The BiteFX Blog for All Things Relating to Occlusion

The Best Bite Tip I Was Ever Given

Posted by Don Reid on Thu, Jul 21, 2011 @ 13:07 PM

This 'Bite Tip' will save you thousands of dollars and keep you from grinding your teeth!

If you've been in practice more than six months, most likely you've experienced this typical occlusion problem. I know it was a great source of frustration and expense for me in my early years.

A patient has a fractured lower second molar and you restore it with a crown. During the seating appointment, you take extra pains to insure there are no interferences to closure into MIP (maximum intercuspation) nor as the mandible moves laterally and protrusively.

[TIP: Using a very thin piece of dual colored Parkell AccuFilm articulating paper coated with a film of vaseline allows the color to literally dissolve on the film surface and expedites this necessary process.]

The patient says the bite feels great; you've verified the occlusion looks perfect; they love their new crown and you instruct them to please call after the anesthetic is worn off if there is any tooth or jaw pain in their new bite.

Two days later they call to tell you they are experiencing pain. You set up an appointment, rearranging the schedule if their problem appears serious enough, and you begin by taking an x-ray to evaluate for nerve involvement, percussing the tooth to determine if the new crown has altered the bite and is the cause of pain, and take out the standard articulating armamentarium to re-verify there are no interferences in the bite during all possible jaw movements and closure into MIP.

Things appear within normal limits so you perhaps conclude that the problem must be a reaction to the bonding cement and explain this to the patient. You believe that such problems typically go away within a short time. They feel reassured, appreciate your time and concern and express their trust in you.

A week later, the phone rings and you hear: "This problem isn't going away, in fact it is only getting worse!"

The patient states they now wake up with a sore tooth and are not biting on that side any longer.

What can you do in this situation? Without a good explanation for the cause of the patient’s problem you are going to struggle to fix it and may end up in a downward spiral from which it may be difficult to regain the patient’s trust in your abilities.

I finally understood the solution to this problem after a course of study with Dr. Peter Dawson. It lies in the fact that patients often have two bite positions but, in the above scenario, the dentist has only accounted for one.

When awake, everyone chooses a bite position that feels the safest and is where most of the teeth interdigitate - commonly called MIP (maximum intercuspation). Think of it as a habitual bite. The image below shows what this looks like. Notice that to achieve this the jaw is pulled forward from its fully seated position (represented in these diagrams by the green lines meeting).

Unstable Bite in MIP

When the jaw is relaxed as occurs at a "rest" position or during sleep, the condyle has the ability to retrude as it positions itself upward in the fossa, commonly referred to as Centric Relation (CR). The image here shows what that looks like and behold all of the forces of the bite are on the new crown!

Unstable Bite in CR

No wonder it hurts and since we only asked the patient to bite for themselves, we were doomed to miss it.

 

If this problem is occuring in your practice and you're unfamilar with locating CR using Bimanual manipulation,simply pick up a leaf gauge, select four or five leaves and ask the patient to gently bite onto it, slide the jaw backwards and foreword, and tap and squeeze. Are there any teeth touching in the back?

If not, remove leaves one-by-one until there is a back tooth contact. Marking it with the AccuFilm technique will reveal the villain tooth contact as the condyle seats upwards and backwards into CR.

Assuming all is healthy with the patient’s jaw joint, you can remove that now obvious interfering contact (and any others you may discover by repeating the process). The bite problem is solved and both you and your patient will stop grinding your teeth!

Have you experienced this situation? How have you dealt with it? - Share your experience by adding a comment below.

Want to learn more about occlusion? – check out our list of educators who understand this topic.

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