Thegosis--a critical review

Area of Science:

• Paleoanthropology
• Dental Morphology
• Behavioral Ecology

Background:

• Tooth modification can serve various functions, including mastication, defense, and social signaling.
• Previous research has explored tooth sharpening in different species, with varying conclusions regarding its purpose and mechanisms.

Purpose of the Study:

• To critically evaluate the evidence for tooth sharpening mechanisms, particularly those independent of masticatory function.
• To investigate the potential role of behavioral and social factors in anterior tooth sharpening.
• To clarify the relationship between stress-related tooth contact and the phenomenon of thegosis.

Main Methods:

• Systematic review of existing literature on tooth morphology and wear patterns.
• Analysis of comparative dental evidence across various species.
• Examination of behavioral observations related to tooth use and modification.

Main Results:

• No evidence supports a posterior tooth sharpening mechanism separate from masticatory function.
• Anterior tooth sharpening (thegosis) may occur in some species as a behavioral activity, potentially related to social contexts.
• Thegosis is not definitively linked to the development of new offensive weapons but may refine existing ones or aid in food manipulation.
• Stress-induced non-masticatory tooth contact, including excessive grinding and clenching, is recognized.
• Pathological thegosis and bruxism are proposed as synonymous terms for stress-related, non-masticatory tooth-to-tooth contact.

Conclusions:

• Tooth sharpening independent of mastication lacks empirical support.
• Thegosis, or anterior tooth sharpening, is a behavior potentially influenced by social dynamics and stress.
• Bruxism and pathological thegosis represent stress-induced tooth grinding and clenching.