Occlusion and Equilibration Flashcards
if occlusal plane is curved and mandibular path is curved, posterior teeth will ____ in excursions?
OCCLUDE
if occlusal plane is flat and mandibular path is curved, posterior teeth will ____ in excursions?
DISCLUDE IN excursion
what tooth set up when H and V are efficient but ridge is not?
use monoplane with flat cusp and flat plane – will go up t0 2/3 height of RM pad because we want mosr retention
what tooth / plane set up when H and V are insufficient and ridge is insufficient
flat cusp with CURVED PLANE
- we need to use a curved plane because we need to provide protection in the anterior – so build in a curve but use flat plane because the ridge is insufficient
using 2/ 3 or 1/2 RMP
when do use anatomical set up
when H and V are sufficient
curve is sufficient
ridge is sufficient
- so we can add cusps – to provide further disclusion when the patient goes into protrusion or lateral movements
2/3 or 1/2
christensen’s phenomena
if occlusal plane is FLAT but the mandibular path is curved posterior teeth will DISCLUDE in excursions
H and V refer to?
anterior teeth – so we do not get anterior guidance
can build in curve to limit incisal guidance
curve of spee is what?
compensating curve
what do curves do?
curves create balance – whatever the cusp is
balancing ramp?
either TIPPING LAST TOOTH or ADD- addition of more wax/ material distal to the last tooth that can act as a compensating curve and create the same effect of curving the mandibular path – creating balance
so if occlusal plane is flat but there is a CURVE with this balancing ramp – posterior teeth with DISCLUDE in excursions
what do cusps create - general
further disclusion
can you have balance with a flat plane?
yes
what is compensating curve compensating for?
the slope of the articular eminence –
if really big overlap?
create a curve that is more severe and add cusps
- protecting the overbite
(little overlap– can create little curve)
relationship between vertical walls and retromylohyoid space
this space is afforded to us by the retromylohyoid space – better vertical walls = better resistance
vertical walls of good ridge give us?
implications on tooth selection?
RESISTANCE to lateral movements – “walls” afforded to us by the retromylohyoid ridge
we use this to determine which cusp to use – as better walls = better resistance in lateral movements
Vertical walls of resorbing ridges?
offer less resistance to lateral movement s
and vertical walls of resorbed ridges offer NO RESISTANCE to lateral movement
implication of cusped teeth in terms of force?
they deliver a greater lateral force than flat teeth
so if patient with no ridge is locked in with cusps – mandible moves and denture wont so pt. cannot retain and resoprtion occurs
cusp teeth stay in what for longer?
CONTACT – we want this only if ridges can support it
bad contact when going into protrusive movements can cuase?
sore spot against the anterior ridge
same thing can happen if bad contact when going into lateral excursions as the denture will push against the ridge
relationship of LOWER teeth to lower crest of ridge in monoplane?
in anatomical?
monoplane = centered to the ridge
anatomical = lingual to the ridge
lingualizing the lower teeth is beneficial how?
lingualizing the teeth will help resist the lateral forces
what is the relationship between the maxillary and mandibular molars in an anatomical set up?
3mm buccal to center of ridge – so buccal cusp of max sits here – so the buccal cusp of the mandibular molars
MANDIBULAR BUCCAL CUSP CENTERED OVER CREST OF RIDGE – aligning with the maxillary central fossa
maxillary central fossa is over what?
centered to the mandibular crest of ridge
long axis of the bicuspids are what to the plan in anatomical set up?
PERPENDICULAR to the plane
what cusps of bicuspids contact the plane in anatomical set up?
except the buccal cusp of the second pre-molar
- creating the curve
contact of maxillary first molar in anatomical set up?
only the ML cusp touches - so it is tilted
explain ‘two curves of spee”
buccal and lingual curves of spee and the difference in them is the curve of wilson
curve of spee starts where?
1/2 height of RMP - so if place second molar the height / tilt of this cannot be placed any higher than 2/3 the height of the pad
key relationship in anatomical set up?
MAX FIRST MOLAR
MB cusp must align in the buccal groove of the mandibular first molar — this is the most important tooth relationship besides the maxillary centrals
if max centrals too far facial? too far lingual?
too far facial – mandibular anteriors are forced to be too facial
to far lingual – mandibualr anteriors will also be too far lingual – so whole set up is too distal and arc is not big enough and wont have enough room
diastemas in anatomical set up?
