Nitrous oxide （N₂O） inhalation sedation is widely used during dental treatments in patients with intellectual disabilities and developmental delay of the brain, in whom management of cerebral circulation is extremely important. While previous studies have reported that cerebral blood flow （CBF） increases with high-dose N₂O administered via a circular breathing system, few studies have reported the effects of low-dose N₂O inhalation sedation on cerebral circulation. Additionally, no previous study has investigated the effects of low-dose N₂O inhalation sedation on intracranial pressure （ICP）. Here, we non-invasively estimated ICP during N₂O inhalation sedation in normal healthy individuals.

The present study is a follow-up on our earlier research series on N₂O inhalation sedation, and is based on reanalysis of the data obtained from the previous research. Eight healthy male volunteers received 30％ N₂O via a nasal cannula, with tonometric measurement of arterial blood pressure （ABP） waveforms in the radial artery, and transcranial Doppler ultrasonography measurement of CBF velocity waveforms in the middle cerebral artery. ICP was calculated offline using these waveforms, by the signal calculator of the nICP-Plugin of the ICM＋^® software for brain monitoring.

CBF velocity increased significantly during 30％ N₂O inhalation, but ICP did not. Further, there was no significant change in either ABP or end-tidal carbon dioxide.

These results suggest that although CBF increases slightly during 30％ N₂O inhalation sedation, ICP does not show a significant difference in healthy male volunteers.

Objective：The current situation of the dental health care delivery system at oral （dental） health centers （oral health centers） is severe, with large regional disparities, and there is an urgent need to correct this situation. Accordingly, we conducted a survey on the roles of oral health centers and how collaboration and support should be provided by our Society, grasped the current situation, extracted issues, and examined the collaboration between oral health centers and the Society in promoting dental care services for children and persons with disabilities.

Subjects and Methods：After obtaining approval from the Japanese Association for Dental Science, we mailed an explanation of the purpose of the survey, the questions, and the URL and a two-dimensional barcode of Google forms with which to answer the questions, to 343 oral health centers.

Results：Responses were obtained from 215 centers that agreed to participate in the survey. Of these, 142 （66.0％） were facilities that accepted dental care for children and persons with disabilities （intellectual disability, physical disability, mental disorder, children with medical complexity, and intractable disease）, so these 142 facilities were included in the analysis. Oral health centers are places to develop human resources to manage oral health and provide dental care for children and adults with disabilities who are difficult to treat at primary dental institutions, but many facilities thought that “dental care by highly specialized staff who can take disability into consideration” was necessary. The most common cooperation and support received so far from the Society was “accreditation and training of training institutions for board-certified doctors and specialists” （29） and “provision of information on dentistry for special needs patients” （13）. The cooperation and support they would like to receive in the future were “dispatch of lecturers for workshops, etc.” （62） and “consultation on expertise in accepting special cases of dentistry for patients with disabilities” （52）.

Conclusion：To provide comprehensive dental health care and oral health management at oral health centers, it is considered necessary for the Society to provide “consultation on expertise in accepting special cases of dentistry for patients with disabilities,” which has not been done much in the past.

Introduction：Congenital heart disease is observed in approximately half of patients with Down syndrome. During the bleeding procedures, administration of antibiotics to high-risk patients is recommended to prevent infective endocarditis （IE）. We experienced a case of a Down syndrome patient with complete atrioventricular deficiency for which surgery had not been performed and who developed a brain abscess after teeth extraction.

Case：The patient was a 28-year-5-month-old female with the chief complaint of teeth extraction. Past medical history：Endocardial defect （no surgery performed）. History of current illness：A facility staff noticed her loose teeth and visited our department. Current symptoms：height 141cm, weight 47kg, SpO₂ 83％（O₂ 2l/min）. Seven teeth needed to be extracted.

