Transcript Restoration of Acquired Hard Palate Defects in Dentate Patietns

Restoration of acquired
defects of hard palate in
dentate patients Part II
Hemant Jivnani
JR II
Brief anatomy of the maxilla, the palate
and the maxillary sinus
How are Scars and scar contractures
different?
Surgical considerations
Maxillectomy
 Several different subtypes of
maxillectomy have been
described and due to the use of many terms like radical, total,
subtotal, limited, partial, medial, extended maxillectomies;
there has been a confusion regarding the nomenclature.
 Maxillectomies can be classified according to spiro et al. based
on the number of walls as
 Limited: one wall
 Subtotal: at least two walls including the palate
 Total : resection of the entire maxilla
Brown’s classification
Surgeon should be
advised the following
considerations.
 Line the reflected cheek flap with a split-thickness skin graft
 If the wound is allowed to epithelialize spontaneously, it results
in formation of poorly keratinized epithelium or respiratory
epithelium which can not be utilized to obtain support, retention
or stability for the obturator. While lining the defect with skin
graft provides a highly keratinized surface that can be used to
obtain support and retention for the obturator prosthesis on the
defect side.
 Provide superior and lateral access to the defect
 To remove the entire soft palate
if less than one-third of the
posterior aspect of the soft
palate is to remain post
surgically. (unless the patient is
edentulous)
 Imbibing the residual fibers of the levator veli palatini muscle
within the lateral wall of the pharynx can enhance the residual
velopharyngeal mechanism and an obturator can aid it to
achieve velopharyngeal closure during swallowing along with a
decreased hypernasality in speech.
 Retain Premaxillary Segment
 Save some of the palatal
mucosa normally included
in the resection and use it
to cover cut medial bone
margin of the palatal
bones.
Bony cut
Palatal
incision
CONSIDERATON IN OBTURATOR
PROSTHESIS DESIGN
 The need for support, retention and stability in designating any
prosthesis should be understood if the objective of prosthodontic
care are to be attained.
 For the patient with an acquired maxillary defect it is often
necessary to modify, and sometimes violate, some of the basic
principles of prosthesis design because of the basic nature of
the defect.
 The remaining structure are most often unilateral, thus
encouraging movement of the prosthesis with associated stress
directed to these remaining structures.
 The frequent location of unilateral remaining structures suggests
that the obturator portion of the prosthesis, in addition to the
residual structures, must contribute significantly to the support,
retention, and stability of the prosthesis to satisfy the basic
prosthodontic objectives.
SUPPORT
 Support is the resistance to movement of a prosthesis toward
the tissue. The support available from the residual maxilla and
from within the defect both must be considered.
Residual maxilla support
 In the residual maxilla the primary areas available for support
are the residual teeth, the alveolar ridge and the residual hard
palate.
A. Residual teeth

Carious involvement of the remaining
teeth should be treated and their
periodontal status made optimal.

Support is also provided by the
placement of occlusal rests, cingulum rest
and incisal rest.

Maximum effort should be directed
toward saving as many teeth as possible
without
compromising
the
tumor
resection protocol.
Within-the-defect support
 Positive support within the defect to prevent rotation of the
prosthesis into it must be considered. This support can be
achieved by contact of the prosthesis with any anatomic
structures that provides a firm base.

In most acquired maxillary defects the floor of the orbit, the
bony structures of the pterygoid plate, and the anterior
surface of the temporal bone near the infratemporal fossa
are considered for positive support.
a. Floor of the Orbit
Use of the floor of the orbit for support should be minimal. It
cannot be used for support, if orbital floor has been removed
then the orbital contents will move with the movement of the
prosthesis.
Drawbacks:
 If prosthesis is extended up to the orbital floor it would make
insertion through the oral opening difficult, unless a two piece
sectional prosthesis is used.
 Additional weight
 Problems of fabrication
 Alteration in speech quality due to too much obturation of the
resonating chamber.

b. Pterygoid Plate or Temporal Bone

Positive contact of the prosthesis with this bony structure can
be relatively extensive and adequate to tripod the support
for an obturator prosthesis.
c. The Nasal Septum
It is a poor support for extensive prosthesis because,

