Thyroid gland dysfunctions, particularly hyperthyroidism and hypothyroidism, can cause systemic alterations such as hypertension, anxiety, and bone changes, as well as oral manifestations including salivary alterations, increased periodontal disease, and dental caries. It is of utmost importance for the dentist to be vigilant about these changes, considering that a decompensated patient cannot be treated, and medications can also interfere with oral microbiota, respecting each patient’s limitations. Thus, the objective of this study is to investigate the influence of hyperthyroidism and hypothyroidism on the oral cavity through a literature review from 2018 to 2023. Articles, monographs, dissertations, books, and websites discussing the correlation between thyroid dysfunctions and dentistry were selected. The 30 references found were thoroughly read, but only 26 were directly related to the proposed theme. Conclusion: The dentist is one of the professionals capable of identifying the initial signs and symptoms of the disease, highlighting the importance of a thorough medical history. Further studies on this topic are necessary to consolidate the results found in the literature.