Success and survival of single dental implants placed in sites of previously failed implants

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

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.

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.

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.