佐藤 公治

Abstract Background The COVID-19 pandemic led to concerns about the potential airborne transmission of the virus during dental procedures, but evidence of actual transmission in clinical settings was lacking. This study aimed to observe the behavior of dental sprays generated from dental rotary handpieces and to evaluate the effectiveness of high-volume evacuators (HVEs) using laser light sheets and water-sensitive papers. Methods A dental manikin and jaw model were mounted in a dental treatment unit. Mock cutting procedures were performed on an artificial tooth on the maxillary left central incisor using an air turbine, a contra-angle electric micromotor (EM), and a 1:5 speed-up contra-angle EM (×5EM). Intraoral vacuum and extraoral vacuum (EOV) were used to verify the effectiveness of the HVEs. The dynamics and dispersal range of the dental sprays were visualized using a laser light sheet. In addition, environmental surface pollution was monitored three-dimensionally using water-sensitive papers. Results Although the HVEs were effective in both the tests, the use of EOV alone increased vertical dispersal and pollution. Conclusions The use of various types of HVEs to reduce the exposure of operators and assistants to dental sprays when using dental rotary cutting instruments is beneficial. The study findings will be helpful in the event of a future pandemic caused by an emerging or re-emerging infectious disease.

Study Design Case Report. Objective To discuss the case of a 55-year-old man who complained of swelling and pain in the left cheek. Methods Computed tomographic images showed a shadow of retained electric toothbrush head in the left infratemporal fossa, heterotopic free air, and abscess formation in the masticatory space. Foreign body removal and surgical drainage were performed under general anesthesia. Result The patient was discharged 6 days postoperatively. Conclusion Computed tomography should invariably be performed on patients with intraoral impalement injury.

OBJECTIVE: Some patients with cleft palate (CP) need secondary surgery to improve functionality. Although 4-dimensional assessment of velopharyngeal closure function (VPF) in patients with CP using computed tomography (CT) has been existed, the knowledge about quantitative evaluation and radiation exposure dose is limited. We performed a qualitative and quantitative assessment of VPF using CT and estimated the exposure doses. DESIGN: Cross-sectional. SETTING: Computed tomography images from 5 preoperative patients with submucous CP (SMCP) and 10 postoperative patients with a history of CP (8 boys and 7 girls, aged 4-7 years) were evaluated. PATIENTS: Five patients had undergone primary surgery for SMCP; 10 received secondary surgery for hypernasality. MAIN OUTCOME MEASURES: The presence of velopharyngeal insufficiency (VPI), patterns of velopharyngeal closure (VPC), and cross-sectional area (CSA) of VPI was evaluated via CT findings. Organ-absorbed radiation doses were estimated in 5 of 15 patients. The differences between cleft type and VPI, VPC patterns, and CSA of VPI were evaluated. RESULTS: All patients had VPI. The VPC patterns (SMCP/CP) were evaluated as coronal (1/4), sagittal (0/1), circular (1/2), and circular with Passavant's ridge (2/2); 2 patients (1/1) were unevaluable because of poor VPF. The CSA of VPI was statistically larger in the SMCP group (P = .0027). The organ-absorbed radiation doses were relatively lower than those previously reported. CONCLUSIONS: Four-dimensional CT can provide the detailed findings of VPF that are not possible with conventional CT, and the exposure dose was considered medically acceptable.

<title>Abstract</title> Background The aims of this study were to perform a four-dimensional assessment of velopharyngeal closure function in pediatric patients with cleft palate using 320-row area detector computed tomography (CT), and to estimate the organ-absorbed doses using Monte Carlo simulation. Methods We evaluated CT image data obtained between July 2018 and August 2019 from five pediatric patients with cleft palate (four boys and one girl; age range, 4–7 years) at Fujita Health University Hospital. The presence of velopharyngeal insufficiency (VPI), patterns of velopharyngeal closure (VPC), and cross-sectional area of VPI were evaluated. In addition, organ-absorbed doses were assumed in the Monte Carlo simulation. However, we did not perform statistical analysis because of the insufficient number of patients enrolled in this study. Results The existence of VPI and hypernasality were completely concordant. The VPC patterns were circular (two patients), circular with Passavant’s ridge (one patient), and unevaluable (two patients). The organ-absorbed doses were relatively lower than those in past reports. Conclusions Our method could be an alternative for patients who refuse the conventional nasopharyngoscopic evaluation.

