Clinical outcomes of fully and partially threaded zygomatic implants in a cohort of patients with minimum 7.5-year follow-up

OBJECTIVE: The aim of this retrospective case series report was to evaluate the results of oral rehabilitation with extra-sinus zygomatic implant surgery with a minimum follow-up of 7.5 years. PATIENTS AND METHODS: A total of 35 patients with 87 zygomatic implants were included. The mean follow-up period of the patients was 93 months. The zygomatic implant survival and complications were evaluated as criteria for success. RESULTS: There were no implant failures. Overall success rate without complications for zygomatic implant was 88.5%. Complications developed in 4 patients (1 cutaneous fistula and 3 mucositis). According to the results on an implant basis, patients with previously failed conventional implants had greater probability of complications. Patients with quad zygomatic implants had higher incidence of complications than those with two zygomatic implants. Fully threaded implant design was associated with higher incidence of mucositis than partially threaded design. No relation was found between implant success and smoking, prosthesis type, and antagonist dentition. When conducting the analysis using the patient as unit, only the antagonist dentition showed significant difference, the worst outcome being associated with the Toronto resin prosthesis. CONCLUSIONS: Zygomatic implants can be considered as a safe alternative to conventional implant insertions and bone grafting procedures in oral rehabilitation of patients with severely atrophic maxillary bone.