[A clinical study on unfavorable cases of dental implant]

The clinical analysis of 462 patients (154 men and 308 women) with problems of implant therapy done at other clinics is reported. They visited the clinic for oral implant of the Tokyo Medical and Dental University Hospital during the period from January 1996 to March 2002. The results were as follows: 1) The majority of the patients (76.6%) were 40 to 69 years of age. 2) Of the total patients, 26.8% had been referred from the other outpatient clinics in our hospital, 14.7% from private dental offices and 2.6% from attending doctors. 3) There were 361 patients with complications related to the implant therapy. Seventy-six patients asked for second opinions concerned about a diagnosis or treatment recommendation. Thirty patients required maintenance of the implants. 4) The most common complications observed were peri-implantitis (184 cases). Prosthodontic complications (72 cases) included framework/resin/veneering material fractures, screw loosening and fractures. There were implant fractures in 21 cases, sensory disturbance in 20 cases, problems related to sinus in 13 cases, problems of connected teeth in 30 cases and phonetic/esthetic complications in 10 cases. 5) The types of problem implants were osseointegrated implants (196 cases), alumina-ceramic implants (74 cases), metallic blade-type implants (35 cases), pin-type implants (10 cases), subperiosteal implants (6 cases) and other implants.