A Retrospective Study of 1,925 Consecutively Placed Immediate Implants From 1988 to 2004

Purpose: The purpose of the present study was to evaluate implant survival rates with immediate implant placement (IIP) into fresh extraction sockets and to determine risk factors for implant failure. Materials and Methods: A retrospective chart review was conducted of all patients in whom IIP was performed between January 1988 and December 31, 2004. Treatment required atraumatic tooth extraction, IIP, and mineralized freeze-dried bone allograft with an absorbable barrier to cover exposed implant threads. Implant failure was documented along with time of failure, age, gender, medical history, medications taken, postsurgical antibiotic usage, site of implant placement, and reason for implant failure. Statistical analysis was performed using chi-square and logistic regression analysis methods. Results: A total of 1,925 IIPs (1,398 machined-surface and 527 rough-surface implants) occurred in 891 patients. Seventy-one implants failed to achieve integration; a total of 77 implants were lost in 68 patients. The overall implant survival rate was 96.0% with a failure rate of 3.7% prerestoration and 0.3% postrestoration. Machined-surface implants were twice as likely to fail as rough-surface implants (4.6% versus 2.3%). Men were 1.65 times more likely to experience implant failure. Implants placed in sites where teeth were removed for periodontal reasons were 2.3 times more likely to fail than implants placed in other sites. Patients unable to utilize postsurgical amoxicillin were 3.34 times as likely to experience implant failure as patients who received amoxicillin. Conclusions: With a 1- to 16-year survival rate of 96%, IIP following tooth extraction may be considered to be a predictable procedure. Factors such as the ability to use postsurgical amoxicillin and reason for tooth extraction should be considered when treatment planning for IIP. Keywords: age factors, dental implants, gender, implant surfaces, implant survival, penicillin allergy, smoking