Open-eye impression technique for orbital prostheses

Alice Katz, B.S.,* and Henry 0. Gold, D.D.S.** University of Illinois Medtcal Center at Chicago, Chicago, Ill.

S culpting an orbital prosthesis which replaces the eyeball and contiguous soft tis-

sues is a complicated and time-consuming procedure (Fig. 1) .le3 Traditional tech-

niques have required the patient’s presence for repeated and prolonged sessions that

are tiresome and costly. An alternative procedure is proposed which shortens the

time spent in the office and laboratory and reduces the cost involved. The procedure is based on modifications of the open-eye impression technique first proposed by

Brown.4

The iadvantage of this technique is that it provides a model of the nonaffected eye and ,adnexa for the reconstruction of the affected side. Thus, the folds and wrin-

kles of the eye are captured in their natural position, allowing a more realistic dupli- cation. Guidelines for the orientation of the artificial eye in three planes of space

are provided by comparison with the cast of the nona.ffected eye (Fig. 2). The availability of impression materials specifically designed for ophthalmologic

use and safe topical anesthetics makes the open-eye impression technique a safe and convenient procedure.

MATERIAL AND METHOD

Ophthalmic Molditet (OM) is an irreversible hydrocolloid material primarily designed for the fabrication of scleral contact lenses for patients with stigmatism or

other pathoses and for making impressions of enucleated orbits. This impression ma- terial, in the nonset stage, will link with other irreversible hydrocolloid materials used

in facia‘l moulage, but not with rubber-base compounds and reversible hydrocolloids. If the 1;atter incompatible impression materials are used with OM, some type of re-

This investigation was supported in part by grants from the National Institutes of Health

(DE-028#72) and the Social Rehabilitation Services (RD2225-M), Department of Health, Edu-

cation and Welfare.

*Instructor in Medical Illustration, School of Associated Medical Sciences, and Medical Artist, Center for Craniofacial Anomalies, Abraham Lincoln School of Medicine.

**Assistant Professor of Prosthetics, College of Dentistry, and Senior Prosthodontist, Max- illofacial Prosthetics Clinic and Training Program, Center for Craniofacial Anomalies.

tObrig Laboratories, Sarasota, Fla.

88

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Impression technique for orbital prostheses 89

Fig. 1. Sculpting an orbital prosthesis to replace the eyeball and contiguous soft tissues.

Fig. 2. (A) Alignment for symmetry in relation to the midsaggital plane. (B) Alignment for

vertical symmetry. A contour gauge is used to measure desired depth of the eyeball in relation

to the forehead.

tention should be incorporated into the outer surface of the setting OM to lock it

into the impression material that completes the facial moulage. This procedure in- sures proper alignment of the impression of the eye to the facial impression.

Alginate (irreversible hydrocolloid) is the preferred facial moulage material to be used in conjunction with OM for a total- or partial-face, open-eye impression. Alginate not only links with the OM but is easy to use and fast setting, thereby re- ducing the length of time of the impression procedure. Most important, alginate is

the most soothing and pleasant of the impression materials for the patient’s skin. To insure accurate reproduction of facial contours, impressions of the patient’s

face, particularly older patients with sagging tissues, should be made with the patient in the upright posture rather than in the conventional horizontal position. Gravity

90 Katz and Gold J. Prosthet. Dent. July. 1976

Fig. 3. Facial mask obtained with patient positioned horizontally. Note the stretching and re-

contouring of the soft tissues producing the effect of a face lift.

Fig. 4, Facial mask obtained with patient in the vertical position. Note the greater accuracy in reproducing the wrinkles and contours depicted in the photograph.

combined with the weight of the impression materials grossly alters the facial con-

tour when the patient is placed in the horizontal position (Figs. 3 and 4).

PREPARATION OF THE PATIENT

Th.e procedure is explained to the patient in detail to allay apprehension and

elicit cooperation. The most satisfactory breathing arrangement should be ascertained in advance. The nasal passages can be left free, allowing the moulage to encompass the mouth. Or if the nasal passages are obstructed, then an oral breathing tube can be provided, and the patient should be allowed to practice breathing through this device. However, a breathing tube invariably distorts the surrounding soft tissues, creating an unnatural posture of the mouth. The best method is to instruct the pa-

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Impression technique for orbital prostheses 91

Fig. 5.. Patient draped for the impression. Orientation lines are marked in indelible pencil for transfer to the die.

Fig. 6. Ophthalmic anesthetic and impression material.

tient to keep his lips slightly parted and avoid covering the mouth opening with

impression material. The patient is draped, exposing only the regions to be included in the impression.

