-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
1/19
1
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
2/19
2
Prosthodontics lab 6 part 1. Done by : Enas Y. Salameh
Jaw Relation Record
After we fabricated the Record Block in the previous lab, today we are going to
learn how to make Jaw Relation Record (JRR) / Jaw Registration / Bite
Registration (informal term), which represents the relation between the maxilla to the
mandible, and the maxilla to the rest of the head, the colour/shade of teeth and so on.
This step will be in the CLINIC which will be the last clinic to register the jawsrelations, then we will attach them to the articulator after that we will start to
do setting of teeth.
The Process of attaching the casts to the Articulator is called Mounting usingPlaster.
** The next process after setting of teeth will be wax trying, if everything is ok we
do processing to the dentures (flasking, dewaxing, curing, deflasking polishing)finally we will do the dental Insertion.
Steps of Jaw Relation record:
1) The Vertical Relationship
** Starts first with the maxillary rim THEN the mandibular rim.
A) Maxillary rim:
1) Labial Fullness:You have to check if the lip has enough support from the opposing teeth (wax
rim till this point).
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
3/19
3
In right situations the angle between the lip and the columella of the nose
equals to 90 degrees ,if this angle is less than 90 (acute angle ) this means that
it's too prominent ,but if it's greater than 90 this means there is not enough
support (the patient will look older).
If it is too prominent I use my wax knife ,heat it then I reduce the anteriorangulations, but if it's position is backward I add more wax to it until I have
adequate prominence .
2) Buccal Corridor:
(check the contours posteriorly) when the patient
smiles there is a space between the occlusal rims and
the cheek (at the corner of the mouth) at both sides.
If the wax rim is too prominent the teeth will look
as they continue endlessly and the smile will look like a
wall which is not aesthetic.
In Normal smile we see the anterior teeth and the most prominent surfaces of
the premolars and barely you see the first molars, but if the teeth are too prominent
we will see the whole teeth specially if you choose small teeth, therefore we will
remove the excess wax from the side and if the corridor is small we add wax.
3) Length:
It depends on aesthetic (which we will concentrate on it), phonetics and
functions.
At rest position where the mouth is a little bit open normally you will see about
1-2 mm of the incisal edges of the teeth (occlusal rim) below the upper lip.
In Old patient the upper lip will look longer because of the change of the muscletone with time, and the gravity will bring it down, so less teeth will be seen, and
the lower lip will go down too and more teeth will be visible. "The smile line will
go down".However, in younger patients you will see more of teeth.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
4/19
4
The natural length of the lip, if the patient has a long lip we expect to see less of
teeth. So, you have to use your artistic sense to see if the smile looks nice or not.
4) Orientation:The occlusal rim should be parallel to the patient's natural occlusal plane.
All my measurements depends on where the teeth should be, but the problem is
that the patient has No teeth, so I need references or guides that was and still
present in the patient face before and after teeth extraction which are:
- One anterior reference and two posterior references to make the occlusal plane
which are imaginary references.
1- ** The anterior reference is called Interpupillary line.**The posterior references are called Ala tragus lines.
Anteriorly: use a ruler and put it in front of the patient's face and keep moving
it until you find the interpupillary line ,then I put the wax rim in the patient's
mouth and mark the excess points then remove the wax rim and remove these
excesses by a hot plate ,and if it's not enough add wax until you find the right
orientation (parallel to interpupillary line) .
In some cases the eyes are not levelled due to trauma so we use other
references like lower lobes of the ears, but in worst cases where you can't find
any references ask the patient to stand up and look forward , if the wax rim is
parallel to the floor then it's levelled .
Posterior References: Alatragus line, from the lower border of the ala of the
nose to anywhere in the tragus of the ear (tip/middle/lower border).
But as you can't see the wax rim orientation through the patient's head, you
have to use an instrument to find campre's plane (interpupillary +Alatragus
Camper'sPlane
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
5/19
5
lines) which is called Fox's Plane. Put this instruments inside the patient's
imouth and put the ruler in front of the eyes, if it's not well oriented I start to
remove the excess from that side .
5) Check:
To see if everything is okay * aesthetically (see if he/she smiles well) we dont
need a gummy smile.
*Phonetically (check the sounds of some letters like (S), (F and V) .
The wax rim should have the same dimension of teeth.
*Functionally
6) Mark the midline:
Which represents the middle of the face not the lips or nose, because people often
have asymmetrical faces, so we use a floss or a ruler to mark it, and we mark the
midline on the occlussal rim where we will start to put teeth on the right and the
left of this line.Then I have to mark the width of the teeth by marking the distal surfaces of
canines by a line that extends from the intercampus of the eye to the outer edge of
the ala of the nose to the occlussal rim on the right and left and the canines will
be determined there. After that ,measure this distance by a flexible ruler which will
help in determining the size of the teeth .Sometimes we take a straight line from
This is the foxs plane instrument Foxs plane used inside the patient
mouth
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
6/19
6
the side of the nose to the occlussal rim which will give me the tip of the canine
,this distance is smaller than what I want, so I use a specific equation to find the
right value.
