Are There Bad Dots and Good Dots?
You try in a crown or bridge and are ready to check the bite.
“Okay, Ms. Hayworth, now please bite on the paper.”
Ms. Hayworth responds with a tap, tap, tap.
You think to yourself: “Oh good… a bunch of dots.”
For years I never understood what I was supposed to be looking for. I was only using articulating paper to determine if the prosthesis was in supra-occlusion I would ask the patient how the bite felt. If it felt “too high” I would grind away the dots until it felt better.
Friends, I was guilty of a poor understanding of occlusion. It’s the kind of thinking that leads to this:
Disrespecting the patient’s occlusal scheme and the plane of occlusion will lead to trouble either immediately or down the road.
The study of occlusion has become one of my most thrilling experiences in dentistry. I promise to share that with you over several posts. Let’s start with the basics.
Don’t Waste Your Time With This
My first venture into learning about occlusion was overwhelming. I took notes from a few books that looked like this:
Wow, that’s confusing. This is a philosophy of occlusion call tricuspidization. It is well-researched, logical, and completely insane. Please don’t ever try to equilibrate someone using this as your guide You may lose your mind.
Basically, those dots represented three spots around the cusp tip (tripod around the cusp – tricuspidization). Allegedly, it’s better to distribute the occlusal load around a cusp rather than have the cusp itself occlude in the opposing tooth. Whatever.
It’s impractical, rarely found in nature, and just plain frustrating to create.
Instead, Do This
I finally checked out the Dawson Academy and the Pankey Institute. They basically have the same approach to occlusion: Cusp-Fossa. According to them, it’s okay to have the cusp tip occlude in the opposing tooth. An occlusal scheme would instead look like this:
For the sake of comparison, one cusp tip VS three points around a cusp tip means 1/3 the number of dots you should be keeping track of. Much more practical, sometimes found in nature, and easier to create than tricuspidization.
To be clear, the dots you see are this:
The maxillary palatal cusp occludes in the central fossa or marginal ridge of the mandibular tooth.
The mandibular buccal cusp occludes in the central fossa or marginal ridge of the maxillary tooth.
Those are the dots on posterior teeth. That’s it. Much easier to visualize and equilibrate.
You should only see a dot on the palatal cusp, the central fossa, and the mesial and/or distal marginal ridge. A mandibular tooth should only have a dot on the buccal cusp, the central fossa, and the mesial and/or distal marginal ridge.
For example, if you see a dot on the buccal cusp of a maxillary tooth and the patient doesn’t have a cross-bite, eliminate the dot. It represents an interference.
What about anterior teeth? We’ll discuss that in another post.
For more information about the TMJ and occlusion, check out my e-book, “The TMJ and Occlusal Adjustment”