Purpose: The aim of the present study was to assess the effectiveness of treating dental caries and degree of stress for junior residents toward the use of a full-body patient simulation system (SIMROID) compared to the conventional phantom.

 Methods: SIMROID, characterized by an elaborate appearance featuring artificial teeth with caries and facial expressions, was employed to introduce a simple scenario. Based on the concept of minimal intervention dentistry (MID), removal of caries, excavation of carious pits, removal of infected tooth substances, and the stress during caries removal (determined based on saliva α-amylase activities) were compared between the conventional phantom and SIMROID.

 Result: Of the 14 junior residents who could completely remove caries, 9 used the phantom (area of cavity outline: 8.55±2.24 mm²), and 6 employed SIMROID (area of cavity outline: 7.20±1.80 mm²) for cervical caries, demonstrating no significant difference in the area of cavity outlines between the phantom and SIMROID (p>0.05). The distal surfaces of the removed caries were 10.27±2.09 mm² for the phantom (7 residents) and 9.67±3.45 mm² for SIMROID (6 residents), demonstrating no significant difference (p>0.05). Saliva α-amylase activities were≥46 kU/l for both the conventional phantom and SIMROID. Of 14 junior residents, 8 had stress.

 Conclusion: Most junior residents could not remove caries in time and excavated carious pits larger than needed, probably because the time for caries removal was set to 10 minutes for both the conventional phantom and SIMROID. The questionnaire survey after training showed that training with SIMROID effectively ensured medical safety because it emphasized the importance of paying attention to the patient’s behavior under conditions similar to daily clinical practice.

 Purpose: Plaque control is the most important factor for preventing and treating periodontal disease. This study aimed to evaluate the plaque removal efficacy of a newly developed ionic toothbrush with soft rubber filaments as compared to that of a conventional manual toothbrush.

 Methods: Ionic or manual toothbrushes were randomly assigned to 30 healthy volunteers divided into two groups (Phase Ⅰ). After 2 min of brushing, all the tooth surfaces were stained with a plaque staining solution. Blinded examiners evaluated the remaining plaque using the Rustogi Modified Navy Plaque Index. As representative teeth, the plaque removal rate was calculated at the central incisors, first premolar, and first molar in the maxilla and mandible. As a crossover design, the same examinations using another toothbrush (Phase Ⅱ) were performed for all the subjects 1 week after Phase Ⅰ. A questionnaire survey was conducted to evaluate the patient-reported outcome measures.

 Results: Ionic toothbrushes were able to achieve a significantly higher plaque removal rate than control toothbrushes in the incisor and first premolar areas (p<0.05). No significant difference was observed in the first molar area. Compared to manual toothbrushes, the newly developed ionic toothbrushes were significantly more efficient, “refreshing”, “easy”, “comfortable”, and “giving slippery feeling” according to the answers provided in the questionnaire survey.

 Conclusion: Compared to manual toothbrushes, the newly developed ionic toothbrushes with soft rubber filaments were significantly more efficient in removing plaque from the incisor and first premolar areas.

 Purpose: Autotransplantation of non-functioning wisdom teeth is a viable and cost-effective treatment option for replacing compromised teeth, particularly in young patients where the transplanted teeth adapt to the growing maxilla or mandible. Furthermore, donor teeth with incomplete root formation or an open apex may remain vital after autotransplantation. This report describes the case of a seven-year follow-up of a young patient whose wisdom teeth with complete root formation were autotransplanted to the extraction sockets of two compromised first molars.

 Patient: A 19-year-old woman visited the dental clinic for dental caries treatment. Her two first molars, 36 and 46, suffered from severe subgingival caries. She had three wisdom teeth, 18, 28, and 48, which were non-functional due to the absence of 38 and the mesial inclination of 48. Due to the difficulty of extracting 48 without splitting, 18 and 28 were selected as donor teeth for autotransplantation into the extraction sockets of 46 and 36.

