Obturators /certified fixed orthodontic courses by Indian dental academy

Obturators .
INDIAN DENTAL ACADEMY
Leader in continuing dental education
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Definitions and types
Anatomy of maxilla
biomechanics
Classification of maxillary defects
Types of Obturators
Clinical steps
Laboratory procedures


Definition of obturator
• GPT –7: a prosthesis used to close a
congenital or acquired tissue opening
primarily of the hard palate and /or
contiguous alveolar structures. Prosthetic
restorations of the defect often includes use
of a surgical obturator, interim obturator,
and definitive obturator.


Anatomy of maxilla
made of maxillary bone and palatine bone

Maxillary bone.

It has the following parts

A. Body it’s a hollow pyramid, enclosing
the maxillary sinus.
B. Processes there are four in number, out
of which alveolar and palatine processes
along with body provide support the upper
denture

1. Frontal process
2. Zygomatic process
3. Alveolar process:
It
arises
from
lower surface of
maxilla and with
its fellow of the
opposite side it
forms the alveolar
arch.


4. Palatine process: Thick, strong, and plate like,
projects horizontally medially from the lower part
of medial surface of the body of maxilla. with its
fellow of the opposite side it forms the anterior ¾
of hard palate and thus forms greater part of roof
of mouth cavity and floor of nasal cavity, fusing in
midline to form the mid palatal suture.


• Palatine bones; It resembles the letter L in
shape .The two palatine bones lie together
at the posterior part of nasal cavity between
the maxillae and the pterygoid processes of
sphenoid bone.


• It has the following parts
A. Processes
I.
Pyramidal: projects backward downward,
and laterally from the junction of horizontal
and perpendicular plates and lies between
the tuberosity of maxilla and the pterygoid
plates of sphenoid bone.
II.
Orbital
III.
Sphenoidal

• B. Plates

i.

Perpendicular plate
ii.

Horizontal plate :
quadrilateral in shape it
projects horizontally
medially from the lower
border of the
perpendicular plate.
Together with the
opposite side it forms the
posterior ¼ th of bony
(hard) palate.

Soft palate
Muscles of soft palate
• Tensor palati
• Levator palati
• Muscular uvulae
• Palatoglossus
• Palatopharyngeus

Movements and functions of soft palate:
Palate separates the
nasopharynx from the
oropharynx,and is looked
upon as the traffic
controller at the
crossroads between the
food and air passages. It
can completely close
them, or can regulate
their size according to
requirements .Its few
specific roles are:

1.it isolates the mouth from the oropharynx
during chewing, so that breathing is
unaffected.
2.it separates the oropharynx from the
nasopharynx during the second stage of
swallowing, so that food does not enter
the nose.


3.by varying the degree of closure of the
pharyngeal isthmus, the quality of voice can
be modified and various consonants
correctly pronounced.
4.during sneezing, the blast of air is
appropriately divided and directed through
the nasal and oral cavities without
damaging the narrow nose. Similarly during
coughing it directs air and sputum into the
mouth and not into the nose.

Functions of obturator
1) Can be used to keep the wound area clean
and to enhance healing
2) To reshape or reconstruct the palatal
contour/or soft palate
3) Improves speech
4) Can be used to correct lip and cheek
position
5) Improves mastication.
6) Reduces the flow of exudates in the mouth

Types of obturator.
• Obturators for congenital defects are of 3 types
1. A simple base plate type helps to correct the
swallowing,feeding,and speech.
2. Obturator with a tail: consisting of a speech
appliance or a speech aid prosthesis which
restores soft and hard palate defects and a
velopharyngeal extension which corrects the
speech.
3. A type of overlay or superimposed denture

• Obturators for aquired defects.


Surgical obturator
• Facilitates oral function immediately after
surgery,significantly reducing the hospital stay and
rehabilitation time.
• Patient may regain speech within a normal range .
• Wrought wire clasps are used
• Acrylic resin facilitates modification by adjustment
or by addition with tissue conditioning material at
the time of surgery.
• Constructed from preoperative impression cast.
• It eliminates the need for the nasogastric tube.
• It can serve as matrix for surgical dressing.
• Some surgeons dispute the necessity of surgical
prosthesis.

Temporary obturator
• After 710 days ,the prosthesis is removed and
reprocessed with new acrylic resin.this becomes a
temporary obturator and serves for 46 months of
healing period.
• Periodic modifications with tissue conditioners
• Multiple wrought wire clasps are used
• Mastication on the surgical side are avoided
• Prosthetic teeth may be added to enhance
esthetics.

Definitive obturator.
• Constructed from the post surgical
maxillary cast.
• Has a false palate ,false ridge ,teeth ,and a
closed bulb which is hollow.


Speech aids
• These are prosthesis that are functionally
shaped to the velopharyngeal musculature
to restore or compensate for areas of the
soft palate that are deficient because of
surgery or congenital anomaly.
• Such prosthesis consists of following 3
parts

The palatal part ,which
provide stability and
anchorage for
retention.
The palatal
extension,which
crosses the residual
soft palate;
The pharyngeal
part,which fills the
velopharyngeal part
during muscular
function

• Pediatric speech aid- made of materials that can be
easily modified as growth or orthodontic treatment
progresses.
• Adult speech aid- when velopharyngeal
insufficiency is a result of a cleft palate or palatal
surgery.
• Both of above are based on the principle of
posterior retention and anterior indirect retention.