Treatment and Course：At the first visit, body movement to refuse oral examination was observed, and it was predicted that treatment under physical restraint would have a high risk of hypoxia. Since the risk of IE increases with multiple tooth extractions, a single treatment under general anesthesia was proposed. However, there was a risk that cardiac function would irreversibly decline due to changes in hemodynamics associated with general anesthesia. According to the consultation results, it was decided to treat the patient with multiple outpatient treatments through cooperation between multiple facilities, and arrangements were made so that the patient could be hospitalized immediately in case of onset of IE. After the third tooth extraction, the patient developed a fever and was immediately hospitalized as planned in advance. After careful examination, a brain abscess was found, so ampicillin sodium was administered, and the patient was discharged 13 weeks later.

Discussion and Conclusion：In this case, we were able to respond immediately to a brain abscess in a Down syndrome patient with untreated congenital heart disease by predicting the onset of IE and coordinating the cooperation between multiple facilities. For patients in IE high-risk groups, it is important to keep in mind the onset of IE and take prompt action through multidisciplinary collaboration.

Introduction：The Fontan procedure is surgical palliation used for a range of congenital heart defects with a single functional ventricle or in conditions for which biventricular repair is impossible or unfavorable. We experienced perioperative management of a patient with Fontan circulation undergoing dental treatment.

Patient：A 22-year-old female. Chief complaint：Dental problems. Past medical history：The patient underwent Damus-Kaye-Stansel anastomosis and Fontan surgery （epicardial conduit type） in childhood due to double outlet right ventricle, hypoplastic mitral valve, and aortic stenosis. History of current illness：The patient had been undergoing dental treatment under intravenous sedation at a dental clinic because of dental phobia and intellectual disorder. She was referred to our hospital due to her markedly low blood pressure during intravenous sedation. Current symptoms：Height 166 cm, weight 70kg. Three teeth required extraction and 13 teeth received caries treatment.

Treatment and Course：The first treatment （extraction of three wisdom teeth and caries treatment of six teeth） was performed in the operating room under inpatient management. Propofol and midazolam were used for intravenous sedation. Intraoperative SpO₂ was 90-95％, and 85-87％ after the treatment under 3L/min of oxygen via a nasal cannula, without dyspnea or cyanosis. One of the possible reasons for the decrease of SpO₂ was considered to be an increase in intrathoracic pressure caused by choking. The patient was admitted to the ward with stable vital signs and was discharged from the hospital without any complications on the next day. The second and third treatments （caries treatment of four and three teeth, respectively） were performed in the outpatient ward. At the time of the second treatment, the patient was crying due to anxiety, so before the third treatment, oral administration of midazolam was performed, leading to smooth induction of intravenous sedation. Preoperative SpO₂ was around 93％, and intraoperative SpO₂ was 95-99％ under 3L/min of oxygen via a nasal cannula. Perioperative heart rate and blood pressure were stable. The patient was allowed to go home after recovering consciousness and confirmation of motor function. The amnesic effect caused by midazolam satisfied the patient.

Discussion and Conclusion：It is very important to assess heart and pulmonary function and other complications before performing dental treatment for patients with congenital heart disease like Fontan circulation. As in this case, patients who are uncooperative with dental treatment because of dental phobia or intellectual disorder undergo pharmacological behavioral adjustment like intravenous sedation, and need consideration to reduce stress using premedication or topical anesthesia.

