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Stents and Splints

Utilizing the knowledge of anatomy, physiology and dental

materials, a dentist can provide innovative prosthetic aids that will

contribute to the total management of the patient.

The prostheses to be discussed in the following seminar are

examples of adjunctive appliances that can be fabricated by the dental

clinician to facilitate the treatment and rehabilitation of patients with

various functional and anatomical deficiencies.

Types

Radiation stents and splints

Burn splints

Occlusal splints

Nasal stent

Auditory stent

Radiation splints

Prosthetic devices frequently called stent, splints, carriers, or

positioners can be used to optimize the delivery of radiation while

reducing the associated morbidity.

Shield.

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This type of appliance positions the anatomical structures to be

irradiated into a predictable and repeatable position while displacing

and/or shielding other normal structures.

Positioner

This type of appliance will permit the radiation oncologist to

correctly position the radiation beam during the required multiple

treatment sessions

Carrier

This is a device which positions the radioactive sources into, or

adjacent to the tumour site.

Many of the custom splints and stents actually incorporate

several of the above criteria into a single device.

Burn stents

Management of burn patients not only depends on the area

involved, but also on the extent and severity of burns.

Often rehabilitation will extend over a prolonged period of time,

therefore the patient requires extensive medical and

psychological support from all concerned.

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During the surgical and physical therapy phases, the

maxillofacial prosthodontist can make valuable contributions to

patient care.

Services that can be provided include the fabrication of the

diagnostic cast of the various areas of the body, to be utilized for

the surgical reconstruction, as well as prosthetic replacement of

the missing facial structures.

Extensive scar contracture occurs during the primary healing

following burns of the skin.

Surgical reconstructive procedures include the releasing of the

scar bands with the placement of split thickness grafts. These

grafts must be in close approximation of the soft tissue bed if

they are to survive.

Appropriate adaptation and support will also minimize graft

shrinkage.

Support for the split thickness graft should be given for at least

6 months.

Replacement of the skin of the anterior part of the neck present a

difficult problem

Devices that are used to prevent the scar formation following the

split thickness graft are elastic bandages, sayer type , cervical

wrap up collar dressings and custom made leather molded

splints.

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Custom splits are also used to minimize the hypertrophic scar

formation, or to flatten the scars already present.

Impressions are made with irreversible hydrocolloid.

The impressions are made at the stage of the first dressing

change.

Petrolatum gauze should be place over the area of the skin graft

to protect the friable tissue.

The impression should be well extended beyond all the margins

of the graft.

A double layer of modeling wax is applied to the inner surface of

the cast to provide space of the silicone rubber foam lining to be

worn inside the splint.

Auto polymerizing acrylic resin stent is formed over the relieved

cast and it is perforated to provide retention to the liner.

Silicone rubber is processed as a liner for the stent.

The stent is secured with a 1 inch hook and loop tape. The

patient is instructed to wear the neck splint 24 hours a day and

remove it only to change liners.

At the end of 6 months the supported split thickness skin graft

and normal neck chin angle is established.

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Prosthesis for electric burns

A burn at the oral commisures is the most common type of injury

occurring in children.

As reported by Curtin et al the injury usually occurs due to

biting or sucking at the end of a charged electric cord, the ionic

saliva completes the circuit.

The localized tissues destruction and the subsequent perioral

contracture may result in microstomia, possibly leading to a

functional and cosmetic deformity of the oral commisure.

Potential dental deformities are cross bite, crowding, retrution,

palatal arch contraction.

Contracture of the wound margins occurs only after 5 days of

injury.

The prompt application of the splint therapy before the start of

wound contracture minimizes post burn scarring and the

development of microstomia.

Oral device

Reinberg proposed the fabrication of an extraoral device of the

prevention of microstomia.

This prevention splint provides a dynamic force to counter the

contracture.

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Softened wax is shaped to the uninvolved side of the cheek and

commisure.

A stone mold is made and the wax is eliminated, clear auto

polymerizing acrylic resin is cured for 20 minutes under 25 psi

pressure.

Rigid wire of 0.06 gauge of wire is attached to the end of the

conformer, and is bent for attachment of a headgear a strap.

The second conformer is fabricated in the similar manner.

Both conformer are attached to the orthodontic head gear cap

which provides traction.

The splint is worn continuously for 4 to 6 months. An additional

period of 4 to 6 months is recommended for night time wear.

Intra oral device

Ryan described the fabrication of the intraoral removable

appliance.

A millimeter ruler is used to measure the lips contour from the

normal side to the midline to determine where the tissues should

be placed on the defect side.

Stone cast are obtained and mounted to an articulator using inter

occlusal wax record.

Two layers of base plate wax are adapted over the maxillary cast

covering the palate and the teeth to the level of the sulcus.

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The wax is warmed to index the occlusal surfaces of the

mandibular teeth.

Wax extensions are added to the wax covering adapted to the

maxillary arch.

These extensions are moulded to curve laterally and posteriorly

to retract both corners of the mouth.

The internal contour of the extensions simulates the desired

contour of the healed tissue in clear acrylic resin.

The prosthesis should be worn 24 hours a day for 6 to 8 months.

It is removed for eating and cleaning of the teeth.

Modification in contour and tension can be developed with soft

wax, and then duplicated with autopolymerizing resin, until

optimal tissue contours are achieved.

A microstomia prevention appliance is available commercially.

Nasal stents

These stents provide support for cartilage transplants during post

surgical healing for the correction of nasal deformities in cleft

lip patients.

Nasal stents also maintain the contour and minimize scar

contracture following skin grafting procedures to the nostrils

The contracture of the scar tissue following facial burns can lead

to obliteration or severe narrowing of the nares.

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Nasal stents should be made as soon as possible to minimize this

constriction of the nostrils.

If narrowing has already occurred, one method is the fabrication

of a series of nasal stents in increasing sizes to gradually enlarge

the nasal passageways.

Doran suggested the incorporation of an orthodontic jackscrew

expander into the lumen of the sectioned stent, and gradually

activate until the desired opening of the nares is obtained

After desired expansion has been achieved, the sides of the stent

are sealed, and the stent was worn to maintain the nostril

opening.

If further corrective surgical procedures are contemplated, the

acrylic resin stent is used to support the split thickness skin

graft.

Auditory inserts

An auditory insert or custom ear plug, made of acrylic resin,

polyvinlychloride, or silicone rubber may be required as a stent

during surgical reconstruction of an ear.

This also serves as a custom ear plug following mastoid surgery

Impressions are made, by injecting the material into the auditory

meatus as well as into the convulsions of the pinna, if present.

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A mold is formed by suspending this impression in a plastic

disposable cup and then filled with rapid setting stone.

After the stone has set initially the mold is scored lengthwise

and split in half.

It is lubricated with petrolatum and reassembled, secured with

rubber bands and filled with silicone or acrylic resin.

Retaining substantial amount of the pinna helps in alignment,

retention and seal.

Trismus appliance

Trismus can be severe following surgical procedures or radiation

therapy to the head and neck. Trismus occurs most frequently

when surgery and /or the fields of radiation involve the muscles

of mastication or the temporomandibular joint

Several methods are used to counter act trismus and increase the

interarch space.

Exercising the mandible during the immediate postsurgical

period will tend to minimize the formation of constricting scar

tissue.

Another method is using a threaded, tapered screw made of

acrylic resin; the patient places the screw between the posterior

teeth and gradually turns to wedge the teeth apart.

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This device can be fabricated with auto polymerizing acrylic

resin.

The threads are refined, and device is polished.