A method of promoting a desired oral microbiota to treat an oral and/or sinus infection condition in a subject in need of such treatment including providing a preformulated prebiotic edible composition including an amino acid containing ingredient comprising individual molecules of L-arginine; substantially removing a biofilm from surfaces within an oral cavity by heating the inside of the oral cavity to a temperature of about 100 deg F. to about 130 deg F.; wherein following removal of the biofilm, the composition is provided contained and at least partially dissolved within an oral cavity of the subject for a period of at least from about 30 seconds to about an hour on a daily basis of at least two consecutive days to promote an increased concentration of selected oral microbiota, the selected microbiota comprising Veillonella and Streptococcus, thereby treating the oral and/or sinus infection condition.