Facebows,
biteforks, and transfers
Mounting in average value
Reference planes
Immediate sideshift
Protrusive movement
Check bites
Spacers
N
NK
TS
TK
TR
AL
AP
AN
Mounting Splitex® Plates,
and Calibrating
Mounting Models in CR
Set-up index Key
Set-up Templates
FACEBOWS, BITEFORKS,
AND TRANSFERS
Q: Is it possible to use the
Rotofix® facebow nose-bar on someone whose nose
bridge is rather flat? If so, how?
A: Yes, by using silicone to
make a custom nasion to wrap around the nose.
Q: We find that sometimes
a bitefork may sit too high in the articulator after
we've done the transfer. What can we do about this?
A: There are several things that
could have resulted in the reference plane being too
low and the bitefork mounting too high. To troubleshoot:
- a. Make sure the facebow is used properly:
- make sure that the patient's mouth
is slightly ajar, in order to open up the ear
canals enough to allow the facebow earballs
to seat properly. This can be done
by placing the bitefork (with bite compound
on three points) in the patient's mouth, with
cotton rolls between the lower teeth and the
bottom of the bitefork. When the patient bites
down to hold the bitefork in place, the mouth
is still slightly open due to the cotton rolls.
Rotate the facebow up and down once or twice.
Then attach the 3-D joint to the bitefork.
- make sure that the person performing
the facebow registration lifts up the skin at
the top of the nose before placing and locking
the nasion against the nose.
- make sure that the facebow is securely
fitted to the face, so that it does not slump
when no one is holding onto it. (NOTE: DO NOT
OVER-TORQUE THE TOGGLE LEVER!)
- b. Consider using the Frankfurt Horizontal
Plane (using axis-plane indicator #48610) rather
than the usual Patient Horizontal Plane for your
reference.
- c. Do not use too much bite compound on
the bitefork. Place only a small amount on three
points, on the upper side of the bitefork. Too much
compound can affect the positioning of the maxillary
cast when mounting. Also, do not let the canines
come in contact with metal, or you will not have
accurate cusp tip impressions for reference when
stabilizing the maxillary model.
d.If the dentist has this
problem often, a solution is to have the patient
oriented horizontally in the dental chair, so
that the facebow is not affected by gravity.
Q: Can the Rotofix facebow be used on someone
with a narrow head?
A: Yes, by adding the "extended ear-balls"
(#48609).
Q: How do you transfer directly into the
articulator without a transfer stand?
A: Use the transfer jig (#48630). Remove the
incisal pin and holder, transfer the incisal table
to the upper arm, and mount the jig, resting the incisal
table on the jig. Mount the universal joint and bitefork
onto the jig. Use support table #47685 to stabilize
the bitefork.
The disadvantage of doing it this way is that the
universal joint is not available until the model is
mounted and the joint can be removed. It's less expensive
to buy tables than joints.
Q: How do you mount a facebow directly
into the articulator without a transfer stand or
a transfer jig?
A: Use the telescopic legs and the level (#47624).
- Note:To mount in an AP, change the condylar
inclination to "0" to recreate the 3.5
mm vertical and 6.5 mm sagittal condyle placement
that is the same as the earhole location. On a non-arcon
type, set the Bennett Angle to "0". Adjust
the condylar inclination to 60°, or else there won't
be a place to mount the earpieces.
Place the balls of the earholes from the facebow
into the pins on the top arm of the articulator.
Remove the lower part of the incisal guidance pin
on the facebow. Rest the facebow on the black housing
of the incisal pin, using the level to make adjustments
to the telescopic legs.
On an NK, exchange the earpin/sidebars on the facebow
so the pointy pieces can fit into the ends of the
condyle ball pins on the articulator.
Q: Can I transfer the Rotofix facebow to some
other brands of articulator? If so, how?
A: Yes, but only directly, not with the Splitex®
transfer stand.
Q: Can I use my Rotofix facebow with a Denar®
articulator? If so, how?
A: Yes
- a. by mounting the facebow into the Denar
articulator and shipping the whole articulator
- b. by shipping the facebow and the bitefork
to the lab for mounting
-
Q: Can we transfer some other brands
of facebow into our articulator? If so, how?
A: Yes, by using part # 47920 for a SAM®,
or part # 47930 for a Whip-Mix®. The incisal pin
sits on the incisal table to make the reference plane
of the facebow level. You must also use the bitefork
support.
Q: Can I transfer a Denar facebow into Artex articulators?
If so, how?
A: Yes, by using Jensen jig for Denar (#47925) and
a bitefork support (#47685).
