Implant Placement in Failed Endodontic Sites: A Review
Dental implants may fail to osseointegrate in sites of endodontic failure. This may occur as a result colonization by various anaerobic and facultative bacterial species. If an implant is placed in a site where vegetative bacteria are residing, the implant may fail to integrate if a bacterial colonization proceeds coronally. If the implant apical cortical bone is thin or if there is an apical fenestration, the colonization may proceed through the thin or nonexistent bone through the covering mucosa, relieving inflammatory pressure to create an apical (retrograde) peri-implantitis. Enterococcus faecalis may be the prime culprit in these types of implant failures. After thorough debridement, the implant may be immediately placed after extraction of an endodontically failed tooth, and the patient treated with an appropriate antibiotic. Alternatively waiting for postextraction healing and subsequent implant placement can be done. Nevertheless, either way may allow for the formation of bacterial vegetative forms or biofilms. The implant surface may be colonized when the surface is exposed to the bacteria. Thorough debridement is crucial. Nonetheless, organisms may persist. Randomized controlled trials are needed to elucidate this issue.

The left maxillary lateral incisor was extracted and an implant placed after healing.

The implant subsequently failed to integrate.

Adjacent septic apex seems to have infected the adjacent implant but residual bacteria may have vegetated after the extraction.

When the apical bone is thick or the apex of the implant is far from the cortical bone, bacterial colonization may advance occlusally and around the fixture, preventing osseointegration. If the apical cortex is thin or there is a fenestration, then an apical (retrograde) peri-implantitis may occur.
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