Which clinical sign is most consistent with a diagnosis of von Willebrand's disorder in the given case?

Von Willebrand's disorder is a bleeding disorder caused by a deficiency or dysfunction of von Willebrand factor, which plays a crucial role in platelet adhesion and stabilizes factor VIII in the coagulation cascade. The clinical signs of this disorder often relate to bleeding tendencies associated with mucosal surfaces and wounds.

Excessive bleeding post-dental procedures is particularly consistent with von Willebrand's disorder because dental work can cause significant trauma to the gingival tissues, which are rich in blood vessels. Patients with von Willebrand's disorder may not form effective platelet plugs to stop the bleeding from these areas due to the impaired platelet function. This results in prolonged or excessive bleeding during and after dental interventions, highlighting the importance of von Willebrand factor in normal hemostasis.

While frequent nosebleeds, prolonged menstrual bleeding, and scattered petechiae can occur in patients with von Willebrand's disorder, excessive bleeding after procedures that disrupt the mucosal integrity, such as dental work, is a hallmark sign that showcases the pathophysiology of the condition effectively. These occurrences reflect the immediate impact of dysfunctional hemostatic response due to the disease in clinical practice.