Q: How can you close the articulator if
the bitefork interferes with the incisal guidance
pin?
A: a) Move the incisal pin away from
the articulator, and move the incisal table out to
match.
b) Use the "cranked
pin" (#47131)
Q: If the teeth are missing, how do you
use a bitefork for a crown or bridge case?
A: Two possibilities:
a) Put a lot of bite compound
on the anterior point of the bitefork, and place two
balls of silicone putty on the back of the bitefork
in place of the missing teeth.
b) Make an individual tray
out of self-curing tray material, and insert the small
Artex handle which will connect with the facebow joint
Q: If you autoclave the entire facebow,
do you have to oil the joints?
A: You can if you want to, with a silicone
spray. Also, the earballs and nosebar are removeable
for sterilization.
MOUNTING IN AVERAGE VALUE
Q: How can you mount crown and bridge models
with the average value template?
A: a. Attach the template holder with the
magnetic plate (#46260) to the upper arm of the articulator,
and add the flat template (#47740) to it. You can
use a rubber band, wrapped around the articulator
in the grooves on the legs an occlusal plane indicator
for lining up the template vertically. Align the mid-line
on the template with the incisal needle. Place the
lower model on the template plate. Line up the incisal
point of the lower incisals with the mid-line on the
plate. Line up the horizontal line with the same place
on both 1st molars, just to make sure the model is
not twisted. Mount the lower model to the buffer plate
with quick-setting plaster. Then bring the upper model
into centric occlusion and mount it with plaster.
b. An alternative is to put the incisal needle
into the incisal pin, and to place a rubber band around
the articulator (in the grooves provided). Then place
enough mounting plaster to reach the lower model,
and fix the model by hand.
Q: How would you mount models in average
value for partially-edentulous patients requiring
dentures?
A: Begin the procedure as above, using the
template holder and flat template. Set the lower teeth
with the incisal edge in contact with the flat plate.
Then change to one of the various curved templates
(chosen based on the cusp inclination of the manufactured
teeth), and mount the teeth to the cusp tip of the
canine and lingual cusp of the first pre-molar.
Q: If you're mounting in average-value,
what do you use as the condylar inclination on an
adjustable articulator?
A: Mounting with the Bonwill Triangle is very
close to the Camper Plane, so you use an average value
condylar inclination of 30°.
Q: How can you mimic long-centric in the
restoration without a centric relation registration
(leaf wafer) from the doctor?
A: Choose an articulator that offers a protrusion
and retrusion indicator, such as the Artex TR or AR model.
REFERENCE PLANES
Q: What's the advantage of using the "Patient
Horizontal Plane", versus the Camper Plane or
the Frankfurt Plane?
A: a) It leaves an equal amount of room for
the model between the upper and lower arms of the
articulator.
b) It represents the
patient looking straight ahead, not up or down, and
the technician can know exactly which direction the
patient would be looking in even if the patient isn't
there. This can help with dentures.
Q: If a doctor wants to work with the Camper Plane
or Frankfurt Plane rather than the Patient Horizontal
Plane, is it possible with the Rotofix® facebow?
A: Yes. Use the reference plane indicator
(part #48610). It screws on to the corner of the facebow,
and swings out to the appropriate reference point
on the patient's face. If necessary, you can also
use the adjustable height nosebar ( #48690). In this
case, the dentist must provide a specific condylar
inclination.
Q: In addition to the hinge-axis, what
is the third reference point in each reference plane,
and which condylar inclination goes with which reference
plane?
A: Frankfurt
The third anterior reference point is the "v"
in the bone under your eye. The corresponding condylar
inclination average value is 40°.
Camper
The third anterior reference point is the bone under
your nose. The corresponding average value condylar
inclination is 30°.
Patient Horizontal
The third anterior reference point is about mid-nose.
The corresponding average value is 35°.
Q: How does each plane relate to the articulator?
A: The reference plane, no matter which one,
will always be parallel with the top arm of
the articulator. However, depending on which plane
you use, the model will be mounted higher or lower,
or at a steeper angle, in the articulator.
Frankfurt
When models are mounted, there will be a large amount
of room between the upper arm of the articulator and
the model, and a small amount of room between the
lower arm of the articulator and the model.
Camper
There will be a small amount of room between the upper
arm of the articulator and the model, and a large
amount of room between the lower arm of the articulator
and the model.
Patient Horizontal
There will be equal amounts of room between the model
and the upper & lower arms of the articulator.
