Abstract The oral cavity being the centre of array of organisms, endorses the establishment of diverse microbial associations like on the mucosa and teeth. Metabolism of these living beings encourages the attachment and development of the ensuing colonisers. A fragile adjust is kept up within the microbial ecosystem, with these life form conferring to normal growth and defences. Nevertheless, any change or disturbance within the microbial outline by reason of either outward or inborn components results unfavourable shift towards pathogenic organisms provoking numerous diseases such as dental caries or periodontitis. Moreover, current exposures also reveal that these microbes induce systemic illnesses such as diabetes or artherosclerosis. This article is an endeavour to confer an overview of the changed flora ailing states.