Cystadenocarcinoma is an extremely rare lesion with a low incidence rate of 0.18% of all salivary gland tumors in the oral and maxillofacial region. Here, we report two cases of cystadenocarcinoma in the lip. Case 1 was of a 79-year-old woman who presented with discomfort in the right upper lip. On examination, a 16 x 10 mm mass was observed on her right upper lip. The superficial mucosa was smooth but with an irregular margin. The mass was clinically suspected to be a malignant tumor, and tumor resection was performed. Case 2 was of a 51-year-old man who presented with a 20 x 20 mm mass on the left lower lip. The mass was hard, and adhesion to the skin was suspected. On T2-enhanced magnetic resonance imaging, high signal intensity and internal non-uniform features were noted. Before the operation, fine-needle aspiration cytology was performed, and atypical cells were observed; therefore, resection was performed assuming a malignant tumor. The surgeries were performed 3 years ago, and no recurrence or lymph node metastasis has been observed in either case to date.

【目的】咀嚼機能は脳機能と密接に関連していることが知られている。骨格性下顎前突症(MP)は咬合機能低下を示すこ とから，MP は脳機能に悪影響を与えると推定される。本研究では，正常咬合者と MP 患者の脳血流を比較することで MP が脳機能へどのように影響するかを解明すべく，機能的近赤外分光法(fNIRS)を使用して脳血流を調べた。 【対象と 方法】正常咬合者 17 人と MP 患者 69 人を研究対象とした。シリコン印象材を用いて咬合接触点数を測定した。噛みしめ 時の咬筋表面筋電図信号(EMG)を記録した。脳血流は fNIRS にて計算タスクと咀嚼タスク(パラフィンワックス自由 咀嚼，ハードグミ咀嚼)時に測定した。統計的有意性は P＜0.05 の場合を統計学的に有意な差を示すとした。 【結果】咬合 接触数は正常咬合者よりも MP 患者で少なかった。噛みしめ時の咬筋活動は，正常咬合者よりも MP 患者で弱かった。計 算タスクでは，両群で oxy-Hb が増加し，群間で oxy-Hb に有意な差はみられなかった。パラフィンワックス自由咀嚼は両 群とも oxy-Hb を上昇させ，この上昇は両側下前頭回において著しかった。興味深いことに両側下前頭回における咀嚼タ スクでの oxy-Hb 増加は，正常咬合者と比較して MP 患者では低かった。ハードグミ咀嚼も同様に両群において両側下前 頭回における oxy-

Here we describe a rare case of mandibular cancer involving almost the entire attached gingiva in a 71-year-old man. First, marginal resection of the entire mandible was performed, followed by one-stage reconstruction comprising application of a split-thickness skin graft onto the wound. This resulted in good alveolar ridge morphology, allowing for a mandibular prosthesis to be installed soon postoperatively. Histopathological analysis revealed a well-differentiated squamous cell carcinoma extending throughout most of the resected attached gingiva, but no malignant features in the stumps. Furthermore, no infiltration into the jawbone was observed, and no vascular or lymphatic invasion or perineural infiltration. At 3 years postoperatively, the patient's clinical course has remained uneventful, with no recurrence or problems arising in the remaining mandible. The patient is also able to eat regularly using the mandibular prosthesis provided.

Most patients with cleft lip and palate receive proper and consistent treatment; however, in some cases, patients are not satisfied with the treatment outcomes regardless of improvements in jaw function and morphology after orthognathic surgery, which is considered as one of the final phases of the treatment. Therefore, to improve patients’ satisfaction with the treatment, their psychological conditions were surveyed before and after orthognathic surgery. Thirty-four patients with cleft lip and palate completed a psychological test （MINI-124） before orthognathic surgery, and the findings revealed that the majority showed high scores in each scale designed for measuring lie, hysteria, and association problem. Furthermore, the scores of hypochondriasis, hysteria, and bodily symptoms were significantly higher in patients with cleft lip and palate than in 70 jaw deformity patients without any congenital anomalies measured before surgery. In addition, a questionnaire survey on the orthognathic surgery performed at more than 6 months after the surgery, showed that patients with cleft lip and palate were mostly satisfied with their surgeries. However, some of them showed a slightly lower degree of satisfaction and a strong obsession with their lip scars and nasal deformities.

Orthognathic surgery has recently become a significant element in the field of oral surgery. Owing to factors such as advancements in surgical techniques and the development and improvement of surgical equipment, orthognathic surgery is becoming increasingly safe ; however, intraoperative blood loss can still pose a difficult problem in some cases. Therefore, we examined whether tranexamic acid (TXA) can reduce intraoperative blood loss during orthognathic surgery. The initial group of subjects in this prospective, randomized controlled trial comprised 377 individuals who underwent orthognathic surgery at the Department of Stomatology, Tokyo Metropolitan Ohtsuka Hospital between April 2006 and March 2017. After excluding patients with congenital anomalies (e.g., cleft lip and palate), combined surgery patients, patients with intraoperative complications, reoperation patients, and patients with incomplete intraoperative records, 270 patients were ultimately included in the analysis. Of these 270 patients, 171 underwent sagittal split ramus osteotomy (SSRO) and 99 underwent Le Fort I osteotomy and SSRO (LFI+ SSRO). The subjects were randomly assigned to a TXA group or a control group. The optimal dose of TXA was set at 20mg/kg. Patients who underwent SSRO were classified into two groups : a TXA20 group, which received TXA 20mg/kg immediately prior to surgery, and a control group. Patients who underwent LF I+ SSRO were classified into three groups : a TXA20 group, which received a single administration of TXA 20mg/ kg immediately prior to maxillary osteotomy; a TXA10+10 group, which received two separate administrations of TXA 10mg/kg immediately prior to maxillary and mandibular osteotomy ; and a control group. Groups were compared in terms of age, male/female ratio, body mass index, body surface area, surgical time, total intraoperative blood loss, and intraoperative blood loss per hour of surgery. Of the patients who underwent SSRO, there was no significant difference in any variable between the two groups. Of the patients who underwent LF I+SSRO, there was no significant difference in total intraoperative blood loss between the TXA20 group and the control group. However, when patients who underwent LF I+SSRO were reclassified based on surgical time, a significant difference was observed in the total intraoperative blood loss in the long surgical time group. In addition, a significant difference was observed in intraoperative blood loss per hour of surgery between the TXA10+10 group and the control group. These results suggest that TXA may be able to reduce intraoperative blood loss during orthognathic surgery.

