Bacterial persistence in dentoalveolar bone following extraction: a microbiological study and implications for dental implant treatment.
BACKGROUND
The microbiological status of apparently healed alveolar bone implant sites is unknown. Implant success may be compromised by site-specific persistence of bacterial biofilm co-aggregations contaminating healed alveolar bone.


OBJECTIVE
The purpose of the present study was to investigate whether extraradicular infection can persist in apparently healed alveolar bone and to develop a surgical debridement strategy that favors implant osseointegration.


METHODS
The study was conducted on 32 private practice patients. Seventy-seven microbiological samples were taken from 16 pre-implant extraction sockets, 56 healed post-extraction osteotomies at fixture placement, and five failed fixtures. Two of the healed osteotomy samples were healed retreatment sites. Tissue fluid and bone samples were analyzed by either anaerobic/aerobic culturing or DNA molecular techniques. All patients were treated ad modum Brånemark, with a two-stage sterile surgical procedure. A search of the medical and dental literature revealed no evidence-based or best practice recommendations for the use of debridement in implant therapy. Thus, we developed a new technique for the debridement of alveolar bone found to be contaminated by persistent biofilm or planktonic bacteria.


RESULTS
The results of the microbiological analysis of 77 bone and effusion samples from 47 implant sites of the 32 patients showed that overall, 32% (n = 25) had bacteria present in the sample. In 16 pre-implant extraction sockets, 69% of samples were positive for the presence of bacteria (n = 11). Of 56 osteotomies with a minimum 3-month healing at fixture placement, 21% revealed a positive culture (n = 12). Two-stage failed fixtures had 100% positive cultures (n = 5) and it was evident from radiographs that all of these failed fixtures had the apical ends close to the former tooth root end. Based on these findings, we have developed a microbiologically based surgical debridement strategy to successfully re-treat early infective failures and to place successful two-stage fixtures.


CONCLUSIONS
Bacteria can persist as a contaminant in apparently healed alveolar bone following extraction of teeth with apical or radicular pathosis. A new technique for surgical debridement to reduce and limit this bacterial contamination has been described.
Nelson
Stephen
S
Department of Obstetrics and Gynaecology, University of Sydney, Sydney, Australia. snel6449@usyd.edu.au
Thomas
Graham
G
D000539:Alveolar Process / Q000382:microbiology* / Q000601:surgery; D001419:Bacteria / Q000302:isolation & purification; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000032:analysis; D003646:Debridement / Q000379:methods*; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D019232:Dental Restoration Failure; D006801:Humans; D010485:Periapical Periodontitis / Q000382:microbiology / Q000601:surgery; D014081:Tooth Extraction; D020390:Tooth Socket / Q000382:microbiology* / Q000601:surgery*
D004269:DNA, Bacterial; D015921:Dental Implants