Obturators ii /certified fixed orthodontic courses by Indian dental academy

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Anatomy
Types of prosthesis
Biomechanics
Classification of hemi maxillectomy defects
and treatment planning.
• Instructions to surgeons.

General principles.
1. Need for a rigid major connector.
2. Guide places and other components that
facilitate stability ad bracing.
3. A design that maximizes support
4. Rests that place supporting forces along the long
axis of the abutment tooth.
5. Direct retainers that are passive at rest and
provide adequate resistance to dislodgement
without overloading the abutment teeth.
6. Control of occlusal plane that opposes the
defect,especially when it involves natural teeth.

Comparison of 3 retentive
concepts(martin and king,1984)
I.

Retention by withdrawing the framework
parallel to the path of insertion is greatest
when both buccal and lingual clasps are
used.
II. Withdrawal of an obturator from the
defect area greatly reduces the retention
of buccaly placed clasps.

III. Withdrawal of an obturator from the
defect area is resisted more effectively
by lingual retention than buccal
retention.
IV. A lingual plate enhances retention in
proportion to the number of teeth and
length of the dental arch covered by the
lingual plate.


Classification of Obturators
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According to Origin of discrepancy :
- congenital defect obturator
- acquired defect obturator.

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According to Location of defect:
i.
ii.
iii.
iv.
v.

labial or buccal obturator
alveolar obturator
hard palate obturator
soft palate obturator
pharyngeal obturator

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According to the Type of to the basic
maxillary prosthesis attachment
1) Fixed obturator
2) Hinged or movable obturator
3) Detachable obturator.


• According to physiological movement of
the surrounding tissue.
a. Static obturator
b.Functional obturator.
Obturators covering defects in the area from
the lips to the junction of the hard and soft
palates are static Obturators.
Those Obturators which provide closure in the
soft palate and pharyngeal areas are
functional Obturators.

Meatal obturator.
• A meatal obturator is static.
• It extends obliquely upward from the hardsoft palate junction to occlude against the
turbinates and the superior aspect of the
nasal cavity.
• It may be preferable obturator when the
cleft is wide,few undercuts exist,and the
patient has an active gag reflex.

Surgical Obturators.
Also called immediate
temporary obturator.
Dentulous patient
• Patient is seen
preoperatively.
• Irreversible
hydrocolloid impression
is made of the maxillary
arch.

• Functional limits of
the palate are to be
recorded in the
impression.
• Cast is poured and
areas to resected
marked on it.

• Teeth are removed
from the cast in the
areas of resection.
• Wrought wire
retainers are placed
on the areas adjacent
to the defect .


• Prosthesis is fabricated with cold cure or
heat cure resin.
• Anterior Teeth can be added if esthetic is
desired.
• clear Heat cure acrylic resin is desired as
transparency will revel any pressure areas.


• If and when any adjustment is needed Build
up of the defect side in modelling plastic is
done and border mold the area. invest the
obturator and replace the modeling plastic
with auto polymerizing acrylic resin.
• To reduce the weight the newly added
obturator bulb is hallowed superiorly.


Edentulous patient
• Fabricated in similar manner as in
Dentulous patients.
• Retention is obtained by using the ligature
wire around the zygomatic arch and through
the obturator.


Other methods of stabilizing the
immediate obturator.
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Piriform aperture wiring
Kirschner wires
Screw fixation
Sectional prosthesis.


• In large maxillectomy cavities ,composition
impression compound is too heavy.
• Radcliffe et al described an immediate
obturator prosthesis of silicone elastomer
foam,which was attached to an acrylic resin
base.
• This prosthesis is light and by engaging
suitable undercut regions was retentive and
avoided the use of accessory wires.

Treatment Obturators.
• Also called temporary or transitional
obturator.
• Constructed about 7 days postoperatively,
right after the packing is removed.
• Used for about 3 months .


• If patient has an existing denture it is used
in the construction of treatment obturator.
– If denture is under extended ,an alginate
impression is made with the denture in the
mouth.
– A cast is poured and cold cure added to the
periphery of the old denture on the cast.

• The old denture can also be readapted to the
mouth using resilient denture lining
material.

Construction of treatment
obturator.
• A stock impression tray which covers the desired
area is selected.
• The tray is built with utility wax in the area of the
defect to support the impression material.
• Wax is placed on the edges of the tray to protect
the soft tissue.
• Adhesive is applied on the impression surface of
the tray .

• Load the tray with alginate.
• Patient instructed to bend his head forward
and also move from side to side so that
functional limits of the soft palate can be
recorded.
• Impression is poured in artificial stone.
• On stone cast a pencil line is drawn slightly
inferior to where the oral mucosa and skin
graft meet on the cheek.


•This area can be
palpated on the patient
as a fibrous band
running horizontally
on the cheek and at the
height of where he
buccal vestibule would
have been.


• This band extend posteriorly and becomes
part of the posterior portion of the defect.
• Obturator should overlap the defect in this
area.