It is partly cartilage

Has little bearing area

Is covered with nasal epithelium.
RETENTION
Retention is the resistance to vertical displacement of the
prosthesis.
 Retention is provided by
A. Within the residual maxilla
B. Within the defect
A. Residual Maxilla Retention-is provided by teeth in a dentate
patient.
 If the defect is small and remaining teeth are stable, intra
coronal retainer can be used. ii) If the defect is large and
all teeth are weak, extra coronal retainers should be used.
i) If the defect is small and remaining teeth are stable, intra coronal
retainer can be used.
ii) If the defect is large and some or all teeth are weak, extra coronal
retainers should be used.
B. Within the defect retention

Retention of an obturator prosthesis cannot be totally and
adequately provided by the residual maxillary structures in
either the edentulous or the dentulous patient unless the defect
in exceptionally small.

Large
defects
that
approach
the
extent
of
the
hemimaxillectomy must contribute intrinsically to the retention
of the obturator prosthesis
if the objectives of prosthesis
design and prosthodontic care are to be achieved.
 If the obturator extension itself could minimize the vertical
displacement of the prosthesis, less stress would be generated
to the residual maxillary structures. The following structures
should be considered for retention within the defect.
a) Residual soft palate
b) Residual hard palate
c) Anterior nasal aperture
d) Lateral scar band
e) Height of lateral wall
a) Residual soft palate
 Provides posterior palatal seal and minimizes passage of
food and liquid above the prosthesis.
 Extension
of the obturator prosthesis onto the
nasopharyngeal side of the soft palate provides retention.
B) Residual Hard Palate
 Under cuts along the line of palatal resection into, nasal or
para nasal cavity or medial wall of defect can increase
retention.
 Obturator extension into the undercut is best provided by a
soft denture base material.
 The extension shouldn’t contact the nasal septum or the
turbinates
C) Lateral Scar Band
 For adequate surgical closure, most maxillary resections are
lined with split – thickness skin graft along the anterior lateral
and postero – lateral walls of defects.
 This results in the formation of scar band which is more
prominent in laterally and postero – laterally as compared to
scar band anterior to premolar region.
 These act as good undercuts for retention.
D) Height of lateral wall
 Engaging lateral wall of defect provides indirect retention.
 Longer radius undergoes less vertical displacement than the
shorter radius.
STABILITY
 Stability is the resistance to prosthesis displacement by
functional forces.
 Because function tends to move an obturator prosthesis, the
principles of obturator design that minimize rotation around the
horizontal plane and minimize movement within the horizontal
plane itself must be considered.
 Rotation of the prosthesis around the horizontal plane is that
rotation seen around the fulcrum line. Many aspects of
obturator design are important to both retention and stability.
 Movement of the prosthesis within the horizontal plane can be
anteroposterior, mediolateral, rotational, or a combination of
any or all of these directions. As with retention and support
specific areas of the residual maxilla, as well as the defect
itself, must be considered in minimizing the extent of these
potential movements.
Residual maxilla
 If natural teeth remain, the bracing components of the prosthesis
framework can be used to minimize movement
directions.
in all three
It is advantageous to provide maximal bracing and
to extend this bracing interproximally when possible to
minimize rotational as well as anteroposterior movement
of the prosthesis.
Within the defect stability
 The defect itself must be considered to enhance the stability of
an obturator prosthesis.
 Maximal extension of the prosthesis in all lateral directions must
be provided.
 Special emphasis must be placed on maximal contact with the
medial line of resection, the anterior and lateral walls of the
defect, the pterygoid plates, and the residual soft palate.
 Contact of the obturator portion of the prosthesis with these
structures minimizes anteroposterior, mediolateral and rotational
movement of the prosthesis.
Occlusion
 Occlusion is a very important aspect for stability of the
prosthesis. an unstable prosthesis is the result if the occlusal
relationship fails to maintain intimate contact of the prosthesis
with the supporting and the retentive structures.
 To minimize the movement of the prosthesis, maximum
distribution of occlusal forces is essential.
 Mastication over the defect should be avoided.
Purpose of the prosthetic dentition on
defect side:
 Esthetic display
 Lip support
 Prevent opposing dentition from supererupting
Occlusal scheme
 Centric only contact on the defect side is
preferred.
 Lateral interferences should be removed.
General considerations concerning the bulb design
 A bulb is not necessary
 Small to average size defect
 Surgical or immediate temporary prosthesis
 Need of hollow
 To aid in speech resonance
 Light weight
 It should not be high as to cause the eye to move during
mastication
 It should be closed superiorly always
 It should not be large as to interfere with insertion if the mouth
opening is restricted.
Principles of framework design for
obturator prosthesis
General requirements of the framework design for
obturator prosthesis, similar to that of a
conventional removable partial denture
 A rigid major connector.
 Guide planes and other components that facilitate stability and
bracing
 Rests that place supporting forces along the long axis of the
abutment tooth
 Direct retainers that are passive at rest and provide adequate
resistance to dislodgment without overloading the abutment
teeth
 Control of the occlusal plane that opposes the defect, especially
when it involves natural teeth.
Unique considerations of the obturator framework
 The location and size of the defect, especially as it relates to
the remaining teeth.
 The importance of the abutment tooth adjacent to the defect,
which is critical to the support and retention of the obturator
prosthesis.
 The usefulness of the lateral scar band, which flexes to allow
insertion of the prosthesis but tends to resist its displacement
and
 The use of the surveyor to examine the defect for the purpose
of locating and preserving useful undercuts or eliminating
