What is the MOST common route for bacteria to enter the dental pulp? (Select the EXCEPTION from the list — the route that is LEAST common)

Anachoresis (bacteremia → blood flow → bacteria localizing in inflamed pulp tissue) is the LEAST common route of pulpal infection. The PRIMARY routes are: (1) dental caries — by far the most common, (2) fractures (crown/root), (3) traumatic exposures, (4) dental procedures, (5) cracks. Anachoresis is a theoretical route that has been demonstrated experimentally but is not clinically significant as a primary cause of pulpal infection. Blood flow as a bacterial entry route is the exception.