Page 92 - Craniomaxillofacial Implant Surgery - Jeroen P.J. Dings

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Chapter 5
years. Visser et al19 demonstrated a survival time of 1.5 to 2 years with some prostheses having a life span of more than 5 years.
Ideal prosthetic material properties include durability, biocompatibility, flexibility, ease of cleaning, and lightness11. The maxillofacial prostheses in this study were made of heat-polymerized and autopolymerizing silicone. Autopolymerizing silicone is the material of choice15,24.The majority of patients (86%) responded that they were comfortable wearing their prostheses; a few remarked on the hardness of the material (5%). Satisfaction is directly related to appropriate retention delivered by craniofacial implants. Several studies showed significant improvements with implant-retained facial prostheses in all domains of QOL in comparison with adhesive-retained groups5,10. In the current study, the distribution of prosthetic retention type was consistent with that of other studies17. In contrast with the findings of Nemli et al14 and Goiato et al,5 overall patient satisfaction scores were similar for the various retentive mechanisms. However, although not statistically significant, patients did tend to give higher scores for bar-clip systems. As in the studies of Chang et al10 and Smolarz-Wojnowska et al8, the handling of implant-retained prostheses proved statistically significantly better than the adhesive-retained methods (‘ease of placement’ (P=.01) and ‘ease of removal (P=.04).
The choice of retentive mechanisms depends on the number of implants, flexibility of the prosthesis, and local anatomic aspects. Bar-clips are the most indicated system for retention of auricular prostheses13. Three patients with bar-clip-retained prostheses reported on mechanical failures of the acrylic resin substructure or the retentive structures. This is in accordance with previous studies where requirements for clip revision and repair are described as disadvantageous compared with the use of magnets12,15. Magnets are mostly used for orbital defects13 and can compensate for nonparallelism of the installed implants. Moreover, magnets induce relatively low lateral forces and minimize the amount of stress delivered to the implants21. Current magnetic systems increase ease of use, are simple to clean, and have adequate retention12,13. In the present study, only one patient wearing an implant-retained orbital prosthesis with a magnet system reported troublesome dislodgment of his prosthesis at inopportune times, such as during exercise.
No statistically significant differences were shown in the prevalence of minor soft tissue complications with regard to different retentive mechanisms, although some