Peri-implant health, clinical outcome and patient-centred outcomes of implant-supported overdentures in the mandible and the maxilla

Abstract Objectives/Aims: The primary aim of this retrospective pilot study was to evaluate the clinical outcome of overdentures on four non-splinted maxillary implants compared to the mandible using locator attachments and secondly to assess patient's opinion of the treatment. Materials and Methods: The treatment protocol used here is summarised as a single-stage surgical approach followed by immediate loading (same day in 12 of 17 patients) of a removable prosthesis in the maxilla and mandible. Most of the implants were installed into fresh extraction sockets. Clinical outcomes were evaluated in 68 southern implants, straight (non co-axis) or angulated (co-axis) in 17 patients. Patients were examined by independent examiners at an average follow-up of 14.5 months after implant placement. Results: Outcomes measured were implant survival, bone loss, bleeding on probing, probing pocket depths and plaque score in addition to quality of life measured with OHIP-14 questionnaires. An overall implant survival of 100% was achieved. The mean marginal bone level (mm) over the entire cohort of 66 measured implants was (1.4 mm; range, 0–5.5). A significant difference (P=0.01) was found between bone level, from implant head to bone contact in the maxilla (M, 0.9 mm; s.d., 1.1; range, 0–4) and the mandible (M, 1.7; s.d., 1.0; range, 0–5.5). The marginal bone-to-implant head distance with the angulated co-axis implants was 1.9 mm (s.d., 1.5; range, 0–5.5) compared to non co-axis, mean 1.2 mm (s.d., 1.1; range, 0–4) (P=0.01). The OHIP-14 overall mean was 3.3 (out of a maximum of 56). Conclusion: The implant survival was 100% and the patients benefited from the overdenture treatment on four non-connected implants. The extremely low OHIP-14 indicated a very high level of patient satisfaction following treatment. The results of this study merit further long-term investigation to fully investigate the success of immediately loading implants in the maxilla as well as cost-benefit.