The document discusses management of acquired maxillary defects through the use of obturators. It describes the history and objectives of obturators, as well as their classification based on factors such as treatment phase, material used, and location of the defect. The key types of obturators discussed are surgical obturators, interim obturators, and definitive obturators. Design principles for obturators include hollow bulb designs to lighten the prosthesis and improve functions like speech.

1. MANAGEMENT OF
ACQUIRED MAXILLARY
DEFECTS
DR. AATIF KHAN
PG-II DEPARTMENT OF PROSTHODONTICS
1

2. CONTENTS
• INTRODUCTION
• HISTORY OF OBTURATORS
• OBJECTIVES AND FUNCTION
• CLASSIFICATION
• PROSTHETIC MANAGEMENT
• FABRICATION METHODS
• DESIGN PRINCIPLES
• REFERENCES
2

3. INTRODUCTION
• The most common of all intraoral defects are in the maxilla, in the form of an opening into the
antrum and nasopharynx.
• These defects may be divided into defects resulting from congenital malformations, and
acquired defects resulting from surgery for oral neoplasms, trauma, disease, pathological
changes, radiation burns.
• Aided with the help of an obturator.
3

4. INTRODUCTION
• An obturator (latin : obturare, to stop up) is a disc or plate, natural or artificial, which closes an
opening or defect of the maxilla as a result of a cleft palate or partial or total removal of maxilla
for a tumour mass. (Chalian 1971).
• A maxillofacial prosthesis used to close a congenital or acquired tissue opening, primarily of the
hard palate and/or contiguous alveolar/soft tissue structures. (GPT-7);
• That component of a prosthesis that fits into and closes a defect within the oral cavity or other
body defect. (GPT – 9)
4

5. HISTORY
• Ambroise Parr was the first to use artificial means to
close a palatal defect during the 1500’s.
• Pierre Fauchard – Winged obturator for enhanced
retention.
• Delabarre (1820) – Hinged obturator.
• Claude Martin (1875) – Surgical obturator.
• KW Coffey (1984) – Inflatable balloon obturator.
5

6. HISTORY
• Historically, these prostheses were made of cloth, leather, wrought or cast metal, vulcanite,
porcelain, and acrylic resin.
• As time progressed, newer and better concepts of obturation evolved.
• Today most are made of medical-grade silicone rubber.
6

7. IDEAL REQUIREMENTS
• A comfortable, cosmetically acceptable prosthesis that restores the impaired physiologic
activities of speech, deglutition, and mastication.
• Design  Easily and swiftly placed and secured.
• Durable for a reasonable period of time, retain its polish and finish.
• Easy to clean and maintain.
7

8. INDICATIONS
• To act as a framework over which tissues may be shaped by the surgeon;
• To serve as a temporary prosthesis during the period of surgical correction;
• Restore cosmetic appearance rapidly;
• When surgical primary closure is contra-indicated;
• When the patient’s age contraindicates surgery;
• When the local avascular condition of the tissues contraindicates surgery;
• When the patient is susceptible to recurrence of the original lesion which produced the deformity.
8

9. 9
FUNCTIONS OF OBTURATORS
Closure of defect
Enhance
Postsurgical
healing
Surgical stent or
to hold surgical
pack
Reduce
postoperative
hemorrhage
Reshape or
recontour the
palate
Improve function
and speech
Reduce flow of
exudates into
nasopharynx
Improve esthetics
Boost patient
morale

10. CLASSIFICATION OF
OBTURATORS
10

11. CLASSIFICATION (BEUMER, CURTIS)
• A. Based on phase of treatment –
• 1. Surgical obturators
• 2. Interim obturators
• 3. Definitive obturators –
• a. closed hollow bulb (one piece/two piece)
• b. open bulb
11
• B. Based on material used –
• 1. Metal obturator
• 2. Silicone obturator
• 3. Resin obturator
• C. Based on area of restoration –
• 1. Meatal obturator
• 2. Palatal obturator

12. CLASSFICATION (RAHN AND BOUCHER)
• D. According to origin of discrepancy:
• Congenital defect obturator
• Acquired defect obturator
• E. According to location of defect:
• Labial/Buccal reflex obturator
• Alveolar obturator
• Hard palate obturator
• Soft palate obturator
• Pharyngeal obturator
12
• F. According to movement of oral, nasal and pharyngeal
tissues adjacent to or functioning against obturator:
• Static obturator, Functional obturator.
• G. According to the type of attachment to the prosthesis:
• Fixed obturator
• Hinged/movable obturator
• Detachable obturator

