Acqiured Maxillary Defects [Compatibility Mode]

7/30/2019 Acqiured Maxillary Defects [Compatibility Mode]

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Acquired MaxillaryDefects


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Basic differences between congenitaland acquired maxillary defects

Congenital clefts are confined to the

lines of union


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Etiology

1. SurgicalIs the main etiological factor namely resection

of tumor masses

2. Diseasee.g. Syphilis, osteomeylitis (rare)

3. Trauma

Gun shots (suicide attempts)


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Disabilities

Most of the disabilities are related to

communication of the oral and nasal cavities

1. Mastication

Regurgitation

.

Hypernasality

3. Appearance

Diplopia etc.4. Psychological

Could be worst of all


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Rehabilitation

1. Surgical

2. Prosthetic


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Surgical reconstruction

Is definitely the best treatment when feasible:

1. No possibility of recurrence after tumorresection

2. After trauma

3. Relatively small defects (great defectsgreatly complicates the surgical approach)


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Prosthetic reconstruction

Is indicated in cases surgical reconstruction is

not possible

1. Possibility of recurrence after tumor

resection

.

greatly complicates the surgical approach)

3. Large soft palate defects


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Phases of prosthetic reconstruction

A. Surgical obturation

Incorporated at the time of surgery or shortlythereafter

1. Immediate surgical obturation

2. Delayed surgical obturation

B. Definitive obturation

Incorporated 3-4 after surgery


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Immediate surgical obturation

- Indicated in edentulous subjects

Functions- Matrix for the surgical pack

- Separates oral cavity from nasal cavity i.e.

patient can speak and swallow with lessdifficulties

- Reduces possibilities of wound contamination

- Reduces psychological impact on patient


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Communication between prosthodontistand surgeon

- Spare post. portion of hard

palate and tuberosity toavoid loss of function of the

soft palate.

- n . nc s on roug atooth socket rather than

interdental ( sectioning of

FPD)


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Communication between prosthodontistand surgeon

- Should terminate short

of skin graft-mucosal

junction.


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Construction of immediate surgical

obturator

- Complete history, diagnosis, shade and form

registration- Tooth analysis and preparation (occlusal

adjustments, occlusal rest seat preparation,

- Modification of the stock tray

- Pt seated upright in order to record the

proper position of the soft palate

- Irreversible hydrocolloid is the material of

choice


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Construction of immediate surgical

obturator

- Provisional jaw relationship

- Pouring the impression and cast duplication- Outline of resection marked on the cast

- Cast alteration

- Clasping the existing teeth- Posterior artificial teeth should not included

- Waxing-up followed by processing

- Drilling interproximal holes- Attaching wire loops to the fitting surface at

the area that corresponds to the resected area


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Incorporation of immediate surgical

obturator

- Obturator picked up from an antiseptic

solution- Modifying the obturator to fit the surgical

defect

-

junction

- Block undesired undercuts with vaselinized

gauze

- Add tissue conditioner or compound to the

fitting surface of the obturator


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obturator

- Fitting surface of the obturator can be used to

support the skin graft. Black gutta percha is

referred because it is less irritant than tissue

conditioning materials

- Donor sites of skin grafts include inner side of

arm (unhairy)


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obturator- Retention could be obtained from:

- Clasps

- Wires ligated to teeth

- In edentulous areas ligation to

.

- Patient is 7-10 days later to

-maintain hygiene underneath the

prosthesis

- adjust retention

- Add tissue conditioner


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obturator

- Adding posterior occlusal ramps

- PIP to check pressure areas


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Delayed surgical obturator

Indications

Extensive surgical defects in edentulous

subjects

Procedure

- Carried out 7-10 after surgery

- Modification of the stock tray

- Irreversible hydrocolloid is the material of

choice


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Delayed surgical obturator

- Block undesired undercuts with vaselinized

gauze

-

the same purpose but after modification


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Definitive obturator- Usually constructed 3-4 months after surgery

- Exact timing is controlled by the following

factors:

