The cause of nutritional deficiencies is either from decreased intake (i.e., a diet that lacks essential nutrients) or the inability to absorb the nutrients (i.e., gastrointestinal conditions such as celiac disease). Children are more at risk for serious complications due to nutritional deficiencies than adults. Nutritional deficiencies affect children of all socioeconomic backgrounds but are more frequently seen in children from economically disadvantaged families and in children with underlying systemic diseases.

In many cases, vitamin/nutrient deficiencies show intraoral manifestation. Although deficiencies can affect the teeth, periodontal tissues, as well as salivary glands, for the purpose of this atlas, we will limit the focus to the mucosal manifestations.