http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Mixed reality for extraction of maxillary mesiodens
Yu Koyama,Masahide Koyachi,Kotaro Tachizawa,Akira Iwasaki,Ichiro Wakita,Akihiro Nishiyama,Satoru Matsunaga,Akira Katakura,Keisuke Sugahara 대한악안면성형재건외과학회 2023 Maxillofacial Plastic Reconstructive Surgery Vol.45 No.-
Background Mesiodentes are the most common supernumerary teeth. The cause is not fully understood, although proliferations of genetic factors and the dental lamina have been implicated. Mesiodentes can cause delayed or ectopic eruption of permanent incisors, which can further alter occlusion and appearance. Careful attention should be paid to the position and direction of the mesiodentes because of possible damage to adjacent roots in the permanent dentition period, errant extraction in the deciduous and mixed dentition periods, and damage to the permanent tooth embryo. To avoid these complications, we applied mixed reality (MR) technology using the HoloLens® (Microsoft, California). In this study, we report on three cases of mesiodentes extraction under general anesthesia using MR technology. Results The patients ranged in age from 6 to 11 years, all three were boys, and the direction of eruption was inverted in all cases. The extraction approach was palatal in two cases and labial in one case. The average operative time was 32 min, and bleeding was minimal in all cases. No intraoperative or postoperative complications occurred. An image was shared preoperatively with all the surgeons using an actual situation model. Three surgeons used Microsoft Holo- Lens® during surgery, shared MR, and operated while superimposing the application image in the surgical field. Conclusions The procedure was performed safely; further development of MR surgery support systems in the future is suggested.
Kissing molars class III detected at a young age
Teruhide Hoshino,Yu Koyama,Akira Katakura 대한악안면성형재건외과학회 2023 Maxillofacial Plastic Reconstructive Surgery Vol.45 No.-
Background Kissing molars (KMs) is defined as a state in which the apex of two impacted molars face opposite directions and the occlusal surfaces touch each other and the crown is in one follicle. Class III KMs have been reported previously; however, reports on class III KMs in young people (< 18 years of age) are limited. Case presentation Here, we present the case of KMs class III confirmed at an early age, supported by a review of the literature. The patient was a 16-year-old female and experienced discomfort in the left molar of the lower jaw and visited in our department. We diagnosed KMs based on an impacted teeth on the buccal side, near the lower jaw wisdom teeth, and a cyst-like low-density area observed around the crown of both teeth, as revealed by computed tomography. We decide to extract the tooth and enucleate the cyst under local anesthesia as the patient experienced discomfort due to occlusion. Furthermore, the cyst-like structure removal and tooth extraction including tooth root were necessary as the patient had KM class III, possibly inducing complicated malocclusion. Although no previous reports recommended timing for KMs tooth extraction, we propose that extraction at an early stage is important regardless of age especially in class III cases. Conclusions We report a case of KM class III detected at an early age.
Keisuke Sugahara,Yu Koyama,Masahide Koyachi,Akira Watanabe,Kiyohiro Kasahara,Masayuki Takano,Akira Katakura 대한악안면성형재건외과학회 2022 Maxillofacial Plastic Reconstructive Surgery Vol.44 No.-
Background: Excessive bleeding is a major intraoperative risk associated with orthognathic surgery. This studyaimed to investigate the factors involved in massive bleeding during orthognathic surgeries so that safe surgeriescan be performed. Patients (n=213) diagnosed with jaw deformities and treated with bimaxillary orthognathicsurgery (Le Fort I osteotomy and bilateral sagittal split ramus osteotomy) in the Department of Oral andMaxillofacial Surgery at the Suidobashi Hospital, Tokyo Dental College between January 2014 and December 2016were included. Using the patients’ medical and operative records, the number of cases according to sex, age at thetime of surgery, body mass index (BMI), circulating blood volume, diagnosis of maxillary deformity, direction ofmaxillary movement, operative duration, incidence of bad split, injury of nasal mucosa, and blood type were analyzed. Results: The results revealed that BMI, circulating blood volume, nasal mucosal injury, and operative time wereassociated with the risk of intraoperative massive bleeding in orthognathic surgeries. Chi-square tests and binomiallogistic regression analyses showed significant differences in BMI, circulating blood volume, direction of maxillarymovement, operative duration, and injury to the nasal mucosa. Operative duration emerged as the most important riskfactor. Furthermore, a >4-mm upward migration of the posterior nasal spine predicted the risk of massive bleeding inorthognathic surgery. Conclusions: The upward movement of the maxilla should be recognized during the preoperative planning stage as arisk factor for intraoperative bleeding, and avoiding damage to the nasal mucosa should be considered a requirementfor surgeons to prevent massive bleeding during surgery
Tong Chen,Lihua Yu,Hongbo Ju,Junhua Xu,Shinji Koyama 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.4
A series of ZrN–Cu nano-composite films were deposited using the RF magnetron sputtering system. The microstructure, mechanical properties and tribological properties were investigated. The results showed that ZrN–Cu films were composed of face-centered cubice (fcc)-ZrN and face-centered cubic (fcc)-Cu. With the increase of Cu content, the hardness of ZrN–Cu composite film increased slowly first and then decreased rapidly. The maximum hardness value was 34.6 GPa at 16 at.% Cu. At room temperature, the coefficient of friction (Cof.) of ZrN–Cu films were lower than the ZrN film. When the content of Cu was lower than 39 at.%, the wear rate of ZrN–Cu films were lower than the ZrN film. When the temperature of tribological testing was between 200–700 ℃, the Cof. of ZrN–Cu films at 16 at.% Cu were lower than ZrN film, while the wear rates were higher than the ZrN film. In summary, the addition of Cu improved the hardness and tribological properties of the ZrN–Cu film at room temperature, and decreased the Cof. of the ZrN-Cu during 200–700 ℃.
