Surgical microscope was reported to have been first used in ear surgery in 1921. Dental operating microscope (DOM) was created in 1978 and incorporated into dental treatment. Today, DOM are an important tool in endodontics. DOM are in use in Japanese dental hospitals, and their rate of use in clinical practices is increasing each year. However, few studies have addressed teaching about DOM in Japanese universities with dental schools. A comparison of the results of previous studies of DOM education in endodontics in universities with dental schools conducted in 2008 and 2012 showed that it had become more widespread in 2012. However, DOM education was not provided in all universities with dental schools. In the present study, conducted in 2022, it was found that all universities with dental schools were offering lectures on DOM and using them in clinical practice. However, fewer universities were using DOM in preclinical practices for reasons of cost and installation condition.

The difficulty of root canal treatment in the mandibular first molars is related to the complexity of their root canal structure. Therefore, knowledge of root and root canal anatomy is important. In this study, the mesial and distal root canal morphologies were analyzed based on Vertucci’s classification. In addition, distolingual root (DLR) may occur as a variation of mandibular first molars. Distolingual (DL) root canals exhibit a severe buccal curve. Curved root canals may be a cause of root canal treatment failure. Ways to prevent root canal treatment failure were investigated by analyzing the frequency of DLR prevalence and the curvature of DL root canals. The DLR frequency was approximately 30% in both male and female. The DLR frequency in the Japanese population was found to be close to that of the Sinodonty in the Mongoloid populations, indicating a high frequency. Mesial root canals were most frequently type 4, whereas distal, distobuccal (DB), and DL root canals were most frequently type 1, similar to those in other studies. There was a significant difference in the incidence of type 1 between distal and DB, distal and DL root canal in both males and females. When a DLR was present, DB and DL root canals were thought to simplify to one root canal (type 1). The angles measured by Schneider’s method were close to the results of other studies in both males and females. However, the angles and radii measured by Pruett’s method were smaller than the results of other studies, suggesting that the DLR of the Japanese population may have a severe curve. Therefore, it was suggested that root canal treatment of DLR should be performed with caution.

Currently, the NiTi rotary file is recognized as an important instrument in endodontics because of its various advantages. The reason why dentists do not adopt NiTi rotary files in their clinical practices may be due to a lack of education and experience with NiTi rotary files. Therefore, a survey of the current status of education about endodontics and NiTi rotary files was conducted in Japan. Questionnaires were sent to the endodontic departments of 29 Japanese universities with dental schools. The response rate to the questionnaire was 93.1% (27/29). Preclinical lectures time was more than twice as long as in other countries with regard to endodontics, and preclinical practices was about the same or longer. The staff-student ratio averaged 1:9.8, similar to other countries. These results suggest that Japan places more emphasis on endodontic education than other countries. In terms of NiTi rotary file education, preclinical lectures on NiTi rotary files were given at most universities, and preclinical practices was also provided in the majority of universities (20/23). This was because NiTi rotary files were used in clinical practices at all but one university, and the purpose was to smooth the transition to clinical education by creating an environment in which students could use NiTi rotary files during their preclinical practices. However, only 11.1% of the universities allowed students to use NiTi rotary files on patients during clinical education. We believe that more opportunities should be provided for students to use NiTi rotary files in clinical education. In doing so, staff should select cases using the endodontic case difficulty assessment form published by the American Association of Endodontists to prevent errors during root canal formation.

There are still few reports on the use of microscopes in implant dentistry (1-4). In this paper, the author reported the usefulness of the microscope through case in which the microscope was used throughout the entire process from preoperative examination, implant placement, prosthetic procedures, maintenance, and troubleshooting.

This paper discusses the use of microscopes in basic periodontal treatment to improve accuracy and patient understanding through a case. The new classification of periodontal diseases and conditions is useful for diagnosis, risk assessment, and treatment planning. The microscope plays three roles in basic periodontal treatment: treatment under magnification, documentation with video and still images, and presentation to the patient. The paper explains the importance of each step of basic periodontal treatment, from medical interview to scaling and root planning, and how the microscope can aid in each step. The paper also discusses the effectiveness of ultrasonic scalers versus manual scalers in scaling and root planning. The use of a microscope in basic periodontal treatment allows for highly accurate treatment.

Due to the declared state of emergency caused by the spread of COVID-19, the university was forced to implement a web-based distance learning course instead of the traditional face-to-face lecture format. In the previous practice sessions of this course, the instructor gave practical demonstrations, but it was often difficult for the students to see the instructor's hand, which made it difficult for the instructor to present the lecture to the students. For this reason, we created video materials with a magnified field of view by applying a dental microscope. We conducted a questionnaire survey without names at the end of each practical training in the academic years 2021 and 2022 to examine the learning effects of the teaching materials and obtained some findings. When conducting crown and bridge prosthetics training, it was possible to conduct the training without a demonstration by the instructor, which had been conducted in the past, by distributing a demonstration video. This enabled us to reduce the risk of infection by preventing the crowding of students in the covid-19 pandemic, and to establish a new form of practical training. It was suggested that the microscope-applied magnification was significant as a practical training material for students.