It is possible that the spray caused some irritation in your mouth or maybe some irritation from the teeth cleaning. Either cause of irritation could have caused a passageway for the natural bacteria in your mouth to enter into your body and cause upper respiratory issues. Often it starts out as a sore throat, cold, etc. and could progress into more, such as pneumonia, if your immune system is unable to tackle it.

Often times I end up getting sick if I fall asleep with the heat up too high and/or if the air is too dry and I sleep with my mouth open/snoring. The back of my throat ends up getting dry and then I wake up with a sore throat, leading to being sick for a few days. It is a vicious cycle!