13. OBTURATORS FOR ACQUIRED DEFECTS -
• Almost all acquired palatal defects are precipitated by resection of neoplasms of the palate and
paranasal sinuses.
• The extent of the resection is dependent on the size, location, and potential behaviour of the
tumour.
• Prosthodontic therapy can be divided into three phases of treatment with each phase having
different objectives.
13

14. 1. SURGICAL OBTURATOR
• A temporary maxillofacial prosthesis inserted during or immediately following surgical or
traumatic loss of a portion or all of one or both maxillae and contiguous alveolar structures. –
(GPT - 9)
• It is of two types –
1. Immediate surgical obturator (inserted during surgery)
2. Delayed surgical obturator (inserted 7-10 days after surgery)
14

15. A. IMMEDIATE SURGICAL OBTURATOR
Less commonly used because of invasive method of securing the prosthesis.
Fabrication procedure:
• An alginate impression of maxilla  Casts are retrieved.
• Surgical outline is marked on the cast and any tumor bulk present is reduced to normal contour;
• Prosthesis can be fabricated with auto polymerizing or heat polymerizing resin.
• Heat processed is not needed since it is only for 7-10 days.
• Composite resins are convenient but quite brittle (fracture with placement of wires or screws).
15

16. Appadurai ET AL - surgical retention for immediate obturator in maxillectomy patients. Indian journal of dental research. 2019 jan 1;30(1):133. 16

17. A. IMMEDIATE SURGICAL OBTURATOR
17
• A clear acrylic plate is fabricated and inserted after surgery.
• Dentulous patient  retention is obtained with simple clasps.
• Edentulous patient  wired into alveolar ridge & zygomatic arch.
• The obturator is retained for 7-10 days post surgically.
• Replaced with an interim or definitive obturator after complete healing.

18. Farias a,et al - A simplified technique to make an immediate surgical obturator for a maxillectomy patient. Journal of interdisciplinary dentistry. 2013 may 1;3(2):125. 18

19. A. IMMEDIATE SURGICAL OBTURATOR
• Principles relative to the design -
• Should terminate short of the skin graft — mucosal junction.
• Simple, lightweight and inexpensive.
• Perforated with small dental bur in the interproximal extensions to
allow the prosthesis to be wired to the teeth.
• Normal palatal contours should be reproduced to facilitate
postoperative speech and deglutition.
19

20. B. DELAYED SURGICAL OBTURATOR
• Given 7-10 days post surgically.
• Treatment of choice in edentulous patients with extensive defect.
• An impression is made after the packing is removed.
• The procedure must be carefully done when the area is raw and tender. Prosthesis is made as
described previously.
• As healing progresses, posterior occlusal ramps are established since posterior occlusion helps
the patient retain the prosthesis in position.
20

21. B. DELAYED SURGICAL OBTURATOR
• Diagnostic casts are made prior to surgery. Post surgically, the surgeon outlines the surgical
margins on the cast. Prosthesis is made and on the day the packing is removed, the prosthesis is
delivered and adjustments are made.
• After initial healing and removal of the pack the immediate obturator is usually discarded and
replaced by transitional prosthesis having a definite bulbous extension and occasionally artificial
anterior teeth.
21

22. 22
B. DELAYED SURGICAL OBTURATOR
Intraoral view of the defect 1 week after surgery.
Immediate Surgical Obturator. Alginate Impression.
Maxillary cast.
Modelling wax adapted in the defect for the
fabrication of open lid obturator.

23. 23
B. DELAYED SURGICAL OBTURATOR
Open Lid Delayed Surgical Obturator. Relined with tissue conditioning material.
Intraoral View of the Defect
after 2 months.
Intraoral- Delayed Surgical Obturator.

24. 2. INTERIM OBTURATOR
• A prosthesis that is made several weeks or months following surgical
resection of a portion of one or both maxillae. It frequently includes
replacement of teeth in defect area. It replaces the surgical obturator
that is placed immediately following the resection and may be
subsequently replaced with a definitive obturator. – (GPT-9)
24
Open Lid Interim Obturator.
Intraoral View of Interim Obturator.

