Effects of tooth loss on anxiety‐like behaviors in Heterocephalus glaber

Abstract

Tooth loss is an ailment affecting a large percentage of the population, particularly individuals of lower socioeconomic status and the elderly. Extensive tooth loss is known to result in anatomical changes in the face, including atrophy of masticatory muscles and decreases in mandibular and maxillary bone density, as well as volumetric changes within the brain. Human studies have reported strong correlations between tooth loss and levels of both anxiety and depression. However, little has been reported to date regarding the effect of dental health on emotional states, with only sparse information available from animal models regarding the psychiatric effects of tooth loss.Our study investigated the short‐term effects of tooth loss on anxiety‐like behaviors using Heterocephalus glaber, an animal with extensive sensory dedication to and behavioral reliance on its incisors. Adult naked mole‐rats underwent either tooth extraction or sham surgeries, followed by testing in both an open field maze and elevated plus maze in the weeks following. As there are no known studies to date that have utilized this animal model in behavioral tests of anxiety, our study provides critical information about the methodologies and modifications necessary to ascertain these important translational behavioral states so that future researchers can apply similar tests in other fields such as neurodegeneration, aging, and oncology.We hypothesized that tooth extraction will result in greater anxiety‐like behaviors, manifesting in various ways: greater defecation in the mazes, more time spent in the outer regions of the open field maze, and less time in the open arms of the elevated plus maze. The study demonstrated a trend towards tooth extraction increasing anxiety‐like behaviors in naked mole‐rats when investigated using the open field maze paradigm. There is evidence that, with an increase in sample sizes, this research will make evident the causal relationship of tooth loss and anxiety. Future research will investigate the long‐term behavioral changes associated with extensive tooth loss and the neurocircuitry associated with these behavioral alterations. Uncovering these details will provide potential therapeutic targets for negating the mental health difficulties associated with deficits in dental health.