Neutral Zone/ Massad Technique

[kcdt]

Back in the not too distant past, I put together a slide series aimed at helping technicians understand the neutral zone technique as Dr Massad was currently teaching it.
My goal was to attempt to put together some hands on that could be taught in conjunction with his chairside courses.
Unfortunately, life events kept me from sticking with it, so the the slides I have are almost unknown. The lecture runs ~ 2hrs, but I've only been invited to speak twice anywhere.
I hate to see waste, so I thought I'd toss them out here and on Facebook to engender discussion.
So, without further ado, here goes nothin':

 

[kcdt]

The first concept is the rim.
In this technique 4 base plates are fabricated, totaling 2 max/mand sets.

One set is used for central bearing devices (Gothic arch tracings).

The mandibular is a neutral zone record made of green/ grey compound sticks.

The maxillary is a wax rim used as an esthetic blueprint.
It is critical the clinician understand the information that is supposed to be conveyed.
Otherwise there is no serious attempt to control the outcome.

So the rim needs to be trimmed or modified to define Buccal corridor. Scribe lines should relate midline, Ala for width, and a high lip line for length. The incisal edge should correspond to the midline at the leading edge.
A fox plane or similar is used to orient the plane to the horizontal and Frankfurt lines.

Note the use of a veneer of yellow beeswax on the labial.
The idea being that tooth display is easier to control in a color that resembles teeth. It's a visual aid for the clinic.

A putty matrix of the rim is made to control tooth placement to those parameters.

 

[AJEL]

As always some really nice information, and fine work.

 

[kcdt]

Definition of the neutral zone:
“The potential space between the lips and cheeks on one
side and the tongue on the other; that area or position
where the forces between the tongue and cheeks or lips
are equal”. Glossary of Prosthodontic Terms.
Dawson, in his landmark textbook says of this potential
space “As each tooth erupts into position within its
respective arch, it is guided into a narrow zone located
between horizontally directed forces. The outward pressure
of the tongue verses the inward pressure of the perioral
musculature defines the neutral zone… The neutral zone
determines the position of each tooth and establishes
the dimensions of the entire arch, including the shape
and position of the alveolar processes. In effect, the
boundaries of the neutral zone form a matrix for the
dental arches. Any attempt to move any part of the
dental arch, including the alveolar structures outside the
neutral zone, will result in increased pressure against the
part that intrudes. There is no occlusal scheme that can
stabilize teeth if they are in an unbalanced relationship
with muscular forces against them.” (Evaluation, Diagnosis,
and Treatment of Occlusal Problems, 2nd ed., p. 74, 75, 82.)



First two are the neutral zone as it leaves the lab, followed by color overlay to highlight detail of muscles imprint on the rim, indexing, and arrangement of teeth.

 

[JohnWilson]

The real issue with this technique is nothing we can control, and like most things if the clients want to learn its golden.

Dentures today really can be SO much easier with all the information we have, HOWEVER we are still forced to fabricate a restoration at an arbitrary CR VD that we do not control. The team needs to be fully aware of what each other needs and when that happens excellence can be achieved.

I get so many photos now AT TRY-IN because it is super convenient to use a cell phone to snap shots and send them. This alone helps communication so much more than any well written script ever can. HOWEVER we are often then the part of the team that arbitrarily changes articulator settings to achieve needed esthetics.

When I work with clients chair side and I have the opportunity to watch their skills it often amazes me how little common sense some of these MED/HIGH end clients have. While I have taken my fair share of CON ED I am always wanting to better myself. What I see is a lot of these guys have success one way and this becomes their barometer/path for future cases.

When techs like us share info we are doing it for selfless reasons and this is truly why I come to sites like these. While I have articles on this concept Ken you have outlined it is simplistic way and many more will find good use for a proven technique

Thanks Ken for being a CONTRIBUTOR here on DLN its people like you that make this site great! Now all you lurkers stop thinking you have nothing to offer or fear of being judged, remember what this site is for and jump in the water it will make this site that much better!

 

[Bumfrey]

I am 8 months away from completing the pros course, and found this very interesting. Thanks for the input.
I wish i had more time to contribute and hope i will in the future. Three young kids (another due in a few weeks),running a business, and this course is somewhat tiring.

 

[kcdt]

I appreciate the enthusiasm this has generated.

Word to the wise. The clinical team has to be well trained to achieve this technique. It's not for everybody, but it conveys some very useful ideas.

Anyway, stay tuned, I haven't yet fleshed out the technique. I have more uploads before we're through.

 

[grantoz]

bumfrey knows all about the neutral zone if he has nearly finished the pros course.It was one of the best things i ever did in my career i finished it back in 92 not 1892 as one of my staff said.I still use the stuff i learned back then every day.A good book on this is by watt and mcgregor

 

[kcdt]

I managed to import my eps illustrations, so I'll put this up now. The NZ record has been highlighted to show the pinch point that indicates where the cheeks and tongue force the food bolus onto the occlusal table. This will line up with the half/two thirds of the retromolar pad. This why we orient the occlusal table this way.
The blue area denotes the insertion are of the buccinator.conform to. This area can often result in a sigmoid curve that the denture base must conform to.