25. 2. INTERIM OBTURATOR
• Baseplate used for surgical obturator can be border molded and relined on remaining hard palate.
• The prosthesis is seated with each increment of material and impression is made to capture a few
mm at a time. This incremental shaping creates a hollow, light prosthesis.
• Technique:
• Patient movements, speech and swallowing are evaluated during border molding :
• Exaggerated head movements, turning right to left with neck flexed and extended.
• The mouth should be opened and closed, mandible moved laterally and asked to swallow.
• Peripheries of bulb portion will be 2-3 cm in height.
25

26. 2. INTERIM OBTURATOR
• Superior area of defect contracts between visits and creates a dislodging force on the prosthesis.
• Inferior aspect should be at the level of original hard palate and soft palate junction. If it extends
below the palatal plane then:
• 1. Space required for tongue function is violated. Prosthesis is dislodged into the defect by the
tongue.
• 2. The injured soft palate junction will contract and elevate back to the level of hard palate very
rapidly over next two weeks and result in irritation of the tissues.
26

27. 2. INTERIM OBTURATOR
• Hypernasal speech occurs due to loss of air form oral cavity into nasal cavity. As the prosthesis periphery is sealed,
air loss will diminish and speech becomes normal.
• Insertion: After impression is made with a reliner, it is then flasked and the prosthesis is fabricated.
• Given on same day otherwise tissue edema will occur and the defect will change rapidly after removal of the
packing.
• Delivery should include a functional impression with tissue conditioner since it allows better assessment of
functional movement.
• Requires several revisions after surgery. Over extensions may occur due to tissue changes and will require
correction.
27

28. 3. DEFINITIVE OBTURATOR
• A prosthesis that artificially replaces part or all of the maxilla and the associated teeth lost due
to surgery or trauma. (GPT – 9)
• Fabricated 3-4 months post surgery.
• Timings will depend on the defect size, healing prognosis, tumor control, the effectiveness of
the present obturator and the presence/absence of the teeth.
28

29. 3. DEFINITIVE OBTURATOR
• Indicated after surgical site is healed and dimensionally stable and the patient is prepared
physically and emotionally for restorative care.
• Reasons for new prosthesis:
• Periodic addition of interim lining material increases the bulk and weight, and this temporary
material may become rough and unhygienic.
• If anterior teeth are resected, addition can be of psychological benefit.
• If retention and stability are inadequate, occlusal contact on the defect side may result in
improvement.
29

30. 3. DEFINITIVE OBTURATOR
• Retention of complete denture in maxillary defects is compromised. Air leakage, poor stability,
reduced bearing surface will compromise adhesion, cohesion and peripheral seal. The contours
of the defects must be used to maximize retention, stability and support.
• Maxillary obturator in edentulous patients will exhibit varying degree of movement depending
on amount of contour of remaining hard palate, size, contour and lining mucosa of defect and
availability of undercuts.
30

31. 3. DEFINITIVE OBTURATOR
• Preliminary impression:
• Fistulas and undercuts are blocked with piece of cotton or gauze tied with
floss.
• An impression is made with alginate in a stock impression tray. Interim
prosthesis can also be used.
• Final impression:
• Custom tray is made such that it extends 2-3 cm into the cavity.
• Undercuts are to be blocked on cast while making custom tray.
• This serves to stabilize and orient the tray to the defect.
31

32. 3. DEFINITIVE OBTURATOR
• Palatal margin is developed: Superior height of this extension should terminate at
junction of oral and respiratory mucosa.
• Soft palate is molded: All eccentric movements are performed to account for
movement of anterior border of ramus and coronoid process of mandible.
• Impression is made with elastic impression material. If soft palate exhibits
elevation during speech and swallowing- a functional impression is made with wax.
• Jaw relation records: Processed record bases are ideal.
• Vertical dimension: Conventional methods.
32

33. 3. DEFINITIVE OBTURATOR
• In the extreme trismus cases vertical dimension must be reduced to allow the passage of food
between denture and teeth.
• Centric relation: Recorded with soft wax/ ZOE paste/ Plaster.
• Graphic tracings are contraindicated, pressure on the defect side will result in some
displacement into the defect and compromise the accuracy of the recording.
• Occlusal scheme: Non-anatomic posterior teeth are preferred.
• All records are verified at try in stage.
33

34. 34
3. DEFINITIVE OBTURATOR
The resected hard palate, alveolar
bone, teeth, and soft tissue on the right
side.
Heat-processed hollow bulb
obturator.
Closely adapted obturator.