Suitable draping materials are disposable plastic sheeting taped in place with par- ticular attention to sealing off scalp hair. Exposed wounds or fistulous openings are protected with gauze lubricated with petroleum jelly, cotton, nylon, or wet facial tissues.

The defect must be studied for undercuts which are blocked out with lubricated

92 Katz and Gold J. Prosthet. Dent. July, 1976

Fig. 7. Moldite is applied for the open-eye impression.

Fig. 8.. Alginate impression material is applied over the Moldite.

Fig. 9. Gauze is applied to the alginate impression material for retention.

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Impression technique for orbital prostheses 93

Fig. 10. The impression is reinforced with orthopedic plaster bandages.

Fig. 11. The full-face, open-eye cast.

gauze or wet facial tissues. Orientation lines are marked on the patient with in- delible pencil to allow for direct transfer to the impression material and ultimately to the final working cast. The orientation is critical for location of the artificial eye in proper spatial relationship to the pupil of the normal eye (Fig. 5).

If either alginate or agar is to be used as the facial impression material, no sep- arating medium is necessary for the facial tissues. However, all hair to be included in the impression should be coated with a petroleum jelly. If silicone rubber is to be employed as the facial moulage material, facial hair must be heavily covered with petroleum jelly and a thin coat of cold cream applied to the facial tissues.

IMPRESSION TECHNIQUE

The patient is lowered into a supine position. Two drops of an ophthalmic local anesthetic solution, such as a 0.5 per cent solution of tetracaine,” are administered and a few minutes allowed for the anesthetic to take effect. The patient is then re- turned to the vertical position.

Measure slightly more sterile distilled water than is directed by the manufacturer and rapidly mix it into the OM (Fig. 6). The patient is asked to keep his eye or eves closed while the OM is applied. The consistency of the OM is important, and , some experimentation may be necessary. It must be thick enough to stay in position

*Cooper Laboratories, Inc., Wayne, N. J.

94 Katz and Gold J. l’rosthet. Dent. July, 1976

over the eye but thin enough to allow the patient to open his eye. With the OM in

place, the patient is requested to open his eye naturally without straining or lifting the eyebrow (Fig. 7). The patient must be instructed to concentrate on keeping his

eye open until the OM sets. With the eye anesthetized, it is difficult for some patients to judge whether their eyes are open. However, it is possible to see light through the

OM, and this can be offered as a guideline to the patient. The borders of the OM are feathered to eliminate undercuts. The alginate (irre-

versible hydrocolloid) for the facial impression is applied immediately before the

OM has completely set. A YJ inch thickness of alginate is built up over the entire face. A heavy application is avoided as it may cause distortion of facial tissues. The

alginate is applied in a thicker layer around the circumference of the face to mini- mize distortion at the edges of the impression. Cotton or gauze is applied to the

alginate before it has completely set to key the fragile alginate impression to a light-

weight, rigid backing. The impression is reinforced with orthopedic plaster bandage* cut to size and moistened in a slurry of fast-setting plaster of Paris (Figs. 8 to 11) . The time for the impression is 10 to 15 minutes.

CLINICAL EXPERIENCE

The authors have made open-eye impressions on 30 eyes of 18 different patients.

To provide for maximum initial safeguards, an ophthalmologist observed all patients

for possible cornea1 abrasions. In all instances, the patient was retained in the clinical

setting for another 10 to 15 minutes following the impression procedure or until the effect of the anesthetic had completely dissipated.

The authors gratefully acknowledge the consultation and advice given by Carol West, M.D., Assistant Professor of Ophthalmology, and Samuel Pruzansky, D.D.S., Director, Center for Craniofacial Anomalies, Abraham Lincoln School of Medicine, University of Illinois at the Medical Center, Chicago, Ill.

*Ostic plaster bandages, Kendall Hospital Products Division, Chicago, 111.

References

1. Bulbulian, A. H.: Facial Prosthesis, Philadelphia, 1945, W. B. Saunders Company, pp. 141-‘148.

2. Chalian, V. A., Drane, J. B., and Standish, S. M.: Maxillofacial Prosthetics. Multidis-

ciplinary Practice, Baltimore, 1971, The Williams & Wilkins Company, pp. 296-304. 3. Roberts, A. C.: Facial Prostheses, London, 1971, Henry Kimpton, pp. 46-48.

4. Brown, .4. M.: Modern Plastic Surgical Prostheses, New York, 1947, Grune & Stratton, Inc., pp. 56-64.

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