Sugar

Free sugars are the essential dietary factor in the development of dental caries because dental caries does not occur in the absence of dietary sugars. Dental caries develops when bacteria in the mouth metabolize sugars to produce acid that demineralizes the hard tissues of the teeth (enamel and dentine). WHO guidelines recommends adults and children to reduce their daily intake of free sugars to less than 10% of their total energy intake.

Tobacco

Tobacco use is a major preventable cause of premature death and of several general diseases. In addition, cigarette, pipe, cigar and bidi smoking, betel quid chewing (pan), guhtka use and other traditional forms of tobacco have several effects in the mouth. Tobacco is a risk factor for oral cancer, oral cancer recurrence, adult periodontal diseases and congenital defects such as cleft lip and palate in children. Tobacco suppresses the immune system's response to oral infection, compromises healing following oral surgical and accidental wounding, promotes periodontal degeneration in diabetics and adversely affects the cardiovascular system. Moreover, tobacco greatly increases the risk when used in combination with alcohol or areca nut. Most oral consequences of tobacco use impair quality of life be they as simple as halitosis, as complex as oral birth defects, as common as periodontal disease or as troublesome as complications during wound healing.

Prevalence of tobacco use has declined in some high-income countries but continues to increase in low- and middle-income countries, especially among young people and women. Undoubtedly, the increasing number of smokers and smokeless tobacco users among young people in different areas of the world will considerably affect the general and oral health of future generations. The prevalence of tobacco use in most countries is the highest amongst people of low educational background and among the poor and marginalized people.