Obturator / orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

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OBTURATORS FOR ACQUIRED

MAXILLARY DEFECTS


INTRODUCTION

DEFINITION

HISTORICAL REVIEW

FUNCTIONS

CLASSIFICATIONS

DESIGN

MATERIALS

BASIC OBJECTIVES

PROSTHETIC MANAGEMENT

WEIGHT REDUCTION

FABRICATION

REVIEWS

REFERENCES www.indiandentalacademy.com

INTRODUCTION

The most common of intra oral defects are in the form of cleft or opening in the palate. These defects may be acquired or congenital. Acquired is due to injuries or surgical excision of tumor. Congenital is due to malformation.

When definite restoration involving fixed or removable prosthesis is needed to replace missing teeth to stabilize and align the arch segment, restore the occlusal function, provide facial support and helps in speech.

All this is usually aided with the help of an OBTURATOR.


DEFINITION

The name obturator is derived from the latin verb “obturare” which means close or to shut off.

According to the glossary of prosthodontic terms obturator is defined as prosthesis used to close a congenital or a acquired tissue opening, primarily of hard palate and or contigious alveolar structures.


HISTORICAL REVIEW

In the early part of the 20th century. Especially during and shortly after World War I, prosthetic restorations were made through collabration of dentists and plastic surgeons. Even so, as recently as 1953, prosthetic reconstruction of head and neck defects was largely neglected by the medical and dental professions. That was the year when a group of dentists founded the American Academy of Maxillofcial Prosthetics.With the continous advancement of maxillofacial prosthetics, the American Dental Association’s Council of Dental Education has now recognized this speciality. Today almost all patients with oral or facial defects are referred to dentists for the construction of maxillofacial prostheses. The reason is that within the profession of dentistry lie the knowledge, artistic skills, materials and techniques for the prosthetic repair of these defects


According to Ambroise Pare (1541) : probably the first person to close a defect. Pare has given excellent description of a simple but a very practical obturator for closing a perforation of the hard palate.

In one variation of this device a dry sponge was attached to the upper surface of the disc. When the sponge becomes moist by the secretion and it expands and hold the prosthesis in place.

In another variation when he used turnbuckle type of mechanism to hold the prosthesis in place.


Pierre Fuchard (1728) : sather of scientific dentistry contributed significantly to maxillofacial prosthetics. He described two types of palatal obturators.


One of the types has a wings in the shape of propellers which can be folded together while being inserted and spread out after insertion with a special key.

In the other type, the retaining feature is in the form of a butterfly wings which are made to open by a key after the closed wings have been inserted through the palatal perforation.

-William Morton (1869) : has been known to treat palatal defect patients with a gold plate to which the patients missing teeth are soldered.

-Kingsley (1880) described artificial appliances for the restoration of conginital and acquired defects of the palate, nose or orbits.


MATERIALS USED FOR OBTURATOR

Primitive man used stone, wood, gum, cotton, to obturate the defect.

Towards the end of the nineteenth century, vulcanite proved patients value in prosthodontics and maxillofacial prosthetics and replaced most of the earlier materials.

Gelatin : gelatin glycerin compound (by hennig) was developed and was widely used to during and after the first world war.

The most common material is used for the fabrication of the intra and extra oral prostheses are polymeric in nature. These includes : vinyl chloride polymer and copolymers, acrylic types and silicon rubbers introduced by Braley. (heat-vulconising and room temperature vulcanization (RTV) type).


FUNCTIONS OF AN OBTURATOR

The obturator fulfills many functions:

1. It can be used to keep the wound or defective area clean, and it can enhance the healing of traumatic or post surgical defects.

2. It can help to reshape or reconstruct the defect.

3. It also improves or in some instances makes speech possible.

4. In important area of esthetics the obturator can be used to correct lip an cheek position.

5. It can benefit the morale of patients with maxillary defects.

6. When deglutition and mastication are impaired, it can be used to improve functions.

7. It reduces the flow of exudates into the mouth.

8. The obturator can be used as a stent to hold dressing or packs post surgically. www.indiandentalacademy.com

Acquired Defects are:-

1. Advanced stage of syphilis.

2. Surgery of malignant tumours.

3. Tuberculosis

4. Necrosis caused by extensive inflammation of dental origin.

5. Extensive fractures.

6. Gun shot wounds.

7. Accidents


CLASSIFICATION OF OBTURATORS

According to Aramany M.A : he has proposed that partially edentulous maxillectomy dental arches be classified into six groups

Class I

Resesction in this group is performed along the midline of the maxilla, teeth are maintained on one side of the arch.


