INTRODUCTION
Melanoma represent 2% of all malignant tumors. Congenital nevus degeneration represent the cause of 50% of all melanoma. The residual 50% are primary lesions. Sun exposure in Caucasian race plays a major role in etiology and pathogenesis of these lesions. Malar region and lateral portion of nose receive the maximum sun exposure and therefore are the most frequent region of disease location. ⁽¹⁾
A superficial spreading melanoma (SSM) and malignant lentigo have a good prognosis after an extended surgical resection. On the contrary primary nodular melanomas or nodular melanomas derived from a SSM show a tendency to produce metastatic lesions and seem to have a poor prognosis even when a wide radical excision is performed. ⁽¹⁾
The choice between a surgical, a prosthetic or a combine surgical and prosthetic reconstruction is not always an easy task. Factors to be considered are dimension and etiology of the defect, age and patient expectations . In presence of a small defect, the surgical reconstruction is the therapeutic option of choice. In selected cases the insertion of endoosseous implants associated to a dental prosthesis may improve functional efficacy and aesthetics. ^(2) (3) In presence of a wide resection and a frequently recurrent lesion a prosthetic reconstruction should be preferred in order to have a visual access for follows up. ⁽⁴⁾ Radiotherapy, where indicated , may severely alter vascularization and promote scar tissue formation complicating eventual surgical reconstruction. The prosthesis can also be utilized as an interim rehabilitation for aesthetic reasons. ⁽⁵⁾
The present clinical report describes an easy and low cost technique that allows to realize a prosthetic rehabilitation with acceptable aesthetic results.

CLINICAL REPORT
The patient, a 74 years old female, with a diagnosis of a nodular type of melanoma at the left coana, underwent to a surgical excision intraorally of the entire pre-maxilla and at external level of the left wing of the nose. The surgical intervention resulted in the loss of the six anterior maxillary teeth together to the bony structures of the premaxilla, the loss of the left wing of the nose and the presence of a wide oral-nasal communication (Figure 1). The patient presented a complete dentition in the posterior maxilla and in the mandible. At the prosthetic examination the patient was already affected by metastatic lesions located in lungs and bones.

1. Fixed partial denture supported by dental implants after bone reconstruction.
2. Fixed partial denture of maxillary premolars with precision attachments and a removable partial denture.
3. Removable partial denture bearing on existing dentition.

The first two options were discarded because of the length of treatment time and the poor prognosis overall due to presence of metastases.
The prosthetic rehabilitation consisted of a removable partial obturator and an extra-oral facial prosthesis.

PROCEDURE
Irreversible hydrocolloids impressions (Alginoplast; Heraeus Kulzer, Hanau, Holland) of both arches were taken, having care of capturing the lower part of oral-nasal communication. Stone casts were poured in type III stone (Dental Hydrocal White; Kerr Italia spa, Torino, Italy). After isolating the stone with a alginate based separating fluid (Separating fluid, Ivoclar.Vivadent AG srl, Bolzano, Italia) a trial base in auto polymerizing resin (Ivolen, Ivoclar-Vivadent AG, Schaan, Lichtenstein) with wax rims (Dental Wax Moyco, Union Broach-Thompson Dental Manufacturing Company Inc.,Philadelphia, USA) were made. Two wire clasps, 0,9 mm diameter, were positioned on the first premolars to stabilize the trial base. Artificial resin teeth Vivodent PE (Ivoclar-Vivadent AG, Schaan, Lichtenstein) were mounted and the set-up was evaluated for aesthetics and optimal bearing surface.
A closed-mouth precision impression in the centric position was made by a tissue conditioner material (Tempo, Lang Dental Manifacturing CO, Wheeling, Illiniois, USA) with the intention of capturing the entire oral-nasal communication. The master cast was poured in type IV dental stone (Velmix-stone, Kerr Co, Orange, USA) and the partial obturator was processed in cold curing resin (Probase Cold; Ivoclar-Vivadent AG, Schaan, Lichtenstein) in a Hydro-muffle (Ivomat IP3, Ivoclar-Vivadent AG, Schaan, Lichtenstein). After refining and polishing the prosthesis was delivered to the patient. The extension of the obturator in the oral-nasal communication was utilized as support for the facial prosthesis.
The following procedure was adopted to construct the facial prosthesis: a facial impression was made in irreversible hydrocolloid (Alginoplast; Heraeus Kulzer, Hanau, Holland) (Figure 2) and poured in type III dental stone (Dental Hydrocal White; Kerr Italia spa, Torino, Italy) (Figure 3).

