Immediate loading of two unsplinted mandibular implants in edentulous patients with an implant-retained overdenture: an observational study over two years.

Objectives: Immediate loading of two unsplinted mandibular implants by means of an overdenture may be a viable and cost-effective treatment option to improve the patient's oral health-related quality of life. We therefore conducted a prospective observational study to estimate implant survival and patient satisfaction after an immediate loading protocol in edentulous patients.

Materials and methods: Twenty edentulous patients who received two interforaminal implants (Straumann Standard implant, length 12 mm) were included in our study. Immediately after implant placement, ball attachments with a diameter of 2.25 mm were placed on the implants and the respective matrices were directly incorporated in the existing complete denture. Clinical recalls were scheduled 1 week, 1, 3, 6 months, and 1 and 2 years after implant placement. The following clinical parameters were assessed: gingival bleeding index (GBI), visual plaque index (VPI), and soft tissue overgrowth. In addition, we also assessed radiological bone level change (RBLC) using panoramic radiographs, and patient satisfaction using a visual analogue scale at baseline, after 6 months and 2 years.

Results: No implant failures occurred during the 2-year observation period, resulting in a survival rate of 100%. The mean RBLC was 0.67 mm (95% Confidence Interval [95% CI]: 0.47-0.86 mm) two years after surgery. The GBI and VPI after two years were 24 (95% CI: 9-38)% and 36 (95% CI: 19-53)%, respectively. Soft tissue overgrowth was 1.6 mm (95% CI: 1.1-2.1) on average after two years. In a multivariate regression model, patients with a GBI ≥50% on average showed an increased RBLC (-0.6 mm, p = 0.007). High patient ratings were recorded for overall satisfaction. Overall patient satisfaction measured on a scale between one and ten was 5.2 (95% CI: 2.1-8.5) before implant placement and 9.5 (95% CI: 9.1-10) after 2 years.

Conclusion: Immediate loading of two unsplinted interforaminal implants in overdenture patients using ball attachments is a clinically viable treatment option that leads to a high survival rate and oral health-related quality of life.