undesirable undercuts.
Class 1- curved arch from
 Tripodal design is recommended if the anterior teeth are to be
used for support or retention
 Linear design is recommended if the anterior teeth are not to
be used for support or retention.
Support
Support for the prosthesis can be derived from: the remaining
teeth, the residual palate, and the structures in the defect that
may be contacted.
 Rests: on most anterior and the mesiocclusal surface of the most
distal abutment tooth when alignment and occlusion will permit.
 The mesiocclusal posterior rest, most often located between
adjacent posterior teeth, is accompanied by a rest on the
distoocclusal surface of the more anterior adjacent tooth.
 Since the prosthesis will first contact the undercuts and the other
support areas, during insertion and the teeth will be engaged
later, the prosthesis needs a compound path of insertion.
 Guide planes will assist in the precise
placement of the prosthesis once the teeth
have been contacted. They will also ensure
more predictable retention and add a greater
degree of stability to the prosthesis. Guide
planes on the anterior abutment should be
kept to a minimum vertical height (1 to 2 mm)
to limit torque on the abutment teeth and
should be physiologically adjusted.
 This is important since movement can be
expected during function because of the
extensive lever arm provided by the defect
and the dual nature of the support system.
 An indirect retainer is usually located perpendicular to the
fulcrum line (which connects the most anterior and most posterior
rests) and as far forward as possible. This is usually a canine or
first premolar.
Retention
 Retention is supplied by direct retainer designs that allow
maximum protection of the abutment teeth during functional
movements.
 On the anterior abutment, a 19- or 20-gauge wrought wire
clasp of the ‘‘I-bar’’ design is often used to engage a 0.25-mm
undercut on the midlabial surface of this abutment.
CLASS I. LINEAR ARCH FORM
Support
 In the linear design, support is provided by the remaining
posterior teeth and the palatal tissues. The palate becomes
more important in the linear design because the use of leverage
to resist vertical dislodging forces is decreased.
Retention
 Retention is usually provided by the combined use of buccal
premolar retention and lingual molar retention.
Class II
 This type of resection is
favored prosthodontically and
should therefore be advised to the surgeon
 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 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 design is linear
 Support –on the center of all remaining teeth.
 Retention -palatal on the premolars;
buccal on the molars.
 Stability - mesially on the premolars.
palatally on the molars.
Class V
 Tripodal configuration
 Splinting of at least two terminal abutment teeth on each side is
suggested.
 I –bar clasps are placed bilaterally on the palatal surfaces.
 Stabilization and support are located on the buccal surface of
the most distal teeth.
Class VI
 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.
Procedures for restoration of maxillectomy defects
in a dentulous oral cavity
 Impressions
 Impression for RPD framework
 Altered cast Impression of the defect
Impression for RPD framework
 A stock tray is used. Periphery wax
is used to extend the tray into the
defect and onto the soft palate.
 The completed impression records
the contours of residual tissues, the
dentition, and the defect.
 Undercuts on the medial side of the
defect should be blocked out.
Otherwise the residual palatal
contours will be distorted upon
removal of the tray.
 Master cast is surveyed.
 The framework design is delineated on the master cast and the
framework is cast.
 The framework is then tried in the
mouth.
 Silicone disclosing materials can be
used to evaluate the intimacy of
contact of the framework to the
tissues and to identify the pressure
areas; and necessary adjustment of
the framework can be done.
Chloroform/halothane and rogue can
also be used for the same purpose,
silicone being expensive.
 The
framework should exhibit
satisfactory frictional fit to the teeth.
Altered cast impression
 Fabrication of an occlusal stop on the oral side of the tray is
recommended.
Border molding
 Use of low fusing compound for border molding the defect.
 Anterior region is border molded first to stabilize the denture
base.
Movements
 Mandible:
 Wide opening
 Lateral
 Head
 Right to left movement
with neck in normal
position
 Right to left movment with
neck flexed
 Right to left movment with
neck extended
 Incremental build up of the border moulding material can cause
unseating of the metallic framework leading to errors in
orientation of the defect to the residual maxilla, which can be
avoided by fabrcation of an occlusal stop on the impression
tray that records the defect and asking the patient to close on
the stop everytime the framework is inserted.
Wash impression
 The compound is cut back 1-2 mm to create space for the wash
material and thermoplastic wax is used to make a wash
impression and record the defect in functional position.
 The
impression is
placed in the mouth
and border molded.
Boxing and pouring of the altered cast
Centric relation records
 The occlusal indices made during the
altered cast impression can serve for
mounting of the cast or centric
relation records can also be obtained
 By conventional method
 After mounting on a suitable articulator, teeth setting is done
keeping esthetics and the occlusal guidelines presented earlier,
in mind.
 The trial prosthesis is then tried in mouth and necessary
adjustments done.
 The quality of obturation is checked during the try in stage by
having the patient swallow water, and speech is evaluated by
having the patient pronounce m and b.
 Palatograms can be used to improve the palatal contour to aid
in speech.
 Occlusion is achieved on the defect side, keeping in mind the
points discussed earlier.
 The prosthesis is processed in heat polymerized acrylic resin.
 Finishing and polishing is done in the usual fashion.
Conclusion
 “The love our face is next only to the love of our life and thus
the mutilated cry for help”
 As a prosthodontist our aim should be to render the best
service possible to the patient in regard to the restoration and
continuity of the defect to its most natural form
 Basic knowledge of the technique, materials is the basic
requirements for any rehabilitation procedure

