Single mandibular midline-implant supported overdentures: Fifteen-year clinical outcome

The aim of this prospective pilot study was to evaluate the 15-year clinical performance of mandibular overdentures supported by a single midline implant in edentulous patients.

Eleven eligible patients were enrolled. A single implant was inserted in the midline of the mandible (Root Line; Promote, Camlog Biotechnologies, diameter 3.8 mm, length 11-13 mm). In 6 patients, a non-submerged protocol with moderate immediate loading on healing abutments was applied. The submerged healing protocol was followed in the other five patients with uncovering taking place two months after insertion. The denture bases were relined temporarily with a soft acrylic temporary relining material during the healing period. Ball-attachments and corresponding matrixes were provided two months after insertion. The baseline data were collected on the day of implant connection. Follow-up examinations were conducted four weeks after loading and then annually. Required prosthodontic maintenance interventions were recorded and conducted.

Six patients died during the fifteen-year observation period; their data were evaluated up to the last clinical recall. The mean observation time was 139 months. No implant loss has been recorded, amounting up to a survival rate of 100 %. The most frequent maintenance intervention was readjustment of the retention, which was performed multiple times for some patients.

The concept of mandibular overdentures supported by one single midline implant in edentulous patients seems to be a valid treatment option, especially for patients that cannot afford the costs of two or more implants or cannot undergo extensive surgery. Periodic recall-appointments are recommended due to the frequent interventions required.

The use of a single midline implant to support mandibular overdentures in edentulous patients appears to be a viable treatment option, particularly for those who cannot afford multiple implants or undergo extensive surgery.