Fixed, Fiber-Reinforced Resin Bridges on 5.0-mm Implants in Severely Atrophic Mandibles: Up to 5 Years' Follow-Up of a Prospective Cohort Study.

PURPOSE: The aim of this study was to evaluate the midterm outcomes of fixed, full-arch, fiber-reinforced resin bridges on ultrashort implants in terms of marginal bone loss and overall implant survival.

PATIENTS AND METHODS: Patients with severely atrophic mandibles, corresponding to Cawood and Howell class V and class VI, were included in this prospective temporal cohort study. Mesial and distal peri-implant bone levels were measured on panoramic radiographs taken at the time of implant insertion (baseline) and at follow-up visits.

RESULTS: A total of 17 patients with atrophic mandibular jaws with an average follow-up period of 2.9 ± 1.5 years were included. The cumulative 1-, 3-, and 5-year patient-based implant survival rates were 94.1%, and the cumulative implant survival rates were 98.5%. The marginal bone level (MBL) of the mesial implants was 0.0 ± 0.3 mm at the time of loading (n = 33), -0.1 ± 0.3 mm (n = 20) after 1 year, -0.4 ± 0.5 mm (n = 10) after 3 years, and -1.5 ± 1.0 mm (n = 4) after 5 years. The mesial bone level depended significantly on time and insertion depth. The MBL of the distal implants was -0.4 ± 0.4 mm (n = 34) at the time of implantation, -0.4 ± 0.6 mm (n = 20) after 1 year, -0.5 ± 0.5 mm (n = 10) after 3 years, and -2.2 ± 1.7 mm (n = 4) after 5 years. The distal bone level depended significantly on time and insertion depth.

CONCLUSIONS: Fixed, full-arch, fiber-reinforced resin bridges retained by 4 ultrashort implants provide a comparatively cost-effective, safe, stable alternative for prosthetic restoration of the severely atrophic mandible. The overall implant survival rate and the MBL after 5 years are equivalent to those of threaded implants of conventional lengths.