Summary: Following favourable results from a previous study, a large, multicentre, prospective, case-control study was performed to further assess the incidence of bleeding complications after dental extraction in patients taking oral anticoagulant therapy (OAT). Four hundred fifty-one patients being treated with warfarin who required dental extraction were compared with a control group of 449 non-anticoagulated subjects undergoing the same procedure. In the warfarin-treated group, the oral anticoagulant regimen was maintained unchanged, such that the patients had an International Normalised Ratio ranging between 1.8 and 4, and local haemostatic measures (i.e. fibrin sponges, silk sutures and gauzes saturated with tranexamic acid) were adopted. All the procedures were performed in an outpatient setting. Seven bleeding complications occurred in the OAT group and four in the control group; the difference in the number of bleeding events between the two groups was not statistically significant (OR=1.754; 95% CI 0.510 – 6.034; p=0.3727). No post-operative late bleeds requiring hospitalisation and/or blood transfusions were recorded, and the adjunctive local haemostatic measures were adequate to stop the bleeding. The results of our protocol applied in this large, multicenter study show that dental extractions can be performed easily and safely in anticoagulated out-patients without any modification of the ongoing anticoagulant therapy, thus minimising costs and reducing discomfort for patients.

The objective of this study was to compare the healing of the augmented sinus at which the antrostomy was covered with a membrane or the repositioned bone plate.Eight sheep underwent bilateral maxillary sinus floor augmentation. The control site was covered with a resorbable membrane, while at the experimental site the bone plate was repositioned, and both were secured with cyanoacrylate. Animals were euthanised after 4 months and histomorphometric analysis was performed.A large amount of the graft appeared to be partially interpenetrated by the newly formed bone. Statistical analysis demonstrated different percentages of the new bone and bone interpenetrated to the graft between test and control site in the close-to-window area respectively 22.1 ± 12.6 vs 7.5 ± 4.5 (P= 0.028) and 66.1 ± 14.7 vs 44.2 ± 15.1 (P= 0.046). Other areas showed no difference in the bone and graft amount. More bone was found at the edges of the antrostomy in the experimental site, without statistical significance. In the centre of the antrostomy, the replaced bony window appeared bonded to the newly formed bone. No remnants and no biological response to cyanoacrylate were observed.The repositioning of the bony window after sinus floor elevation in sheep led to a larger amount of newly formed bone in the close-to-window zone of the grafted area. The bony window appeared partially bonded to the new bone. Newly formed bone was found interpenetrating the graft granules.