Or you can use the corners of the mouth; when the patients lips are at restplace a lecron carver in the corner of his mouth which will mark the distal
surface of the canine.
The canines is called eye tooth because its located below the pupil of the
eye .
Then I need low and high smile lines, when the patient relaxes draw a curve
line with a lecron carver that represents the position of the lips at rest (low
smile line), then let the patient smile and I draw another line curve (high smile
line) which is important in selecting the length of teeth.
~END OF PART ONE~
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
7/19
7
Prosthodontics lab 6 part 2. Done by: Osama Yusuf
Now that we have finished the vertical relation of the maxillary occlussal rim, we
are going to make the same for the mandible.
B)THEMANDIBULARRIM
There is a reference called VerticalDimension ofOcclusion (VDO). It is
a measure I take, which start from the tip of the nose to the chin. This
measure will help me to select how tall the mandibular rim should be.
Unfortunately this reference is gone when there are no teeth present,
meaning this reference is not found on edentulous patients.
Luckily, I have another reference I could use which is not affected by
the presence or absence of teeth. It is called Vertical Dimension at Rest;
(VDR).
This reference is always constant before or after teeth extraction. Most
of us when resting (watching TV, listing to a lecture ...etc) our teeth are
not touching each other; the mandible is hinging a specific distance
below the maxilla with a space between the teeth (Freeway space).
The hinging of the mandible at rest depends on A) Gravity B) the
muscles.
Please take into consideration that VDR measures the space between
the jaws, but Freeway space is between the arches (teeth).
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
8/19
8
Asking the patient to sit upright, the lower jaw will relax in a specific
distance between the upper and lower arches. Measuring this distance
will result in a reference that is stable; VDR.
You dont need VDR, you need VDO. You measure VDR because thepatient has no teeth, and then you calculate VDO = VDR3.
The number 3 came from many studies which have concluded that the
freeway space in a huge numbers of patients to be 3-4 mm. Take in mind
in some rear cases this might reach to 9mm.
Now we got the VDO, we have to do a check to make sure that it is correct. We will
do a visualcheck and aPhonetic check
In the patient mouth I should see that the lower wax rim should beleveled with the vermilion border (the red border which is between
the mucosa and the skin )
Wax rim should be leveled with the corner of the mouth by thesides.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
9/19
9
The height of the wax rim should be 2/3 of the height of theretromolar pad
The occlussal rim plane must divide the tongue into an upper half and alower half when the tongue at rest; in other words the occlussal rim plane
must be in the equatorial of the tongue.
We said that there is a natural space between teeth when at rest; we said
it is called freeway space. This space is good, teeth touching each other
always are not good for many things (TMJ, muscles ... etc) even when
talking you dont hear yourself clicking your teeth, and you talksmoothly without your teeth touching.
I have to make a check to make sure that when applying the wax rims to
the patient mouth that when he is talking he is not touching his teeth
together. How to do this?
There are some specific sounds, when pronounced the teeth willbe as
close as possible (try to say Faaa , and try to say Saaah , in
Faa they are not close as in Saaah ). Saah , Chaah are some examples
when the teeth are very close to each otherbut they dont touch.
Asking the patient to count from 60-70 fast, we observe if the wax rims
are touching or not. This is one example for this; there are too many
other tests you can do on your patient. Anything with Shaa and Chaah is
good.
If there is 2 mm between his teeth when he says these words, fantastic.Even if there is 1 mm this is still good, there must not be a contact
between teeth when speaking.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
10/19
10
This space is included within the freeway space, it is called the Closets
speaking Spaceand it is less than the free space (1 mm while freeway is
3 mm).
Now that we have finished the vertical occlussal relationship, logicallywe have to do the 2
ndstep which is the Horizontal relationship
What relates the upper jaw and the lower jaw together? It is the TMJ.
From this I know that my reference for the horizontal relation is the
TMJ, but still the lower jaw can move lots of movement, we need
something accurate which is Centric Relation reference.
We use it to bring the rims together in the horizontal plane, if you didnt
do the horizontal relationship and just inserted the rims in the patients
mouth he could close them many directions each time he close. This is
certainly not good and more importantly not natural.
Centric Relation means the zero point or the middle point. I want themandible to be at the mostposterior position (which is the natural
position of the mandible).
If the lower jaw is in the most posterior position, the condoyle will be
actually on the mostAnterior Superior position in the genloyid fossa.
