THE CASE ARRIVES IN THE LAB

Aside from model appearances and a properly filled out lab-slip, the "relationship" that the
upper and lower models hold is the key to fabricating an accurate and comfortable
appliance that will give the patient many years of service. Similar to an artist painting a
masterpiece, she will visualize the painting COMPLETED. Although the motions she goes
through to arrive at the end are routine and mundane, the end result is a true work of art;
admired by all and relished by the creator.

Sitting at the bench and working on case after case, these essentials play over in my mind.
Please consider the following.

ESSENTIALS FOR ACHIEVING THE BITE FOR  PARTIAL DENTURES:

1.  Find a material that works well for you to take a bite, one that’s reliable and affordable.

2.  Identify the patient's Centric and become familiar with where the patient’s   
teeth come together. Don’t afford the patient the opportunity of changing this once you have
obtained it.

3.   There is only one bite.

4.   Don’t rely on the impression material to take the bite for you. Play an active roll in
controlling the circumstances and the outcome.

5. Don't block your view of the anteriors with the bite registration material, as this will help
you to be certain the patient hasn't moved or adjusted their occlusion while your asking
them- "Please Close". (This may require you use bilateral material applications).Please
see photo insert. (5a.), (5b.)

6.   If possible, ALWAYS “TAKE THE BITE” IN THE EDENTULOUS AREAS. This ensures
full, balanced, Occlusal contact of the posterior teeth or any remaining teeth.

7.  Confirm your work.

8.   Train your assistant to properly package the bite to prevent distortion or breakage.

9.   Contact the lab immediately to ensure impression and bite transfer accuracy.

Written by:  Tony DeAngelis C.D.T./Depot Dental Lab Inc.
TECHNICIAN'S CORNER

Where’s the bite?

The Model - "Poor"

Bruxing Blues
Depot Dental Lab, Inc.
TECHNICIAN'S CORNER is a new element
we've added to our web-site. It offers helpful
hints and interesting insights into the mind of
the technician that is intended to help the
Dentist chair-side and the assistant as well. The
articles presented will promote proficiency,
efficiency, and accuracy. They are designed and
written to offer suggestions and insight only.
150 E. Irving Park Road
Wood Dale, IL 60191
(630) 616-1021


Quality and
Craftsmanship Coming
Together Since 1965
(5a.)















Above is an example of an attempt at achieving a
patient's bite using the "triple-tray" technique. ( The tray
was cut away to display the inaccuracy) Notice how the
anteriors are in contact, edge to edge and the
posteriors are open. This is perfect example of the
patient's attempt at "HELPING",  extending their
mandible - showing their teeth for the doctor. DOCTOR
HAD NO IDEA THIS WAS HAPPENING BECAUSE THE
TRAY WAS BLOCKING  VIEW OF THE ANTERIORS.

After re-articulating the case "by-hand", the correct bite
offers itself up as obvious. Below is the example. The
extractions were done and the partials were fabricated.
At which time little or no Occlusal adjustments were
necessary.
(5b.)


One of the most challenging aspects of Technical Dental Laboratory work is
Model-Pour accuracy. Some model pours are left up to the lab to handle.
However, many times model pours are conducted in the dental office, and are
performed by doctor’s assistant.
CONSIDER THE FOLLOWING STEP BY STEP, whether pouring-up alginate or
rubber base impressions the steps are the same:

1. Make sure the impression material is clean and seated correctly in
the impression tray. Avoid all debris by removing any pieces of loose
impression material. If the impression is of the “lower” arch, tongue the
impression first by placing wax or wet paper towel bundled up in between
either side of the lower arch, lingual. Keeping the paper flush or level with the
edge of the tray, fill in the space from the lingual vestibule to the lingual of the
retro-molar pads. When completed, it will look triangular in shape.

2. Mix your plaster or stone very well. It is better to mix too long than not
long enough. Careful however, over mixing will cause the plaster to set much
faster. Under mixed plaster on the other hand is brittle and in most cases will
not stand up to the rigors of the work to be performed. Somewhere in the
middle is where you want to be.
Note: If the impression you are pouring contains a partial that is in need of a
repair, make certain that it too is seated properly and has not risen out of
place prior to the pour or during the pour (over-vibrating).

3. Before the pour - check if the impression tray itself is visible along
the periphery of the impression, place a little wax in these areas to
make model separation easy and to minimize breakage. Using a vibrator
or bowl tapping technique, start your pour at one end; fill EACH tooth one
space at a time. Once each tooth is full, add more plaster to fill the remainder
of the impression then set it down on the table. Depending on the speed of
the plaster set, using intervals of time, begin layering plaster on top of the
impression (on top of the already placed plaster from the initial teeth fill). Two
or three layers should do it. Wait one more interval, and then flip the loaded
impression over onto the table with one fluid motion. Be careful not to smash
the tray down to the table or allow it to sag. (Slumping will occur only if the
plaster and water ratio is too liquid). A good model pour will have a base of
approximately 1\2in. - 3\4in. in thickness.

4. Allow the plaster to set fully. It will go through a couple stages as it sets:
First it will solidify as it looses its shine. Then it will heat up. (The better the
mix, the more the heat). Finally, it will cool down. Once it has cooled, it’s a go
for separation! 24 hours between pour and separation is optimal. You could
leave this up to the lab or you could give it a go yourself.
    Remember, practice makes excellence.

If you have any questions pertaining to this article and would like further assistance, Tony
can be reached at (630) 616-1021. Please feel free to call.

TECHNICIAN'S CORNER Written by Tony DeAngelis CDT
THE MODEL -  "POOR"
_________________________________________________________________________
Articles:
               3.
Because wax wasn't place in the  
required areas as a block-out,
the mixed stone was permitted to
engage the undercuts of the
impression tray, resulting in
model breakage.