A filter unit for a conventional suction system of dental equipment is proposed. It consists of a disposable filter and a connecting module fixed to the suction system. The connecting module removably connects the disposable filter to the system, and includes—；an inlet pipe passing a water flow and solid contents from the system,—；an outlet pipe returning the water flow into the system,—；a hole communicating with the inlet pipe,—；a pipe projection communicating with the outlet pipe, and—；fixing slots. The filter includes—；a container collecting the solid contents,—；a cover including inlet and outlet holes and provided with fixing projections removably engaged with the fixing slots, and—；a lock-fixer rotatably mounted within the cover. It allows for removable connecting the filter to the system, which significantly improves convenience of servicing the system, safety and sanitary protection of dental personnel.
