by Norm Culver, DDS
What are your thoughts on equilibration. Is it necessary? Do
you even really care about it? If not, how come? Are you afraid
of it? Do you understand it?
Here’s what Dr. Peter E. Dawson says about it from his book
Functional Occlusion: From TMJ to Smile Design: “If the importance
of occlusion in dentistry were universally understood, no
dentist would even consider practicing without a working
knowledge of the principles and skills required for successful
Equilibration is actually quite simple. In fact, in the 1995
JADA article “Abnormal Occlusal Conditions: A Forgotten Part
of Dentistry,” the godfather of modern dentistry, Dr. Gordon
Christensen writes it’s as simple as balancing tires on an automobile,
or shortening one leg on a four-legged table when it won’t
stand without movement.
Are you afraid to do equilibration because you think your
patients will have trouble adjusting to it? In my experience,
that’s never the case. In fact they usually say it feels better.
Do you avoid equilibration because you think grinding
makes the teeth sensitive? If it does, the sensitivity rarely sticks
around for too long. That is because, when you do it right,
there’s usually little grinding to be done (and what is done is
where the enamel is its thickest).
Do you think it s too hard to justify equilibration to
patients? Not once you’ve learned how simple the procedure can
be and how it can improve symptoms. The key to patient
acceptance is like anything else. It starts with a thorough exam
and a careful explanation of your findings at the first appointment
when the impression is fresh.
Do you think equilibration isn’t profitable enough? Not
when you’ve learned to do one in 30 minutes, and along with
other treatment. I don’t know why equilibration has to be so
complicated. Let’s say you could simplify the process. Then you
could do more of them and get faster at it. Remember the “90-second crown?” Wouldn’t equilibration be more profitable if you
could do it faster? Yes, a complicated equilibration takes more
time, but routine equilibration doesn’t.
Think it’s not covered by insurance? Not so. About half of
them are covered and the other half of them are usually worth it
to patients for the benefits.
Think removable appliances are better because they’re
reversible? Well, restorations aren’t, but you do plenty of those!
Wouldn’t your patients who wear removable appliances love to
get rid of them for an occlusion that feels better?
Equilibration might be the most overlooked and misunderstood
area of dentistry. It’s an easy procedure to learn and relatively
easy to do. So why isn’t it done more? Dentists know little about
it, shy away from it and often find reasons for not doing it. That’s
because the answer as to whether or not equilibration should be
done varies from recommending it whenever teeth are restored to
almost never doing it. So how are dentists to know what to do?
Think of it this way. Done properly – which isn’t difficult to
do – equilibration can cause no harm. Drs. Dawson and José dos
Santos Jr. agree (see page 171 of the book Occlusion: Principles
and Treatment). That’s because, instead of establishing any new
occlusion, it only frees whatever occlusion the patient might
Looking at this issue another way, why should an equilibration
ever be done? Because several of dentistry’s leading key
opinion leaders have shown that it can be of great benefit to
patients. It can ease TMJ symptoms, prevent grinding and fractures,
improve function and even help periodontal disease.
Take one example: abfractions. These are the little notches at
the cemento-enamel junction that were once thought to be
caused by acidic foods. Now they’re believed to be caused by
stresses from occlusion – and adjusting the occlusion for these
stresses is the answer. That’s what equilibration is all about.
What about other examples like bruxism and TMJ? If
proper equilibration causes no harm, then why not at least try it
in some of these cases. In hundreds of cases, I have not only
found that equilibration can help these conditions, but can prevent
patients from having to wear appliances.
What about mobile teeth, perhaps associated with vertical
bone loss? If an equilibration can make these teeth tighter, how can it be said that the equilibration has not
helped? What about related problems that
are said to be neuromuscular? Wouldn’t a
traumatic type occlusion contribute to that?
If you haven’t turned to another article
by now, I’m going to explain exactly how a
basic equilibration can be done. It’s a simplified
way I’ve developed over the years after
learning from the early experts like Pankey,
Jankelson and Dawson.
Equilibration really comes down to a simple
three-step procedure: 1) Correction of
eccentric contacts, 2) Adjustment of working
and balancing sides and 3) Improvement of
anterior guidance and cosmetics. Furthermore,
with some experience, it can usually all
be done in two short appointments.
If the equilibration is being done for
mobility or for symptoms, then a third
appointment might be necessary in order to
assure that the mobility or symptoms have
subsided and this would of course require
I’ve already discussed a few indications for
equilibration, but what about cases with heavy
wear (especially when some crowns are being
done on those patients)? It could be a onetime
opportunity to perhaps establish a better
occlusion rather than perpetuating whatever
occlusion the patient happens to have.
What about the contraindications? Some
of the usual ones are inter-capsular TMJ
problems, severe bruxing and pure muscle
disorders. Some of these conditions can be
hard to determine and, even though equilibration
or appliances might help, it’s usually
better to refer such patients to a qualified specialist.
How do you determine if a TMJ problem
is inter-capsular? Perhaps by load testing
with upward joint pressure or by the use of a deprogramming device. Other probable contraindications for equilibration
are cases with Class III occlusion, full cross-bite and lost vertical dimension.
Of course it all starts with the exam. First, ask the patient about grinding,
clenching, sore masticatory muscles and sensitive teeth. Then examine the
patient for the following: limited mandibular movements, signs of clenching
or grinding, degree and pattern of occlusal faceting, occlusal and cervical sensitivity,
abfractions, occlusal fracturing and cracked teeth, hyper-mobility, vertical
bone loss, and muscle and joint tenderness.
