Which of the following is NOT a type of saliva evacuator?

The selection of "None of these" implies that all the listed items are indeed types of saliva evacuators. Saliva evacuators are essential tools in dentistry, primarily used to maintain a dry operating field by removing excessive saliva and other fluids during procedures.

The Speejector is a type of saliva ejector that uses a suction mechanism to remove fluids from the oral cavity efficiently. The Svedopter is similarly designed for high-volume suction, making it useful in various dental procedures. The disposable hygoformic aspirator system is another saliva evacuator designed for use in single dental appointments, which helps maintain hygiene and reduces cross-contamination.

As all the options listed represent legitimate types of saliva evacuators, selecting "None of these" correctly identifies that there is no option among them that does not belong to this category. Therefore, understanding the function and application of each of these devices reinforces the correct choice.