- Possibilities of recurrence

-

effected by size and whether patient receivedradiotherapy

- Presence of teeth which greatly contributes

to retention and stability- Effectiveness of the present obturator


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Design features of definitive obturators

-Movement of theobturator

- Is affected by:

a. Size of the defectb. Number of missing

teeth


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-Movement of the obturator

c. Distribution of missing teeth

- o ssue-war an ssue-away movements are

expected and unless properly

controlled could be extensive


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- Tissue changes

- Could extend for a long period

- Results in tissue contracture especially in the

- Is more pronounced in patients receivingradiotherapy

- Acrylic resin is the material of choice to

facilitate rebasing and relining


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- Covering prosthesis

- Main objective is to separate oral and nasal

cavities

-

extensively movable


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- Extension into thedefect

- Extension in the

e ec s ou e

minimally without

compromising

retention, stability and

peripheral seal.


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- Extension into the defect

- Need for extension into the

defect is controlled by:

.

b. Nature and configuration

of the remaining supporting

structures


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- Extension superiorly along

the nasal se tum is not

recommended becausepseudostrafied columnar

epithelium offers little

mechanical advantage


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- Lateral extension is

recommended especially when

- Posterior undercuts related tothe soft palate are favorable

- Anterior undercuts are usually

not engaged


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- Presence of teeth

- Is crucial in

mprov ng prognos s


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- Weight

- Hollow design is

recommended

- Controversy exists as towhether to use

a. open or

b. closed designs


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Definitive obturators in edentulous

subjects

- Lack of teeth greatly worsens the prognosis

especially in large defects- Implants improve prognosis

-

implants in irradiated subjects- Axis of rotation depends on the location and

configuration of the defect

- Increased engagement of the defect isimportant to improve retention and stability


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Definitive obturators in edentulous

subjects

- Square and ovoid arches provide a better

configuration of the palatal shelf compared totapered arches

- S arin art of the osterior maxilla im roves

prognosis- Proper extension in the sulci of the intact side

is important

- Engagement of the lateral scar band- Engaging favorable undercuts

- Resilient materials


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Technique of construction of definitive

obturators

Primary impression

- Tray modification

- Blocking unfavorable undercuts

-

- Irreversible hydrocolloids is the material of

choice


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obturators

Secondary impression

- Special tray is constructed on blocked-outmodel

-

- Rubber base is the material of choice(alginate is the cheap alternative)

- Tissue conditioner on the surgical obturator is

an alternative


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obturators

Jaw relation registration

- Record bases or the definitive obturator basecan be used in this step

-

- Metallic oxide impression paste and plasterof Paris are better than wax for jaw relation

registration

- VDO could be reduced especially in cases ofbruxism


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obturators

- Occlusal schemes

- Non anatomic teeth are prefered

- Try in

-

- Mostly acrylic resin

- Soft liners could be used in selected cases

- Polished fitting surface at the side of the

defect


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Definitive obturators in dentulous

subjects

- Cases of total unilateral maxillectomy should

be treated as an extensive Kennedy class IIpartial edentulous case


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Retention of definitive obturators- Clasping

- Buccal retaining flanges

- Swing-lock design

- Undercuts in the defect

-

- Magnets

- Adhesives

- Intermaxillary springs (obsolete)


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subjects- Guide planes and a precisely controlled path

of insertion is of prime importance

- Multiple extensive occlusal rests- Mostly rigid major connectors are employed

-

the defect should be used for support andretention

- Due to lack of cross arch retention and

stabilization, such RPD could sometimes beviewed as unilateral RPD. Double retention

double bracing is sometimes indicated


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subjects

- Existing teeth controls the location of the

fulcrum line- Metal framework is used in making the

im ression im lementin the altered cast

technique- The prognosis of the obturator improves as

the margin of resection moves posteriorly


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Hollowing the obturator bulb

- Cellophane bag

containing sand

- Lid made of acrylic

resin

Acqiured Maxillary Defects [Compatibility Mode]

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