mutans is a bacterium which is prevalent within the oral environment and is thought to be a vital microorganism that contributes to this initiation. S. mutans thrives in acidic conditions, becoming the main bacterium in cultures with permanently reduced pH . If the adherence of S. mutans to the surface of teeth or the physiological ability (acidogenity and aciduricity) of S. mutans in dental biofilms can be reduced or eliminated, the acidification potential of dental biofilms and later cavity formations can be decreased. Ideally, we can stop the early various lesion developing beyond the white spot stage. Once beyond here, the enamel surface is irreversibly damaged and cannot be biologically repaired. In young children, the pain from a carious lesion can be quite distressing and restorative treatment can cause an early dental anxiety to develop. Dental anxiety has knock-on effects for both dental professionals and patients. Treatment planning and therefore treatment success can be compromised. The dental staff can become stressed and frustrated when working with anxious children. This can compromise their relationship with the child and their parents. Studies have shown a cycle to exist, whereby dentally anxious patients avoid caring for the health of their oral tissues. They can sometimes avoid oral hygiene and will try to avoid seeking dental care until the pain is unbearable. Susceptibility to disease varies between individuals and immunological mechanisms have been proposed to confer protection or susceptibility to the disease. These mechanisms have yet to be fully elucidated but it seems that while antigen presenting cells are activated by S. mutans in vitro, they fail to respond in vivo. Immunological tolerance to S. mutans at the mucosal surface may make individuals more prone to colonisation with S. mutans and therefore increase susceptibility to dental caries. In children S. mutans is often acquired in the oral cavity subsequent to tooth eruption, but has also been detected in the oral cavity of predentate children. It is generally, but not exclusively, transmitted via vertical transmission from caregiver (generally the mother) to child. This can also commonly happen when the parent puts their lips to the child's bottle to taste it, or to clean the child's pacifier, then puts it into the child's mouth. Cardiovascular disease S. mutans is implicated in the pathogenesis of certain cardiovascular diseases, and is the most prevalent bacterial species detected in extirpated heart valve tissues, as well as in atheromatous plaques,