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Background/aim Road traffic accidents (RTAs) are a common cause of maxillofacial injuries. The aim of this retrospective multicentre study was to investigate the characteristics of maxillofacial fractures and dental injuries that occurred in RTAs in Miyagi, Japan. Materials and methods The records of 404 patients with maxillofacial injuries treated at the Oral and Maxillofacial Surgery Departments of four different institutions over a period of 12 years were analysed. Ninety-nine of these patients had suffered these injuries in an RTA. RTA-related cases were divided according to age, gender, presentation month, presentation day of the week, transportation mode, time of accident, fracture sites and fracture mechanism. Results There were 72 males and 27 females who suffered injuries as the result of an RTA, for a male-to-female ratio of 2.7:1.0, with a mean age of 35.3 years (range, 1-86 years old). Most of the accidents occurred in June and on a Wednesday, and most of the affected patients were riding a bicycle at the time. The number of patients with maxillofacial injuries related to bicycle riding showed an increasing trend in recent years. Mandible fractures were the most prevalent, followed by dental injuries and maxilla fractures. In cases with a single fracture of the mandible, the symphysis was the most frequent site, while in those with multiple fractures, the association of symphysis and bi-lateral condyle fractures was the greatest. For bicycle-related accidents, a single fracture in the mandible occurred more often than multiple fractures. Conclusions The number of RTA-related injuries while bicycle riding showed an increasing trend with mandible fractures commonly seen in those cases. Efforts to reduce maxillofacial injuries related to bicycle accidents are needed.

The aim of this study was to investigate the clinical course of masticatory function recovery following arthrocentesis. Patients with a unilateral condylar head fracture who underwent arthrocentesis for therapeutic reasons were evaluated and compared with patients with a unilateral condylar head fracture who did not undergo arthrocentesis. At 3 months after treatment, the occlusal contact area and maximum bite force in patients with a fracture treated with arthrocentesis were greater than in those who did not receive arthrocentesis at the same time points, although the differences were not significant. Moreover, at 1 and 3 months following arthrocentesis, mean (±SD) occlusal contact area (1 month: 1.99 ± 0.55 mm

Introduction The relationship between impacted mandibular third molars with angle and condylar fractures is subject of many publications, yet their conclusions differ widely, hence the authors wanted to investigate this topic in their patients. Methods The authors designed a retrospective study including 241 patients who presented with angle and/or mandibular condyle fractures over a 13-year period at the authors' institution. The study variable was the presence/absence of third molars. The authors used the Pell and Gregory system to classify their position, whereas the angulation was classified using Archer classification. The outcome variables were the presence of angle and condylar fractures. Other study variables included fracture etiology. Results Assaults were the most frequent cause of angle fractures (62.7%), whereas falls were mostly responsible for condylar fractures (79.6%). Angle fractures were mostly isolated (66.3%), whereas condylar fractures were mostly associated with other fractures (62.6%). The majority of the angle fractures occurred in patients with third molars (63.6%), on the contrary the majority of the condylar fractures occurred in patients without mandibular third molars (78.3%). Angle fractures were mostly associated with fully erupted or superficially impacted third molars (90,9%). Finally in the presence of mesioangulated third molars, condylar fractures did not happen in 83.8% of patients. Conclusions According to the authors' findings, fully erupted or superficially impacted mandibular third molars are a risk factor for angle fractures but at the same time a protective factor for the condyle. On the contrary, the absence of mandibular third molars "strengthens" the angle and represents a risk factor for condylar fractures.

Background/aim Maxillofacial trauma is frequent and represents a heavy burden for patients and society. The aim of this study was to investigate the characteristics and management of mandibular fractures caused by falls. Material and methods One hundred thirty-nine patients with 185 mandible fractures caused by falls were included in this retrospective study. The patients were grouped according to age, gender, fitness level (as classified by the American Society of Anesthesiology physical status classification), the month of the accident, sites of fractures and treatment methods. Results Most adult and fit patients were treated with open reduction and internal fixation, except for intracapsular condyle fractures. Conservative management was chosen for paediatric patients and in all cases deemed at high risk for lengthy procedures under general anaesthesia (physical status III according to the American Society of Anesthesiology). Young patients were mainly males, whereas geriatric patients were mainly females. In cases of single-site fracture, condylar fractures were the most prevalent. In cases with multiple sites, the association of condyle and symphysis fractures was the most frequent. Conclusions The results show an increasing trend in geriatric condyle fractures, especially in females. The epidemiology of fall-related mandibular fractures is subject to the influence of seasonal, historical, cultural and demographic factors.

Piezosurgery is an innovative technique widely used for osteotomies in the field of oral and maxillofacial surgery. The surgical technique has been clinically supposed to cut mineralized bone selectively with reducing the risk of damage to adjacent soft tissues. However, none of the previous literature has reported any evidence of scientific experiments to examine performance of the piezoelectric device, i.e. the time required for cutting bone and the effect on soft tissues under the standardized conditions. This study was designed to test the hypothesis that cutting time of the piezoelectric device is longer than that of rotary instruments while the cut surface of bone is smoother and soft tissues are less damaged with piezosurgery under the standardized experimental system. We measured the time for cutting bone and soft tissues of rats with the piezoelectric device and rotary instruments. Damage to soft tissues was examined histologically, and the cut surface of bone was investigated using scanning electron microscopy. Our study demonstrated experimentally that piezosurgery provides a smooth cut bony surface with no damage to soft tissues and takes longer time to cut bone than conventional drillings. We propose that piezosurgery is beneficial for medical safety and usability.

