TRIPASS XR تري باس

 • Plastic ocular prosthesis is superior to the glass ocular prosthesis.

Advantages of plastic acrylic ocular prosthesis

• As it is custom-made, adjustability to the size and form is easier.

• It offers actual three-dimensional effect in iris constriction.

• Prefabricated iris buttons can be stocked.

• Plastic acrylic eye permits elimination of time-consuming steps such

as multiple mould fabrication and precision grinding.

• It is relatively easy to fabricate.

• It has more strength and is less fragile as compared with glass eye.

Procedure

• The patient is lowered in a supine position and two drops of

ophthalmic local anaesthetic solution is administered.

• Impression material, such as elastomer or irreversible

hydrocolloid, is injected into the socket with a syringe.

• After setting, cheek, nose and the eyebrow region are massaged to

break the seal.

• The patient is instructed to gaze upwards and the impression is

removed from the socket.

• Impression is boxed and the lower half of the impression is poured

in dental stone.

• Once the stone is set, separating medium is applied and key ways

are made.

• Again the upper half of the impression is poured in dental stone.

• After the stone is set, both the assemblies are separated and the

impression is removed.

• Wax is flown into the empty mould to form a wax pattern.

• Preformed iris of appropriate size is attached to the wax pattern

after checking the distance of iris in the normal eye when the

patient looks straight.

• Wax pattern is tried in the patient’s socket and checked for form, fit

and contour.

• After satisfactory trial, the wax pattern is invested and processed

with heat-cured acrylic resin.

• Various colouring procedures are available to give colouration to

the eye in order to match the normal eye.

• Processed prosthesis is finished and polished.

• The final ocular prosthesis is inserted in the socket.

Postinsertion care of ocular prosthesis

• Adjustability to the new prosthesis varies between individuals.

• The prosthesis should never be left dry and should always be kept

in lens solution or water.

• The patient is advised to wear eyeglasses in order to protect the

natural eye.

• The ocular prosthesis may not make all the movements possible

with the natural eye.

• The patient is educated about the postinsertion care of the

prosthesis.

• Rough cloth or paper towels should not be used to clean the

prosthesis, as it may produce scratch.

• The patient should be kept on regular recall so as to assess the

prosthesis.

Auricular prosthesis or ear prosthesis

It is defined as ‘a removable maxillofacial prosthesis that artificially restores

part or the entire natural ear called also artificial ear, ear prosthesis’. (GPT

8th Ed)

• Causes of auricular defects are congenital, trauma or malignancy.

• It is easier to restore total resected auricle than a partially resected

auricle.

• If the surgical reconstruction of the auricle is not contemplated, the

entire ear should be removed, leaving a fixed tissue bed.

• Residual tissue tags, if any, should be removed, as they prevent

proper sculpting and positioning of the prosthesis.

Definitive auricular prosthesis

• This type of prosthesis is given after the wound has completely

organized.

• The definitive prosthesis should not only match in colour, form and

feature but also be correctly oriented to the surrounding tissues.

Impression procedure

• The patient is made to lie in the supine position with defective side

facing upwards.

• The external auditory meatus is blocked with wet cotton gauze or

cotton.

• The entire skin is coated with petroleum jelly.

• The entire area is outlined with the boxing wax.

• In the boxed area, silicone or irreversible or reversible hydrocolloid

is poured.

• Prebent L-shaped paper clips or suitable support gauges are used to

provide reinforcement.

• Quick setting plaster is poured over it as backing.

• The impression is carefully removed after it is set.

• Similarly, impression is made of the natural ear on the other side.

• Stone is poured into the impression to form the master cast.

Wax pattern fabrication

• If presurgical cast is available, it is reproduced in the wax and

compared with the remaining ear.

• Wax ear is positioned and adjusted to achieve natural symmetry in

all planes with opposite side.

• Modified facebow can be used to verify the position of the wax

prosthesis.

• If presurgical cast is not available, the prosthesis is sculpted from

the beginning or made from the donor.

• The wax pattern is checked for the form, contour and position.

• The entire surface is stippled to match the skin texture of the patient.