Class II

Defect is unilateral, retaining the anterior teeth on the contra lateral side


Class III

Palatal defect occurring on the central portion of the hard palate and may involve part of the soft palate. Dentition is preserved.


Class IV

Defect crosses the midline and involves both sides of the maxilla. Few teeth remain which lie in the straight line.


Class V

surgical defect in this case is bilateral and lies posterior to the remaining abutment teeth.


Class VI

it is rare to have maxillary defect anterior to the remaining abutment teeth. This occurs mostly in trauma or congenital defects rather than in planned surgical intervention.


DESIGN OF OBTURATORS :-

Class I design:

Design can be either linear or tripodal

Two or three anterior teeth are splinted whenever possible, and support is derived from the central incisor and the most posterior abutment tooth. If the dental arch is curved the principle of effective indirect retention is utilized by the location of the rest on the canine or on the distal surface of the 1st premolar in a tripodal design. Direct retention is obtained either from the labial surface of the anterior teeth with I bar on the central incisor.www.indiandentalacademy.com

If the anterior teeth are not included in the design the linear design is recommended. Miller (1972) stated that unilateral design required bi-lateral retention and stabilization on the same abutment teeth. A diagonally opposed retention and stabilization system can be utilized. Retention is located in the buccal surface of the premolar and palatal surface of the molar. Stabilizing components are placed on the palatal surface of the premolar and buccal surface of the molar.


Class II

Design is linear.

Primary support is based on the tooth nearest the defect as well as the posterior molar on the opposite side. An indirect retainer is positioned perpendicular to the fulcrum line. Guiding planes are located at the distal surface of the anterior tooth as well as the molar tooth. Retention on all the abutment teeth is located on the buccal surface and stabilizing components are on the palatal surface. www.indiandentalacademy.com

Class III

Design is quadrilateral.

Design based on the quadrilateral configuration. Support is distributed both on premolar and molars. Retention is derived from the buccal surface and stabilization from the palatal surface.


Class IV

Design is linear.•Support is located on the central of all the remaining teeth.•Retention is located mesially on the pre molar and palatally on the molar.•Stabilizing components are palatal on the premolars and buccal on the molars. www.indiandentalacademy.com

Class V

Design is tripodal.

Anterior teeth are preserved and the posterior teeth, hard palate and portion of the soft palate are resected. Splinting of at least two terminal abutment teeth and I-bar clasps are placed bilaterally on the buccal surface of the most distal teeth and stabilization is located on the palatal surface.And indirect retention is located on central incisor.


Class VI

Design: Quadrilateral

Two anterior teeth are splinted bilaterally and connected by a transverse splint bar.

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


BASIC OBJECTIVES OF AN OBTURATOR

•It should be comfortable.

•Should restore adequate speech, deglutition, and mastication

•Should be acceptable cosmetically.

To achieve all these objectives, the obturator should have adequate support, retention and stability.


1. SUPPORT: Support gives the resistance to movement of the prosthesis towards the tissue.

Support is available from

Residual maxilla

Within the defect

I. Residual maxilla support : includes:

A. Residual teeth

1.carious involvement of the remaining teeth should be treated and their periodontal status made optimal.

2.Support is also provided by the placement of occlusal rests, cingulum rest and incisal rest.


B. Alveolar Ridge

1.Large, broad and ridge with square or provide better support than the small, narrow ridge with a tapering contour.

2.In patient with a retained premaxilaary segment or a tuberosity, the arch form is improved and also the support.

3.The healthy well formed edentulous ridge with extensive sulci will enhance support.

C. Residual Hard Palate

1.The palate shelf is located perpendicular to the direction of the occlusal stress and provides considerable support during function.

2.The broad, flat palate is more support than the high tapering palate.

3.Large palatal tori and pendulous soft tissues should be removed because the process will require relief and this will decrease the support.


II WITHIN THE DEFECT SUPPORT

It is necessary to prevent the rotation of the prosthesis into the defect.

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:

i)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.

ii)Additional weight

iii)Problems of fabrication

iv)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 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.


2. RETENTION

Retention is the resistance to vertical displacement of the prosthesis.

Retention is provided by

- Within the residual maxilla

- Within the defect

Residual Maxilla Retention

is provided by

a. Teeth

i) 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.www.indiandentalacademy.com

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.