Gillespie syndrome is a congenital neurological disorder characterized by nonprogressive cerebellar ataxia, partial aniridia, and intellectual disability. It is an extremely rare disease, with fewer than 30 individuals affected globally. We report a case of a 9-year-old male patient with Gillespie syndrome to whom general anesthesia was administered in order to perform a tooth extraction for a maxillary impacted supernumerary tooth. The patient presented with symptoms of Gillespie syndrome, including cerebellar hypoplasia, partial aniridia, cervical hypoplasia, and intellectual disability. General anesthesia was slowly induced with sevoflurane. The intubation dose of muscle relaxants was reduced considering the decreased muscle tone from cerebellar ataxia, and the effect was equivalent to that of the standard dose. Tracheal intubation was performed using a video laryngoscope due to cervical hypoplasia. In addition, patients with Gillespie syndrome are prone to aspiration due to dysphagia caused by cerebellar ataxia, so intraoral suctioning was performed immediately before extubation, and EEG monitoring confirmed that the patient had awoken from anesthesia before extubation. After leaving the operating room, the patient was hospitalized for observation to prevent aspiration, and safe perioperative management was ensured. The key considerations for general anesthesia management in patients with Gillespie syndrome are：there is a risk of prolonged effect of muscle relaxants due to decreased muscle tone caused by cerebellar ataxia；there is a risk of aspiration during the perioperative period due to dysphagia and the effects of anesthesia；and some patients may have a variety of clinical symptoms in addition to the triad of signs. Patients with Gillespie syndrome should be thoroughly examined preoperatively, monitored and evaluated for muscle relaxants and sedation levels, and managed postoperatively on an inpatient basis to avoid aspiration.

Objective：The purpose of this study was to grasp the actual status of dental care for persons with disabilities at oral （dental） health centers （oral health centers） and to identify and organize problems in order to establish a system in which children and adults with disabilities can receive higher quality dental care in their familiar communities at any time.

Subjects and Methods：After obtaining approval from the Japanese Association for Dental Science, we mailed an explanation of the purpose of the survey, the questions, and the URL and a two-dimensional barcode of Google forms with which to answer the questions, to 343 oral health centers.

Results：Responses were obtained from 215 centers that agreed to participate in the survey. Of these, 142 （66.0％） were facilities that accepted dental care for children and persons with disabilities （intellectual disability, physical disability, mental disorder, children with medical complexity, and intractable disease）, so these 142 facilities were included in the analysis. Most of the facilities were staffed by part-time dentists on a rotating basis, and outpatient care was the main service provided in 134 （94.4％） of the cases. Despite collaboration with other medical institutions, the referral rate was 21.1 （28.5％）, while the reverse referral rate was 8.7 （14.8％）. 105 （73.9％） and 89 （62.7％） of the respondents answered that they had “current or anticipated medical and managerial difficulties/problems,” respectively. The most common medical problem was “Insufficient personnel,” followed by “Lack of expertise to accept special cases considering the characteristics of the disabled,” and “Few dental clinics that can make a reverse referral.”

Conclusion：The results suggest that it is necessary to provide dental health counseling and home-visit dental care, secure highly specialized personnel, and establish a system for smooth cooperation among dental care institutions, to improve the provision of dental care for children and adults with disabilities in the community.

Due to the current super-aging society, hemodialysis patients （HD patients） are also aging and the number of elderly HD patients visiting dentists has increased in recent years. In the oral cavity, hygiene worsens due to decreased saliva flow and decreased ADL. Systemically, cerebrovascular disorders and cardiovascular diseases are common, and many patients are treated with antithrombotic therapy. Tooth extraction in HD patients is generally avoided due to the unique nature of the disease, and patients often do not receive adequate treatment. Furthermore, there are few reports on tooth extraction in HD patients, and the safety of tooth extraction has not been sufficiently investigated. Therefore, in our department, we compared the complications that occurred during tooth extraction under continued antithrombotic therapy in an HD group and a non-HD group, and examined the safety. The results showed a statistically significant difference in gender, number of teeth extracted, bleeding complications, or other complications. Furthermore, there was a statistically significant difference in the severity of bleeding complications and gingivitis. The risk factor for serious bleeding complications during tooth extraction under continued antithrombotic therapy was local gingival inflammation, suggesting that HD may not be a risk factor. In this study, we conducted a study on normal tooth extraction in patients undergoing antithrombotic therapy, and found that there were no serious complications in either the HD or non-HD group, and there was a significant difference in complications depending on the presence or absence of HD. Therefore, it was considered that normal tooth extraction could be performed in HD patients as well as in non-HD patients.