• If teeth are present wrought wire
retainers are build.
• 2 thickness of baseplate wax is adapted
over the whole cast.
• No undercuts should be present along
the walls of the defect side.


• Prosthesis is processed by Flasking
,dewaxing and packing with acrylic
resin.
• Prosthesis is deflasked ,trimmed and
polished.
• Prosthesis placed in patients mouth and
checked for extent and compatibility of
oral tissues.

• Fabrication of palatal contour.
– Cavity on the palatal side of the obturator
is filled with wax till proper palatal
contour is established
– Thin layer of separating media is placed
over the wax and acrylic resin.
– A plaster core is then poured over the wax
and extended onto the acrylic resin to a
point where reorientation of the core can
be easily done

– Wax is removed from the defect side
.
– Separating medium is applied over
the superior potion of the core.
– Self cure acrylic resin is sprinkled to
a thickness of 1 to 2 mm on the core.
– Core is inverted and pressed into
contact with the prosthesis and held
till acrylic resin has set.

• Access resin is
trimmed away and
obturator is
polished.
• Alternatively
whole defect side
can be processed
in acrylic and is
then hollowed
superiorly.

Permanent obturator for
edentulous patients.
• Given after 2 –3 moths after the operation.


Impression.
• Position
– Supine to be used for preliminary impression
for patients with extensive surgical defectsprovides more more visibility and access.
– Erect position to be used for final impression so
that dependent tissue do not become displaced
from normal.

• All other positions usually induce gagging
and so should be avoided.

• Place an airway in the nostrils and
pack the throat with gauze.
• Extreme undercuts blocked with
petrolatum impregnated gauze.
• Lubricate the lips with petrolatum to
prevent impression material from
sticking to it.

Primary impression
Build the stock tray with wax in the defect
area to direct the impression material into
the defect.
• Make an alginate impression and pour the
cast.
• Fabricate individual acrylic resin
impression tray.

Final impression
• Impression material
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rubber base
Irreversible alginates
Reversible alginates
Zinc oxide eugenol.

• Place holes in the tray to retain impression
material.or use adhesive in case of rubber base.
• Impression tray tried in mouth to ensure that 2 mm
space exist between the tray and the tissue.

• Tray loaded and inserted and patient told to
purse his lips and swallow.
• Some material can be directly put into the
defect to insure that material reaches
inaccessible areas.
• Impression is boxed and stone is poured.
• Any undesirable soft and hard tissue
undercuts are blocked out,but these will be
salvaged later to help increase the retention.

• Acrylic resin bases are made Occlusal rims
are adapted and correct vertical dimension
and centric relation is established
• Tracing devices are not used due to lack of
resistant base after surgery.
• Teeth selection is done and baseplates are
related to the articulator with a face bow
transfer.

• The upper posterior teeth are occluded and
balanced with the lower cast of the natural
teeth.
• Wax trial done in patients mouth to check
esthetic and functional relationship.


Processing.
• Denture base invested in the lower flask.
• Palatal defect filled with modeling clay and
given a palatal shape.
• An acrylic bur is used to create a ledge
around the periphery of the defect and to
reduce the thickness of the bulb to about
2mm

• Tinfoil is adapted over modelling clay and
extended beyond the periphery of the
palatal defect by 1 cm.

• Denture is packed processed , deflasked
,trimmed and polished.

• Portion of palate covering the modelling
clay is removed readily as separating
medium was applied in this area.
• Modelling clay is removed and palatal
section is cemented over the defect area
with auto polymerizing resin.


• The denture with the
hollow bulb is
trimmed and polished
and inserted in the
patients mouth.


Alternative method.
• Non defect side
– Preliminary impression made of non defect side
in alginate.
– Stone cast is made and and acrylic resin custom
tray is fabricated on it.
– Tray is border molded in mouth and rubber
base impression made of intact maxilla.
– An acrylic resin base is then processed on the
cast.

• Defect side.
– Modelling plastic is adapted to he acrylic resin
base on the defective side.
– Distal buccal surface is molded by making the
patient open and close his mouth .when
maxillary resection is extended into the
pterygoid region,this area will be influenced by
the ramus of the mandible.when properly
molded ,there will be an index of the anterior
portion of the ramus evident in the posterior
portion of the bulb.

• Patient is told to wear the obturator until
the next day to determine any overextension
and uncomfortable areas.
• Patient instructed to eat only cold food as
heat will have softening effect on the
modelling plastic.
• Sore areas are relived and additional relief
of 1 to 2 mm given over the entire surface
area of the bulb.

• Korecta wax painted over the relived modelling
plastic .
• The wax is applied over a number of time till a
glossy appearance is obtained.
• Prosthesis is left in mouth for 2-3 hours to get
good final adaptation.
• Impression poured in dental stone.
• Cast is invested in lower portion of flask.
• The bulb portion is waxed in proper thickness and
contour.
• Defect area processed in acrylic resin ,deflasked
and polished.

Other Impression methods
• Schmaman and carr(1992)
• A foam impression technique for maxillary defects
• This technique overcomes the problems of
withdrawal of maxillectomy defect impression
with or without limited space as he result of
trismus.
• Silastic foam material is used to make an
impression which expands inside the defect and is
extremely elastic to escape any deformation on
removal.

