break and absorbing some of the bite force that would otherwise be passed on to the jaw joints.
An even more important cushion is your periodontal ligaments. Although your teeth are surrounded by bone, they’re not actually part of that bone. Instead, they’re connected by tough but flexible ligaments. That’s why even healthy teeth have just a little bit of wiggle, and that wiggle comes into play when you bite down. The ligaments flex under your bite force, absorbing some of the force so that your jaw joint ligaments don’t have to.
Lessons from a Lizard: Dental Implants Will Work Fine
Dental implants are the tooth replacement option most like our natural teeth, but they’re not identical. Unlike natural teeth, dental implants are made of hard, rigid material–titanium and/or ceramic–that doesn’t have the same flexibility as dentin or pulp. And dental implants actually are bonded directly to your jawbone.
This makes some dentists worry that too much stress will be put on our jaw joints if we get dental implants. But that’s probably not the case, according to studies of an unusual lizard-like reptile from New Zealand, the tuatara.
The tuatara is a living fossil. It’s a type of reptile that evolved before the dinosaurs, and has a couple of important distinctions from its cold-blooded relatives. Most reptiles don’t chew. They just use their teeth to grasp and hold food. If they need to break food down, they rely on a gizzard full of stones. But tuataras actually have a complex chewing mechanism.
Tuataras also have the distinction that their teeth aren’t connected by a periodontal ligament–they’re imbedded directly in the bone! But this doesn’t lead to extra stress on the tuatara’s jaw joints. The feedback mechanisms that regulate how much the reptile bites down controls the bite forces so that the tuatara doesn’t damage its jaw joints.
It’s likely that our jaw joints will compensate for the change to dental implants, as well.