維持透析下の二次性副甲状腺機能亢進症患者22名 (高感度副甲状腺ホルモン (HS-PTH) が30-200ng/rnL) を対象に, マキサカルシトール (以下OCT) を添付文書上の用法・用量に従い, 9か月間投与した. 投与期間中のHS-PTHの最小値が21ng/mL以下となった症例を達成群 (10例), ならなかった症例を非達成群 (12例) として, 両群の背景および骨代謝マーカーの推移をretrospectiveに比較検討した. 投与開始時のHS-PTH, I型プロコラーゲンN末端プロペプチド (P1NP) およびI型コラーゲンC末端テロペプチド (1CTP) は, 達成群において有意に低値であった. 投与開始時および3か月後のHS-PTHは, 達成群では39.0±15.2ng/mLより20.7±7.8ng/mL, 非達成群では118.0±46.0ng/mLより90.9±57.6ng/mLへ低下していた. 骨吸収マーカーである1CTPは, 達成群では47.0±26.6ng/mLより3か月後には38.2±15.1ng/mL, 非達成群では123.2±100.8ng/mLより3か月後に99.3±116.9ng/mLへ, さらに9か月後には46.3±19.8ng/mLと有意に低下していた. 骨形成マーカーであるP1NPは, 達成群では投与開始時179.4±155.4ng/mLから3か月後には109.1±62.3ng/mLと有意に低下していた. 非達成群では515.1±461.6ng/mLから3か月後に380.3±368.3ng/mL, 9か月後には117.5±71.0ng/mLと達成群と同レベルにまで有意に低下していた. 血清補正Caは達成群, 非達成群ともに同様の推移を示したが, 血清補正Caが11.5mg/dLを超えた症例は達成群で6例に認められ, うち3例は目標PTHレベルに達成した時期と一致していた.以上より, OCTはPTH抑制効果とともに, 骨代謝マーカーの推移から骨代謝回転の改善作用を示すと考えられた. また, 骨代謝の治療マーカーとして新規骨形成マーカーであるP1NPは, 腎不全患者においても有用であることが示唆された.

混合型 (Mixed type) クリオグロブリン血症 (クリオと略) がC型肝炎ウイルス (HCV) 感染と密接に関係していることが最近明らかになった. また維持透析患者中のHCV感染率が極めて高いことはよく知られている. そこで我々は透析患者中のクリオの頻度, C型肝炎感染との関係ならびに臨床意義について検討した.三愛記念病院で1997年4月現在透析中の患者531名の血清についてクリオを調べ, 対照として千葉大学第1内科の外来で経過観察中の慢性C型肝炎患者242名, および健康成人183名について血清のクリオを調べた. その結果, HCV感染の慢性透析患者170名中30.6%, 慢性C型肝炎患者中29.8%, HCV感染のない透析患者中10.8%, および健康成人中0%にクリオが証明された. 過去6か月以内に透析に入った腎不全患者30名中4名がHCV抗体陽性, 中1名がクリオ陽性, 26名はHCV抗体陰性, 中4名 (15%) がクリオ陽性であった. クリオ陽性患者は陰性患者にくらべて平均午齢は若かった. なお生成するクリオ沈澱量は透析患者では対照にくらべ, また他の報告の量より遥かに低かった. 輸血歴, 透析期間とクリオとの間には相関は無かった. クリオ陽性患者には皮膚のかゆみの訴えが多かった. HCV抗体陽性患者につき肝機能, HCVウイルス量を検討したが, クリオ陽性患者と陰性患者間に差は無かった. 維持透析患者は非透析患者にくらべHCV感染に起因するクリオ発現率は低く, クリオの生成能は低く, クリオに起因する臨床症状は著しくなく, クリオが肝疾患を悪化させるという所見は得られなかった. 透析患者の中のかなりの数の者は透析前よりクリオをもっており, またクリオを有する患者は若い年齢で透析に入るように思われる.

In recent years, it has become important to consider environment around the constructed river according to the demands of the citizens.Now, we are constructing the fishways considering hydraulic characteristics and ascending effectiveness in Akigawa River.This paper presents a summary of the field reserch according to the velocity measurement and other observation in the fishways.

It has been shown that hepatitis C virus (HCV) infection is closely associated with mixed type cryoglobulinaemia. It is also known that HCV infection is rampant among chronic haemodialysis patients. We studied 531 renal failure patients on maintenance dialysis including 170 with positive HCV antibodies for cryoglobulinaemia, and its incidence was compared with controls which consisted of 242 chronic hepatitis C patients without renal failure and 183 healthy adults. Cryoglobulinaemia was present in 30.6% of dialysis patients with HCV infection, 10.8% of dialysis patients without HCV infection, 29.8% of patients with chronic hepatitis C without renal failure, and 0% of healthy adults. Among the 30 new renal failure patients who were started on dialysis within 6 months, four were positive for HCV antibodies, and one of them had cryoglobulinaemia; of the 26 HCV-negative patients, four (15%) were cryoglobulinaemic. The cryocrit values among dialysis patients were much lower than those of the control cases and other reports on non-dialysis cases. Patients with cryoglobulinaemia were generally younger compared with patients negative for this condition. There was no correlation between cryoglobulinaemia and past blood transfusion, underlying disease or length of dialysis. Cryoglobulinaemic patients seem to develop renal failure at relatively young ages and a considerable proportion of cryoglobulinaemic dialysis patients may have already had cryoglobulinaemia at the time of the start of haemodialysis. There was no indication that the presence of cryoglobulin in serum adversely affects the liver disease nor increases serum virus load in HCV-infected dialysis patients. Thus, it was concluded that although HCV infection has a certain role in the development of cryoglobulinaemia in dialysis patients, they develop cryoglobulinaemia less frequently and produce cryoglobulin to a lesser degree in the presence of HCV infection as compared with non-dialysis patients.