Orthodontist spreading throat infection

Since 2015 I have gone to a orthodontist and everytime I come back home with severe throat infection and fever.the orthodontist says it's not die to the treatment. But the suction machine he uses to suck out sputum is the same for all patients it does not look like it has ever been disinfected. !! Oshiwara
The throat infection attacks the roof of the mouth .the throat glands and neck glands with fever all night .?