Amalgam has been used as the standard material for filling cavities in posterior teeth for over a century. However, there is growing concern over the use of amalgam restorations due to the possible release of mercury into the body. Therefore, clinicians are increasingly choosing resin composites for esthetic restorations as an alternative to amalgam. However, it remains difficult to reconstruct the individual tooth shape and achieve functional and individual occlusion while working in the oral cavity. In addition, both the accuracy of the reconstructed tooth shape and the risk of secondary caries are known to be significantly affected by the skill of the clinician. Therefore, we have devised a novel technique to achieve the treatment goal of reconstructing the individual tooth shape and improve outcomes. All the procedures involved in this technique are performed using a microscope. Dental microscopy greatly improves both anatomical precision and hermetic sealing; consequently, it may help maintain the long-term stability of treated teeth.

A patient was referred for endodontic treatment in a mandibular premolar and a diagnosis of Pulpal Necrosis with Asymptomatic Periradicular Periodontitis was formulated. Preoperative radiographs revealed a complex root outline along with periapical pathosis. Laser-assisted endodontic treatment was rendered within an unusually rare root canal configuration.

A patient was referred to our department complaining of the appearance and persistence of occlusal and percussion pain after pulp extirpation, with X-rays showing a radiopacity protruding from the apical foramen. Panoramic and dental X-rays showed a foreign body, and the fracture surface of a broken instrument was visible in the apical one-third of the mesiobuccal root under microscopy. However, the broken piece was firmly wedged. Computed tomography showed that it extended close to the maxillary sinus floor. The fracture surface of the foreign object in the root canal was subjected to ultrasound vibration under rubber dam isolation, and on the third visit, it became possible to move it, after which it was grasped with a stainless-steel wire loop and removed under traction. Lateral condensation root canal filling was then performed, and the patient’s subsequent course has been uneventful.

Breakage of an instrument inside a root canal is an accident that can occur in endodontics, and removal of the broken instrument is essential in order to carry out appropriate root canal treatment. Combined use of a microscope and ultrasonics is useful as a removal method. If ultrasonic vibrations are applied to the broken instrument under microscopic observation, it can be seen that the grip of the broken instrument inside the root canal becomes weakened until it eventually jumps up and stays on the floor of the pulp chamber. In such cases, use of a magnetic tool rather than forceps to lift out the broken instrument is simple and convenient. In the two cases reported here, broken instruments were found in the lower right second molar and upper right lateral incisor, where root canal treatment had been carried out. Ultrasonic vibration was applied to the broken segments, which were then lifted out by magnetic force. Root canal treatment was subsequently continued. Following root canal filling and prosthetic placement, the patients’ progress was favorable.

Distinguishing between odontogenic and rhinogenic maxillary sinusitis is still not an easy task. It is also not uncommon to make a quick decision to treat suspected odontogenic sinusitis by extraction, based on factors such as the size of the radiolucency. A case of a patient diagnosed with rhinogenic sinusitis who did not respond to drug treatment or endoscopic sinus surgery at an ear, nose, and throat clinic, but who recovered well after root canal treatment of the right first premolar using mineral trioxide aggregate under microscopic observation is reported.

A patient was referred for endodontic treatment in a mandibular molar. A diagnosis of Previously Initiated Endodontic Treatment with Asymptomatic Periradicular Periodontitis was confirmed. Preoperative digital imaging revealed a complex root canal anatomy as well as periradicular pathossis. Endodontic treatment was recommended and completed in conjunction with adjunctive laser therapy.