35. General considerations for bulb design
(Chalian) :
• Not needed in surgical or immediate temporary prosthesis.
• It should not be so high as to cause eye to move during mastication.
• Should always be closed superiorly.
• Should not be so large as to interfere with insertion if mouth opening is restricted.
• Should be hollow to aid speech resonance, to lighten the weight on unsupported side and to act
as a foundation for a combination extraoral prosthesis in communication with intra oral extension.
• An open or topless bulb is unhygienic, foul smelling and unpleasant for the patient to tolerate.
35

36. There are essentially two principle styles
of obturators:
• 1. The fully extended closed hollow bulb (usually rigid),
• 2. Open top which may be designed with either a rigid or flexible rim.
• Use of either design is dictated by the requirements of individual cases.
36
Two- part obturator with a flexible open lid
one-part obturator with a rigid open lid

37. HOLLOW BULB OBTURATORS
• Minimize any downward displacement of the prosthesis due to gravity or function.
• The bulb must be carefully manufactured to produce an adequate seal and partition between
the oral and nasal cavities.
• They can also gain support from structures within the defect.
37

38. HOLLOW BULB OBTURATORS
• Patients may have problems with insertion, and therefore a two-part design may have to be
considered to overcome this problem, especially if the patient has significant trismus.
• If a two part obturator is used, magnets can be used to unify the segments into one prosthesis.
38

39. HOLLOW BULB OBTURATORS
39
• ADVANTAGES –
• Reduced weight, making it more comfortable and efficient.
• Increases retention and physiologic function.
• The decrease in pressure to the surrounding tissues aids in deglutition and encourages the
regeneration of tissue.
• Does not add to the self- consciousness of wearing a denture.
• Reduces excessive atrophy and physiologic changes in muscle balance.

40. Controversies between closed and open
hollow obturators:
CLOSED OBTURATOR
Prevents collection of fluid and reduces air
space in the defect.
However, fluids can be absorbed through
porosity in the acrylic resin seal between lid
and obturator extension.
Patient is unable to clean the hollow inner
surface in a closed system.
This non-hygienic condition creates a medium
for growth of microbes.
OPEN OBTURATOR
Reduces the weight, improve speech and facilitate
hygiene, easier to make.
Acts as a receptacle for nasal secretions and food.
More cleaning required, difficulty in polishing the
internal surface.
An alternative to both is an obturator with
removable lid.
Thin and small lid can be made up of vacuum
formed thermoplastic resin sheets.
40

41. SILICONE OBTURATOR PROSTHESIS
Advantages –
1. Flexible material permits partial collapse of obturator, which overcomes the problem of
trismus.
2. Allows entry through a palatal fenestration to a larger cavity above
3. Enhances potential for retention by use of more severe, divergent undercuts
4. May gain additional support from the cavity and so minimize both the leverage and force
applied to the residual ridge.
5. It may also be remade independently of the associated denture.
41

42. TECHNIQUES FOR HOLLOWING AN
OBTURATOR
• Classic technique is to grind out the interior of the bulb after processing while monitoring the
thickness of walls. Once hollow, lid is fastened to the superior border.
• Parel and La Fuente used cellophane and sugar to make hollow obturator.
• Elliott used clay and cellophane paper.
42

43. TECHNIQUES FOR HOLLOWING AN
OBTURATOR
• El Mahdy and Guelde used two flasks with interchangeable parts.
• Silicone rubber foams and polyurethane foams were used.
• Worley and Kniejski used asbestos. Schneider used crushed ice.
43

44. A new technique for constructing a one-piece hollow obturator after partial
maxillectomy V A chalian, M O barnett 44
Procedure for one-piece hollow obturator:
• The trial denture is flasked and boiled out in the usual manner.
• A shim is constructed in the following manner: the undercut areas are blocked out and the entire defect
area is relieved of 1mm thickness wax.
a] Case waxed and flasked b] Wax boiled out

45. A new technique for constructing a one-piece hollow obturator after partial
maxillectomy V A chalian, M O barnett 45
Procedure for one-piece hollow obturator:
d] Acrylic added to defect and stops
c] Tissue stops prepared
• Three stops are placed in the wax to facilitate proper positioning of the
shim.
• 1mm of wax is also placed in top half of the flask over the teeth and palate
area to form top wall of shim.
• A layer of self-cure resin is then contoured over the wax relief in the defect
site, with another layer over the wax in the top half of the flask.

