Microbial analysis of the autogenous bone collected by bone filter during oral surgery: a clinical study.

Purpose: The purposes of the study presented are to identify the microbial content of the collected bone debris and to determine the antibacterial efficiency of chlorhexidine mouth rinse in reducing the microbial content of the collected bone debris.
Patients and Methods: Twenty-five patients who had asymptomatic fully impacted mandibular third molars bilaterally underwent surgical removal for prophylactic and orthodontic considerations. Immediately before surgery all patients rinsed with 10 mL of their assigned solution (chlorhexidine or sterile saline) for 2 minutes. Before surgical removal of the teeth, bone debris was collected with a stringent aspiration protocol from the ramus by bone filter. The microbial content of the bone debris was assessed and the bacterial levels between the 2 groups were compared statistically.
Results: All samples from both groups (chlorhexidine or sterile saline) yielded viable microorganisms. There was no significant difference between the mean/median colony-forming units (CFU)/g values of both group samples, for aerobes (Streptococcus salivarius) and anaerobes (Bacteroides, Peptococcus, Peptostreptococcus, and Veillonella species). With regard to total microorganisms, the mean CFU/g derived from the chlorhexidine group samples were 1.5 x 10(8) CFU/g per bone sample compared with 1.5 x 10(9) CFU/g for the sterile saline control group (P < .05).
Conclusion: Although chlorhexidine rinsing immediately before surgery reduced the levels of total microorganisms when compared with stringent aspiration protocol alone, it has not been found effective on aerobic Streptococcus salivarius and, importantly, on anaerobes. The reduced bacterial levels may still carry high infectious risk and may lead to failure in autogenous grafting procedures in oral surgery.