Within the defect Retention Provided by

a) Residual soft palate

i) Provides posterior palatal seal and prevent ingress of food.

ii)Extension of the obturator prosthesis into the nasopharyngeal side of the soft palate provides retention.

b) Residual Hard Palate

-Under cuts along the line of palatal resection into, nasal or paranasal cavity or medial wall of defect can increase retention.

-Obturator extension into the undercut is best provided by a soft denture base material. www.indiandentalacademy.com

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.

Stability is offered by:

i) Residual Maxilla Stability

ii)Within the defect stability

Residual Maxilla Stability:-

This is done by providing bracing components of the prosthesis frame work.

Extending bracing inter proximally will minimize rotational as well as anterioposterior movement of the prosthesis.

Within the Defect Stability:- is provided by

Maximal extension of prosthesis in all lateral directions.www.indiandentalacademy.com

Prosthodontic Management:-

If the defect is to be restored prosthetically, prior to surgery, the prosthodontist should examine the patient thoroughly, make impressions for diagnostic casts, mount these casts on suitable articulators with jaw relation record and obtain appropriate dental radiographs. If time permits, a routine prophylaxis can be preformed, any teeth with carious lesion be restored and arrangements made for any extraction of teeth, at the time of surgery.

Prosthetic therapy for patients with acquired surgical defects of maxilla can be arbitrarily divided into 2 phases of treatment:-

The initial phase called surgical obturation which entails the placement of prosthesis at surgery (temporary prostheses) or immediately thereafter (transitional). The objective of surgical obturation is to restore and maintain oral function at reasonable levels during the postoperative period until healing is completed.

Three to four months after surgery, the surgical site becomes stable dimensionally thus permitting construction of the definitive prosthesis or the second phase of prosthodontic therapy.


Pre – Operative Care

These are certain dental needs that should be considered in the preoperative course for the patient.

- Large carious lesions should have temporary restored.

- Periodontal evaluation in the preoperative period.

-Diagnostic cast impressions should be made to reassess all the clinical and radiographic findings.

- Minor surgical problems such as removal of teeth for carious, periodontal, malposed and removal of hyperplastic tissues or bony exostosis.

-There are a number of modifications of surgery that may improve the prognesis for prosthetic rehabilitation.

First, an attempt should be made to save as much of the maxilla as possible consistent with tumour control.


Second, presurgical radiographs enables the surgeon to fairly accurately outline the extent of the tumour.

Third, significant portion of the maxilla, mainly the premaxillary segment of the tumour side can often be identified as being free of disease.

-In both edentulous and edentulous patients the retention of the premaxillary segment improves the prosthodontic prognosis immeasurably by enhancing stability and support for the prosthesis.

-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 the obturator resulting in mucosal irritation.

-The surgeon improves the tolerance and retention of the obturator if he lines the reflected cheek flap with a split thickness skin graft.This keratinized surface is more resistant to abrasion than in respiratory mucosa and therefore is a more suitable denture-bearing and support the surface.


Surgical Obturator:

It is defined as a temporary prosthesis used to restore the continuity of the hard palate immediately after surgery or traumatic loss of a portion or all of the hard palate or Contiguous alveolar structure. The obturator may be placed immediately after surgery or seven to ten days post surgically.


IMMEDIATE SURGICAL OBTURATION:

Immediate surgical oburator is a baseplate type of appliances which is constructed from the preoperative impression cast and inserted at the time of resection of the maxilla in the operating room.

Advantages:

1. Prosthesis provides a matrix on which the surgical packing can be placed.

2. Prosthesis reduces the oral contamination of the wound thus reducing the incidence of local infection.

3. Prosthesis enables the patient to speak more effectively postoperatively by reproducing the normal palatal contours.

4. Prosthesis permits deglutition thus the nasogastric tube may be removed at an earlier date.

5. Prosthesis may reduce the period of hospitalization (cost reduced).


These are several principals relative to the design of immediate surgical obturators.

1. The obturator should terminate short of the skin graft – mucosal junction.

2. Prosthesis should be simple, lightweight and inexpensive.

3. prosthesis for dentulous patients should be perforated with small dental bur in the interproximal extensions to allow the prosthesis to be wired to the teeth.

4. Normal palatal contours should be reproduced to facilitate postoperative speech and deglutition.

5. Posterior occlusion should not be established on the side of the defect until the surgical wound is well organized. If the patient is for total maxillectomy three maxillary anterior teeth included in the resection may be added to the prosthesis to improve esthetics.