46. A new technique for constructing a one-piece hollow obturator after partial
maxillectomy V A chalian, M O barnett 46
Procedure for one-piece hollow obturator:
f] Wax boiled out leaving shim
e] Flask closed for shim polymerization
• After curing the flask is opened and wax is flushed off the shim.

47. DOUBLE FLASK TECHNIQUE (CHALIAN, BARNETT ET AL) 47
Procedure for one-piece hollow obturator:
• Heat cure acrylic is placed and pressed to bottom of defect, and the shim is
reinserted for final processing.
• After curing, it is finished and polished.
• Advantages:
• No lines of demarcation on denture to discolor.
• Undercut areas of defect are thick enough to allow for adjustment.
• Simple, more accurate and less time consuming.
h] Shim encased internally in obturator bulb
g] Hard shim embedded into final packing

48. TROUBLE SHOOTING:
• 1. Leakage into the nose:
• May occur several month or years after insertion of the prosthesis due to the continued fibrosis
in the tissues bordering the prosthesis.
• The prosthesis should be disclosed with a tissue conditioning material and the patient performs
functional movements.
• If swallowing and speech improves, then it should be evaluated for the area where the tissue
conditioner is thickest.
• These areas should be relined.
48

49. TROUBLE SHOOTING:
• 2. Hypernasal speech:
• The prosthesis may be adequately closed at periphery, but the patient’s soft palate and
pharyngeal closure mechanism are not functional as fibrosis of soft palate progresses.
• Often seen when a portion of soft palate was resected.
• If there is adequate space to add a pharyngeal bulb to the posterior medial aspect of the
prosthesis, this bulb can pass superiorly to the cut edge of soft palate and extend into the
pharynx.
• In this way, the minimally functional soft palate is by-passed by pharyngeal obturator.
49

50. PALATAL OBTURATOR
(GIBBONS & BLOOMER)
• Elevates soft palate to its maximal position during normal speech &
deglutition enabling closure by pharyngeal wall actions.
• Facilitates separation of oral and nasal cavities for speech, feeding,
swallowing and hypernasality.
50

51. 51
MEATAL OBTURATOR PROSTHESIS
(SCHALIT & SHARRY)
• Establishes closure with nasal structures (against the conchae and roof of nasal
cavity) at a level posterior and superior to posterior border of hard palate.
• Separates oral and nasal cavities.
• Indicated in patients with extensive soft palate defects.

52. SYSTEM OF FORCES
• The weight of the nasal extension of the obturator exerts dislodging and rotational forces on
abutment teeth.
• It is desirable that the weight of the obturator be minimal.
• Direct retention and extending the buccal wall of the nasal extension superiorly help resist such
forces.
52
Occlusal vertical force
Vertical dislodging force Lateral force
Rotational force
Anterior-posterior force

53. SYSTEM OF FORCES
• Occlusal vertical force - activated during mastication and swallowing. Wide distribution of
occlusal rests will help counteract such force.
• Lateral forces – stresses are minimized by the proper selection of an occlusal scheme,
elimination of premature occlusal contacts, and wide distribution of stabilizing components,
covering the medial wall of the defect by a palatal flap.
• Anterior-posterior movement - counteracted by the inclusion of guiding planes on the proximal
surfaces of abutment teeth.
53

54. SUPPORT,RETENTION
AND STABILITY
54

55. SUPPORT
• Support is the resistance to movement of a prosthesis toward the tissue.Available from – (1)
Residual maxilla (2) Within the defect –
• (1) Residual maxilla support includes:
• A. Support from Residual teeth:
• Carious involvement of the remaining teeth should be treated and their periodontal status
made optimal.
• Placement of occlusal, cingulum and incisal rests.
55

56. SUPPORT
• B. From Alveolar ridge:
• Large, broad and ridge with square or provide better support than small, narrow ridge with a
tapering contour.
• In patient with a retained pre-maxillary segment or a tuberosity, the arch form is improved and
so is the support.
• The healthy well formed edentulous ridge with extensive sulci will enhance support.
56

