National Dental Examining Board of Canada (NDEB) Practice Exam 2026 – The Comprehensive All-in-One Guide to Exam Success!

If post-operative bleeding occurs 48 hours after a dental extraction, the most likely cause would be the action of bacterial streptokinase on the clot within the alveolus. This is because streptokinase is an enzyme produced by bacteria that can dissolve clots, making it difficult for the blood to coagulate and stop bleeding. Therefore, options A, B, and D are incorrect because they do not involve the action of bacterial streptokinase. Improper wound dressing may cause bleeding immediately after extraction, but not after 48 hours. Patient non-compliance with post-op instructions may increase the risk of bleeding, but it does not involve the action of bacterial streptokinase. Secondary infection from adjacent tooth may cause local inflammation and swelling, but it does not directly affect the clot formation and stability within the extraction site.