The process of sharpening teeth by grinding one anterior tooth against another to create wear facets. In some mammals it keeps the teeth sharply honed for use as weapons. It has been suggested that this is a biological process and that pathological thegosis, predominantly in response to stress, is synonymous with bruxism.
Murray C. G., Sanson G. D. Thegosis—A critical review. Australian Dental Journal 1998;43(3):192–8.