Intra-operative application of chlorhexidine gel reduces bacterial counts in internal implant cavity

A prospective clinical trial was conducted to assess the bacterial-inhibitory potential of 1% chlorhexidine (CHX) gel in the internal cavity of implant screw holes, when utilized at the time of implant placement. A total of 40 Straumann (S) and Nobel Biocare (N) implants were divided into test (ST or NT; implant + CHX gel) and control (SC or NC; implant only) groups. Total numbers of colony-forming units (CFUs ml(-1) ) were assessed at a minimum of 3 months postsurgery by aerobic and anaerobic culture. A set of specimens was stained with Gram stain. The mean sample-collection time was 110 d for the test population and 98 d for the controls. The use of 1% CHX gel significantly reduced bacterial counts in both the ST and NT samples by over three logs compared with controls. No statistical differences in the numbers of CFUs ml(-1) were evident between aerobic and anaerobic cultures. Differences in the numbers of CFUs ml(-1) between ST and NT groups were not statistically significant. Microscopic analysis showed mainly Gram-positive coccoid species in most samples.