Bloggin' along with 'MUSCLES'
c/o Carol Lee Skerpan DMD
a dental & doggy blog
' Oh, really??!!! I bring smiles & happiness to our readers?!! Well, that makes
me feel all fuzzy from my snoot-to-my-tail! Every fur on my body is tingling!
At least I know I've got a good purpose with my bloggin'.
O-KAY! Here we go! '
' " It's a Curved 'Ball'-Park "? There's that reference to 'balls' again.
Are you still referring to the 'Ball'-Joints of the lower-jaw bone? I thought
we covered "Muscles, 'Ball'-Joints (TMJoints) & Teeth" in our last Dental-Blog?
I thought we were going to discuss the occlusion (or 'bite') & it's dynamics? '
Dr Skerpan: We did cover the topic of the Mouth-Jaw System already (i.e., the
Muscles, TMJoints & Teeth), but there are a couple more important concepts
which will greatly add to the understanding & appreciation of the occlusion
& it's dynamics. In general, these basic fundamentals are greatly overlooked,
misunderstood and/or dismissed.
The Temporo-Mandibular-Joint Reviewed
' Well, that covers the TMJoint. How about the Muscles? '
Dr Skerpan: The Muscles of the Mouth-Jaw System are responsible for initiating,
directing and controlling these movements. They are also responsible for con-
necting the lower-jaw, upper-skull and TMJoints to each other at different
strategic points. Hence, all movements of the lower-jaw with the upper-skull
are able to be synchronized and coordinated.
The TMJoints & Lower-Jaw Move in Curves
' Again, why is this review of the 'Ball'-Joint so important?
How is this going to help understand the 'bite' & dynamics of the Teeth? '
And there's the rub!!! The human lower-jaw does not and can not work
straight 'up-and-down', straight 'front-and-back', straight 'side-to-side'---
and it certainly does not work 'all-around' in any straight-line ever!
It simply can't!!
Simply put, a TMJoint is made up of a CURVED "ball-shape" within a CURVED
"socket-shape". Working together as a unit, the 'ball-in-socket' can only allow
CURVED lower-jaw movements ! In other words, how the two TMJoints of the
lower-jaw are shaped-to-move, dictates how the lower-jaw can move!!
The Lower Jaw & Teeth Move in Curves
' Well then, here's a question 'begging for another rub'!!!
I now know that the human-jaw can not move in straight-lines.
So, how do the teeth in the lower-jaw meet & "relate" against the teeth in
the upper-skull? How do the upper & lower Teeth get to meet & 'play'
within this CURVED dental 'Ball'-Park? There must be some 'Ball'-Park rules. '
Dr Skerpan: Good 'fur' you, MUSCLES! Great thinking!
But it's mind-boggling how you have trouble
understanding 'sit', 'stay' & 'come'.
Anyway, simply put---how the TMJoints are shaped dictates how the lower-jaw
moves. And how the the lower-jaw moves dictates the range of arcs that the
lower-teeth must work within.
But first remember, how & where the Teeth meet & "relate" is not a one-position
'bite' place! The occlusion (loosely called the 'bite') is BOTH static AND dynamic!!
The right & left TMJoints can only move as their articulated-shapes allow---and
they can only reach 'so-far-out' 'on-an-arc' 'in-any-direction'. Hence, the TMJoints
can only give the lower jaw & teeth limited CURVED-ranges for any oral-function
and the occlusion (static and dynamic).
The Teeth 'Bite' in 2 CURVED Planes
' It seems like curves, curves & more curves---balls, balls & more balls.
It's giving this doggy a dizzy-head! '
And I hate to "throw you another curveball", but there are more curves to
discuss for everything to come together workably!!
If the moving lower-teeth are positioned in a U-shaped arch and oriented on
2 CURVED planes--then the corresponding stationary upper-teeth also must
be positioned as a U-shaped arch in the upper-skull to compliment the lower-
arch. In addition, the upper-teeth must have both a Curve-of-Spee and a
Curve-of-Wilson to match the 2 CURVED planes of the lower-teeth.
The lower-planes-of-teeth must be in a concave-shape (a 'scooped-shape')---
and the upper-planes-of-teeth must be in a convex-shape (a 'humped-shape').
When these concave and convex shapes come together, the two arches of teeth
can meet and "relate" both statically and dynamically.
Simply put--the resulting 'CURVES-within-CURVES' design of the Mouth-Jaw
System allows the lower-teeth to move within 2 CURVED planes, and makes it
possible for the lower-teeth to meet & move complimenting the stationary
upper-teeth. This design allows the Teeth in both U-shaped arches to come in
maximum contact with each other. It also allows for limited-but-sufficient-
contact between the 2 arches of Teeth as they move against each other.
With this design, it is possible for the upper & lower arches of Teeth to actually
meet & "relate" in both a static AND dynamic occlusion. Both the Curve-of-Spee
AND Curve-of-Wilson together allow the upper & lower arches of Teeth to
"spoon" together for their static occlusion.
In addition (like the two spoons moving above), the plane of the Curve-of-Spee
allows the 'front-and-back' dynamic 'bite' movements. And the plane of the
Curve-of-Wilson allows the 'side-to-side' dynamic 'bite' movements. Both the
Curve-of-Spee and Curve-of-Wilson together give the 2 arches of Teeth
2 CURVED planes for their 3-dimensional dynamic occlusion.
In other words, BOTH the Curve-of-Spee and Curve-of-Wilson allow BOTH
upper & lower arches of Teeth to come together for BOTH static AND dynamic
Opening & Closing in Curves
' One thought is really bothering me. Because pup-jaws move so little
'side-to-side' or 'front-and-back', it is often said pup-jaws don't move
in those directions at all. I myself prefer chewing only 'up-and-down'.
So, is my pup-jaw a NUTCRACKER-JAW? '
Dr Skerpan: No, no. Pups don't have NUTCRACKER-JAWS either! Your lower-jaw
opens & closes in a CURVED-arc, and not in an 'up-and-'down' straight-line. And
in this Dental-Blog, this will be the last 'CURVE' of the CURVED dental 'Ball'-Park
we will discuss.
Healthy human right & left TMJoints allow the lower-jaw to open down & backward
in CURVED-arcs. The TMJoints accomplish this in 2 CURVED Phases.
Simply put--The lower-jaw opens in 2 separate Phases and in 2 separate CURVED-
arcs. Nevertheless, both Phases together increase the opening size
of the mouth---and both Phases together offer the lower-jaw & Teeth
a larger CURVED 'Ball'-Park to 'play' within.
' Well, that has got to be it! I don't want anymore 'curves',
I don't want anymore 'balls'. I don't want anymore 'curveballs'.
How can there be so many curves for one body-area to work?
You'd think we curved ourselves into another 'Ball'-Park
dimension already! '
Dr Skerpan: I hate to break the news to you, but we've
got more curves to cover in our next Dental -Blog.
The Teeth must have CURVED shapes (anatomies) in order
to function with the CURVES discussed in this blog. But the
individual Teeth also must be able to work with each other
as an ensemble.
Keep in mind---The CURVED dental "Ball'-Park must be
complete and usable for the Teeth to function within it.
However, the Teeth themselves must also be shaped so they
can 'play' within it!!!
But more about the CURVED Teeth next time! To be continued....
' WHA--AA--AAA--AAA--AAAA--AAAA--AAAAA--ATTT ??!!!'