Standard maxillary impression trays must be extended posterior with base plate or waxes to record a significant portion the soft palate in the impression. The patient should be placed in an upright position so that soft palate assumes a relative normal relaxed position. It is important to make an accurate impression of the vestibular depth on the resected site so that the approximate position of the skin graft mucosal junction can be determined. The maxillary cast is altered to conform to the proposed surgical resection. Teeth to be included in the resection are removed from the cast, but alveolar height is maintained. The residual alveolar ridge is trimmed on the labial and buccal surface to reduce the stress on the soft tissue closure. In patients with excessive vertical overlap the obturator extension anteriorly must be trimmed to avoid occlusal interference with mandibular anterior teeth.


After the cast is altered the wire retainers are adapted and the prosthesis is waxed, invested and processed in autopolymerizing methyl-metha-acrylate and finished, and polished in the customary manner. Clear resin is suggested so that the extension and possible pressure areas can more easily visualized at surgery. In most instances the immediate surgical obturator is easily fitted and secured. The care should be taken to adjust the lateral extension of the obturator short of the skin graft mucosal junction to avoid pressure. However, if the surgery was more extensive than planned it is preferable to add an immediate denture reline material to the prosthesis. A thick mix is made and added to the deficient areas. The prosthesis is inserted as the material sags, it is manipulated to the position with a wet finger.


In dentulous patient retention is obtained by wiring the prosthesis to the existing teeth. In edentulous patient the prosthesis is wired to the alveolar ridge and zygomatic arches and/or anterior nasal spine. Seven to ten days after surgery the prosthesis and surgical packings are removed.

Squamous cell carcinoma of right maxilla (upper jaw) invading bone

A surgical obturator wired in place after the tumor was removed.


DELAYED SURGICAL OBTURATOR

An alternative is to place the prosthesis 7-10 days post surgical. After initial healing and removal of the pack the immediate obturator is usually discarded and replaced by transitional or temporary prosthesis having a definite bulbous extension and occasionally artificial anterior teeth.

Soft palate defect: Patient has a defect in the upper palate due to surgery to remove a mucoepidermoid cancer.

Obturator prosthesis for soft palate defect www.indiandentalacademy.com

DEFINITIVE OBTURATION

Three to four months after surgery consideration may be given to the construction of the definitive obturator prosthesis. The timings will vary depending on the size of the defect, the prognosis of the healing, prognosis of the tumor control, the effectiveness of the present obturator and the presence or absence of the teeth.

Large soft palate defect: The patient had a large portion of the soft palate removed.

Obturator prosthesis for large soft palate defect

Final result of inserted soft palate prosthesis


EDENTULOUS PATIENTS WITH TOTAL MAXIALLEXTOMY DEFECTS

MASTER IMPRESSION

Edentulous stock metal tray is selected according to the configuration of the remaining maxilla. Prior to making impression, the medial and anterior undercuts are blocked out with a gauze lubricated with petroleum jelly, because these undercuts are engaged by the prosthesis. Irreversible hydrocolloid impression material is mixed and loaded in the tray prior to seating of the tray, impression material is injected into the posterior and lateral undercuts. Impression is made and cast is poured. The undesired undercuts recorded in the cast are blocked out with wax. Relief of one thickness base plate wax is provided for the skin graft mucosal junction and the postero lateral aspect of the defect.


The custom tray is fabricated in acrylic resin. Extension of the tray is verified in the mouth. Conventional border molding technique are advocated using modeling plastic. The modeling plastic is relieved approximately 1mm in all the areas prior to obtaining the final impression. Several perforations are made for the exit of the impression material with at least 3 perforations along the medial palatal margin. The tray is painted with the adhesive and elastic impression material is loaded on the tray, excess secretions are wiped from the surface of the palate, material is injected into the reasonable undercut areas and impression tray seated into position. The lip and cheek are manipulated and patient is instructed to perform movements of the mandible. After the material is set the impression is removed with a gentle teasing action.


The vertical dimension of occlusion is established in the customary manner with the wax rim on the record base. Incase of patal defects stabilized baseplate is made and followed into the defect area. At this stage, a wax lid is fitted over the defected area to leave it hollow and provide the effect of a complete palat. The wax rim are reduced to the proper level, the arbitrary face bow is obtained and centric jaw relation is recorded. Graphic centric relation records produced by intra or extra oral devices are contra-indicated.

Occlusal Scheme

The teeth are set to contours established by the wax rim. In edentulous patient non anatomic posterior teeth are preferred and tried in patients mouth and changes are made if necessary.


Processing, Delivery and Follow-up

The dentures are made in the standard manner with heat cure methyl metha-acrylate. If more retention is necessary consideration should be given to using a soft silicon material for the obturator segment of the prosthesis. This soft material allows the prosthesis to engage more aggressively.