• Luebke
– Use of sectional tray in patients with trismus.

• Beumer et al.
– In this method the impression is refined with
modeling plastic,a soft flowing wax,and an
elastic impression material to record the defect.

• Carl
– Use of adhesive and undercuts that add
additional alginate to a set impression when
necessary.

Use of sectional
impression was
pioneered by
Adisman
It can be used where full
depth of undercut
must be recorded and
a special tray loaded
with impression
material cannot be
inserted.

• In this technique
,different sections of
silicone putty are
removed from mouth
and reassembled.
• Accurate impression
of full depth of the
defect has been
obtained.


Permanent obturator for
Dentulous patient.
• Wire clasp embedded in the acrylic resin
base are usually used when the prognosis
of the remaining teeth is questionable.
• Obturator bulb on cast frame is used for
partially edentulous patients who have a
significant number of sound teeth
remaining.

Cast frame is preferred as it is
– Less bulky
– Less likely to distort
– Stabilizes remaining teeth effectively.


• The frame and retentive portion of the
frame is made and the obturator
portion is made utilizing the cast frame
as a base.
• Wax (kerr utility wax) is adapted over
the defect area of the frame.
• Wax is softened and placed in moth .

• Patient asked bend his head from side to
side and to swallow.
• Glossy areas indicate tissue contact.and the
whole procedure is repeated till wax fills
the whole defect area.
• Wax is then relived by 2 mm and adhesive
is applied over it.
• Heavy bodied rubber base material is
applied over the wax.


• Patient told to do functional movements
• Frame and obturator are removed and
invested in stone .
• Clear acrylic resin is processed to the cast
frame.
• Prosthesis is trimmed polished and painted
with pressure indicating paste.


• Patient asked to do functional movements
and then to swallow water. areas of pressure
identified and relived.
• Procedure repeated till no pressure areas are
evident.
• 1 mm of acrylic resin is trimmed off the
obturator.
• Oral thermoplastic wax is added to the
tissue contacting surface(adaptol or iowa
wax)

• Patient told to do functional movements
and pressure areas relived and repainted
with wax.
• Patient told to sit with the impression in
mouth for 2 hours to get the functional
impression.
• Impression chilled in cold water and
processed.

• The prosthesis is polished and painted
with pressure indicting paste to detect
processing discrepancy.
• Functional positional records are made
and occlusion is refined.


Procedure for one piece hollow
obturator.
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Advantages
i.

There are no lines of demarcation on the
denture to discolor
ii. The undercut areas of the defect are thick
enough to allow for adjustment if necessary.
iii. It is simple and consumes very little more
laboratory time than a conventional denture.
iv. Accuracy is assured

• The denture is waxed
as any conventional
denture


• The denture is flasked
and boiled out in usual
manner.
• The undercuts areas in
defect are blocked out


• Entire defect area is
relived with one
thickness of baseplate
wax.
• Three stops deep
enough to reach the
underlying stone of
the master cast are
placed in the wax to
facilitate proper
positioning of the
shim.

• One thickness of base plate wax is also
placed in the top half of the flask over the
teeth and palate area to form the top wall of
the shim.


• Auto polymerizing
acrylic resin is mixed
and rolled to about
2mm in thickness after
reaching the dough
like stage.
• A layer of resin is
contoured over the
wax relief in the defect
site,with another layer
over the wax in the top
half of the flask.

• Flask is then
closed and
allowed to
set for a
minimum of
15 minutes.


• After curing the flask
is opened and the wax
is flushed off the shim
with a stream of
boiling water.


• Excess of acrylic is
removed from the
shim and placed back
into the defect,using
the three stops for
correct positioning for
final processing with
heat cure resin.


• A layer of material is
presses to place in the
bottom of the
defect,and the shim is
reinserted for final
processing.


Factors to consider for superior
height of bulb.
1. If patients speech cannot be understood the bulb
should be extended upward.
2. With maxillary resection much of the bone
support for the cheek is removed.the obturator
bulb height will reestablish this contour.
3. According to brown (1968) height of the bulb
relates to the retention of the completed
obturator.
4. Amount of Mouth opening of the patient

General considerations for bulb.
• Bulb is not necessary with central palatal defect of
small to average size where healthy ridge exists.
• Not necessary in the surgical or immediate
temporary prosthesis.
• It should be hollow to aid speech resonance and to
lighten the weight on the unsupported side.
• It should not be so high as to cause the eye to
move during mastication.

• It should be one piece,if possible,to provide
better color matching and maximal patient
acceptance.
• It should always be closed superiorly
• It should not be so large as to interfere with
insertion if the mouth opening is restricted.


Instruction to patient .
• To remove the prosthesis several times a
day to wash the prosthesis and rinse the
mouth.
• Prosthesis to be cleaned thoroughly every
evening.
• Patient advised not to wear prosthesis while
sleeping.

Thank you
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