National Dental Assisting Examining Board (NDAEB) Practice Exam

What term describes free-floating bacteria in dental unit water lines?

1. Colloidal bacteria

2. Suspended bacteria

3. Planktonic

4. Colonial bacteria

The correct answer is: Planktonic

The term "planktonic" correctly describes free-floating bacteria in dental unit water lines. Planktonic bacteria exist in a suspended state within a liquid environment, as opposed to being attached to surfaces or forming biofilms. This characteristic is significant in the context of dental units, where water lines can harbor various bacterial species that can influence patient safety and treatment quality. Planktonic bacteria are typically more reactive to antimicrobial treatments compared to their biofilm counterparts, which can be difficult to eradicate due to their protective environment. Understanding this distinction helps in implementing effective infection control practices in dental settings, ensuring that water quality remains within safe limits for patient use. The other terms do not accurately describe the nature of free-floating bacteria in this context. Colloidal bacteria usually refer to very small particles that may remain suspended in a solution but do not specifically pertain to bacterial organisms. Suspended bacteria might imply bacteria held in suspension but lacks the specific connotation of free-floating organisms found in aquatic environments. Colonial bacteria refer to bacteria growing in groups or colonies, which can emphasize aggregation rather than the free-floating nature characteristic of planktonic forms.