Prosthodontic complications in a prospective clinical trial of single-stage implants at 36 months

The present material reports on prosthodontic complications in a trial of 51 patients with prostheses supported by single-stage implants over a period of 36 months.

One hundred eighty-six single-stage implants were placed in 51 patients over a 3-year period in 2 carefully controlled prospective clinical trials. Nineteen of the patients (103 implants) were completely edentulous and restored with a maxillary complete denture and a mandibular fixed-detachable complete prosthesis. Single metal-ceramic crowns or fixed partial dentures were fabricated for the remaining 32 patients (83 implants). The fixed restorations were either screw-retained or cemented.

All patients/implants were followed for a minimum of 3 years. Complications in the edentulous patients included fracture of denture teeth, fracture of the maxillary denture, and occlusal screw loosening. Occlusal screw loosening and loss of the resin composite access plug were the only complications observed in the patients treated with screw-retained restorations. No complications were found in the patients restored with cemented restorations on solid abutments.

Problems with prostheses were very common in the completely edentulous patients (13 of 19 patients encountered complications), possibly a result of increased bite force or inadequate laboratory technique. Tooth fractures were seen more frequently in men than in women. Complications occurred in only 5 of the 32 partially edentulous patients.

Complications were associated with laboratory-related procedures rather than the implant system itself.