A 30-year-old female patient presented with swelling and discomfort in the region of the upper right incisors. She underwent root canal treatment on #11 and #12 at a private dental clinic; however, the condition persisted. Cone-beam computed tomography (CT) was performed for proper diagnosis. CT showed resorption of the upper labial and lingual cortical bone. The patient was referred to the hospital attached to Nihon University School of Dentistry at Matsudo. The teeth were root canal treated under a microscope. Calcium hydroxide was applied to the resorbed apical foramen. Gradually, the patient’s symptoms disappeared, and the apical foramen calcified. Finally, cortical bone was recovered, and the periapical lesion disappeared. The conditions were confirmed using three-dimensional (3D) CT. CT and microscope are useful for endodontic therapy, especially in persistent periapical lesions.

We report a case in which a piece of a file that had broken inside the root canal as a result of inappropriate device manipulation by a dentist and was protruding through the apical foramen into the maxillary sinus was removed non-surgically under microscopic guidance via the root canal, and a good treatment outcome was achieved.

The patient was a 36-year-old woman. A dental X-ray showed an opacity caused by a broken instrument projecting from the apical foramen of the maxillary left second premolar. Computed tomography (CT) showed that most of the broken piece was located in the left maxillary sinus, and that the mucosae of this sinus were hypertrophic around the apical foramen of the maxillary left second premolar. As only a small part of the broken piece remained within the root canal, we began root canal treatment after explaining to the patient that there was a possibility that the broken piece might come free in the maxillary sinus and that if this happened then surgery under general anesthesia would be required, and obtaining her consent. A MICROFILE Type-H fitted with an ENDOHOLDER was used under microscopic guidance to remove the broken piece by rotating it anticlockwise (as the microscope generated a mirror image, the rotation appeared to be clockwise) to loosen it. An ultrasound tip was not used out of concern that it might cause the broken piece to come free in the maxillary sinus. After the broken piece had been removed, the damaged apical foramen was plugged with calcium hydroxide–distilled water paste, and the root canal was filled after the apex had become calcified.

In this case, CT simulation before the procedure and manipulation under microscopically guided visual observation enabled the broken piece to be removed non-surgically via the root canal, and a good treatment outcome was achieved.

Perforation repair was considered to be an unpredictable treatment in the past. Recently, new techniques and materials like Mineral Trioxide Aggregate (MTA) are being successfully used to repair perforations. The introduction of the dental operating microscope into clinical practice has enabled more precise and predictable treatment of teeth and dental pulp. Advanced approaches, such as the use of a dental microscope, have improved the outcome of perforation repair procedures. This article presents the significance of microscopic perforation repair therapy, and discusses the latest literature on use of MTA and the dental microscope.

If the conditions are appropriate, the success rate of perforation repair when using a dental microscope and MTA is predicted to be 70% to 90%. The dental microscope has proven to be useful for detection, confirmation, diagnosis, and especially repair of perforations.

A patient referred with a suspected temporomandibular disorder was examined. Initial temporomandibular symptoms and pain subsided with normal dental treatment. However, over time, the patient began to develop trigeminal neuralgia-like symptoms. Typical symptoms appeared after about 1 year, and trigeminal neuralgia was eventually diagnosed. Surgery was performed at a neurosurgery department, leading to recovery. The initial symptoms in this case were pre-trigeminal neuralgia, the precursor to trigeminal neuralgia.

Human extracted teeth are often used by students for basic endodontic training. However, recent advances in endodontic and periodontal treatment have made it difficult to obtain extracted teeth from general practitioners. Therefore, we developed a dental model and artificial teeth for basic endodontic training. A microscope was also used to evaluate students’ work as it is difficult to assess intracanal work with the naked eye. The purpose of this study was to examine the benefits of practical training using a dental model and artificial teeth under microscopic observation. In 2012 and 2013, third-year students performed root canal treatment using artificial teeth. We examined the remaining infected dentin indicated by discoloration, the external form of the access opening, excessive preparation, the perforation rate and the root canal filling. Two microscopes were available for training, but students only used them when they needed to check the condition of their artificial teeth in 2012. Instructors checked every step in the artificial tooth preparation under a microscope for each student in 2013. As a result, there was a decrease in the remainder rate of discoloration in 2013 compared to 2012. Specifically, it decreased from 67.2% to 49.6% in the apical third of the buccal root canal and from 55.2% to 41.5% in the palatal root canal. There was a decrease in excessive preparation in 2013 compared to 2012. Evaluations of good preparation increased approximately 2 times. The perforation rate was 41.2% in 2012 and decreased to 19.4% in 2013. The occurrence of over filling in the buccal root canal was lower in 2013 than in 2012. However, good fillings did not increase. There was a clear decrease of over filling in the palatal root canal, and good filling increased from 8.6% to 30.6%. Therefore, the use of a microscope was effective for basic endodontic training in students.