Palatal lifts.
• Prosthesis which lift the flaccid palate
posteriorly and superiorly to narrow the
Velopharyngeal opening.
• Velopharyngeal incompetency; patients
with normal,intact anatomy but with
hypernasality and nasal emission of air.


• This condition results
from a paralysis of the
activating muscles and
soft tissues.


Palatal augmentation
• If a part of tongue is lost ,the ability of the
tongue to reach the palate for appropriate
speech and swallowing is compromised.
• The contour of palate can be augmented by
a prosthesis to fill the space of donder so
that a food bolus can be more easily moved
posteriorly into the oropharynx.

Stability of obturator
• The terminal abutment teeth of the
remaining arch determine the fulcrum line .
• 2 lines are drawn from the fulcrum line to
the canine away from the defect,a stable
triangle is established.


• When the defect enlarges and the remaining palate
and dental arc decreases, the area within the triangle
diminishes, as does the stability of the prosthesis.


Quality of retention depends on
• Muscular control.
• Size of surgical cavity
• availability of tissue undercut around the
cavity
• Direct and indirect retention provided by
any remaining teeth.


Retentive regions are
• Fibrous tissue scar bands in the buccal
sulcus.
• Rolled edge of the palatal remnants
• Base of the nasal mucosa of the nasal
septum.


Forces on Obturators
These forces can be
• Vertical dislodging force
• Occlusal vertical force
• Torque or rotational force
• Lateral force
• Anterior posterior force.

dislodging and rotational forces
The weight of the nasal extension of the
obturator exerts dislodging and rotational
forces on abutment teeth.
To resist these forces
-weight of the obturator be minimal
-direct retention
-extending the buccal wall of the
nasal extension superiorly.

• Coronal view of a
typical maxilloectomy
area .


Value of the lateral wall height in design of
partial denture obturator
• As defect side
of prosthesis is
displaced ,lateral
wall of obturator
will engage scar
band and aid in
retaining the
prosthesis.


• Variance in
vertical
displacement
which two
different radius
lengths produce
when arcing
through a given
horizontal
dimension.


Relation of the scar band to the
lateral portion of the obturator.
• Buccal scar band will
develop at height of
previous vestibule
where buccal mucosa
and skin graft in
surgical defect join.


Occlusal vertical forces
• Activated during mastication and
swallowing.
• Wide distribution of occlusal rests will help
counteract such force


Lateral forces.
It can be minimized by
• Covering the medial wall of the defect by a
palatal flap.
• Proper selection of the occlusal scheme
• Elimination of premature occlusal contacts
• Wide distribution of the stabilizing
components.

Classification of maxillectomy
defects
• By Aramany (1978)
• The classification is divided into 6 different
groups based on the relationship of the
defect area to the remaining abutment teeth.
• class sequence reflects the frequency of
occurrence in a patient population of 123
patients treated during a 6 year period at
univ of Pittsburgh.

Rationale for classification
1. The increase in the no of partially edentulous
patients undergoing partial resection of the
maxilla
2. The increase in the life expectancy after
surgery,creating a need for definitive
restorations,
3. An ever increasing percentage of younger
patients in the maxillary resection patient
population.

Class I
• This is the most frequent
maxillary defect and most
patients fall into this
category.
• The dentition and the
alveolar bone are
removed along the
midline.

Prosthetic design
• Two designs are possible
Linear
Anterior teeth are not included in
the design.
Support- located in a linear fashion.
Stability –palatal surface of
premolars ;
buccal surface of molars.

Retention –buccal surface of the premolar.
palatal surface of molars.


Tripodal
2 or 3 anterior teeth are splinted.
Retention –from labial surface of anterior teeth
with gate design or an I bar on the central
incisor;
-Buccal surface of the molars
Stability –from molars palatally
Support – rest on the distal surface of the first
premolar

Class II
• Defect is unilateral, retaining
the anterior teeth on the
contra lateral side .
• This type of resection is is
favored prosthodontically
and should therefore be
advised to the surgeon


Prosthetic design
• The bilateral design is similar to a Kennedy
class II RPD design
• Splinting of the 2 teeth adjacent to the
defect is advisable
• Abutments : tooth nearest the defect and the
most posterior molar.


• Support- perpendicular to the fulcrum line rest is
placed
• Stability –from palatal surfaces of abutments
• Retention – from buccal surfaces of the abutment
teeth


Class III
• The palatal defect
occurs in the central
portion of the hard
palate and may involve
part of the soft palate.
• Surgery does not
involve the remaining
teeth.

Prosthetic design
• The design is based on quadrilateral
configurations.
• Support is widely distributed on both
premolars and molars.


• Retention is derived from the buccal surfaces and
stabilization from the palatal surfaces.


Class IV
• The defect crosses the
midline and involves
both sides of the
maxillae.
• There are few teeth
remaining which lie in a
straight line.