The first step in an equilibration is to determine centric relation. This
too is controversial, but it can usually be determined by easy hand manipulation
of the mandible into centric relation closure. It can also be determined
with a deprogrammer. The advantage of a deprogrammer is that it requires
no manipulation. After wearing the deprogrammer, the patient simply taps
the teeth together in what should then be a centric relation position. The
advantage of manipulation is that it can be done “right now” without the
necessity of fabricating, fitting and monitoring a deprogrammer.
Using either of these methods, contacts, which prevent occluding in
centric relation, are marked by lightly tapping the teeth on a sensitive ribbon.
These contacts, called eccentric prematurities, are lightly ground with
a rotary instrument and preferably, “hollow-ground” to preserve tooth
structure. The usual rule here is to grind only on inclined planes and preserve
the tips of “stamp cusps.” These cusps are the all-important centric
stops, which maintain vertical dimension and I prefer doing most of this
adjusting on the mesial inclines of the uppers rather than compromising the
lower buccal cusps.
This process of marking and adjusting is continued in the same manner
until all premature contacts are removed and there’s no more slide when the
patient closes into full centric relation occlusion (CRO). This means that
cusp tips are probably now contacting flat areas of opposing teeth and that
centric occlusion (CO) and centric relation (CR) match. This adjusting creates
what is called a “long centric,” which is a flat antero-posterior slide.
Once the removal of eccentric prematurities is accomplished, lateral working
and balancing excursions need to be addressed. With a cuspid rise occlusion
however, there should be few such corrections needed because the cuspids
cause posterior disclusion with little if any lateral contact.
The next question is how to register, or mark, the excursive movements.
Since manipulating or directing a patient through these movements can be
difficult, I simply ask them to bite on the ribbon and grind all around on
the back teeth. This is not only simpler but usually also marks a wider range
of mandibular movements.
Balancing contacts need to be adjusted first because they can not only
interfere with working occlusion but they’re considered destructive, even
pathologic. This is the opposite from full dentures where contact on both
sides may be needed to stabilize the dentures. After any such balancing
interferences are removed, further balancing and working contacts need to
be adjusted together because, as working contacts are adjusted, for instance,
it can bring more balancing contacts into play on the opposite side; and
vice-versa as balancing contacts are adjusted.
Exactly where should balancing contacts be adjusted? On the upper or
the lower teeth (See sketch)? Either way, the necessary amount of this adjusting
could compromise some stamp cusps. Adjusting the buccal inclines of
the upper lingual cusps could remove some to that cusp tip; and adjusting the lingual incline of the lower buccal cusp could do the same
thing to that cusp tip. Of the two choices, I’d rather adjust the
uppers and keep the lower buccal cusps, which seem more centrally
located over the ridges.
In adjusting the working side, this is where the old “bull”
rule applies. That is, the adjusting should be done on the buccal
of the uppers and the lingual of the lowers (See sketch). This is the only good choice because adjusting the
opposing surfaces would otherwise affect both stamp cusps.
Another reason for adjusting lower molar lingual cusps is
because these are the cusps that are most likely to fracture off
badly and this adjustment can prevent it.
Furthermore, these lingual cusps are usually unneeded, nonworking
cusps and this adjustment alone can be one of the biggest
benefits of an equilibration. Therefore, these areas should be
adjusted plenty and the lingual edges rounded off so they’ll be easier
on the tongue. Note that, except for this adjustment, almost
all the adjusting so far will have been done on the upper teeth.
Next comes the anteriors and most of this adjusting should
usually also be done on the uppers. That’s in order to even the
protrusive excursions without changing the centric contact (See sketch). If however, there are long heavy facets,
which commonly occur on the labial surface of the lower incisors,
those facets, in order to improve incisal function, should be
adjusted by removing all but their incisal-most ends.
What about the deep wear depressions that sometimes form
in upper cingulum areas? The best choice here is to keep the
deepest parts of these depressions, which are centric contacts,
and from there, flatten out the facets to a more normal anatomy
Beyond these anterior adjustments, the incisal edges should
also be adjusted for cosmetics.
There’s one other adjustment that’s not usually addressed. It’s
common to have broad areas of wear on the buccals of lower and
the linguals of upper, especially molar surfaces. These facet should
be adjusted (as shown on the sketch) reducing all but their
occlusal ends. The purpose of this adjustment is reshape the teeth
to a more normal anatomy with better cusp-to-fossa relationships.
This reduces the food table, directing forces to more limited areas
for more effective mastication. It also creates vertical rather than
lateral forces in line with the long axis of the teeth.
How about finishing an equilibration? Again, keeping it
simple, I usually only use finishing burs for the concavities and
softened sandpaper disks for the convexities.
What about implants? The same principles apply to equilibrating
implant teeth as constructing them in the first place.
Implants are osseo-integrated and immobile so they need axial
loading as much as possible, with vertical rather than lateral
forces, in line with the long axis of the teeth. Any adjustments
should end up with only one area of contact with the implant
no matter how wide the opposing tooth. That contact should
be at the axial center of the implant, directly over the implant,
both bucco-lingually and mesio-distally, with one centric stop.
There should be a “centric platform” with plenty of freedom of
movement and short enough cusps (of either the implant or the
opposing tooth) so there’s no contact in any excursive movements.
This means flat or nearly flat occlusion depending on
the amount of cuspid rise.
Finally, how about fees? If the equilibration is being done
along with other treatment and if it can be done in about 30
minute’s time, doesn’t $200 sound reasonable – both for you and
for the patient? And if it’s being done separately, in two or more
appointments, does at least two or three times that fee sound reasonable,
depending on the estimated required time?
To summarize, even though equilibration might seem
hard to justify, there are times it’s harder not to justify and
what I’ve presented is a way to make it as practical and simple