Immediate Loading of Two Freestanding Implants Retaining a Mandibular Overdenture: 1-Year Pilot Prospective Study

Purpose: The aim of this 1-year pilot prospective study was to evaluate the implant success rate, peri-implant tissue response, and complications associated with the immediate loading of two freestanding implants retaining mandibular overdentures. Materials and Methods: Ten adults with a mean age of 59.7 years (range, 43 to 78 years) underwent treatment that included a maxillary removable complete denture opposing a mandibular removable overdenture retained by two freestanding, threaded, titanium oxide-surface implants with a 3-mm machined collar (n = 20 implants). The success of each implant was evaluated clinically and radiographically. Marginal bone levels and changes were evaluated using sequential standardized periapical radiographs. Surgical and prosthetic complications were recorded. Results: Two patients, one with one failed implant, dropped out prior to completion of the study. The failed implants were included in the evaluation of cumulative implant success. The cumulative implant success rate at 1 year was 94% (16/17). The mean marginal bone loss was 1.12 ± 1.10 mm at 12 months. However, if the expected bone loss of 0.39 mm above the smooth-rough implant surface junction was considered, the mean marginal bone loss was only 0.73 mm. Mean Periotest values of -4.25 ± 0.93 at 1 year implied that osseointegration had been achieved for all successful implants. Modified Plaque Index scores of 0 and 1 were recorded throughout the duration of the study. No irreversible surgical and/or prosthetic complications were observed. Conclusions: In this 1-year pilot prospective study, two immediately loaded unsplinted mandibular symphyseal implants retaining an overdenture resulted in favorable implant success and peri-implant tissue response. Keywords: ball-attachment, immediate loading, implant-supported prosthesis, mandibular overdenture, prospective, two freestanding implants