Maxillary Implant-Supported Fixed Prosthesis: A Survey of Reviews and Key Variables for Treatment Planning

Purpose: This review was conducted to provide information to support the establishment of clinical guidelines for the treatment of maxillary edentulism using implant-supported fixed dental prostheses. Materials and Methods: Initial efforts were directed toward a systematic review with a defined PICO question: "For maxillary edentulous patients with dental implants treated using a fixed prosthesis, what is the impact of prosthesis design on prosthesis survival and complications?" Following a title search of more than 3,000 titles identified by electronic search of PubMed, 180 articles were identified that addressed the clinical evaluation of maxillary dental implant prostheses. The broad methodologic heterogeneity and clinical variation among reports precluded this approach for a systematic review. The information was extracted using a standardized extraction table by two pairs of investigators, and the reported outcomes were then summarized according to reported outcomes for implant prostheses supported by four, six, or eight implants using unitary or segmented prostheses. Results: This review indicated that high prosthetic survival is observed using all approaches. The advantages of using fewer implants and a unitary prosthesis are revealed in the surgical phases, and complications commonly involve the fracture or detachment of acrylic teeth and reduced access for proper oral hygiene and related biologic complications. Using six implants typically involved grafting of posterior regions with advantages of reduced cantilevers and redundancy of implant support. Reduced prosthesis survival in these cases was associated with poor implant distribution. Segmented prostheses supported by six or more implants offered greater prosthetic survival, perhaps due to posterior implant placement. Advantages of a segmented prosthesis included pragmatic issues of accommodating divergent implants, attaining passive fit, combining prosthetic materials, and relative simplicity of repair. Conclusion: The existing literature demonstrated that maxillary edentulism may be treated successfully using alternative approaches involving four, six, or more implants. The procedural diagnostics, treatment, and maintenance for these different approaches all require advanced knowledge and careful communication among the therapeutic team. The prosthetic therapeutic success requires maintenance, repair, and possible multiple replacements within the patient's lifetime.