IMMEDIATE SIDESHIFT
Q: How do you achieve an I.S.S. adjustment?
A: It depends on the articulator model. One
turn of the screw in the middle of the upper arm of
the TS or the TR equals 1mm of I.S.S. (note: you must
open the two screws on either side of the middle screw
first). On the AR, adjust the lateral slide with an
allen wrench.
Q: Does the TS or TR always have to be
locked out of I.S.S. when checking or working in centric?
A: Yes, the I.S.S. screw must always be closed.
There is a new screw available to be able to do a
quick check in centric by pushing down on a button
that locks it and keeps it from allowing I.S.S. at
that moment.
PROTRUSIVE MOVEMENT
Q: Can you measure protrusive movement in a TS?
A: Yes, by moving the set-screw directly above
the condyles from the rear hole to the hole nearer
the incisal pin. Then add the protrusion indicator
on the back of the condyle, in place of the existing
screw. The protrusion indicator shows you how many
mm of protrusion you are adjusting.
Q: Can you use the protrusion indicator on the
NK or TK?
A: No, because there's no second hole to move
the set-screw to. The protrusion indicator only works
on the TS. (The TR shows protrusion, but doesn't require
the addition of the indicator. It has a built-in system).
Q: Is the method for measuring or locking
protrusive movement in a TR the same as a TS?
A: No, you don't need to move the screw in
a TR. You unscrew the fatter, top screw to allow protrusive
movement. You unscrew the bottom screw under the fat
screw, with the fat screw tightened, to allow
the condyle housing and condyle to move in the same
protrusive movement, but this screw combination will
allow you to lock it into this position in
case you want to do a build-up in that position.
Q: What comes with the complete set of the #48170
individual incisal table? How do you use it?
A: It comes with the special incisal pin and
table, a calibration bar, and an allen wrench. You
exchange the incisal pin for the normal one and then
calibrate the pin to your articulator. Replace the
normal table with the special one, and set the pin
all the way to the front. Loosen the screw on the
front of the incisal pin. Put the piece of calibrated
metal bar on top of the special table, all the way
to the back. Push the incisal pin all the way to the
point where it touches the bar, and then lock the
incisal pin. Remove the metal bar. Now you can raise
or lower the table to the correct individual guidance
without having the upper arm of the articulator move.
(or, "without changing the vertical dimension").
CHECK-BITES
Q: What is the Regi-wax® used for?
A: It's used for protrusion check-bites, which
relates to the condylar inclination in the articulator,
and for lateral check-bites, which relate to Bennett
Angle.
Q: How do I use it, or a similar wax product?
A: There are 8 wax plates for protrusive check-bites
and 16 wax plates for lateral check- bites. The wax
should be warmed in hot water. Take an incisal check-bite
using the plate that has a cut-out in front, and lining
up the incisal edges of the teeth with the cut-out.
Have the patient bite down to make an impression in
the wax. Use the wax plate with a cut out on the left
side for a lateral check-bite on the left side of
the mouth, and use the plate with a cut-out on the
right to line up the teeth on the right- hand side
of the mouth.
Place the protrusive wax bite on the lower model,
replace the upper model. Turn the articulator upside
down. Turn the condyle housing until there is no contact
between the condyle ball and then back again until
there is a "first contact". Then set the
screw for the condylar inclination in that position.
Do the same on the other side.
For the Bennett Angle, mount the models with the
wax bite in between. Open the condyle boxes. Make
the Bennett Angle adjustment on the opposite side
of the canine contact that was registered in the wax.
Turn the wall of the condyle housing until it hits
the metal condyle ball and lock it.
Note: This works best in an arcon-type articulator,
such as an AP or AR. However, if the doctor uses an
AP or an AP and takes check-bites, and the lab uses
a TS or a TR, the lab can match the condylar inclination
and the Bennett Angle settings.
SPACERS
Q: What are the spacers for?
A: They can be used when making occlusal splints,
only with certain non-arcon articulators. For diagnostic
purposes, you can work not only in the lateral, horizontal,
and sagittal planes, but also in the vertical plane.
For example, when the doctor decides to lift the bite
on the incisal edge by 2 mm, you lift the incisal
pin by 2 mm. This does not yet raise the incisal edge
by 2 mm, because the closer you come to the center
of rotation, the smaller the radius of opening is.
You must use spacers to also raise up the entire upper
arm by 2 mm, and then lower the incisal pin until
it hits the table.
This is also helpful when overbuilding porcelain
to compensate for shrinkage. After baking the porcelain,
go back to "0".
Revision 0, 1/19/00