Five-year outcome of a retrospective cohort study on the rehabilitation of completely edentulous atrophic maxillae with immediately loaded zygomatic implants placed extra-maxillary

Purpose: To report retrospectively on the 5-year follow-up results of the rehabilitation of complete edentulous atrophied maxillae, using extra-maxillary zygomatic implants alone or in combination with conventional implants. Materials and methods: This retrospective report includes an initial cohort of 39 patients (30 women and 9 men), with a mean age of 53 years, followed for 5 years. The patients were rehabilitated with 39 fixed prostheses and 169 implants (92 zygomatic implants inserted extra-maxillary and 77 conventional dental implants). A provisional prosthesis was manufactured and attached via multiunit abutments secured to the implants on the same day as implant placement. According to patient desires and each clinical situation, either an acrylic resin, a metal-acrylic or metal-ceramic final prosthesis was inserted approximately 6 months after implant placement. Outcome measures were: prosthesis success; implant success; complications; probing pocket depths; marginal bleeding; and marginal bone levels (only for conventional implants). Data were analysed with descriptive statistics. Results: Two patients died after 8 and 30 months of follow-up due to causes unrelated to their oral rehabilitations, and 5 patients dropped out of the study. No prosthesis was lost; one zygomatic implant was removed after 46 months of follow-up, giving cumulative success rates of 97% and 98.8% (patient and implant related, respectively). Twelve complications occurred in 12 patients: 5 sinus infections in 5 patients, all with a previous history of sinusitis and whose sinus membrane was disrupted during surgery; one oroantral communication (leading to removal of the implant), 2 all acrylic resin prostheses fractures, 1 ceramic crown fracture (on a metal-ceramic prosthesis); and 3 screw loosenings. Bleeding on probing was recorded in 6 patients (13 implants). Probing pocket depths >4 mm were present in 13 patients (23 implants) at 5 years of follow-up. The average (standard deviation) marginal bone loss on conventional implants was 1.16 mm (0.77 mm) in those 9 patients having the intraoral radiographs. Conclusions: The long term outcome (5 years) of rehabilitations performed on patients with completely edentulous, severely atrophic maxillae supported by immediately loaded zygomatic implants alone, or in combination with conventional implants, is satisfactory. Keywords: all-on-4, completely edentulous, dental implants, extra-maxillary, immediate loading, zygomatic implants Conflict of interest statement: Professor Maló is currently a consultant for Nobel Biocare. This study was not supported by any grant.