Transcript Proximal Contacts

RSD 812
: #30 Full Crown Wax Up
PPT developed by Dr. Steve Selwitz
Locate and mark the reference contact point
that will hold shim stock tightly.
Know the Goal!
Use your Knowledge of
dental Anatomy and
Morphology….
Mark areas of contact
on the maxillary cast.
Red dots are the
contacts from the
centric cusps of #30.
Blue dots are the
centric cusps of #3.
You should have a
minimum of six
contacts on your wax
pattern for #30.
Use your Knowledge of
dental Anatomy and
Morphology….
Mesiobuccal cusp of #30
contacts here
Contacts central fossa #30- flat
area or tripod
Distobuccal cusp of #30 tripods
here
Contacts distal fossa or
marginal ridge of #30
Use your Knowledge of
dental Anatomy and
Morphology….
Apply one coat of Slaycris die lubricant on
the occlusal surfaces of the opposing teeth
•Lightly mark the
margin
•Use wax pencil, no
graphite
•Contrast: blue pencil
for red wax & vice
versa
•Hold sharpened pencil
parallel to die, lightly
touch and mark margin
Do not mark margins on clinical cases! UKCD
Begin waxing by applying a thin layer (↓1 MM)
to the external line angles of the occlusal
surface. Then flow wax onto the occlusal
surface, melt each addition into the previously
added wax.
Set yourself up to work easily. Rest your
hands on the bench-top when possible. Keep
a small work triangle.
Wax the axial surfaces from the occlusal
downward toward the finish line. Again, melt
each addition into the previously applied wax.
Add a slight excess of wax around the finish
line. Seal the margin by allowing a small
amount of wax to flow over the finish line.
1.) Melt the wax well to
seal the margin.
Then…
2.) Use the Hollenback
carver to remove the
excess wax. Keep the
carver in contact with
the die & properly
aligned.
Make sure that you
have trimmed back
exactly to the finish
line. You should
see a very distinct,
smooth junction of
wax and stone.
Any irregular area
usually indicates
that there is still
wax over the finish
line.
Goal
Small additions of wax slightly past the
finish line will secure the pattern.
Seat the die on the cast, but do not force it. If
the proximal surfaces bind, remove the die and
carve off some of the wax. Continue until the
die seats easily.
Close the articulator gently. Verify that no wax
on #30 is touching the opposing tooth and that
the reference contact still holds shim stock.
Proximal Contacts
Location: Determine how much wax will be
needed and where will you add it.
Raise the die slightly, add the wax that you
estimate will be needed, allow the wax to cool
slightly then push the die back to place.
Adjust the wax, either remove excess reheat
and reseat or add more wax and seat before
the addition has hardened.
Facial view
Occlusal view
Develop the size and location of the proximal
contact. Go ahead and develop the marginal
ridge at this time also.
Be sure and close the articulator before each
addition of wax has cooled*. At some point
you will pick up the contact for the DL cusp of
#3. Notice that the facial and lingual
embrasures may be begun at this time.
Discipline # 1
•1) The die must be in the articulator
when you are making additions to the
occlusal surface.
•2) Allow the wax to cool slightly then
close the articulator. This will prevent
you from waxing in a high occlusal
contact.
Develop the mesial proximal contact following
the same procedure. There will not be an
occlusal contact on the mesial marginal ridge,
just make the height equal to the distal
marginal ridge of #29.
Scribe in lines indicating where the opposing
triangular ridges are located. This tells you
where your buccal grooves will be located and
dictates the proportion of the buccal cusps.
Close the articulator to visualize where the
buccal cones are going to be placed.
Blue Wax: begin the cone for the MB cusp,
close the articulator. Adjust the position and
height of the cone with each addition.
Continue until the cone touches exactly on
the mark. Trim it to the appropriate size.
The blue cone for
the distobuccal
cusp is positioned
in the center of
the tripod marks.
It does not
contact the center
of the central
fossa of #3.
Add wax to form the mesial cusp ridge, the
wax addition will flow into the marginal ridge.
Close the articulator while the wax is still
warm. There should be no contact except
on the cusp tip.
Add wax for the distal cusp ridge of the MB
cusp. Notice that it ends at the line
indicating the MB groove.
Close the articulator again; if there is contact
anywhere other than the cusp tip, carve it
away.
Add wax for
the MB cusp
ridge of the
Distobuccal
cusp. This
cusp ridge will
contact the
triangular ridge
of the MB cusp
of #3 and form
the first of the
tripod contacts.
Add wax to
the mesial
cusp ridge
until you
see that
you are
getting a
contact.
Add wax to form the distal cusp ridge. The
contact with the triangular ridge of the DB
cusp of #3 will be the second tripod mark.
Wax in the distal cusp in whatever space is
left distal to the DB groove. It does not need
to have an occlusal contact in this case.
