00:00:00
hey guys it's Ryan and this video we're
00:00:02
going to be talking about selective
00:00:04
equilibration of denture teeth so say we
00:00:09
set all of our denture teeth and wax so
00:00:11
that the occlusion is absolutely perfect
00:00:14
well it's usually not absolutely perfect
00:00:17
but let's just say for this instance
00:00:19
that it is and we send it off to the lab
00:00:22
only for them to well mess it all up
00:00:25
it's not really their fault though
00:00:27
because the acrylic resin is shrinking
00:00:29
and expanding and the teeth get shifted
00:00:32
all around so usually the vertical
00:00:35
dimension of occlusion increases so you
00:00:38
can imagine if we were to set those
00:00:39
dentures back on the articulator the
00:00:42
incisal pin would be a little bit off
00:00:44
the incisal guide table as certainties
00:00:47
are contacting before they should so we
00:00:51
would need to selectively grind away
00:00:52
some surfaces to restore our video and
00:00:56
restore the occlusal scheme that we
00:00:57
started with but how do we know which
00:01:01
services to grind and that's when it
00:01:03
gets really freakin confusing so
00:01:08
hopefully this video is going to help
00:01:09
with that and I have one drawing here
00:01:12
that's going to hopefully help us work
00:01:14
through it so this is our base drawing
00:01:19
here and I want you to imagine you're
00:01:22
riding the Magic School Bus
00:01:24
and it drives right into your mouth and
00:01:27
sits at the back of your tongue so
00:01:29
you're looking at the left side of the
00:01:31
mouth on the left side of this drawing
00:01:33
and the right side of the mouth on the
00:01:36
right side of this drawing so this is
00:01:37
like a cross-section of some molars and
00:01:41
this would be buccal and lingual of this
00:01:44
side and lingual and buccal of this side
00:01:47
so again this would be the left side of
00:01:49
the mouth and the right side of the
00:01:50
mouth and let's say for this example
00:01:52
that the patient is moving their jaw to
00:01:55
the left okay so both of these sides
00:01:58
enough would be moving left and that
00:02:00
would make the left side of this mouth
00:02:03
the left side is drawing the working
00:02:06
side and the right side the non-working
00:02:09
or balancing side so if you're drawing
00:02:12
along with me that's awesome
00:02:13
and this is kind of our baseline drawing
00:02:16
what will work from okay so let's say
00:02:21
that when we're looking at our dentures
00:02:23
that were processed one cusp is just
00:02:26
hitting way before everything else in
00:02:29
both centric and eccentric movement so
00:02:33
one you're biting down and when you're
00:02:35
sliding the dentures around this one
00:02:38
customer is just way too high so we
00:02:39
would just grind that cusp down but
00:02:42
let's say it contacts early in centric
00:02:44
but not eccentric when we're sliding the
00:02:47
dentures around then we just make the
00:02:49
opposing marginal Ridge or fossa deeper
00:02:52
and grind that down okay so that's not
00:02:56
too bad so far
00:02:58
but it gets a bit more complicated and
00:03:01
that's when this drawing really comes in
00:03:03
handy so let's say there's not enough
00:03:06
overlap what does that mean so say that
00:03:10
this maxillary molar is too far lingual
00:03:13
or this mandibular molar is too far
00:03:16
buccal and they're kind of in like an
00:03:18
end-to-end relationship so these lingual
00:03:21
cusps are on top of each other and these
00:03:23
buccal costs are on top of each other so
00:03:25
that would be like not enough horizontal
00:03:28
overlap well we would grind down a
00:03:31
couple surfaces here we grind down the
00:03:34
lingual inclines of the maxillary buccal
00:03:37
cusp which would be this one and just
00:03:39
before I keep going so when it says
00:03:44
lingual inclines that means that it's
00:03:48
like the lingual facing inclined so if
00:03:51
you imagine this is the face of this
00:03:53
incline its facing towards the lingual
00:03:57
side of this side of the mouth so
00:04:00
lingual inclined means lingually facing
00:04:03
inclined it's also sometimes called like
00:04:05
an inner inclined because these two
00:04:08
would be the inner inclines of the molar
00:04:11
and then these two would be the outer
00:04:13
inclines of the molar so you'll see them
00:04:15
refer to in both context so again if we
00:04:21
had not enough overlap we would grind
00:04:23
down the lingual incline of the
00:04:26
maxillary buccal cusp
00:04:27
and or the outer aspects of the
00:04:31
mandibular buccal cusp and weird grind
00:04:36
down the buccal inclines of the
00:04:37
mandibular lingual cusps and/or they
00:04:40
asked the outer aspects of the maxillary
00:04:42
lingual cusps so be these four right
00:04:46
here and that would be to broaden the
00:04:49
central fossa and to narrow the centric
00:04:52
cusps okay so it's a little bit
00:04:55
confusing but as long as you follow
00:04:57
along with this drawing and can
00:04:58
reproduce it that's the key to answering
00:05:02
like an exam question now say we had too
00:05:06
much overlap so this mandibular molar
00:05:10
was too far lingual and this maxillary
00:05:11
molar was too for a buccal we would just
