Koji Satoh

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.

In recent years, some research on postoperative computed tomography evaluations of secondary bone grafting into the alveolar cleft have been reported. Here we report a study on volumetric evaluation and the prognostic factors of bone bridge formation after secondary bone grafting into the alveolar cleft using computed tomography. For 60 patients with unilateral cleft lip and palate patients (30 with unilateral cleft lip and alveolar: UCLA, 30 with unilateral cleft lip, alveolar, and palate: UCLP), we performed computed tomography scanning pre- and post-operatively. We calculate bone bridging ratio from bone defect volume and evaluated the prognostic factors of it. The median of bone bridge ratio was 83.6% and 66.3% in UCLA and UCLP, respectively. Both from uni- and multi-variate analysis, the existence of cleft palate and preoperative bone defect volume were selected as statistically significant prognostic factors. The type of tooth inducted into alveolar cleft or its state of eruption were not related with prognosis.

BACKGROUND: Nasopharyngoscopy is a common method to evaluate velopharyngeal closure in patients with cleft palate. However, insertion of a fiberoptic nasopharyngoscope causes discomfort in patients. The aim of this study was to estimate the reliability of short-time exposure images obtained using 320-row area detector computed tomography (320-ADCT) as a novel evaluation method for the assessment of velopharyngeal function. METHODS: We evaluated five healthy adult volunteers and five postoperative adult patients with cleft palate. During a 3.3-s imaging exposure, the participants were asked to perform two tasks: nasal inspiration and subsequent oral expiration through a catheter into a water-filled cup. The movement of the velopharyngeal structures was recorded during each examination, and the presence of velopharyngeal insufficiency (VPI) and velopharyngeal closure (VPC) patterns were estimated. If VPI was detected, the cross-sectional area was also calculated. Cohen's kappa and weighted kappa coefficients were used to evaluate the concordance of nasopharyngoscopy and 320-ADCT evaluation. RESULTS: Speech pathology evaluation did not reveal hypernasality in any study participant. Micro-VPI was detected by nasopharyngoscopy in one healthy volunteer and two patients. 320-ADCT detected micro-VPI in two more patients. The cross-sectional area of the VPI in these subjects ranged from 2.53 to 16.28 mm2. Nasopharyngoscopy and 320-ADCT were concordant in detecting VPI in eight participants (κ = 0.6) and in assessing VPC patterns in nine (κ = 0.82). Moreover, images obtained using 320-ADCT allowed for reduced dead angle and, thus, easy detection of micro-VPI and Passavant's ridges. CONCLUSION: Although the radiation exposure cannot be ignored, our novel evaluation method using 320-ADCT enables more detailed evaluation of VPC than nasopharyngoscopy. Future studies should investigate the relationship between 320-ADCT findings and speech pathology evaluations.

Objective The usefulness of computed tomography (CT) for measuring bone defect volume in the alveolar cleft has attracted considerable attention in recent years. Moreover, 320-row area detector CT (320-ADCT) is currently widely utilized. This technology helps to acquire smooth three-dimensional images, with a reduced exposure dose and improved image resolution, similar to those of dental cone-beam CT (CBCT). We compared the exposure dose of 320-ADCT with that of dental CBCT, and analyzed the reliability of a volumetric method for measuring bone defects in the alveolar cleft using 320-ADCT, both experimentally and clinically. Methods We performed thermoluminescent dosimeter measurements using an anthropomorphic RANDO phantom. Additionally, we evaluated the reproducibility of the volumetric measurement method for the bone defective volume using CT images of simulated bone defects in pigs. In addition, we evaluated the inter-rater reliability of the volumetrically measured values of bone defects in 20 patients with a unilateral cleft. Results The exposure doses of 320-row area detector CT and CBCT were similar. The errors of volumetric values between calculated and actual bone defects created in pigs were up to 7.6%. Inter-rater reliability of the calculated volumes of bone defect was evaluated as high, according to Bland–Altman analysis. Conclusions CT examination with a low exposure dose and precise analysis is feasible without the use of highly specialized dental CBCT.

A new disease concept called mammary analog secretory carcinoma (MASC) has been reported recently among acinic cell carcinoma (AciCC) of the salivary gland and cystadenocarcinoma of low malignant potential. MASC exhibits histological and immunohistochemical findings similar to those of secretory carcinoma of the breast. Recently, it has been pointed out that a considerable number of cases believed to be AciCC are in fact cases of MASC. We report our experience with a case of MASC that developed on the lower lip after originating from the minor salivary glands. The patient was a 41-year-old man who consulted our department with a chief complaint of a painless mass on the right lower lip. After a clinical diagnosis of a benign tumor, the mass was surgically excised with the patient under local anesthesia. Histopathological examination of the excised mass indicated AciCC. Two years postoperatively, metastasis to the submandibular lymph nodes was observed, for which right suprahyoid neck dissection was performed. No subsequent local recurrence or distal metastasis has been observed. This case was originally diagnosed as AciCC, but was diagnosed as MASC on histopathological reexamination.

Objective: Our objective is to determine appropriate specifications for smaller tongue blade for Japanese pediatric patients with cleft palate (CP) and mandibular micrognathia. Patients: We investigated 59 patients who underwent palatoplasty. Patients were divided into two groups: the micrognathia (MG) group consisted of 11 patients and the normognathia (NG) group consisted of 48 patients. Interventions: The following five items were investigated retrospectively: (1) gender, (2) cleft type, (3) age at the time of surgery, (4) weight at the time of surgery, and (5) distance from the tongue blade base to the posterior pharyngeal wall (Dis). Results: There was a significant difference (P &lt; .01) in age at the time of surgery and in Dis between groups, but not in weight. The minimum values were 55 mm for the MG group. As for correlations between age and weight at the time of surgery, the P values for the MG and NG groups were .993 and .052, respectively. As for correlations between weight at the time of surgery and Dis, the P values for the MG and NG groups were .987 and .099, respectively. Conclusions: It was difficult to predict Dis on the basis of the patient's age and weight measured preoperatively. The minimum Dis was 55 mm, equal to the length from the base to the tip of the Dingman Mouth Gag tongue blade currently in use, suggesting that a tongue blade of approximately 50 mm in length, shorter than the current minimum specifications, may be appropriate.

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。

A case of follicular dendritic cell tumor (FDC tumor) arised in the aro-pharyngeal region is reported in a 16-year-old Japanese boy. He had a swelling in the right retromolar trigone and soft palate. Clinical examination disclosed a 25 mm x 30 mm, elastic hard, ulcerated mass. CT scans showed a low density lesion in the right medial parapharyngeal area. The biopsy specimen revealed a low-grade malignant tumor. The patient underwent a tumorectomy which was extended to include the adjacent palatine tonsil. The tumor cells. with a clear cytoplasm and oval nucleus, were immunoreactive for S-100 (N/A), CD 21 (1F8), fascin (55K-2) and FDC (CNA42). The fascicular sheet pattern arrangement of the tumor cells was partly characteristic. The final diagnosis was an follicular dendritic cell tumor. Three courses of adjuvant chemoradiotherapy were administered postoperatively. Clinical features, pathological diagnosis and immunohistochemical markers for distinguishing FDC tumor are reviewed. (C) 2003 Elsevier Science Ltd. All rights reserved.

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.