Selective-pressure impression technique for nasal prostheses

Selective-pressure impression technique for nasal prostheses Arie Shifmam, D.M.D.* Israel Defense Forces Center of Oral and Dental Medicine, Tel-Hashomer, Israel

I?

ostsurgical nasal defects can be restored to a pleasing facial appearance with a nasal prosthesis.‘-’ The degree of success depends on the form and characterization of the prosthesis, the shade of the prosthesis, and the adaptation of .the prosthesis margins to adjacent tissue contours.’ Margins can be partially masked by eyeglass frames in all patients and by mustaches in men. Concealing the margins of the nasal prosthesis, however, still remains a barrier to achieving natural facial appearance. Nasal prostheses are usually fabricated of hollow nonrigid (elastic) materials with thin margins that overlay structures adjacent to the defect. They are retained with a skin adhesive that also adapts the margins to the underlying structures. Sensitive nasal mucous membrane prevents engagement of retentive undercuts. Adaptation of a nasal prosthesis is often interrupted at the lateral and inferior aspect because of the movement of the underlying structures with slight smiling or grimacing’, 6 (Fig. 1). Facial muscle pull results in deepening of the superior end of the nasolabial sulcus with the appearance of a depression. The adhesive contact is interrupted and the patient exerts repeated finger pressure to readapt the prosthesis in these regions. The selective-pressure impression technique described in this article takes advantage of the flexibility of elastic materials to maintain tissue contact in highly movable facial regions.

Fig. 1. Postsurgical nasal defect.

TECHNIQUE, 1. Make a nasal impression with irreversible hydrocolloid and plaster backing in the usual manner and pour a cast in quick-setting plaster (Fig. 2). 2. Use three plastic disposable needle covers to construct a U-shaped frame by connecting their edges with autopolymerizing acrylic resin (Fig. 3). Two of these covers are oriented so that their blunt edges contact the cast lateral to the residual nasal alae. This device may also be constructed directly on the patient’s face The views expressed herein are the private ones of the author and do not necessarily reflect the views of the Medical Corps, Israel Defense Forces. *Lieutenant Colonel; Chief, Department of Prosthodontics and Maxillofacial Prosthetics and Director of the Center. THE JOURNAL

OF PROSTHETIC

DENTISTRY

Fig. 2. Preliminary

cast.

if the nasal aperture is packed to protect the patient from the vapor of the acrylic resin monomer. 3. Adapt the two ends of the frame to the facial depressions with modeling compound. 4. With the frame in place, make an irreversible hydrocolloid impression. While the material is setting, 349

SHIFMAN

Fig. 3. Ends of U-shaped frame are adapted to preliminary cast.

Fig. 5. Final impression shows two pressure areas.

Fig. 6. Final cast with bilateral depressions. Fig. 4. Diagrammatic orientation of impression against face. A, Facial tissues; B, U-shaped frame; C, modeling compound; D, irreversible hydrocolloid; E, plaster back-

ing. apply moderate finger pressure to the horizontal connecting bar of the frame. Keep the bar completely exposed above the impression surface and maintain finger pressure while the plaster backing is applied to the elastic impression material (Figs. 4 and 5). 5. Pour a cast in the final impression with an improved artificial stone. Compare this cast to the preliminary and note the presence of defined depressions at the superior ends of the nasolabial sulci (Fig. 6). 6. Sculpt the nasal prosthesis on the master cast, fabri-

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cate in an appropriate elastic material,7 and deliver the finished prosthesis to the patient (Fig. 7). 7. The impression frame may be preserved for subsequent impressions. SUMMARY An impression technique for nasal prostheses that places pressure in the superior regions of the nasolabial sulci is described. The pressure is delivered through a U-shaped frame embedded within the impression. Better adaptation and camouflage of the finished prosthesis is achieved and the improved esthetics enhances the confidence of the patient using a nasal prosthesis.

SEPTEMBER

1987

VOLUME

58

NUMBER

3

SELECTIVE-PRE!%URE

IMPRESSION

TECHNIQUE

REFERENCES 1,

Ko SE, Fine L, Robinson JE. Total rhinoplasty or prosthesis? J PROSTHETDENT 1980;44:74-7. 2. Bulbulian AH. Facial prosthetics. Springfield: Charles C Thomas Publisher, 1973;133-277. 3. Beumer J, Curtis TA, Firtell DN. Maxillofacial rehabilitation: prosthodontic and surgical considerations. St Louis: The CV Mosby Co, 1979;333-40. 4. Fonseca EP. The importance of form, characterization, and retention in facial prosthesis. J PROSTHETDENT 1966;16:33843. 5. Martone AL. Anatomy of facial expression and its prosthodontic significance. J PROSTHETDENT 1962;12:1020-42. 6. Rubin LR. The anatomy of a smile-its importance in the treatment of facial paralysis. Plast Reconstr Surg 1974;55: 384-7. 7. Taicher S, Bergen SF, Rosen A, Levy M, Lepley JB. Hollow polydimethylsiloxane facial prostheses using anatomic undercuts. J PROSTHET DENT 1982;48:444-7. Refmnt

reqmts

to:

DR. .~RIE SHIFMAN P.O. Box 1031

Fig. 7. Nasal prosthesis in place. Note improved margin adaptation at left superior nasolabial region.

Urethane-lined Ariyadasa University

PETACH-TIKVAH ISRAEL

silicone facial prostheses

Udagama, D.D.S., M.S.D.* of Texas System Cancer Center,

M.D.

Anderson

S

Hospital

ilicones are widely used for fabrication of facial prostheses.‘-5 Biologic inertness, superior esthetic qualities, technical simplicity, and availability in several chemically compatible preparations have made the silicones among the best facial prosthetic materials available. However, weak tear-resistance, poor adheophilic properties, nonwettability, nonpolishability, affinity to support fungal growth, and absorption of oils and grease tend to limit their use.6 Because of poor adheophilic properties, silicone prostheses cannot be used with nonsilicone-base adhesives because of the difficulty in removing the old adhesive.’ If the internal surface of a silicone prosthesis could be lined with a material of high tear-resistance and compatibility with commonly used adhesives, silicones could be used more effectively for facial prostheses. This article will describe evolution of potential silicone lining materials

*Dental gy.

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Oncologist (Maxillofacial),

THE JOURNAL

OF PROSTHETIC

Department of Dental Oncolo-

DENTISTRY

and Tumor

Institute,

Houston,

Tex.

and a technique for successful lining of silicone facial prostheses with prefabricated polyurethane films. METHODS

AND MATERIAL

For 14 months, beginning in March of 1980, ethyl methacrylate, polyvinyl buteral, methyl methacrylate, polyvinyl acetate, corrugated polyethylene, polyvinyl chloride, and prefabricated polyurethane films were tested for bonding to silicone. Although all of the materials tested, except polyvinyl chloride, bonded to silicone, prefabricated polyurethane film (Factor II, Inc., Lakeside, Ariz.) was selected as the lining material of choice because of its transparency, high tear-resistance, moldability, and compatibility with water-base skin adhesives. Silicone preparations were applied to and processed against urethane sheets by using several methods and the bond strengths were evaluated through pilot studies. Of the methods tested, three produced bonding sufficient to warrant clinical trials. In method 1, the urethane sheet was cleaned with

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