Anomalies of Tooth Structure
Alterations in the Size of Teeth

Tooth size is variable among racial groups and between genders.^7,9 Generally speaking, males have larger teeth than females.^7,9 Both genetic and environmental factors can impact the size of the developing teeth.⁷ Microdontia is the term used for teeth that are smaller than normal while macrodontia is the presence of teeth that are larger than usual.^7,9,10 Typically, these conditions do not affect the entire dentition.⁹

Microdontia
In microdontia, the teeth are visibly smaller and may have an altered shape.⁷ Supernumerary teeth may present as microdonts as well.⁹ The maxillary lateral incisor tooth (Figure 26) is the most frequently involved and typically demonstrates a peg-shaped crown.^7,9,10 Microdontia is associated with hypodontia and occurs more frequently in females.⁷ Third molar teeth are often affected by microdontia as seen in Figure 27.⁹ Of note, these same teeth are often congenitally missing.

Macrodontia
Macrodontia is sometimes called megalodontia or megadontia.^7,9,10 Macrodont teeth appear larger and may be associated with crowding, malocclusion, or impaction.⁹ Often a single tooth or several teeth are involved rather than affecting the entire dentition.⁷ Macrodontia is associated with hyperdontia and occurs more frequently in males.⁷ Macrodontia tends to occur in incisor or canine teeth but may also occur in second premolars and third molars.⁷ Macrodontia terminology should not be applied to teeth that have been altered by gemination or fusion processes which will be discussed next.⁷