NO – percise alignemnt in centric will facilitate alignement in excursions
- means no diastemas and no wax on occlusions
how is vertical overlap created?
by raising the lowers
when can you never have a vertical overjet?
with a flat tooth and a flat plane
flat tooth curved plane in relationship to H and V? - deciding to raise plane?
can lift up the lower anteriors
cusped teeth with curved plane H and V relationship if need to adjust?
can have vertical overlap and can get more close horizontally as well – because the cusps afford dislcuson in anterior
cusp affords what?
ability to disclude in protrusion
rotational and lapping in anterior teeth?
may need to occur in the anatomical set up of mandibular anterios if there is not enough room and need to fit the teeth in the arch
working contact?
THE TEETH ARE EDGE TO EDGE ON WORKING – the mesial and distal inclines are aligned
all cusps contacting buccal-buccal
lingual- lingual
we get it to look like this by eliminating canine guidance
balancing contacts where?
contact between SUPPORTING CUSP INCLINES — incline of max lingual and incline of mandibulr buccal
centric occlusion contact in anatomical
NO ANTERIOR CONTACT
- there is contact between the supporting cusps
cusps in fossas
*the inner inclines of the upper cusps should be visible
what should be visible in centric in anatomical- what inclines? if cannot see what are you in?
INNER INLCINES of the upper cusps– teeth are NOT edge to edge
need to have the inner inclines visible as this is the ‘reveal’ area – if not = EDGE TO EDGE
REVEAL
in centric occlusion – the reveal of the inner inclines of the max buccal – so we are ofset a bit and this should be UNIFORM
what can you manipulate in upper or lower teeth to provide the reveal?
upper teeth can be rotated
lower teeth can be labialized
anterior contact / relationship in centric in anatomical? posterior?
anterior =NO CONTACT - but we can have overlap
posterior = SUPPORTING / functional cusp contact – cusps in their fossas
cusp relationship in left working?
incline relationship?
how do we achieve this?
cusps are EDGE TO EDGE – all are touching
mesial and distal inclines are aligned – they slide through eachother
we get it to look like this by ELIMINATING canine guidance
same if this was for right working too
right balancing contact?
in SUPPORTING CUSP INCLINES – maxillary LINGUAL
– mandibular buccal
as mandible moves left – this is what contacts
what can go wrong in terms of lab remound with exothermic reaction or wax on teeth?
if dough too rubbery?
teeth can move – if not enough wax on record base part – cannot separate as well
dough too rubbery = excessive VDO
proccessing error in terms of occlusion? how does this happen?
IF WAX LEFT ON TEETH — the space between tooth and investement from wax remaianing on occlusal
so results in space b/w the tooth and investment – allows tooth to MOVE and there WILL BE AN OCCLUSAL ERROR
tooth movement during processing causes?
occlusal errors
what can go wrong before processing?
poor tooth position
wax shrinkage
during processing errors
wax on teeth poor luting exothermic reaction overpacking packing too slowlt insufficient pressure heating/cooling too fast
ALOT can go wrong and can all effect the occlusoin when back on the patient
after processing errors?
heat from polishing
dessication (if dentures not kpet in water until the insertion)
sequence of corrections
- lab remount
2. clinical remoount
Lab remount
when
check what
IMMEDIATELY AFTER processing and BEFORE decasting and polishing
checks VDO and re-establishes VDO
number one reason is to RESTORE THE VDO
clinical remound
when
check what
DONE AT INSERTION
checks centric and eccentric
maintains the VDO
EQUALIBRATE THE OCCLUSION
describe lab remount
processed dentures on their final casts
plaster mountings on articulator and pin at VDO
final casts remounted via notches with pin up
dentures ground down to re-establish the VD) - pin down
when does de-casting occur?
after the lab remount
what could go wrong in the clinical remount?
- facebow preservation BEFORE THE final occlusion check
- CR registration incorrect - or perforation of aluwax
- mount without luting or lack of stablizatoin
- pt. remount not in CR
6 main goals of equilibration
- to have CO=CR
- to maintain VDO
- to distribute stress
- to retain cusp shape
- to smooth contacting surfaces
- to achieve balanced occlusion
polymerization shrinkage occurs towards what?
the greatest bulk of the denture – so towards the posterior – so where we may have an interference — like
adjusting monoplane occlusion where do you start?
look at the height of the RMP – make sure we are at 2/3 if this is correct (area C and B) – we go to area D - maxillary
with monoplane if need to reduce VDO?
need to adjust both up and bottom
but can only adjust C to 1/2 if need to
what type of adjustemnts are we doing in monoplane?- general
what to do with bulls eyes?
flat adjustments – this is a flat occlusion
do not aim at the bullseye – adjust into it - remove them
if incisal or canine guidance exists what do you do?
create WEAR FACETS
– CONSIDER BEVEL
desired contact in CR for monoplane
no anterior contact no canine contact - contact in posterior
any tooth that has gone beyond occlusal plane in monoplant posterior is considered?