 

[kcdt]

Teeth are arranged with minimal wax.
If aesthetics are approved, then the clinician will apply medium body PVS and direct the patient through a series of facial/tongue movements to define the cameo functionally
Note the ledge created on the lingual flange of the mandibular.

 

[denturist-student]

I usually do a neutral zone impression for those with flat ridges...I wil use something similar..sometimes I will use parts of the procedure to modify either the intaglio surface to the buccal and lingual contours...It results in an extremely comfortable set of dentures....but don't expect good esthetic results...I have a powerpoint if you like...I did a neutraql zone fora n elderly lady and she actually takes the y upper dentures out during the evening...Says the lower ones feel just like her own...

 

[kcdt]

I usually do a neutral zone impression for those with flat ridges...I wil use something similar..sometimes I will use parts of the procedure to modify either the intaglio surface to the buccal and lingual contours...It results in an extremely comfortable set of dentures....but don't expect good esthetic results...I have a powerpoint if you like...I did a neutraql zone fora n elderly lady and she actually takes the y upper dentures out during the evening...Says the lower ones feel just like her own...

You certainly do have to let go of the current trend for hyper real artwork in the gingival.
But honestly, a decent set up with a quality tooth can nail a natural feel.

I find the dentures stable enough that the patients really hit a comfort groove with them. In someone who has lived in dentures a long time, with all the attending negatives, this technique can yield rewarding outcomes.
I've heard a number of Dr Massad's patients say they sometimes have to check to see if they're wearing them, they just don't fight the mouth.

 

[kcdt]

I usually do a neutral zone impression for those with flat ridges...I wil use something similar..sometimes I will use parts of the procedure to modify either the intaglio surface to the buccal and lingual contours...It results in an extremely comfortable set of dentures....but don't expect good esthetic results...I have a powerpoint if you like...I did a neutraql zone fora n elderly lady and she actually takes the y upper dentures out during the evening...Says the lower ones feel just like her own...

I love to see that PowerPoint. I'm well aware there's all sorts of nifty variations and tricks. I can never learn enough.

 

[XxJamesAxX]

I love to see that PowerPoint. I'm well aware there's all sorts of nifty variations and tricks. I can never learn enough.

X2.....

 

[kcdt]

Post process of case study 2. These are the polished prosthesis. I tend now towards a high polish with no stippling. As part of the delivery protocol, the clinician pips out the intaglio, then, employing low viscosity PVS with NO adhesive, will test out the cameo for impingment. Application is made in small areas, after insertion, the patient is directed through facial movements. Any thin or burn through is revealed by running a sharpie marker over the pvs, then it's peeled away. Relieve the marks left. After this the tracing devices are mounted (this is when disposable ones come in handy),and an intra oral equilibration is performed.
Pleas note the photos with the tracing device are from another case. i did not have them for this one.

I am grateful for your attention and enthusiastic responses.
Thank you all.

 

[denturist-student]

This subject is one of the more important subjects in our work. Forget about esthetics it just makes function a priority. Were I able to upload a PowerPoint I would be glad too but most info needed is right here....I do work with a lot of elderly patients who cannot afford implants but are sensitive to irregularities in their dentures... I recently participated in a symposium featuring one of Massad's fellow prosthodontists who gave us a synopses of Massad's technique in full. Best symposium ever. Also bought a set of Massad's CD's....which I found interesting..however more related to clinical rather than lab work..Wondering if affordable dentures could be done that way...I would need to charge about 3500 - 5000 for a set that follows his protocol. But I think some people would pay a little extra for some options such as Massad's or Turbyfill's techniques....Totally agree with kcdt's assertion that we need to do away with esthetic concepts such as stippling and anatomically correct detail...To me the buccal surfaces and intaglio are as equally important as the occlusion....further to all of this I am leaning away from intra oral equilibration in favor of a clinically mounted post insert equilibration of the occlusion...the intra oral environment is not stable enough to perform any sort of equilibration especially given the instability of the lower denture.

 

[JKraver]

Would powerpoint be available to an email? dropbox? Snail mail usb....

 

[lcmlabforum]

Thanks, and Congrats to Bumfrey!
BTW - who made those central bearing device set for you?
LCM

 

[denturist-student]

Would powerpoint be available to an email? dropbox? Snail mail usb....

yep

 

[Bumfrey]

yeah!! I'm 4-5 weeks to the finish line. A F/F and a P/P left to finish with 2 exams in the final weeks. Fairly confident I am good to go. Looking forward to making people some new teeth!!!!
Let the grey hair come forth!