The effects of preoperative resorption and jaw anatomy on implant success. A report of 303 cases.

The purpose of this paper is to report the outcome of 1097 consecutively implanted endosteal implants (Brånemark) into 303 jaws, between September 1983 and May 1990. All implants were placed using the prescribed technique suggested by manufacturer, and were restored either with fixed or removable prosthesis. Alveolar bone resorption (quantity) was scored from lesser to greater degree by assigning a value of 1-5 to each jaw, and jaw anatomy was scored from 1-4, based on decreasing cortical and cancellous bone quality. The data were separated into fixed and removable prosthesis and analyzed to determine the correlation between success and the scored resorption and jaw anatomy, as well as implant position. Assessment demonstrated a maxillary success rate of 93.4% and a mandibular success rate of 97.2% over a 36-month period (mean). Results of correlations of success with jaw anatomy for both fixed and removable prosthesis revealed that bone quality 4 exhibited the greatest failure rate. Preoperative resorption values (1-5) had little effect on failure, and quality appears to influence failure more than quantity.