Proper oral health care has an impact on the health of the entire body. The COVID-19 pandemic has affected the functioning of the healthcare sector, including dental services. The aim of this study was to analyse the behaviour of patients with regard to their use of dental services during the pandemic. The data were obtained from paper registration forms taken from five dental offices in the city of Cracow between March 2019 and February 2021. During the analysed periods, interest among first-time patients in dental services decreased to 37% (during the month when interest in dental services was at its lowest) compared to the year preceding the COVID-19 pandemic. The number of cancelled visits increased by between 15% and 50% compared to the pre-pandemic period. During the pandemic, appointments made by existing patients increased by up to 84% compared to 2019. The decision by patients to postpone dental treatment not only has adverse effects on their oral and body health, but in turn results in higher health care costs. Given the potential for another pandemic, further long-term research is required to develop and implement special protocols to make the public aware of the safety of health care.