57. SUPPORT
• C. From Residual Hard Palate:
• The palate shelf is located perpendicular to the direction of the occlusal stress and provides
considerable support during function.
• Broad flat palate > high tapering palate.
• Large tori and pendulous soft tissues  removed, because they require relief and decrease
support.
57

58. SUPPORT
• (2) Within the defect – (necessary to prevent the rotation of the prosthesis into the defect)
• A. Floor of the Orbit: Its use should be minimal, if orbital floor has been removed, 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.
58

59. SUPPORT
• B. Pterygoid Plate or Temporal Bone:
• Positive contact of the prosthesis with this bony structure can be relatively extensive and
adequate to 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,
• covered with nasal epithelium.
59

60. RETENTION
• It is the resistance to vertical displacement of the prosthesis.
• Provided by – (1) Within the residual maxilla (2) Within the defect.
• (1) Within the residual maxilla –
• A. Teeth: If defect is small and remaining teeth are stable, intra-coronal retainer can be used.
• If defect is large and all teeth are weak, extra-coronal retainers should be used.
• B. Alveolar Ridge: A large ridge with a broad ridge rest and flat palate is more retentive than
small ridge with tapering ridge crest and high tapering palate.
60

61. RETENTION
• (2). Within the defect Retention –
• A. Residual soft palate :
• Provides posterior palatal seal and prevent ingress of food.
• Extension of the obturator prosthesis into the nasopharyngeal side of the soft palate.
• B. Residual Hard Palate:
• Undercuts along the line of palatal resection into nasal or paranasal cavity or medial wall of defect.
• Obturator extension into the undercut is best provided by soft denture base material.
61

62. RETENTION
• 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 the defects.
• Resulting in formation of scar band which is more prominent laterally and postero-laterally as
compared to scar band anterior to premolar region.
• These act as good undercuts for retention.
62

63. RETENTION
• D. Height of lateral wall –
• Engaging lateral wall of defect provides indirect
retention.
• Longer radius sweep undergoes less vertical
displacement than shorter radius.
63

64. STABILITY
• The resistance to prosthesis displacement by functional forces.
• Stability is offered by: (1) Residual Maxilla Stability and (2) Within the defect stability
• A. Residual Maxilla Stability:
• Providing bracing components of the prosthesis frame work.
• Extending bracing inter-proximally will minimize rotation and movement.
• B. Within the defect stability:
• Provided by maximal extension of prosthesis along all lateral directions.
64

65. PRE-OPERATIVE CARE
• If the defect is to be restored prosthetically, prior to surgery -
• Examine the patient thoroughly, make diagnostic impressions and casts.
• Obtain appropriate dental radiographs.
• Mount casts on suitable articulators with jaw relation records.
• Oral prophylaxis recommended, carious lesions can be restored.
• Arrangements made for any extraction of teeth during surgery.
65

66. PROSTHODONTIC MANAGEMENT
• Modifications to improve the prognosis for prosthetic rehabilitation:
• Save as much of the premaxilla as possible consistent with tumor control.
• Presurgical radiographs  accurately outline the extent of the tumour.
• Significant portion of the maxilla, mainly the premaxillary segment the tumour side can often
be identified as being free of disease.
• Retention of the premaxilla improves prognosis immeasurably by enhancing stability and
support.
66

67. PROSTHODONTIC MANAGEMENT
• In resections that extend posterior onto the soft palate, it may be advisable to remove the
coronoid process.
• Otherwise, as the mandible moves downward and forward the coronoid process may displace
the distolateral of surface of the obturator resulting in mucosal irritation.
• The reflected cheek flap should be lined by a split-thickness cheek flap, this keratinized surface
is more resistant to abrasion than respiratory mucosa and therefore is more suitable for
prosthesis support.
67

68. DENTULOUS PATIENTS
AND MAXILLECTOMY
DEFECTS:
PRINCIPLES OF DESIGN
68

69. PRINCIPLES OF DESIGN
• The need for a rigid major connector;
• Guide planes and other components that facilitate stability and bracing;
• A design that maximizes support;
• 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.
69
Rahn AO - Prosthodontic principles in the framework design of maxillary obturator prostheses. J prosthet dent 1989;62(2):205-12.

