If you intend tackling biofilms then you should look for Quorum Sensing Inhibitors which are specific to the organism that you intend to destroy.

QSI affect the communication of organisms in a biofilm. They can sense different signals from other organisms which tell them to perform different tasks such as build the biofilm, spread etc. Finding working QSI can prevent them from re-inforcing the biofilm or spreading if you get the correct QSI's for the right strain of the organism that you have.

Biofilms can harbour multiple organisms which cooperate and help each other.

Look at essential oils because some of them can be used without resistance forming.

The commonest biofilm in the mouth is dental plaque but that is more a risk factor for gum disease and tooth decay rather than candida.