Dental Assistant Practice Exam

Which type of sterilizer is known to be the least expensive but requires higher temperatures?

1. Steam sterilizer

2. Dry heat sterilizer

3. Ethylene oxide sterilizer

4. Hydrogen peroxide plasma sterilizer

The correct answer is: Dry heat sterilizer

The dry heat sterilizer is recognized for its affordability and its operational requirement for higher temperatures compared to other sterilization methods. This type of sterilizer utilizes hot air that is circulated in an enclosed environment, generally reaching temperatures between 160°C to 190°C (320°F to 375°F) for sterilization to occur effectively. One of the unique aspects of dry heat sterilization is the way it destroys microorganisms: it oxidizes cellular components, which is a different mechanism than that of steam sterilization that relies on moisture. While the process is cost-effective due to inexpensive equipment and its ability to sterilize without the use of chemicals, it also demands longer exposure times and elevated temperatures to achieve sterilization outcomes, particularly for different materials. Other sterilization methods, such as steam sterilizers, are often more expensive due to the technology and pressure needed, while ethylene oxide sterilizers, although effective, involve costly chemical agents and highly controlled environments. Hydrogen peroxide plasma sterilizers also rely on complex technology and are more costly than dry heat sterilizers, limiting their cost-effectiveness for many applications.