In the present study, we summarize our experience with a case of salivary duct carcinoma occurring in the orifice of the parotid gland that was suggested to originate in Stensen’s duct. The patient was a 78-year-old man who consulted our hospital because of a mass in the left buccal mucosa. Although a biopsy strongly indicated salivary duct carcinoma, no cervical lymph node metastasis or distant metastasis was evident; therefore only local resection was performed. The tumor was located near the orifice of the parotid gland. Because the histopathological examination showed that the ductal epithelium was continuous around the tumor, the tumor was considered to be a salivary duct carcinoma that had developed in Stensen’s duct at the orifice of the parotid gland. After postoperative radiation, there has been no evidence of recurrence or metastasis for 3 years.

We report a case of Pruzansky grade II hemifacial microsomia, where a patient had improved facial asymmetry with modified simultaneous maxillomandibular distraction, so-called hybrid osteodistraction. A female patient was diagnosed with first and second branchial arch syndrome and was followed up at another pediatric hospital. She came to our hospital to receive treatment for facial asymmetry with jaw deformity at the age of 9 years. She had right hemifacial microsomia with her chin distorted on the right side. Examination of her oral cavity revealed occlusal plane inclination and an Angle Class II occlusion. The patient underwent corrective surgery at the age of 14 years after presurgical orthodontic treatment was finished. The first step for this corrective surgery involved Le Fort I osteotomy of the maxilla and removal of a 5 mm cuneiform bone fragment of the left side. Next, the left piriform aperture was loosely wired. This step was followed by right horizontal osteotomy and left sagittal osteotomy of the mandibular ramus. The mandible body was advanced 5 mm in order to improve the Angle Class II occlusion, and an intraoral distractor was placed parallel to the right mandibular ramus. From the third day after surgery, the distractor device was lengthened while the occlusion was maintained by intermaxillary fixation. Using this approach, the integrated maxillomandibular bone could be extended on the right side and shortened on the left side as it rotated. Thus, the patient’s mandible was gradually distracted in a vertical vector after instantaneous advance. As a result, facial asymmetry and the tilt of the occlusal plane improved with completed functional occlusion.

Cystadenocarcinoma is an uncommon malignant salivary gland tumor that rarely occurs in the retromolar region. In this paper, we report a case of cystadenocarcinoma that caused considerable resorption of the mandible. The patient was a 79-year-old woman who had a painless swelling, measuring 25 × 25 mm, in the left retromolar region. Panoramic radiography revealed a multiple cystic lesion from the molar to ramus of the left side of the mandible. The tumor was excised by mandibular marginal resection. There was or recurrence or metastasis during 3 years of follow-up.

Pycnodysostosis is a rare autosomal recessive skeletal dysplasia characterized by short-limbed dwarfism, acroosteolysis, and a specific facial appearance associated with dysplasia of the jaw. We report the treatment of osteomyelitis of the mandible in a patient with pycnodysostosis that had not been diagnosed until 60 years of age. The patient visited our department because of buccal phlegmon arising from mandibular osteomyelitis. Pycnodysostosis was diagnosed on the basis of osteomyelitis of the jaw and other physical findings. He was treated under hospitalization. First, anti-inflammatory treatment of the right buccal phlegmon was performed. Subsequently, sequestrectomy was performed, and an external dental fistula was simultaneously constructed using the rhomboid-to-W technique. There has been no recurrence of acute inflammation, and the postoperative course has been favorable up to the present （2 years 10 months after operation）. However, the patient is being very closely followed up because the formation of a new sequestrum.

A clinical study was carried out on 498 patients who underwent orthognathic surgery between July 1989 and March 2007 in our department.The results were as follows:1. The number of orthognathic surgery cases increased annually, exceeding 30 cases a year after 2000.2. The ratio of female patients was higher than that of males. Among age groups, the number of patients aged between 20 and 29 was the largest.3.Regarding the clinical diagnosis, the number of mandibular protrusion patients (212 cases) was the largest, accounting for 42.6%.4. Regarding surgical types, SSRO (361 cases) was the most freauent.accounting for 67.7%. The combineduse of LF-land SSRO was applied in 110 cases, accounting for 20.6%.5. Administration of anesthetics during surgery, which was performed based on the results of cause and effect analysis, was considered markedly useful for decreasing the amount of bleeding.6.Smooth treatment of maxillofacial deformity patients and various improvements to decrease complications during and after surgery were performed.Furthermore, due to the introduction of the critical path, effective treatment for patients was achieved, and the quality of care was improved.