1.
2.
3.
4.
Which is not a surgical enhancement procedure for a
maxillectomy patient
Maintaining more contra lateral premaxillary area
Maintaining the anterior alveolus and the floor of the nose
Placement of a skin graft over denuded surfaces
Resection of the inferior turbinate when the hard palate is
resected but the tumor does not involve the nasal cavity

1.
2.
3.
4.
Treatment following resection of hard palate does not involve
Allowing the sinus walls to become load bearing
The palatal bone screw can be placed through the acrylic
resin baseplate in the midpalate and secured to the middle
turbinate
Avoid placing a bone screw in the irradiated palate
Bone screws, sutures and packing can be removed without
sedation

1.
2.
3.
4.
Which of the following is false
Nasal reflux and hypernasal speech is caused by continues
fibrosis in the tissues bordering the prosthesis
Improvement in swallowing and speech can be tested by m
and s sounds
Relining of the prosthesis will not alter hypernasal speech
when the soft palate is short in an antero-posterior direction
Pharyngeal obturator extension can be arbitarily shaped to
extend into the pharyngeal opening over the soft palate

1.
2.
3.
4.
Which is false when hypernasal speech occurs
Disclosure of the bulb with tissue conditioning material often
reveals that the surface is inadequate
The prosthesis is adequately closed at the periphery
Patient’s soft palate closure mechanism is not functional
Patient’s pharyngeal closure mechanism is not functional

1.
2.
3.
4.
Which of the following classification system does not involve
dental criteria for maxillectomy
Aramany, 1978
Okay, 2001
Brown, 2000
Rodriguez, 2007
 Answers
 1. 1
 2. 2
 3. 2
 4. 1
 5. 3