Page 19 - Craniomaxillofacial Implant Surgery - Jeroen P.J. Dings

3.3 Retention methods and prosthetic materials
Successful prosthetic rehabilitation depends largely on the quality of retention and stability of the prosthesis. There are four ways to retain a prosthesis: anatomically, mechanically, surgically, or by adhesion3. The choice of retentive mechanisms depends on the number of implants, flexibility of the prosthesis, and also local anatomic aspects. Bar-clips, for example, are the most indicated system for retention of auricular prostheses. Magnets are mostly used for orbital- and nasal defects, because they can compensate for non-parallelism of the installed implants3,25. Moreover, magnets induce relatively low lateral forces and minimize the amount of stress delivered to the implants19. Current magnetic systems increase ease of use, are simple to clean, and have adequate retention63.
Generally, a prosthetic material must possess and maintain physical- and mechanical properties comparable to the tissue it replaces. Ideally, material properties include durability, biocompatibility, flexibility, reasonable tensile strength, softness, ease of cleaning, and lightness64. A variety of materials have been used including metal, glass, rubber, porcelain, plastic, or silicone. Established materials for CMF prostheses comprise methacrylate’s and silicone elastomer products24. Although methacrylates are more durable, they are relatively hard in comparison to silicones. Today, silicone rubbers are the most widely used materials in CMF prosthetics with regard to ease of manipulation, their absorbance of pigmentation and ability to match the color and texture of surrounding structures, low viscosity, capacity to adapt to body temperature, high tensile strength, high elongation, and dimensional stability65,66. However, drawbacks are their restricted mechanical- and physical properties and tendency for discoloration requiring replacement as early as six months3. To date, none of the commercially available materials satisfy all the requirements of the ideal CMF prosthetic material. Further research into the development of new or alternative CMF prosthetic materials is essential, as clinical practice still faces problems with the serviceability of CMF prostheses3.
3.4 Quality of life and patient satisfaction
The face has a unique role in social- and emotional expression and communication67. Therefore, reconstruction of CMF defects may have important psychosocial implications in affected patients, because social interactions and emotional expression depend mainly upon the structural and functional integrity of the head- and neck region68. A successful prosthetic rehabilitation is one, in which patients do not experience the
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General introduction and outline of this thesis
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