From 2020, medical practices have been severely restricted owing to the influence of COVID-19 worldwide. Recently, it was proposed by the International Society for Experimental Microsurgery and International Microsurgery Simulation Society that the COVID-19 pandemic and restriction measures applied have significantly impacted medical education and mandated the development of new approaches based on the remote educational system.1 Remote diagnostic methods that allow patients to receive expert diagnosis without directly visiting a specialised medical institution are also gaining attention.
Co-authors Kobayashi et al. developed an 8K ultrahigh-definition video system and developed and reported the Micro 8, which enables lymphatic anastomosis with a 0.1-mm-diameter super-resolution microscope.2 The mechanism has the function of obtaining pseudo 3D through the drop shadow effect created by the ultrahigh definition and deepening the depth of focus by tilting the firing axis.3 In the future, as a heads-up surgery whilst looking at a wide-area screen, it has the potential for broad clinical use in the same way as conventional microscopes.
From these urgent backgrounds, we are establishing a new attempt to use the aforementioned ultrahigh-definition video microscope for the specialised diagnosis of oral diseases. The patient consults a general dentist (Figure 1A) and transmits the 8K image in 5G to obtain a specialist’s diagnosis and treatment policy (Figure 1B). The 8K ultrahigh-definition microscope can project an object thinner than hair. As such, it allows detailed diagnosis to be done remotely for cases that require a microscope or magnifying glass even in clinical practice, such as determining small caries and cracks in the teeth, initial inflammation around the periodontal pocket, oral mucosal diseases such as stomatitis, degree of malignancy of oral cancer and observation of prognosis. Combined with the development of 5G and further communication, it can be expected to contribute to quick and accurate diagnosis.

(A) Acquisition of images in the general dental examination room. (B) 8K ultrahigh-definition imaging diagnosis by a specialist in a remote location
Since the transmission of images from this ultrahigh-definition video microscope remains subject to time lag, its application to telemedicine requires further improvement of the image transmission system and robotic surgery.
Acknowledgements
The authors would like to thank Mr. Hiroyuki Takagi, Ms. Miyuki Imai and Dr. Hiromasa Yamashita of AIR WATER BIODESIGN INC. for their assistance.
Conflict of interest
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Eiji Kobayashi is one of the inventors of 8K ultrahigh-definition video system (Micro 8). Hiromasa Kawana and Seiji Asoda declare that there is no conflict of interest.