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UBC Theses and Dissertations

Comparison of treatment protocols to reduce the total bacterial load in the implant screw hole Ghannad, Farzan


Objective: A prospective multi-centre clinical trial was conducted to assess the biofilm inhibitory potential of 1% chlorhexidine (CHX) gel in the internal cavity of implant screw holes, when utilized at the time of surgical implant placement. Methods: The study included a total of 40 Straumann (S) and Nobel Biocare (N) implants, divided into test (ST or NT) and control (SC or NC) based on the implant system. The implants were placed by two periodontists (private practice) as well as by senior Graduate Periodontics residents at the University of British Columbia. Total colony forming units (CFUs/ml) were assessed 3 months post surgery by means of aerobic and anaerobic culturing and Gram staining was conducted on 15 of the samples. Univariate Mann-Whitney U tests were used to analyze differences between groups (p <0.001). Gender distribution and sample collection times were compared by means of Fisher’s exact test and Student t-test respectively. Results: The mean sample collection time was 110 days for the test population and 98 days for the controls (p > 0.05). No statistical differences in term of CFUs/ml were evident when comparing aerobic and anaerobic culturing methods (p > 0.05). The use of 1% CHX gel significantly reduced biofilm formation in both the ST and NT samples when compared with controls (SC and NC) (p < 0.001). Differences between ST and NT did not reach statistical significance (p > 0.05). Overall, 13 implants from the test population demonstrated CFUs/ml below a threshold of 1000 compared to only 1 implant from the control population. Microscopic analysis revealed the presence of mainly Gram-positive coccoid species in 14/15 samples; one sample consisted mainly of rod shaped bacteria. Conclusion: The application of 1% CHX gel in the internal implant cavity at the time of initial implant surgery greatly reduces the biofilm formation over a 3-month period.

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