近年，口唇口蓋裂患者に対する二次的顎裂部骨移植術の術後評価に，CT画像を用いた検討が報告されている．われわれは，二次的顎裂部骨移植術による骨架橋容積の評価と，骨架橋成立に寄与する予後規定因子を明らかにするため，CT画像を用いた検討を行ったので報告する．二次的顎裂部骨移植術を行った片側性唇顎裂（unilateral cleft lip and alveolar: UCLA），片側性唇顎口蓋裂児（unilateral cleft lip, alveolar, and palate: UCLP）の各30例，計60例を対象とし，術前後にCT画像を撮影した．骨欠損腔の容積から顎裂部骨架橋率を算出し，その予後規定因子について検討を行った．骨架橋率の中央値は片側性唇顎裂で83.6%，片側性唇顎口蓋裂で66.3%となった．単変量解析，多変量解析双方において，口蓋裂の有無および術前の顎裂部骨欠損腔容積の大きさが有意な予後規定因子として抽出された．顎裂部誘導歯の種類や萌出状況は予後に関連しなかった．

1歳10ヵ月の女児。Pierre Robin Sequenceおよび口蓋裂の診断のもとに口蓋形成術(粘膜弁法)を施行した。手術直後、術野からの少量の出血を認め、口腔外科医が5分間圧迫止血を行い、止血を確認して小児病棟へ帰室させた。帰室2時間後に再出血を認め、口腔外科医が圧迫止血で対応した。その50分後に再々出血し、陥没呼吸とチアノーゼが出現し始めた。かけつけた小児科医が救命処置を行ったが改善傾向は認められず、院内救急コールを要請した。応援にかけつけた麻酔科医とICU医師がアンビューバッグで補助換気を行ったが徐々に換気困難となり、気管挿管を試みたが、唾液とセルロイド製口蓋床(シーネ)から溢れ出た血液などで挿管困難であった。SpO2の低下と徐脈傾向を認めたためアトロピンとアドレナリンを投与した。ICU医師の判断で輪状甲状腺間膜に16G針を穿刺したところ、直後にSpO2が99%まで回復した。自発呼吸を保ちつつ直ちに手術室へ移動して経口気管挿管と止血術を行い、救命することができた。

This report presents a case of extensive oral cancer suspected to be a granulocyte-colony-stimulating-factor (G-CSF)-producing tumor in a 63-year-old man who complained of dyspnea, dysphagia, and dysmasesis. Laboratory findings on admission showed marked leukocytosis (35, 900/μl) and thrombocytosis (527, 000/μl).<BR>Pathological examination of a biopsy specimen revealed an undifferentiated squamous cell carcinoma. Chemotherapy with PEP, CDDP, MTX, UFT, and concurrent irradiation resulted in shrinkage of the tumor and a decrease in the leukocyte and platelet counts. Soon after 10 Gy of radiation had been administered, the serum G-CSF concentration reached the abnormally high level of 329pg/ml and was still 132pg/ml at death about a month later. Over the entire course of treatment, the leukocyte count changed with changes in tumor size. Both findings suggest that the tumor cells produced G-CSF.

A rare case of a 2-year-old girl with encephalocele is reported. She was admitted at birth to the department of pediatric surgery because of a hydrocele and a left buccal tumor. The buccal tumor was irradiated up to 30 Gy under a tentative diagnosis of a low malignant neurogenic tumor. A V-P shunt operation was performed for the hydrocele. The tumor gradually enlarged postoperatively, resulting in facial asymmetry. An ulcer formed in the buccal mucosa because of close contact with ID. The patient was referred to our department because of the buccal ulcer and facial deformity. The buccal tumor was of the size of a hen's egg and had an irregular surface. Intraorally, it was multilobulated and extended to the palate and pharyngeal space. Before surgery, an encephalocele was suspected on the basis of imaging findings, including 3 D-CT and MRI. ID extraction and partial resection of the lesion were performed. Degenerated brain tissue with calcification was identified pathologically. For six years postoperatively, the patient has been free from severe complications and can lead normal life.