On delivery the resin extensions into the undercuts may require considerable relief in order to permit seating of the prosthesis. The superior surface of the obturator should be rounded and lightly polished with fine pumice. Polishing improves cleansibility and results in less friction as the prosthesis soft tissue interface during functional movement. Pressure indicator paste is used to find the excessive tissue displacement. Disclosing waxes are used to check the peripheral extension or monitoring tissue displacement. Most maxillary obturators will require rebasing in the first year of delivery because of further organization of the defect with subsequent dimensional changes.


Fabrication of definitive obturator for prosthesis for partial resection of the edentulous maxillae is similar to the prosthesis for the total maxillectomy resections. In these defects, more of the hard palate remains and subsequently the prosthesis has more stability and support.


DENTULOUS PATIENT WITH MAXILLECTOMY DEFECTS

Dentulous patient with maxillectomy defectsThe prognosis improves with the availability of teeth to assist with the retention, support and stability of the prosthesis.

In dentulous patient with partial maxillectomy defects impression and cast is made and surveying is done for class and partial frame work design. Frame work is seated on the master cast, and desirable undercuts are blocked and acrylic baseplate is constructed on the defect side. The frame work is placed in the mouth and try the extension of the tray and modeling plastic is added to the tray material until the desired extension have been achieved and secondary impression is made and processing the denture in usual manner.


Dentulous patient with partial maxillectomy the fulcrum line is dependent on the placement of the occlusal rest. As more teeth are retained on the defect site the fulcrum line shift posteriorly. As the fulcrum line shifts posteriorly the disto lateral extension of the obturator should be lengthened as this area offers the greatest mechanical advantage. Indirect retainer should be placed anteriorly as possible from the fulcrum line.


OBTURATION FOR TOTAL SOFT PALATE DEFECTS

The soft palate normally establishes separation between the oral and nasal cavities. The soft palate moves in response to the physiologic demands of speech, deglutition, and respiration. The movement of the soft palate is a coordinated activity that results in varying degrees of closure between the soft palate and pharyngeal walls during breathing, speaking and swallowing. At some times there may be complete closure while at other times there may be varying degrees of opening. Palatopharyngeal inadequacy results in physical and psychological cocerns for the patient.

The objectives of prosthetic intervention are to prevent food and fluid leakage into the nose and to improve speech intelligibility.


METHOD OF FABRICATIONConstruction of obturators for soft palate deficiencies begins with the

fabrication of the conventional prosthesis. In obtaining impressions for diagnostic casts the palatal portion of the stock tray should be extended with wax so that the defect will be recorded.

Partial denture designs must consider the long arm created by the extension for the obturator. Multiple occlusal rests on either side of the fulcrum line willl tend to resist the downward displacement of the obturator and will increase the stability of the prosthesis. Multiple retainers are suggested for selected teeth with the retentive arms engaging distal undercuts. Such retainers will tend to disengage with any inferior movement of the obturator and will minimize the stress to abutment teeth. In patients with an anterior edentulous area, consideration should be given to the placement of crowns on the adjacent adutment teeth with the attachment of an anterior bar. The bar will act as an indirect retainer and provide excellent stability for the obturator extension. Modelling plastic is added to tray resin and border molding is started at the anterior margin of the defect and then continued postero- laterally.


The activated pharyngeal musculature will displace the excess modeling plastic superiorly and inferiorly and these excesses should be trimmed. When the modelling process is completed, the patient is asked to speak, to swallow, and to breathe through the nostrils to test the effectiveness of the formal obturator if the position and contours of the obturator are satisfactory, all extensions are reduced approximately 1 mm with sharp scalped. The mouth temperature thermoplastic wax is added to the obturator, flamed, temepered and placed in mouth. The functions activating the palatopharyngeal musculature are repeated to re-establish the contours.

The use of thermoplastic waxes ensures against over extension of the obturator. Adequate areas of contact of demonstrate a dull stippled appearance, whereas a shiny surface indicated a lack of contact.


The obturator is processed in a customary manner with either heat activated or autopolymerizing methyl-methacrylate. The processed prosthesis is trimmed and polished. The oral surface of the obturator should be concave to provide adequate tongue space. The superior surface should be convex and well polished to facilitate the defection of nasal secretions into the oropharynx. The patient is scheduled for subsequent adjustment appoinments. Many obturators for soft palate defects require reduction after delivery. If patient complains of soreness and pressure, the obturator should be reduced accordingly.