Novel condylar repositioning method for 3D-printed models
Sugahara, Keisuke,Katsumi, Yoshiharu,Koyachi, Masahide,Koyama, Yu,Matsunaga, Satoru,Odaka, Kento,Abe, Shinichi,Takano, Masayuki,Katakura, Akira Korean Association of Maxillofacial Plastic and Re 2018 Maxillofacial Plastic Reconstructive Surgery Vol.40 No.-
Background: Along with the advances in technology of three-dimensional (3D) printer, it became a possible to make more precise patient-specific 3D model in the various fields including oral and maxillofacial surgery. When creating 3D models of the mandible and maxilla, it is easier to make a single unit with a fused temporomandibular joint, though this results in poor operability of the model. However, while models created with a separate mandible and maxilla have operability, it can be difficult to fully restore the position of the condylar after simulation. The purpose of this study is to introduce and asses the novel condylar repositioning method in 3D model preoperational simulation. Methods: Our novel condylar repositioning method is simple to apply two irregularities in 3D models. Three oral surgeons measured and evaluated one linear distance and two angles in 3D models. Results: This study included two patients who underwent sagittal split ramus osteotomy (SSRO) and two benign tumor patients who underwent segmental mandibulectomy and immediate reconstruction. For each SSRO case, the mandibular condyles were designed to be convex and the glenoid cavities were designed to be concave. For the benign tumor cases, the margins on the resection side, including the joint portions, were designed to be convex, and the resection margin was designed to be concave. The distance from the mandibular ramus to the tip of the maxillary canine, the angle created by joining the inferior edge of the orbit to the tip of the maxillary canine and the ramus, the angle created by the lines from the base of the mentum to the endpoint of the condyle, and the angle between the most lateral point of the condyle and the most medial point of the condyle were measured before and after simulations. Near-complete matches were observed for all items measured before and after model simulations of surgery in all jaw deformity and reconstruction cases. Conclusions: We demonstrated that 3D models manufactured using our method can be applied to simulations and fully restore the position of the condyle without the need for special devices.
Yasuda Tatsuya,Togawa Daisuke,Hasegawa Tomohiko,Yamato Yu,Kobayashi Sho,Yoshida Go,Banno Tomohiro,Arima Hideyuki,Oe Shin,Hoshino Hironobu,Koyama Hiroshi,Hanada Mitsuru,Imada Takayuki,Matsuyama Yukihir 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.4
Study Design: Large cohort study of volunteers.Purpose: The purpose of this study was to investigate the relationship between the severity of knee osteoarthritis, assessed using the Kellgren-Lawrence (KL) grading scale, and spinopelvic sagittal alignment in older adult volunteers.Overview of Literature: The relationship between spinopelvic alignment in the sagittal plane and knee osteoarthritis in the coronal plane is unclear.Methods: Volunteers over 50 years of age underwent radiographic analysis. Radiographic parameters including pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), thoracic kyphosis, and sagittal vertical axis (SVA) were measured. The the three Scoliosis Research Society-Schwab sagittal modifiers (PT, SVA, I–LL) were categorized and the KL grade was assessed. Differences in spinopelvic parameters and Oswestry Disability Index (ODI) scores among KL grades were evaluated.Results: A total of 396 volunteers (160 men, 236 women; mean age, 74.4 years) were analyzed. PI–LL and PT in KL4 were significantly higher compared to that in the other KL grades. However, there were no significant group differences in SVA. In women, but not in men, higher frequencies of the worst modifier grade (++) were observed for PI–LL and PT in the KL3 and KL4 groups compared to those for the other KL grades. In women, the ODI score in KL4 was worse compared to that in the other KL grades.Conclusions: Individuals over 50 years of age with severe knee osteoarthritis had poor lumbo-pelvic sagittal alignment. Moreover, the progression severity of knee osteoarthritis had more impact onstronger relationship with lumbo-pelvic malalignment and disability-related low back pain in women than in men.