Prosthetic design
• The design is linear
• Support –on the center of all remaining
teeth.
• Stability-palatal on the premolars;
buccal on the molars.


• Retention- mesially on the premolars.
palatally on the molars.


Class V
• Surgical defect is bilateral
and lies posterior to the
remaining abutment teeth.
• Posterior teeth,hard
palate,and portions of the
soft palate are resected.


Prosthetic design
• Tripodal configuration
• Splinting of at least two terminal abutment
teeth on each side is suggested.
• I –bar clasps are placed bilaterally on the
buccal surface of the most distal teeth.


•Stabilization and support are located
on the palatal surfaces.

• A gate prosthesis is a viable alternative for these
patients .

Class VI
• Least frequently
occurring class.
• This occurs most in
trauma or in congenital
defects rather than as a
planned surgical
intervention.

Prosthetic design
• 2 anterior teeth are splinted bilaterally and
connected by a transverse splint bar.
• A clip attachment may be used without an
elaborate partial framework.


• If the defect is large,or the remaining teeth are in
less than optimal condition,a quadrilateral
configuration design is followed.

Surgical considerations
• Efforts should be directed towards
conversion a potential class I maxillary
defect into a class II defect to provide a
superior prosthesis both functionally and
esthetically.


Recommendations to surgeon.
1.

Preservation of the contra lateral anterior
teeth,if it does not compromise tumor
eradication.
2. If the palatal mucosa is not invaded by the
tumor,it is preserved and reflected to
cover the medial wall. this procedure
provides superior tissue quality coverage
for the nasal septum.

3. Preservation of the posterior hard plate on
the defect side if the tumor is situated
anteriorly or laterally.
4. Resection through the socket of the tooth
closest to the specimen allows for
maintenance of the proximal alveolar
bone adjacent to the abutment tooth.

Classification by okay et al.
(2001)
• New prosthodontic guidelines that relate to
surgical reconstruction of the maxilla seem
o be mandated as a result of advancements
in micro vascular surgical techniques.
• Micro vascular free flap surgery allows the
transfer of muscle ,connective
tissue,skin,and bone to recipient sites.

Class I a
• Defects that involve the hard palate but
not the tooth –bearing alveolus.
• Prosthesis created for prosthetic
obturation were stable and well tolerated.


• Patient can be rehabilitated by
Local island flap- in defects involving less
than one –third of the hard palate.
Fasciocutaneous free flap- in large defects and
irradiated patients .


Class I b
• Defects
that involved any portion of the maxillary alveolus
and dentition posterior to the canines
or that involved the premaxilla .


• Soft tissue flap without osseous
reconstruction because the remaining
dentition and palate were considered able to
support occlusal contacts over the
reconstruction with a removable partial
denture.


Class II
• Defects -that involved any portion of the toothbearing maxillary alveolus but included only 1
canine .
- anterior trans verse palatectomy defects
that involved less than one half of the palatal
surface.


• Prosthetic rehabilitation of class II defects
was less predictable than that of class I
defects.
• Factors for instability
Fewer teeth for clasping
Reduces arch size and form
Diminished supporting palate.

• Some class II defects are best reconstructed
and rehabilitated by vascularized bone
containing free flaps .


Class III
• Defects that involved any portion of the toothbearing maxillary alveolus and included both
canines,total palatectomy defects,and anterior
transverse palatectomy that involved more than
half of the palatal surface.


• These defects left little or no residual palate
or dentition for the secure retention of an
obturator,which led to a poor prosthetic
prognosis.
• These defects were best restored with
VBCFF.


Subclass f and z
• F- defects involving
inferior orbital rim.
• Z – defects involving
body of the zygoma.
• The orbital floor and
zygomatic body play
both functional and
cosmetic roles.
• These defects are best
restored with VBCFF.

• The defect – oriented approach of this
system is intended to facilitate and
coordinate treatment planning among
surgeons and prosthodontists.
• New surgical reconstruction techniques may
or may not provide a more conventional
setting for prosthodontic rehabilitation.


Other classifications
• Ohngren’s classification(1933)
• Spiro et al (1997): a relatively simple
classification in which defects can be
termed as “limited” or “subtotal” on the
basis of the number of maxillary “walls”
involved in the resection.


• Davison et al: reconstruction algorithm based on
the review of 108 patient treatments. They are
divided into 2 broad categories as “complete” and
“partial”.
• Brown : first to discuss a multi disciplinary
(surgical and prosthodontic) approach to
palatomaxillary reconstruction. based on both the
vertical and horizontal dimensions of a defect.


Preoperative evaluation
1) Psychological support : the patient should be
aware of the potential physiologic and cosmetic
deficiencies that will result from his treatment
and subsequent prosthodontic management.
2) Preoperative dental management.
1. Temporary restoration of teeth with severe
carious lesions
2. Removal of disesed or malposed teeth at the
time of the operation.
3. Treatment for acute oral infections such as
necrotizing ulcerative gingivitis.

3) Preoperative impressions:for diagnostic
casts and for fabrication of temporary
obturator.
4) Suggestions to the surgeon


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