In such patients, PT-INR values before and after the tooth extraction were 2.27 and 2.26, respectively, and not significantly changed. These data suggest that selleck chem the possible bias derived from PT-INR values measured within 7 days in advance were minimal. Second, we performed all the analyses by tooth, not by patients. We hypothesised, based on previous studies that found no significant correlation between the numbers of teeth extracted and incidence of postextraction bleeding,2 4 5 7 that risks for postextraction bleeding may vary depending on the position and/or condition of the tooth extracted even in the same individual. In order to detect possible influences of

local factors, such as position of tooth extracted (foretooth vs molar tooth) and gum conditions (presence of inflammation and/or inappropriate granulation) on risks for postextraction bleeding, we chose to present our data by tooth, despite a possible bias of including some of the patient data multiple times when multiple teeth were extracted from a single patient. When analysed by patient, clinically significant postextraction bleeding occurred in 2.77% and 0.39% in the WF and non-WF group, respectively, the difference between

which was 2.38% (95% CI 0.65% to 4.10%) and similar to that found in analysis by tooth. These data suggest that the bias that might arise from the analyses by tooth was minimal. Third, evaluation of the postextraction bleeding events was not blinded and choice of secondary haemostasis

means were left at the discretion of the operator in charge, which might have affected the outcome of our analyses. However, the definition of the clinically significant bleeding events was made clear, minimising the influence by the person who evaluated the individual event. Indeed, there was little difference in postextraction bleeding incidence between patients whose wounds were sutured and those whose were not (0.6$% and 0.2%, respectively), further supporting the notion that means of haemostasis have minimally affected the present findings. Conclusion The difference in incidence rates of postextraction bleeding between WF and non-WF groups was 3.24% (95% CI 1.49 to 4.99%). Age, PT-INR and history of acute inflammation at extraction site were risk factors for postextraction bleeding in WF-receiving patients. Supplementary Material Author’s manuscript: Click here to view.(2.4M, pdf) Cilengitide Reviewer comments: Click here to view.(295K, pdf) Footnotes Contributors: Hiroshi Iwabuchi designed the study protocol and wrote the manuscript. Hirohisa Imai analysed the data and contributed to edition of the manuscript. Hiroshi Iwabuchi, YI, SA, MS, G-yY, HO, KK and MM contributed to data collection. HN participated in data analyses. YI is the principle investigator of the present study. All the authors have approved the final version of the manuscript to be published.