The coronavirus disease 2019 (COVID-19) is a major public health problem. Dental and oral surgical procedures that generate aerosols are considered to have a high infection risk. However, few studies have reported COVID-19 clusters in dental and oral surgical care settings; therefore, with the aim of understanding the infection situation in actual dental and oral surgical care settings during the COVID-19 epidemic, we conducted a questionnaire survey on infection control measures and infection status in dental and oral surgery practice. The results showed that the risk of spread of COVID-19 infection through dental and oral surgical care is very low. However, there is no doubt that the risk of infection exists in dental and oral surgical procedures involving saliva and other materials. The results of this study indicate that infection risk in dental and oral surgical practice can be avoided if the epidemic situation is correctly judged and appropriate measures (screening, triage, infection control, avoidance of close contact, and health care of medical staff) are taken. Correctly identifying the COVID-19 infection status in this study will be important not only for measures to prevent the spread of new infections in the future, but also to avoid the health consequences of withholding or refusing medical treatment based on inaccurate information.

There is an urgent need to examine the risk of infection from aerosols generated during dental treatment and to review infection control. However, existing research on aerosol particles associated with dental treatment is by no means sufficient, and little research has been done on the details of aerosol particle generation in the clinical environment, the mechanisms, and patterns of distribution in open and closed spaces, the time they are suspended in the air, the amount and size of particles present. Therefore, to minimize the influence of background particles, laser beams, a high-sensitivity camera, and a particle counter were used in a large super-clean laboratory (SCL) to investigate the dynamics of aerosols generated during dental micromotor operation. The large number of aerosol particles generated by the use of the micro-engine rose rapidly within 30 seconds and were suspended in the room atmosphere. Within a 100 cm radius of the user, the scattering peaked at about 90 seconds. The particles were further diffused into the room with the passage of time, reaching a maximum at 210 seconds and gradually decreasing thereafter, confirming that the 4 x 4 m room had returned to equilibrium. The experiment was conducted under sealed conditions in the SCL without the use of any suction device inside or outside the oral cavity. Although the conditions did not faithfully reproduce the actual conditions in a dental clinic, we were able to obtain groundbreaking results that demonstrated for the first time the scattering of fine particles, eliminating various possible complications in the background. At present, our knowledge of the infectivity of COVID-19 from patients' oral cavity and saliva is still insufficient, and further studies and information are needed.

We report three cases of recurrent oral cancer with carotid blowout syndrome (CBS). In case 1, the recurrent tumor reduced in size during chemoradiotherapy. As a result, the external carotid artery was exposed in the oral cavity and ruptured. The patient was treated via embolization in the external carotid artery. In case 2, the recurrent tumor markedly reduced in size during chemotherapy, resulting in exposure of the internal carotid artery in the skin fistula posterior to the auricle. The exposed artery was prophylactically treated by embolization. In case 3, the internal carotid artery was ruptured due to recurrent tumor invasion and wound infection. The patient presented massive hemorrhage and was treated with stent placement on an emergency basis. The surgical site was covered by a pectoralis major myocutaneous flap. The frequency of treatment for progressive and recurrent oral cancers has been increasing due to progress in medical technology and chemotherapy. A multidisciplinary team approach should always be available for emergencies, including potentially fatal complications such as carotid system hemorrhage.