• Stippling should be made more prominent as some of the details are

lost during processing.

• Margins are then feathered and wax pattern is then luted to the cast.

Processing and surface characterization

• Wax ear is invested and after dewaxing, cured with appropriate

material.

• Surface characterization can be done either intrinsically or

extrinsically.

• Intrinsic colouration is better because extrinsic colouration tends to

wear off with time.

• Intrinsic colouration is done during the processing and extrinsic

colouration is done after complete processing is done.

• Completed auricular prosthesis is supported with eyeglass frame.

• For additional retention, adhesives can be used.

• Retention can also be improved by extending the prosthesis into the

enlarged canal.

• After the removal of prosthesis, the adhesive should be removed

from the skin and prosthesis.

• Most of the patients wear the prosthesis for 2–3 days before

removing it.

Nasal prosthesis

It is defined as ‘a removable maxillofacial prosthesis that artificially restores

part or the entire nose’. (GPT 8th Ed)

They are fabricated after partial or total rhinoplasty.

Aetiology of nasal defects

• Congenital deformity of nose such as fissure, double nose, bifid nose

or cleft nose

• Trauma: During birth, burns, sports accidents, automobile accidents,

injuries, gunshot wounds

• Neoplasms: These are rare, usually the squamous cell carcinoma or

adenocarcinoma of mucous glands of the nose.

Prosthetic rehabilitation of the nasal defect

• Most of the nasal defects are corrected with surgery.

• Smaller defects are reconstructed with plastic surgery using local

flaps, composite grafts or forehead flaps.

• Larger external defects are rehabilitated using prosthesis.

• Choice of rehabilitation depends on the size, type of defect and

present condition of the remaining tissues.

Impression making

• The facial tissues are coated with Vaseline, undercuts are minimized

using wet gauze packing and the nostrils are packed to prevent

adherence, seepage and breakage of the impression material during

removal.

• Irreversible hydrocolloid is mixed in order to make a thin mix.

• The material is painted over the defect and the surrounding

structures.

• Preshaped L-shaped paper clips are placed in the hydrocolloid

before setting of the impression material.

• Quick setting plaster is added as a backing to the setting material.

• The patient is instructed to wrinkle the facial muscles to aid in

removal of the impression.

• Impression is poured with stone to form a master cast.

Wax pattern

• Wax pattern of the nose is carefully carved keeping in mind the skin

texture and the dominant wrinkle.

• Preoperative photograph of the patient is useful in carving the nose

closely.

• Final wax pattern is invested and acrylized in conventional manner.

Ideal characteristics of the male and female nose

• Nose is relatively larger in male than in females.

• Dorsum of nose is wider in males.

• In females, the narrow tip of the nose is desirable.

• Wide nares are desirable in males as compared to females.

• Textured surface can be acceptable in males, whereas smooth

surface is desirable in females.

Painting of the external mould and the tissue-side

mould

• To give life to the prosthesis, the external surface and tissue-side

mould is painted with a layer of vinyl resin.

• Skin-coloured resin is painted to enhance the effect.

• The painted mould is processed and the final prosthesis is finished

and polished before inserting it into the defect.

Role of implants in maxillofacial prosthodontics

P.I. Branemark and his associates in 1977 first placed osseointegrated

implants in the cranial skeleton to retain a prosthetic ear (Fig. 32-17).

FIGURE 32-17 Implant supported auricular prosthesis.

Dental implants can be placed in root of zygoma, palatal vault,

nasal floor, and pterygoid region to stabilize or retain a facial

prosthesis.

Advantages

• Reliability of retention from the implant and the abutment

• Reduced dependence on availability of undercuts and use of

adhesives

• More aesthetics

• Increased psychological comfort to the patient

• Increased patient’s sense of security

• Valuable in patients where use of adhesive is limited due to

perspiration

Contraindications

• The patient may refuse an additional surgery.

• The patients who had undergone radiotherapy have additional risk

of osteoradionecrosis.

• Elderly patients may not agree for implant treatment.

General principles

• Site is assessed to determine the quality and quantity of bone

available for implant placement.

• Computed tomographic scan may be utilized to evaluate the bone

quality.