Postoperative bleeding in patients taking oral anticoagulation therapy after 'All-on-four' rehabilitation: A case-control study.

The aim of this study was to estimate bleeding prevalence and postoperative peri-oral purpura after full-arch immediate implant rehabilitation according to the 'All-on-four' technique, in patients on different oral anticoagulant therapies (warfarin and rivaroxaban).A total of 120 patients (47 women, 73 men, mean age 66.4 years) presented with edentulous or partially edentulous arches. All patients were treated with immediate full-arch fixed prostheses (28 maxillary, 34 mandibular), each supported by four implants (two vertical, two distally tilted). Participants were divided in three groups: 40 patients under treatment with warfarin formed group A, 40 patients under treatment with rivaroxaban composed group B, and 40 healthy subjects composed the control group. As the primary outcome measure, mild, moderate and severe postoperative bleeding was recorded. As the secondary outcome measure, the presence of postoperative petechiae, ecchymoses and haematomas in oral and peri-oral tissues was recorded.Patients under treatment with warfarin (group A) showed a higher prevalence of postoperative bleeding (P = 0.002) and purpura (P = 0.012) in comparison with other groups. No severe bleeding took place and no haematomas appeared in any patient. Prefabricated metal-reinforced, screw-retained, acrylic resin provisional restorations were delivered in all patients.The preliminary results of this prospective case-control study showed how immediate rehabilitation according the 'All-on-four' technique could be a safe and predictable procedure in anticoagulated patients where anticoagulation therapy is not discontinued or modified.