A Retrospective Evaluation of 1,387 Single-Tooth Implants: A 6-Year Follow-Up

Success and Survival of Single Dental Implants Placed in Sites of Previously Failed Implants

BACKGROUND

The aim of this study was to assess the clinical effectiveness of single dental implants placed in sites of previously failed implants.

METHODS

The study consisted of a consecutive cohort of 1,215 patients who received 1,387 single implants for single-tooth replacement during a 6-year period (1999 to 2005). Inclusion criteria were a single implant replacing a previously failed implant and follow-up data > or =6 months. Data were recorded and analyzed regarding implant survival and location, need for bone augmentation, and implant dimensions.

RESULTS

A total of 75 patients experienced the failure of 96 implants. Of those, 31 implants in 28 patients were replaced by a similar implant placed in the same location. Nine of the replacement implants failed, resulting in an overall survival rate of 71%. Follow-up ranged from 6 to 46 months (mean, 19.4 +/- 11.4 months). Replacement of maxillary and mandibular failed implants was similar. All failures occurred during the first year after implant replacement. On average, implant replacement occurred 5.8 +/- 5.2 months after original implant removal; three implants were placed immediately after implant removal. A third attempt for single implant replacement was made in two patients. However, one failed.

CONCLUSIONS

Replacement of a failed implant presents a challenge to achieve osseointegration in a healed bone site and may result in a decline in the survival rates. Patients and clinicians should be aware of these results before a replacement attempt is considered. The success of replacement may be increased by the use of wider implants or with improved surfaces.

Dental Implants for Immediate Fixed Restoration of Partially Edentulous Patients: A 1-Year Prospective Pilot Clinical Trial in Periodontally Susceptible Patients

BACKGROUND

The aim of this study was to evaluate the survival of dental implants in periodontally susceptible patients using immediate loading/restoration (ILR) protocols and the factors that modulate this response.

METHODS

Systemically healthy patients who were treated previously for chronic periodontitis and who required implant therapy were recruited. Following data collection, "surgical templates" and provisional fixed restorations were fabricated. Transgingival implants were inserted, and surgical measurements were performed. After abutment connection, the crown/bridge was relined and cemented. Patients were monitored for 12 months, at which time final measurements were performed.

RESULTS

Twenty patients (49 implants) completed this study; five implants failed and were removed (90% survival rate). All implants were removed during the first 6 months. At 12 months, the mean implants' probing depth was 2.87 +/- 0.9 mm. The mean electronic mobility testing device value (-1.3 +/- 0.7) was slightly higher than at baseline (-3.53 +/- 10.7). Radiographic bone loss ranged between -1.24 and 2.77 mm (mean +/- SD: 0.91 +/- 0.2 mm). All of the implants (16) that were inserted in the premolar region were successful, whereas three of nine implants in the molar region and two of 24 implants in the canine/incisor region failed (P = 0.0278). Survival in the immediately loaded group (83%) was slightly lower than in the immediately restored group (96%); however, these differences did not reach statistical significance. None of the other variables (smoking, arch, stability, implant length and diameter, and bone width) affected the outcome of this procedure.

CONCLUSIONS

ILR protocols are predictable alternatives in periodontally susceptible patients. Results in the molar regions suggested that careful consideration should be given to implants placed in these sites. Long-term success in these patients has not been addressed.