Speech Evaluation Following Obturator Placement:-

Prosthodontist can administer the lower pressure articulation test and evaluate articulation errors and inappropriate nasal resonance with the help of a speech pathologist.

Weight Reduction (Hollow Obturators)

Obturators should be hollow and light weight. So that teeth and supporting structures are not stressed unnecessarily.


Advantages of a Hollow bulb obturator:

Weight of prosthesis is reduced, and it is more comfortable and efficient.

Changes one of the fundamental problems of retention and increases physiologic function.

The decreases 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.

Does not cause excessive atrophy and physiologic changes in muscle balance.

Techniques:

Several techniques are used for the fabrication of hollow bulb obturator .

The commonly used ones are:

1.two piece hollow obturator

2.one piece hollow obturatorwww.indiandentalacademy.com

FABRICATION OF ONE PIECE HOLLOW BULB OBTURATOR (According to Challan and Barnett)

Procedure

- Try the trial denture in the mouth and make necessary modifications.

- Waxup the denture after the try in.

- Invest the denture in the flask in the usual manner.


- Boil out the wax in the conventional manner.

- Block out the undercut area in the cast of the defect.


Construction of autopolymerizing acrylic resin shim

- Relieve the entire defect area with one thickness of base plate wax.

- Place three stops in the wax which will be deep enough to reach the underlying stone of the master cast.

- Place one thickness of base plate wax in the top half of the flask over the teeth and palate area to form the top wall of the shim. This will provide space for heat cure acrylic resin on the palatal side of the denture.


- Make the autopolymerizing acrylic resin and allow it to come to a dough consistency.

- Contour a layer of dough consistency acrylic resin over the wax relief.


- Close the flask, Allow the resin to cure for 15 min.


- Flush the wax from the acrylic resin shim with a steam of boiled water.


- Trim all the excess of acrylic resin from the shim.

- Replace the heat cure acrylic resin shim using 3 stops for correct positioning. At this stage see that there is at least one thickness base plate wax between the shim and the cast.


Placement of acrylic resin shim and denture processing

- Mix the heat cure acrylic resin in the usual manner.

- Place a layer of acrylic resin in the bottom of the defect.

- Reinsert the processed acrylic resin shim over the still soft acrylic resin mix in the defect.

- Add more acrylic resin to the top half of the flask and packing is done.

- Cure the resin in the usual manner.

- Deflask it and trim and polish in usual manner.


Maxillary obturator with silicone-lined hollow extension (Takashi Ohyama, and Gold 1975)

The hollow extension consists of two layers of different materials. The exterior of the hollow extension, which is in apposition with the defect, is coated with a soft, resilient silicone. The interior of the hollow extension is fabricated of hard self-curing acrylic resin.

The resiliency of the outer surface of the hollow extension facilitates insertion of the prosthesis into deep undercuts, providing for improved retention while minimizing the tissue irritation.


Fabrication:-

Step 1. Investing the obturator. Invest the wax denure-obturator in a flask, and boil out the wax in the conventional manner.


Making the shim in self curing acrylic resin:-

-Outline the seat, cut keys for the shim in the stone of the bottom half of the flask. The seat shoud encircle perforated palate, measuring about 3-5mm in width and extending laterally 1-2mm.

-To maintain the relationship of the shim to the cast, 3 cone shaped keys should be cut within the stone of the seat of the shim. The cone shaped keys relate the shim to its proper seat.


-Place 2 sheets of base palte wax over the mould of the defect in the flask to provide space for the silicone between shim and the defect. Fill all remaining undercuts with wax so that the shim, made from self-curing acrylic resin, can be removed.

-For relief, place one thickness of baseplate wax over the teeth and palatal part of the mold on the side of the palatal defect in the top half of the flask. This wax will provide space for a thickness of heat-curing acrylic resin over the oral aspect of the prosthesis.


-Paint a layer of thin foil substitute on the wax relief and keyed seat for the shim. Put a mixture self-curing acrylic resin into the top and bottom halves of flask on the relief wax, and spread the resin evenly to approximate one or two thickness of baseplate wax. Then, close the flask.


-Completely flush the wax away from the cured resin shim.

-Drill holes with a No.3 round bur at ½ inch intervals through the lip of the shim which communicates with the space for silicone.


-Before packing the heat cure acrylic resin the silicone escape holes in the shim are cleaned out and closed by adding self-curing acrylic resin.

-Premade shim is then pressed into position over the silicone.

-Packing is done.

