Teeth don't vary in size a great deal from person to person or mouth to mouth. And what constitutes a "large" tooth in one individual is relative only to how the size of the teeth compare to the teeth in the same mouth. For example, an oversized tooth will be obvious next to teeth of "normal" size. Macrodontia is characterized more by how many teeth and where they appear than by norms of measurement. Cases documenting large teeth represent a range of sizes from small child to adult. The main types of macrodontia include the following:
- Localized or regional macrodontia -- One tooth or single teeth in one location or on one side of the mouth is larger than others, but otherwise normal in every other way.
- True generalized or diffuse macrodontia -- A very rare form where all teeth in the mouth are larger than what would be considered normal for a person's mouth.
- Relative generalized macrodontia -- Teeth may be normal size or slightly larger than normal but appear very large due to the small size of a person's jaw. This is not true macrodontia, but is relative to jaw size and gives the appearance of macrodontia [sources: Cameron and Widmer; Langland, et al.; NIH].
Some tooth or facial irregularities give the appearance of or are similar to macrodontia, such as micrognathia, which is the presence of normal-sized teeth in a small jaw. With micrognathia, however, the jaws are often too small to accommodate the teeth, which is rarely the main issue with macrodontia. Another condition that can mimic or give the appearance of macrodontia is fusion, or gemination. While macrodontia is the development of an oversized tooth, fusion is when two teeth grow together into one large tooth formation. It is a growth irregularity of more than one tooth [source: Cameron and Widmer].
Are there any similarities in people who experience the irregularity of large teeth? We'll look outside the mouth for some clues to who may develop macrodontia, next.