70. Principles of design (aramany 1978) 70
PRINCIPLES OF DESIGN (ARAMANY 1978) –
• Class I: Resection is along midline.
• A. Linear design: when there are no anterior teeth or they are not used and all posterior teeth
are in straight line. Support is form posterior teeth and palatal tissue.
• B. Tripodal design: when anterior teeth are used for support and retention

71. CLASS 1 DESIGN - TRIPODAL
• Direct retention – labial surface of the anterior
teeth with an I-bar on the central incisor.
• Posterior retention is placed on the buccal surface
of the molars and bracing is located palatally.
• Indirect retention – canine rest/distal surface of
the first premolar in a tripodal design.
71
Principles of design (aramany 1978)

72. CLASS 1 DESIGN – LINEAR
• Linear design  when anterior teeth absent or cannot be
used. The remaining posterior teeth are usually in a relatively
straight line.
• Miller states that a unilateral design requires bilateral
retention and stabilization on the same abutment teeth.
• A diagonally opposed retention and stabilization system can
be utilized.
72
Principles of design (aramany 1978)

73. CLASS 1 DESIGN – LINEAR
• Support : 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 : buccal surfaces of the premolars and the palatal
surfaces of the molars.
• Stability : palatal surfaces of the premolars and buccal surfaces of
the molars.
73
Principles of design (aramany 1978)

74. CLASS 2 DESIGN
• CIass II: Unilateral defect, anterior teeth on contralateral side are retained.
• Recommended design - Tripodal.
• Retention - buccally on all abutment teeth.
74
Principles of design (aramany 1978)

75. CLASS 2 DESIGN
• Indirect retention - located on opposite side of defect.
• Primary support - tooth nearest the defect as well as the most posterior
molar on the opposite side and remaining palate.
• Guiding planes - located proximally - on the distal of the anterior tooth and
the distal of the molar.
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Principles of design (aramany 1978)

76. CLASS 3 DESIGN
• Design – quadrilateral, simple and effective.
• Support - widely distributed on both
premolars and molars.
• Retention - buccal surfaces and stabilization
from the palatal surfaces.
76
Principles of design (aramany 1978)

77. CLASS 4 DESIGN
• Design - linear.
• Support – centrally on all remaining teeth.
• Retention - mesially on premolars and palatally on
the molars.
• Stabilization - palatal on the premolars and buccal
on the molars.
77
Principles of design (aramany 1978)

78. CLASS 5 DESIGN
• Design - Tripodal
• 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 - palatal surfaces.
78
Principles of design (aramany 1978)

79. CLASS 6 DESIGN
• Design – Quadrilateral
• Two anterior teeth are splinted bilaterally and connected by a transverse splint bar.
• Support – From remaining teeth.
79
Principles of design (aramany 1978)

80. SURGICAL CONSIDERATIONS
• Efforts are directed toward converting a potential Class I maxillary defect into
a Class II defect to provide a superior prosthesis both functionally and
esthetically.
• Recommendations are directed toward:
• 1. Preservation of the contralateral 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 provides superior tissue quality
coverage for the nasal septum.
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81. SURGICAL CONSIDERATIONS
• 3. Preservation of the posterior hard palate 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
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82. ASSESSING EFFECTIVE OBTURATION:
• Hahn - Silicone obturator enhances retention and seals the cavity tightly.
• Vergo and Chapman - Obturation restores function to near normal.
• Wood and Carl - Consider treatment to result in a functional and esthetic compromise
• Laney and Gibilisco - Border molding to ensure posterior seal and an extension over soft palate
margin to create retention.
• Desjardins - Obturator should make positive contact across the superior surface of soft palate
and extend toward the pharynx for effective seal.
• Watson - Lung function tests and radiography, simpler means to evaluate subjective
experiences of the patient.
82

83. REFERENCES
• Obturator prosthesis design for acquired maxillary defects - Ronald P. Desjardins,
• Basic principles of obturator design for partially edentulous patients. Part II: Design principles
• Impression Materials and Techniques for Maxillofacial Defects: A Comprehensive Review -
• International Journal of Drug Research and Dental Science Volume 2 Issue 4 (Page: 55-60), 2020
• Rehabilitation of Oncology Patients with Hard Palate Defects Part 1
• Rehabilitation of Oncology Patients with Hard Palate Defects Part 2 – Design Principles
• Rehabilitation of Oncology Patients with Hard Palate Defects Part 3 - Construction of an Acrylic
Hollow Box Obturator
• Prosthodontic principles in the framework design of maxillary obturator prostheses - Gregory R.
Parr,
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84. THANK YOU
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