-Place the flask in a 165oF water bath for 9 hours.

-Trim and polish the acrylic resin parts of the obturator, trim the silicone flash with scissors, a sharp blade, or abrasive finishing wheels.


FABRICATION OF TWO PIECE HOLLOW BULB OBTURATOR (According to Bob Palmer and Coffey in 1985).

Method:

1. Make an impression that includes the palatal defect to be obturated.

2. Pour a stone cast, separate, and key at the border of the cast.


- Apply a suitable separating media to the stone surface.

- Clay is sculpted to the palatal defect and missing alveolus.


Pour a plaster (plaster cap) over the clay, including the keys in the master cast.


- Remove the plaster cap when it sets, take out the clay and discard it.

- Coat the tissue side of the plastic cap with a suitable separating media.

- Apply thin layer of self cure acrylic resin to the defect (E) and tissue surface of the plaster cap(F).

- Soft acrylic resin is added into the border of E and F and into the border of D adjacent to E.

- Invert the plastic cap and F into the master cast. Be sure the acrylic resin is kept moist with monomer before closure.

- Check the key for the proper fit and allow the acrylic resin to cure.


- Remove and finish the bulb in usual manner.


Simplified method of making a hollow obturator (Victor Matalon in 1986)

Method:-

- Invest the impression for obturator in a flask in the normal manner

- Remove the impression material.

- Place separating medium on the investment surface

- Roll out heat-curing acrylic resin to an approximate 2 mm thickness when it is in the doughy stage.

- Pack the periphery of the obturator with rolled out heat cure acrylic resin.

- Fill the center of the concavity created in the previous step with granulated sugar to within approximately 2 mm of the top.


-Pack the mould with rolled out heat-curing resing in the usual manner.

-Process the acrylic resin according to manufacturer’s specifications.

-Deflask the prosthesis.

-Using a No.8 bur, drill a hole in the superior surface of the obturator.

-Pour out the sugar.

-Use autopolymerizing acrylic resin to seal the hole made by the bur.

-Finish the restoration in the customary maner.


Simplified Techniques for fabricating light weight obturator (Tanaka and Henry, Polyurethane foam core)

-Impression is made, cast is poured.

-Defect is covered with single layer of baseplate wax.

-Excessively deep undercuts are blocked out to facilate removal of the polyurethane foam core and allow for later adjustments without risk of perforating the core. www.indiandentalacademy.com

-Several 2 mm perforations are made through the wax in the top and bottom of the flask in the region of the defect.

-4 mm sections of a 2 mm diameter heat cure acrylic resin rod asre cut, placed into the perforations, and allow to project approximately 2 mm. into the region of the defect. The projection attached to the polyurethane foam and act as a guides to center the core.


-A liquid-foil seperator is applied to the wax surface.

-Polyurethane foam base is catalyzed and approximately one fifteenth of the chamber of the defect is filled and the flask is quickly closed.

-The flask is heated for 10 minutes at 1200C in a dry oven.

-The flask is opened and the wax is peeled off of the foam core. Boiling water should not be used to soften the wax over the core since it will destroy the foam.


-The foam core is coated with a waterproof separator to avoid direct contact with the acrylic resin monomer, which would soften the foam.

-The coated polyurethane foam core with its acrylic resin guides for centering the core.


-Core is coated a thin layer of acrylic resin of a putty-like consistency. A thin layer of acrylic resin is placed over the defect in both halves of the flask.

-The coated core is pressed into position on the top of the flask, additional acrylic resin is packed in the remaining portion of the flask is then closed, The foam core is sufficiently rigid to withstand the intraflask pressures.


-The acrylic resin is cured in hot water bath. The complete obturator is deflasked, finished and polished.


REVIEW OF LITERATURE

In 1957, Nidiffer and shipman wrote about hollow bulb obturator for acquired palatal defects. A hollow bulb obturator offers certain advantages.

1) The weight of the prosthesis is reduced, making it more comfortable and efficient.

2) The lightness of the prosthesis changes one of the fundamental problems of retentions and increases physiologic function.

3) The decrease in pressure to the surrounding tissues aids in deglutition and encourages the regeneration of the tissue.

4) The light weight of the hollow bulb does not add to the self consciousness of wearing a denture.


-Matalon, Victor et al in 1976 described a simplified method for fabrication of hollow bulb obturator. The waxed up denture and obturator is inverted and wax eliminated. Heat cure acrylic resin is rolled out to 2mm thickness when in dough stage and packed align the periphery of the obturator. The center of the concavity is filled with granulated sugar. The mould is packed in a usual manner and processed. After deflasking a hole is drilled on the superior surface of the obturator with a number 8 bur and sugar is poured out. The hole is sealed using autopolymerizing resin.