Keep in mind that the condoyle isbone to bone relationship not tooth to
tooth, because of its bone to bone relation it saves repeatable positions
this is why I use the condoyle as my reference, because it is repeatable
or habitual position. This means when I put the teeth on, the patient will
close and open in the same position. Keep in mind that this will only be
correct if the vertical relation is correct.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
11/19
11
This is the facebow instrument
From all the information above I can say that, the centric position is
when:
The mandible is at the most posterior position There is bone to bone relationship in the TMJ The condoyle is at the most superior anterior position in the genlyoid fossa It is a repeatable/Habitual positionas long as the vertical relation is correct.
Now that we have talked about the vertical and horizontal, the third step is
facebow record.
This step came from the need to know where exactly I put the upper and
lower rims on the articulator. In this step we use another instrument
called Facebow.
Its function is tomeasure the relation between the upper jaw and the rest
of the skull or between the upper jaw and the hinge axis that go through
the TMJ. Keep in mind it is unlink the Foxs plane instrument which
locate (not measure) the occlussal plane. While the facebow relates the
occlussal plane to the base of the skull.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
12/19
12
100 years ago anatomists gathered in Frankfort-Germany and agreed that
the zero reference is called Frankfort Horizontal Plane; it is present on
the patients head as follows: from the inferior margin of the orbit we
mark a point to the external auditory meatus we mark a point. If I drew aline between them while the patient is standing this will give me two
lines. (4 points, 2 for the orbit and 2 auditory meatus = 2 lines). So my
reference for this step is the Frankfort plane.
Keep in mind 3 points are enough to draw this plane (2 auditory meatus
/TMJ and one infraorbtial will make a line).
FH = Frankfort plane
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
13/19
13
Although we will not use the Facebow instrument, it is wise to show you
how to use this instrument. It will become handy to learn this now and
be ready to use it in the upcoming years nshallah.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
14/19
14
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
15/19
15
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
16/19
16
This step includes choosing the proper teeth, teeth color and other
properties; we will talk about this more in later lectures.
With this we have finished the theory part for this lab. The only thing
left now is the practical part, but before that we will show you the
different parts of the articulator.
You have three types of Articulators,Non-adjustable, Semi-adjustableandFully adjustable. And you also haveaverage value andnon-
average value.
If you look at your Articulator box there is a phrase says AS 5000 which means
your articulator doesnt accept facebow record. But if it were AS 5010 it can
accept facebow record but costs more.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
17/19
17
A very important note you should note, is that the condylar in nature is attached tothe mandible. But in the articulator it is attached to the maxilla ( not like nature ).
A new classification rises with this note, we haveArticulator Condylar orARCON. Which they have their condylar attached to the maxilla.
We haveNon-Articulator Condylar or Non-ARCON, Which have it onmandible.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
18/19
18
The articulators are not always centered by default by the manufacture.
So I need you every time you use yours to make a check on the
following things:
- Open the incisal pen screw, allowing the incisal pen to movefreely. Look at the incisal pen you will see we have three lines
above and then a heavy line and then a three line below. The heavy
line should be leveled with the top of the articulator, after you
adjust it tighten the screw to hold it in the correct place.
- Some of you when opening the condylar screw you will hear aclick. This click is because it is tripped in a wrong position, what
you have to do is using the condylar screws; adjust them by
pushing them in the correct way and then hold them in that place
by tighten the screw.
Angles :In (1) which is the angle of the incisal table laterally
which is 10. And the angle of the incisal table (2)
which is 15. You also have the angle of the condylar
assembly which is 30.
-
8/3/2019 Prosthodontics LAB 6 ,Jaw relation Record ,cont
19/19
19
Keep in mind that each one of you has a different length of wax rims. We wanted
you to be all equal so we didnt do the facebow technique, instead we made a
maxillary jug and a mandibular jug (not sure of the word but it is something jug),Attached them to the rim while working. So you all had the same method of
constricting it. So you are not going to do any of what we disscuesd , but you must
remember it.
Before doing anything we have to bring the cast and make a three retention
notches one labillay and two behind. If you are not sure
where to trim the cast using the bur draw three triangles
and then cut it like the pictures on the right.
After that we will use the jigs (or whatever their name is
look at the last right picture) for the upper and lower.
Remember we dont do this at the clinic it is just a
method to make us all have equal results.
Then we will pour the plaster and we will remove the
excess using the plaster knife until we have a nice clean
looking plaster attached to the cast. We can polish the
surface of the plaster with sandpaper.
We soak the cast for 3-5 min, do you know why?
Because the plaster will not sick to the cast when it is
dry (the thin layer between the cast and the plaster will
become dry because the water moved from the plaster to
the cast). While if we soaked the cast in water we can
start the mounting without any problems.
Done by : Osaka Yusf (yes Ali it is Osaka )