Key facts Worldwide, 60–90% of school children and nearly 100% of adults have dental cavities. Dental cavities can be prevented by maintaining a constant low level of fluoride in the oral cavity. Severe periodontal (gum) disease, which may result in tooth loss, is found in 15–20% of middle-aged (35-44 years) adults. Globally, about 30% of people aged 65–74 have no natural teeth. Oral disease in c