-Tanaka, Gold and Pruzansky in 1977 described a simplified technique or fabricating a light weighted obturator using poly urethane foam as a core material. This is a time saving method of achieving a meaningful reduction in the total weight of the prosthesis while increasing the strength and facilitating repair.


- Aaron Schneider in 1978 described another method of fabrication of hollow bulb obturator where the defect cavity is filled with crushed ice of filled with water and freezed overnight. After processing two halves are drilled to remove the water and the holes are closed with autoploymerizing resin.

- Desjardins in 1978 described obturator prosthesis design for acquired defects in detail. He gives an elaborate account on the best ways of achieving support, retention and stability. Support within the defect is primarily obtained in the posterolateral area of the defect which may be the pterygoid plate or the anterior surface of the temporal bone. In certain cases where no orbital extension has been carried out the floor of the orbit can provide useful means for support. In defects that extend across the midline the nasal septum becomes available for support.


Some areas which can provide retention to the obturator are:

Residual soft palate.

Residual hard palate.

Anterior nasal aperture

Lateral scar band

Height of the lateral wall

- J.D.Browning in 1984 described about the procedure for fabrication of hollow obturator with fluid resin. The construction technique is simple and accurate.


- Challan, Barnett et al in 1972 described a technique for the fabrication of one piece hollow obturator for patients who have had maxillary resection. The process is simple and light weight and easy to clean. It requires little more laboratory time than is needed to fabricate usual complete denture.

- Ohyama, Gold and Pruzansky in 1975 described the hollow extension obturator comprised of two materials. One is inner hard acrylic resin hollow core to decrease the weight and provide dimensional stability. Second is the outer layer of soft silicon to enhance the retention and tissue tolerance.

- Aramany M.A in 1978 classified the partially edentulous maxillectomy patients, and suggested six different classification forms and also described the design for construction of obturator in each of them.


- Houck Medford in 1981 described the repair of hollow bulb obturator where cotton gauze is adapted to the defect surrounding to which gauze is secured. This serves as a matrix for repair with the autopolymerizing resin.

- Knapp in 1984 described a simplified approach for the fabrication of maxillary hollow obturator prosthesis. A technique that simplifies the maxillary hollow obturator has been described. This procedure is simple and time saving and results in accurate, light weighted and non porous prosthesis.

- Russel et al in 1997 did a study on refining the hollow obturator base using a light activated resin. This article described an easy time saving procedure that uses visible light activated denture base material to close an open type interim obturator.


- Hahn in 1972 described advantages of the silicon bulb and the plastic insert. He said that the combination of these two materials has the following advantages :

a. allows the patient to wear the bulb and insert without wearing his denture.

b. Allows more undercuts to be used for retention.

c. Seals off the surgical defect tightly with very little discomfort.

d. Is much lighter in weight than the acrylic resin.


References:

1. Aaron Schmider: Method of fabricating a hollow obturator. J. Prosth. Dent 40:351, 1978.

2. Aramany M.A: Basic principles of obturator design for partially edentulous patients. Part I : Classification, J. Prosth. Dent, 40:351, 1978.

3. Desjardins R.P. : Obturator prosthesis design for acquired maxillary defects. J. Prosthet .Dent, 1978, 39; 424.

4. Matalon J.W. et al – A simplified method for making a hollow obturator. J. Prosht. Dent. 36:580-82, 1976.

5. Tanaka et al – a simplified method for fabricating a light weight obturator. J. Prosth. Dent. 38:638-42, 1977.

6. Russell R. Wang – Refilling hollow obturator base using light activated resin J. Prosth. Dent. 78:327, 1997.


7. Gregory R. Parr – Prosthodontic principles in the frame work design of maxillary obturator prosthetics. J.PD. 62:205, 1989.

8. Oscar E. – Rapid technique for constructing a hollow – bulb provisional obturator. JPD 39:237, 1978.

9. Bob Palmer – Fabrication of the hollow bulb obturator. JPD 53:595, 1985.

10.Mohamed A. Aramany – Basic principles of obtuarator design for partially edentulous patients. Part II : Design principles. JPD 40:656, 1978.

11. Oral and maxillofacial rehabilitation by Buemer.

12. Maxillofacial Prosthetics by Chalian.


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Obturator / orthodontic courses by Indian dental academy