You now have two parameters established:
1) Location of the cusp tips and grooves
2) Contour of the wax at the finish line
Add wax to fill in areas between the two.
Heat smooth and carve to form. Adjust the
contours by viewing the waxing from
various angles.
Occlusal View
Look at buccal
embrasures
and buccal
contours.
Buccal, viewed from
the anterior.
Compare the profile
of the waxing to the
profile of the
adjacent molar.
Complete the buccal
surface before
moving on to the
next step.
Lingual Cusps – Cone Location
Mark the linguoocclusal lines on both
adjacent teeth. This will help you with the
buccal – lingual position of the cusps.
Mark the location of the cusp tips of the
contra-lateral with vertical lines. This will
help give you an idea of the mesiodistal
spacing of the cusp tips.
The mesiolingual cone should be over the
embrasure between #3 & #4. The distolingual
cone should be over the lingual groove of #3.
There should be some space (1-1.5 mm)
between the distolingual cone and the lingual
surface of #3.
Mesiodistal orientation of the cones for the
lingual cusps. They are usually spread farther
apart than you would expect.
Comparing linguoocclusal lines.
Add mesial and distal cuspal ridges on both of
the lingual cusps.
Fill in the areas between the cusp tips and
ridges on top and the contour established at
the gingiva on the bottom.
Maintain the separation of the mesial and distal
lobes of the lingual surface. The lingual groove
on the occlusal continues over onto the lingual
surface in the form of a concavity.
Add wax in the
central fossa to
capture the cusp
tip of the ML cusp
of #3. Use either
blue or red wax.
Trim the
indentation back
until the landing
area is about
2mm wide.
Scribe in the basic occlusal pattern of the tooth.
The triangular ridge of the DB cusp usually
“points” to the lingual groove.
The central groove moves forward from this
pattern to the mesial fossa.
The central groove goes to the distal to end
in the distal fossa.
Begin with the DB cusp, add wax to form the
triangular ridge. Close the articulator while the
wax is still soft. Continue to build up the ridge
until the desired contact is achieved.
Look for a flat facet to appear.
Fill in the
remaining
triangular ridge
areas one
segment at a
time. You do not
want contacts
on any of the
other areas.
Refining occlusal contacts: Verify that the
shim stock reference still holds. If it does not,
use the powdered wax to mark contacts.
Carve them all down until the shim stock will
hold.
To redefine contact points: Add a small drop of wax
to one contact point and close the articulator. Heat
smooth and carve to blend the addition into the
adjacent wax then recheck with the powdered wax.
Continue to reestablish the
contact points
one at a time
until you have
them all.
Dust off the
powder.
Smooth areas
than don’t have
contact points
with the pointed
end of a #7 wax
spatula or other
instrument.
Define the
groove pattern.
Check for interferences in lateral movements
First:
Lower
the
latch
pin
Gently, move the articulator through right
and left working and protrusive movements.
• You should be able to visually see that your waxing of #30 is separating
immediately in both excursive movements. If you think that there may
be a working or nonworking interference then use your powdered wax
to try to locate it.
You would like
to see your
original MI
contacts only!
Any new
marks or
streaks should
be carved
away - these
marks
represent
lateral
interferences.
Working
interference –
the lingual
groove is
placed too far
distally.
Next, remove the die and reseal the margin all
around with a small new addition of wax. Melt
the wax well as you seal.
Re-carve the margin as
described earlier. Blend
with the existing axial
contour. Look closely
for any defects in the
margin, if noted re-wax
and re-carve until the
margin is perfectly
sealed, smooth and
well contoured.
Inspect the margin while viewing from an
apical direction, defects will be more apparent.
FINAL CHECKLIST
1.) Reference point
still holds shim stock
2.) Occlusal contacts,
free from lateral
interferences
3.) Proximal contacts
4.) Line angles,
embrasures & axial
contours
ATTENTION!
•
1.
2.
3.
4.
At the end of the Practical session the last thing
that you should do is:
Carefully check for and remove any wax that is in
heavy occlusion.
Set your guide pin so that the casts are slightly
separated
Make sure that your student number is written on
the casts where it can easily be seen
Turn in your articulator with the casts
Tripoding the mesiolingual cusp
of #3 is optional. A flat landing
area in the central fossa of #30
is all that we require. If you do
want to tripod follow these
steps:
You already have a
contact on the
triangular ridge of
the distobuccal
cusp. This will be
a “shared” contact
with both tripods.
Add wax to
increase the
convexity of the
triangular ridge of
the distolingual
cusp until a contact
is achieved.
Carve this stop
away by refining
the central groove
and central pit
area.
Add wax to
increase the
convexity of the
triangular ridge of
the mesiolingual
cusp until a contact
is formed.
Congratulations! You have
completed your task.
Thank you for all your Hard
work.