   

On the stone cast a partial nose was waxed in hard wax (Moyco Beauty Pink-X-Hard; Moyco Industries Inc., Philadelphia, USA) (Figure 4) and then tried directly on the patient face to verify aesthetics and adaptation (Figure 5-6) . The bearing surface of the obturator was crucial to maintain in situ the facial prosthesis and to allow the try-in. The facial prosthesis was processed in silicone (Dropstil FA557, Prevent Transformations, Borge de Peage, France) and colored with oil colors (Fine Oil Colours; Maimeri spa, Italy) chair-side in order to achieve better color-matching to the patient skin (Figure 7).

   

   

The colored silicon was then pressed and hot cured for 20 minutes in water at 100°C in hydro-muffle (Ivomat IP3, Ivoclar-Vivadent AG, Schaan, Lichtenstein).
The prosthesis was seated on the defect site and the borders sealed with transparent auto polymerizing silicone (Silastic, Dow Corning Co, Midland, USA). The prosthesis was hold in place by a biocompatible glue (Prothelem Ocularistes, Paris, France) (Figure 8).

The patient was instructed to the use and the hygiene of both prosthesis.

DISCUSSION
The illustrated clinical case is a combination of a partial obturator and a facial prosthesis. According to Aramany, the defect fall in the class VI. in a long term plan the removable partial denture should have been designed providing a framework with cast clasp assemblies with retentive and balancing arms, correctly positioned occlusal rests, an anterior and posterior palatal strap-type connector. ⁽⁶⁾
Because of the health status of the patient a simplified design with wrought wires was preferred. The residual palate and the residual nasal bony structures allowed an acceptable support for the prosthesis stability. The anterior teeth were kept out of occlusal contacts.
Treatment of facial defect can be either surgical, prosthetic, or a combination of both. Whenever the overall prognosis does not allow a surgical reconstruction the prosthetic option represents the treatment of preference. ^(1) (7)
The retention of a facial prosthesis can be obtained either by mean of engaging the undercuts in the defect site or by mean of specific glues ^(8) (9), eye-glasses mounts ⁽⁷⁾, magnets or dental implants.
A frequently used treatment option is the connection by mean of magnets of the intra-oral prosthesis to retain the facial one ⁽¹⁰⁾.
In the present case report magnets were judged not necessary because of the small dimensions of the facial prosthesis. In fact adequate support was achieved by the presence of the obturator and satisfactory retention was guaranteed by the glue at the silicon margins.
Advantages of this treatment option are: good soft tissue support, good aesthetic results, ease of use and maintenance for the patient, ease of fabrication and relative low costs.
Disadvantages of the present technique are possible areas of irritation of the skin due to the presence of the glue and limited retention if the borders of the extra-oral prosthesis are located in a mobilized area during respiratory or masticatory functions.

REFERENCES
1. Beumer Jr CTMM. Maxillofacial Rehabilitation: Prosthodontic and Surgical Considerations. St. Louis, Missouri, USA: Ishiyaku EuroAmeraca INc, 1996.

2. Jacobs JR, Marunick MT. Surgical considerations in maxillofacial prosthetic rehabilitation of the maxillectomy patient. Journal of surgical oncology 1988;37:29-32.

3. Parel SM, Tjellstrom A. The United States and Swedish experience with osseointegration and facial prostheses. The International journal of oral & maxillofacial implants 1991;6:75-79.

4. Marunick MT, Harrison R, Beumer J, 3rd. Prosthodontic rehabilitation of midfacial defects. The Journal of prosthetic dentistry 1985;54:553-560.

5. Newton JT, Fiske J, Foote O, Frances C, Loh IM, Radford DR. Preliminary study of the impact of loss of part of the face and its prosthetic restoration. The Journal of prosthetic dentistry 1999;82:585-590.

6. Aramany MA. Basic principles of obturator design for partially edentulous patients. Part II: design principles. The Journal of prosthetic dentistry 1978;40:656-662.

7. Rodrigues S, Shenoy VK, Shenoy K. Prosthetic rehabilitation of a patient after partial rhinectomy: a clinical report. The Journal of prosthetic dentistry 2005;93:125-128.

8. Guttal SS, Patil NP, Shetye AD. Prosthetic rehabilitation of a midfacial defect resulting from lethal midline granuloma-a clinical report. Journal of oral rehabilitation 2006;33:863-867.

9. Cheng AC, Wee AG, Tat-Keung L. Maxillofacial prosthetic rehabilitation of a midfacial defect complicated by microstomia: a clinical report. The Journal of prosthetic dentistry 2001;85:432-437.

10. Takahashi T, Fukuda M, Funaki K, Tanaka K. Magnet-retained facial prosthesis combined with an implant-supported edentulous maxillary obturator: a case report. The International journal of oral & maxillofacial implants 2006;21:805-807.