Which of the following is not a typical feature of Down's syndrome?

Severe caries but minimal periodontal disease is not a typical feature of Down's syndrome. Individuals with Down's syndrome often present with specific dental and oral health issues. Although they may experience dental caries, studies and clinical observations indicate they usually have a higher prevalence of periodontal disease compared to caries. This is attributed to several factors, including anatomical differences in the mouth, an increased tendency for gum disease, and challenges in maintaining proper oral hygiene.

In contrast, the other options reflect more common characteristics associated with Down's syndrome. For instance, individuals with this condition are often noted to have multiple immunodeficiencies, leading to a higher susceptibility to infections. The presence of multiple missing teeth and malocclusion is also a frequent observation due to the development of dental irregularities and differences in jaw size and shape. These aspects all contribute to the overall dental health profile observed in people with Down's syndrome.