Numerous writers have investigated the etiology of tori, but no consensus has emerged yet. Some of the speculated causes include genetics, environmental factors, masticatory hyperfunction and continued growth.^3-6

Torus palatinus (TP) and torus mandibularis (TM) tori prevalence varies with sample population, ranging from 0.4% to 66.5% and 0.5% to 63.4%, respectively. Racial differences seem to be considerable with a significant prevalence among Asian and Eskimo communities.^7,8 There have also been reports of gender-specific variations in tori prevalence. The majority of authors asserted that while TM presented more in men than women, TP mostly prevailed in women.⁹Table 2 provides a summary of some of the theories and mechanisms that might be involved in their formation.

Alveolar bone exostoses (ABE), also known as buttress bone formations, are benign, isolated, convex outgrowths of the buccal or lingual bone that may be distinguished from the surrounding cortical plate.⁶

Glickman and Smulow³⁵ distinguished between two categories of buccal alveolar bone enlargement: exostosis and lipping. Exostoses were described as harmless, isolated, convex outgrowths of the buccal or lingual bone that could be distinguished from the cortical plate around them. On the contrary, identifiable thickenings in the alveolar bone at the direct crestal edge were referred to as buccal lippings.⁶

ABE are multiple bony nodules that are found less often than tori. In contrast, Horning et al.,⁶ found ABE or lipping to be present fairly frequently, with 76.9% of all the specimens having at least one, in a study on 52 skulls with complete dentition.