Midfacial defects are classified as midline midfacial defects, that include the nose and/or upper lip; and lateral defects, which include the orbital contents and cheek. Combinations of these two categories are also common. Severe disfigurement and functional impairment are seen with acquired midfacial defects. Facial prosthesis is generally considered over surgical reconstruction to restore function and appearance in patients with facial defects that resulted from cancer resection.1,2 The health of the patient might not permit to undergo another surgery. An intraoral prosthesis such as an obturator is often needed to restore mastication, speech and improves patient appearance.3 Fabrication of an extra oral facial prosthesis is a challenging task as it tests the creative ability of the prosthodontist. The choice of material for extraoral prosthesis depends on the need to engage desirable undercuts, mobility of tissue bed, defect size and the weight of the prosthesis. Retention of the prosthesis may be a difficulty due to its size and weight. It may be retained by means of medical grade adhesives, resilient attachments, clips and osseointegrated implants. It can also be connected to obturator by magnets.4 This clinical report highlights the rehabilitation of a lateral midfacial defect with a two piece prosthesis that included an intraoral obturator and extra oral facial prosthesis with the use of magnets.

A 55-year-old man reported to the Department of Maxillofacial Prosthodontics for a definitive prosthetic rehabilitation with a surgical defect subsequent to radical surgery involving subtotal maxillectomy of left side performed six months before (Figs. 1A and 1B). The patient was wearing interim obturator prosthesis. Clinical examinations revealed complete healing of the surgical wound. The palatal defect was in continuation with the orbital defect. The margins of the defects and tissues within were healthy and normal.

Radiological examinations revealed loss of floor of left orbit and left half of the maxilla along with the teeth. The range of mandibular movements was found to be normal. Speech intelligibility and deglutition were severely affected since the patient's tongue could not make effective functional contacts due to lack of anatomic boundaries during speech and deglutition.

Hence prosthetic rehabilitation was planned with magnet retained intraoral-extra oral combination prosthesis. Fabrication of such prosthesis was planned in two sections to close the intraoral defect and create a partition between the oral cavity and nasal cavity for facilitating speech and deglutition. Firstly the extra oral prosthesis was fabricated, followed by fabrication of intraoral obturator prosthesis.

Orofacial defect results in communication between the oral and nasal cavity. It causes difficulty in deglutition, nasal regurgitation, loss of speech intelligibility and unesthetic appearance, leading to significant psychological problems. With acceptable cosmetic results, a reduced amount of retention can handicap the prosthesis. Unlike a conventional prosthesis, additional factors should be taken into consideration such as method of impression, materials to be used in laboratory procedures, prosthesis design, method of connection, direction of insertion and removal, esthetic factors, and maintenance protocol. With the understanding of the remaining anatomic structures, intraoral and extraoral prostheses that mutually retain one another can be constructed. Various methods of retention for facial prostheses have been described in the literature; they include eyeglasses, eye patches, extensions from the denture that engage desirable tissue undercuts, medical grade adhesives, magnets, and osseointegrated implants.5-7 The introduction of rare-earth permanent magnets made of alloys such as Neodymium-Ferro-Boron and samarium cobalt has resulted in magnets of very small dimensions. Tarnish and corrosion can be overcome by coating these magnets with nickel, gold and titanium.8 Although osseointegrated implants may provide the most reliable prosthesis retention but additional surgeries, expenses, inadequate available bone, and prior radiation to the area may contraindicate this type of treatment.9,10

Mutual retention of the intra- and extra- oral prosthesis can be successfully achieved through magnets. The force needed to separate magnets was designated as breakaway load expressed in terms of grams. The value of breakaway load is inversely proportional to the distance of separation and inclination between the magnets. These magnets are wholly biocompatible in the human body and exert no deleterious effects in human tissue. Inert magnetic field is harmless to human body and can be safely used for patients with cardiac pacemaker. There may be a gradual decrease in retentive force upon usage while some open field uncoated magnet exhibits significant cytotoxic effects which may be attributed to the release of corrosion by products from them. Therefore, magnets should be replaced as early as signs of corrosion develop.

The cast-metal framework improves retention, stability, support and bracing of the prosthesis and thus increases prosthesis longevity. Problem of two piece prosthesis is that the mobility of intraoral obturator can make facial prosthesis mobile especially during functions but the light weight of the prosthesis can alleviate this problem.11 Many methods and materials have been used to fabricate a hollow obturator such as salt, sugar and ice. A lightweight prosthesis which was fabricated in this case by lost salt technique and putty not only counteracted forces due to gravity but also enhanced speech intelligibility.12,13

The rehabilitation of a patient with a combined intraoral-extra oral defect has been presented. A two-piece prosthesis that included an intraoral obturator and extra oral facial prosthesis was fabricated. Magnets were incorporated into each unit to mutually retain each segment of the prosthesis. Marked improvement in appearance, speech intelligibility and deglutition were noted.