Burning mouth syndrome (BMS) is a burning sensation that occurs in the mouth without any underlying cause. There is no satisfactory treatment for BMS, so far. Herein, we report the case of a 74-year-old female with untreated depression who presented with BMS. Despite taking antidepressants, she developed suicidal thoughts, particularly due to the increasing number of coronavirus disease 2019 (COVID-19) cases and suicides in Japan. The symptoms of BMS and the oral discomfort were eliminated using a multifaceted approach, which included the following: continuous application of the oral care gel "REFRECARE-H®" to the mucous membranes, regular dental visits, collaboration with medical and dental professionals, and administration of zinc preparations. Her suicidal thoughts had disappeared, and her quality of life, assessed using the visual analogue scale, was improved following the treatment. Dentists should strive to provide oral care, while providing treatment in collaboration with specialists, for the early detection of depression and zinc deficiency in patients with BMS.