Some brands of smokeless tobacco contain high sugar content, increasing susceptibility to caries. Tobacco use is a significant risk factor for periodontal disease, which can cause the gingiva to recede. As the gingiva loses attachment to the teeth due to gingival recession, the root surface becomes more visible in the mouth. If this occurs, root caries is a concern since the cementum covering the roots of teeth is more easily demineralized by acids than enamel. Currently, there is not enough evidence to support a causal relationship between smoking and coronal caries, but evidence does suggest a relationship between smoking and root-surface caries. Exposure of children to secondhand tobacco smoke is associated with tooth decay.Intrauterine and neonatal lead exposure promote tooth decay. Besides lead, all atoms with electrical charge and ionic radius similar to bivalent calcium,
such as cadmium, mimic the calcium ion and therefore exposure to them may promote tooth decay.Poverty is also a significant social determinant for oral health. Dental caries have been linked with lower socio-economic status and can be considered a disease of poverty.Forms are available for risk assessment for caries when treating dental cases; this system using the evidence-based Caries Management by Risk Assessment (CAMBRA). It is still unknown if the identification of high-risk individuals can lead to more effective long-term patient management that prevents caries initiation and arrests or reverses the progression of lesions.Saliva also contains iodine and EGF. EGF results effective in cellular proliferation, differentiation and survival.
The age of those with AK ranged from 8 to 82 years old and 58% of the people were female. The data showed that 89% of the infected patients were contact lens wearers, almost all cases occurred only in one eye, and 19% required a corneal transplant. References
Shandilya VK, Parmar LD, Shandilya AV. Functional ambulation with bent knee prostheses for an adult with bilateral 90 degrees knee flexion contractures—A case report. J Family Med Prim Care [serial online] 2020 [cited 2020 Jun 2];9:2492-5. Available from: Journal of Family Medicine and Primary Care

External links
Acanthamoeba keratitis - Centers for Disease Control and Prevention
Picture reference of the life cycle of Acanthamoeba