a posterior INTERFERENCE - need to adjsut this
adjust D
adjusr pad
what do you adjust first plane or pad
PLANE – so perfect lower plan to 2/3 RMP then adjust maxillary D area
anterior interference in CR for monoplane? incisal guidance?
increase the horizontal and decrease the vertical
bevel it - to try and keep the height if we can so adjust the facial aspect
monoplane posterior interference in lateral?
want group function – but if not cannot just remove single tooth interference — have to adjust ENTIRE OCCLUSAL PLANE – and create a curve of wilson
what type of occlusal shceme are we aiming for in monoplane?
group function -
T/F with all flat mandibular you use same rules for adjusting occlusion if have flat upper OR lingualized
TRUE – true for all flat mandibular monoplane
equilibration sequence for anatomical set up
- centric interferences
- lateral interferences
- protrusive interferences
interference
any contact that interferes with desired outcome
what will grinding supporting cusps do
results in LOSS of CR and VDO
primary and secondary cusps are move vs non -movable in working movement/ balancing on other side
primary = upper lingual – do NOT MOVE
secondary = lower buccal = move
aka mandible is moving
centric prematurity AKA…
implication?
interference and will OPEN OCCLUSION ON OPPOSITE SIDE
vertical centric interference in centric occlusion do you grind cusp (mandibular buccal) or fossa (maxillary){
DEPENDS
before grinding you have to check?
excursions - so check right lateral/ left lateral and protrusion
when to grind fossa if centric interference
if all excursions are okay because cusps contact in these
grind cusp when? for adjusting vertical interference in centric for anatomical?
only adjust cusp if there is interference in eccentric and centric
what are our contacting inclines in centric for anatomical?
MUDL = mesial of upper and distal of lower BUCCAL
DUML = distal of upper and mesial of lower BUCCAL cusps
horizontal contacts will exist between? which will you grind to get rid of
MUDL
mesial of upper and distal of the lower
BUCCAL cusps
grind the mesial of the upper because these are not the functional ones like the lower buccal
left working = what for right
left working = right balancing
if you touch a supporting cusp what will you lose?
VERTICAL
what contacts in working? non-working/balancing?
pairs of cusps = working so each working cusp opposes a non - supporting cusp
example – upper and lower buccal
upper and lower lingual
one pair = non -working ; the supporting functional ones (upper lingual, lower buccal
how to restore bilateral balance if interferences in working movements?
BULL rule
buccal of upper
lower of lingual
grinding ‘centric stops’
this is okay - no loss of CR or VDO
T/F contact of supporting cusps on balancing side
TRUE – so grinding these WILL change CR or VDO
how to adjust for balancing side interference?
in order to maintain CR and VDO grind ONLY the INNER INCLINE of the secondary supporting cusp – so the lower buccal inner incline
*INCLINE OF BL
what do you use for articulating paper to remove lateral interferences?
use 2 COLORS of paper
what if there is posterior disclusion in lateral?
there is CANINE GUIDANCE
Rules for adjusting occlusion with canine guidance?
GRIND LOWERS FIRST
lower canine
lower premolar
then upper canine as last resort
what contacts in protrusion for anatomical dentures
ONLY BUCCAL CUSP INCLINES
so contact between supporting and non supporting cusp inclines
DUML
- distal upper mesial of lower buccal
no lingual cusp contact in protrusion
which inclines do you adjust if have interfernce in protrusion?
DISTAL OF UPPER – because these are the non- supporting/functional cusps
when is the only time you can have anterior contac??
IN PROTRUSION but only with POSTERIOR CONTACT AT SAME TIME — BALANCE IN PROTRUSION
what is the desired balance in anatomical set up
simultaneous anterior and posterior contact in protrusion
reason for posterior disclusion in protrusion?
INCISAL GUIDANCE
Iif in wax vs if in processed denture and we have incisal guidance?
wax = move or TRANSPOSE DO NOT TIP
cut– create wear facets if in the processed denture
how to create a wear facet? what does it do?
- look at overlap you have – look at the shadow you have this is A - this is the furthest gingival point
- go half way up on your overlap and this is B
- then bevel – which is C — C = 1/2 bevel
This is first bevel – if need more – bevel until A
decreases vertical and gives you more horizontal
what to do if full bevel is NOT sufficient enough to eliminate incisal guidance in protrusion?
upper LINGUAL may be ground but only as a last resort
marking on the lower lingual and upper buccal.. what type of interference is this?
WORKING INTERFERENCE – USE BULL RULE
marking on maxillary lingual and mandibular buccal?- what type of interference?
Balancing interference so grinf the BL - INCLINES ONLY
grind only what?
THE BULLS EYES