00:05:14
grind down the two surfaces that we
00:05:16
didn't talk about these two inner ink
00:05:19
lines here so it would be the buccal
00:05:21
incline of the maxillary lingual cusps
00:05:23
and the lingual in class of the
00:05:25
mandibular buccal cusp so let's check
00:05:29
this out a little bit more so we can see
00:05:31
how this works so let's go back to our
00:05:36
not enough overlap example and molars
00:05:42
are in like an end-to-end relationship
00:05:44
so we would grind down those four
00:05:47
surfaces that we talked about so we
00:05:50
grind this one down grind this one down
00:05:52
grind this one down and grind this one
00:05:54
down and now you have the the effect
00:05:58
that we kind of moved these cusps buccal
00:06:02
e and move these cusps lingually and so
00:06:04
instead of being and to end we kind of
00:06:10
restore the occlusion so that this
00:06:13
maxillary molar appears to be more
00:06:15
buccal and this mandibular molar appears
00:06:17
to be more lingual so you can kind of
00:06:19
see how that works out and honestly you
00:06:22
could do this with all of the examples
00:06:25
we talked about you can draw them and
00:06:27
erase the lines and redraw of them as if
00:06:30
they were ground down so that can kind
00:06:32
of help with the I think look working
00:06:35
through the concept and making sense of
00:06:37
it okay so let's go back to our drawing
00:06:41
and that's not this time talk about the
00:06:45
working side specifically so say the
00:06:49
buckle cuffs contact but not the lingual
00:06:52
cuffs so these two when we're doing a
00:06:57
working motion here and we're moving the
00:07:00
mandible to the left
00:07:01
these buckle cuffs are contacting but
00:07:03
the lingual ones are not so that means
00:07:05
the buckle costs are probably too long
00:07:08
so we would grind down the lingual
00:07:11
incline of the maxillary buccal cuffs
00:07:14
now if the opposite is true the lingual
00:07:16
cuffs contact but not the buccal cusp
00:07:18
then we would just grind down the buccal
00:07:21
inclines of the mandibular lingual cuffs
00:07:24
and this is purely on the working side
00:07:28
so let's say it's now the working side
00:07:31
contacts but not the balancing side so
00:07:34
when we move the mandible to the left
00:07:36
teeth on this side are contacting and
00:07:38
teeth on this side are completely
00:07:40
missing each other
00:07:41
which if you want bilateral balanced
00:07:44
occlusion is not what you want to happen
00:07:46
so that means that T's on decide are
00:07:49
just too high so we grind down
00:07:54
conveniently enough the two inclines we
00:07:56
didn't talk about it would be the buccal
00:08:00
incline of the maxillary molars at the
00:08:03
maxillary lingual cusps and the lingual
00:08:06
inclines of the mandibular buckle cusps
00:08:08
okay so that's on the working side and
00:08:12
now it would be vice-versa if say the
00:08:15
working side wasn't contacting and the
00:08:17
balancing side was contacting you just
00:08:20
apply these same concepts to the
00:08:22
balancing side and then one thing I want
00:08:25
to add in here if you have the working
00:08:30
side contacts but not the balancing side
00:08:32
another option would be to make a little
00:08:35
notch or sluice way in the buccal the
00:08:39
mandibular buccal cusp right where the
00:08:42
palatal cusp was contacting during
00:08:44
working side movement and again you
00:08:47
could apply this to the balancing side
00:08:49
if the opposite were true
00:08:53
so this is kind of like our completed
00:08:55
diagram if you had you know colored
00:08:58
pencils or markers or something in the
00:09:00
exam and you could reproduce this I
00:09:01
think this would be pretty much all you
00:09:04
need to know to be able to answer any
00:09:07
question about selective equilibration I
00:09:10
did want to add one other drawing though
00:09:12
and this one is from like a facial view
00:09:16
so we're no longer looking from the back
00:09:18
of the mouth were looking from the
00:09:19
outside and so this is sort of like our
00:09:23
typical class one relationship where the
00:09:27
mandibular teeth are slightly advanced
00:09:29
like one cusp from the maxillary teeth
00:09:33
and so this is our mesial side and this
00:09:36
is our distal side and so let's say the
00:09:40
maxillary molars were not only shifted
00:09:43
around vertically and horizontally
00:09:45
they're shifted forward and so these
00:09:49
maxillary molar cusps are just too far
00:09:51
mesial and so we would grind away to
00:09:56
musial inclines of the upper teeth and
00:10:00
the distal inclines of the lower teeth
00:10:02
and if the opposite were true and the
00:10:05
maxillary molar cusp or to distal we are
00:10:08
just grind down the distal inclines of
00:10:11
the upper teeth and the mesial inclines
00:10:13
of the lower teeth so that's all I have
00:10:18
guys if you have these drawings down pat
00:10:20
and you can reproduce them with color I
00:10:23
think that's all you need to know I
00:10:25
think that will be super helpful for the
00:10:27
exam and I hope this video is helpful
00:10:30
give it a like if you found it helpful
00:10:32
and thanks for watching guys I'll see
00:10:35
you all next time
