Ten-year clinical outcome of single implant-retained mandibular overdentures-A prospective pilot study

The aim of this prospective pilot study was to evaluate the concept of one single implant placed in the edentulous mandible to retain a complete denture with regard to implant survival and prosthodontic maintenance over an observation period of 10 years.

Eleven edentulous patients were included and received one implant in the midline of the mandible. Five implants healed submerge and were uncovered 2 months later. The other six healed un-submerged and were provided with a healing abutment 4 mm in height thus moderately loaded. All denture bases were temporarily relined during the healing period and two months later provided with a ball attachment for implant retention. Implant related parameters and prosthodontic maintenance interventions were assessed four weeks after implant loading and then annually.

Over a mean observation period of 108.9 months (35-136 months), no implant was lost. The most frequent prosthetic maintenance intervention was activation of the matrix due to loss of retention, followed by exchange of the female part. Fracture of the denture base in the attachment area was a frequent complication and occurred in 8 cases. Two denture bases fractured twice.

Within the limitations of this prospective pilot study, the concept of a single midline implant to retain a mandibular complete denture is promising over ten years for edentulous patients. Regular recall visits should be scheduled due to frequent maintenance interventions. Further research on this topic with a larger study cohort is needed.