 Results: The severely compromised 46 was first extracted and replaced with 18. The severity of 36 was confirmed by removing the carious tissue and 36 was then replaced with 28. Based on radiographs, the cervical area of the transplanted tooth in 36 fitted well into the recipient socket, whereas 46 was small for the recipient socket, creating considerable space between the transplanted tooth and the mesial bone wall. The transplanted tooth in 46 did not react to the electronic pulp test two weeks after transplantation and was subjected to root canal treatment. In contrast, the transplanted tooth in 36 remained vital, requiring no endodontic treatment. When the temporary splints were removed three months after transplantation, no pathologic mobility was observed. The occlusal surfaces of the transplanted teeth were then adjusted by composite resin filling. At the 7-year follow-up, we observed no percussion pain, pathologic mobility, or discoloration on either transplanted tooth.

 Conclusion: Two severely compromised teeth, 36 and 46, of a 19-year-old woman were replaced with non-functional wisdom teeth, 28 and 18. At the 7-year follow-up, we observed no symptoms on either transplanted tooth. One transplanted tooth received root canal treatment, while the other remained vital. For young patients, endodontic treatment of transplanted teeth should be carefully considered with reference to the results of a pulp viability test, irrespective of a completely formed donor tooth root.

 Purpose: Several strategies exist for treating congenital defects of permanent teeth. One treatment strategy for children is tooth autotransplantation. Because the tooth roots of children are still developing and have wide apical foramens, endodontic treatment may be unnecessary following tooth autotransplantation. In addition, root growth can be expected if intact Hertwig’s epithelial root sheath is attached to the transplanted teeth. We report a case of congenital defects of permanent teeth, which were treated by autotransplantation of a tooth with incomplete root formation from a region lacking eruption space.

 Case: A 2-year-old girl was brought to the Takatsu Dental Clinic with the chief complaint of class Ⅲ malocclusion. A panoramic radiograph at the age of 5 revealed a congenital defect of four permanent teeth: 15, 24, 25, and 45. By the age of 7, her permanent teeth had begun to replace her deciduous molars. The root of 65 was resorbed, but there was no succedaneous permanent tooth. Coincidentally, there was insufficient eruption space for 34 and 35. Therefore, we planned to transplant 34 into the extraction socket of 65.

 Results: The deciduous molar 65 was extracted and the recipient socket was carefully prepared to avoid penetration into the maxillary sinus. Tooth 34 was then carefully extracted to avoid damaging the growing root and periodontal ligaments. Donor tooth 34 was positioned into the recipient socket and fixed with nylon thread. The root of tooth 34 was short and the pulp cavity was wide open at the time of transplantation. Three years after transplantation, the tooth root had developed into its regular length and the root apex had completed its development. The transplanted tooth was vital and had no percussion pain or discoloration.

 Conclusion: After transplantation of tooth 34 to extraction socket 65, the number of teeth in the upper and lower jaws filled in the left side, which solved the esthetic and functional problems of the patient. The tooth root developed into its regular length three years after the transplantation without any discomfort. This case shows that autotransplantation of a tooth with an incomplete root in the mixed dentition stage is an option for effectively treating congenital defects of permanent teeth.

 Introduction: The goal of endodontic treatment is to clean the root canal system as thoroughly as possible and to fill in all its dimensions. The main causes of endodontic failure are thought to be incomplete root canal obturation and untreated root canals. We report a rare case of five root canals in a maxillary first molar.

 Case report: A 23-year-old Japanese male was referred for root canal treatment of the maxillary left first molar. A pretreatment radiograph and cone-beam computed tomography (CBCT) were taken, and two root orifices were observed in the mesiobuccal root. In addition, root canal treatment was performed under dental microscope observation. The anatomy of the first maxillary molar was determined as follows: two canals in the mesiobuccal root, one canal in the distobuccal root and two separate canals in the palatal root with separate foramina. After cleaning and shaping of the second mesiobuccal canal and two separate canals in the palatal root, these canals were obturated by the lateral condensation method with gutta-percha and sealer.

 Results: Five years after treatment, the prognosis has been favorable, and no problem was found radiologically.

 Conclusion: Cone-beam computed tomography and a dental microscope seem to be useful for diagnosis and treatment in endodontic therapy.