Embodiments of a system and method for characterizing a mouth-associated condition in relation to a user can include one or more of: a handling network operable to collect containers including material from a set of users, the handling network including a sequencing system operable to determine microorganism sequences from sequencing the material; a microbiome characterization system operable to determine microbiome composition data and microbiome functional diversity data based on the microorganism sequences, collect supplementary data associated with the mouth-associated condition for the set of users, and transform the supplementary data and features extracted from the microbiome composition data and the microbiome functional diversity data into a characterization model for the mouth-associated condition; and/or a therapy system operable to promote a treatment to the user based on characterizing the user with the characterization model in relation to the mouth-associated condition.