We examined the effectiveness of electric toothbrushes for the elderly by investigating their feeling of use, cleanability, and effect on the periodontium. We also considered the muscle strength, dexterity, and visual acuity necessary for their use. We conducted a preliminary survey using a questionnaire on health status and oral cleaning for 10 patients aged 65 and over who visited a dental clinic, and 7 patients who were admitted to a rehabilitation hospital. We selected 17 subjects who did not use electric toothbrushes for this research. We examined the periodontal pockets (PD), bleeding during pocket measurement (BOP), tooth mobility, plaque control record (PCR%), grip strength, and dexterity. The same examination was done 3 weeks later after we gave guidance on oral cleaning with an electric toothbrush, and had the patients clean their oral cavities at home for 3 weeks. Use of the electric toothbrush significantly reduced both PCR and BOP (p<0.01). Regression analysis of variance showed that the PCR before using the electric toothbrush was greater in the older subjects, the grip was weaker, and the BMI was smaller. In addition, the decrease in PCR resulting from use of the electric toothbrush was greater for older subjects who had weaker grip strength, and fewer remaining teeth.

We concluded that the electric toothbrush is useful for the elderly. We also found that its usefulness is related to the grip strength and number of remaining teeth. Shika Igaku (J Osaka Odontol Soc) 2022; Mar; 85(1): 1-7

We devised a new system for evaluating all students studying pathology. Although some students tend to study only the day before the examination, this may not be beneficial for their knowledge of pathology. Pathology classes at our university have three intermediate examinations, one practical examination, and one unit exam. Multiple-choice tests were used for the three intermediate examinations for the second year students in 2018, while a new system of three intermediate exams was used in 2019. We call this new system the sandwich-type written exam. It is composed of two written examinations (A and B) and self-study hours between the two. The students were evaluated by three multiple-choice tests in 2018. We used the sandwich-type written exams as the three intermediate exams in 2019. The number of students passing the unit exam increased in 2019 over that in 2018, suggesting that using the sandwich-type written exams enhanced the students' knowledge of pathology. Shika Igaku (J Osaka Odontol Soc) 2022; Mar; 85(1): 8-13.

The start of radiology classes at the Osaka Dental University and diagnostic imaging at the hospital date back to 1917, which was about the same time as the current Tokyo Dental College (1914) and the current Nihon Dental University (1916). Until now, research on the actual number of examinations and their transition performed at the Central Imaging Center in the Osaka Dental University Hospital has been insufficient, and the role of the center in this Hospital has not been clearly defined. Therefore, the purpose of this survey was to investigate the actual number of examinations and their transition performed at the central imaging center over the past 10 years, and to clarify the future role of the Center and the Department of Oral Radiology.

The survey was conducted on patients who visited the University Hospital and underwent imaging examinations in the Central Imaging Center between April 1, 2010 and March 31, 2020. The number of examinations since 2010 has been increasing every year, with the highest number of 33,403 in 2019. A total of 269,170 imaging examinations was performed for the past 10 years. The number of examinations including MRI has increased 1.4 times from 24,106 to 33,403 in the last 10 years, and the number of examinations is expected to increase further in the future. In particular, the number of dental cone-beam CT examinations increased remarkably, approximately six times.

Based on the results of this survey, the role of dental cone-beam CT is expected to increase in the future, and the application of MRI in the diagnosis of temporomandibular joint disorder and oral lesions is also expected to expand. For imaging diagnosis, knowledge of the device principles, imaging anatomy, and diagnostic techniques of dental cone-beam CT and MRI will be also required. Based on this knowledge, we will continue to devote ourselves to clinical practice, education, and research in order to fulfill the roles of the Central Imaging Center in the Osaka Dental University hospital and the Department of Oral Radiology in the university. Shika Igaku (J Osaka Odontol Soc) 2022; Mar; 85(1): 14-20.

We inserted nasogastric tubes (NGTs) into 47.4% of the 586 patients who underwent oral surgery under general anesthesia (GA) at our hospital in 2020. This study outlines our recommended checklist for recording details related to the NGTs and our procedures for verifying if they were malpositioned. The checklist is followed to assure safety of the patient. This procedure was followed in 53.6% of our cases where an NGT was used. Recording of this information on the NTGs was more complete than that in the anesthetic record. Analyzing our checklists, we found that 13% of the cases required more than one attempt to insert the NGT, probably due to malpositioning of the tube. We attempted to determine if the NGT had been malpositioned by a combination of drainage or auscultation, and by another method using a CO2 monitor and pH tester. The pH measurement, which was used in 12.5% of the cases, was adequate in most instances. We found that the checklist was useful in managing the NTGs from the standpoint of patient safety. We recommend use of this checklist for all cases. Shika Igaku (J Osaka Odontol Soc) 2022; Mar; 85(1): 21-27.

Afferent stimulation from the oral cavity affects swallowing reflex movements. The purpose of this study was to investigate the effect of sensory input to the oral mucosa on the voluntary swallowing reflex.

[Aims/objectives]. The subjects were the patients over 65 years old who was hospitalized in the convalescence ward, and 3 meals ingestion was possible. Thirty-one subjects [Nine, male and Twenty-two, female (Average age: 82.4 years old)] were randomly divided into stretch (n=15) and vibratory (n=16) groups. The Repetitive Saliva Swallowing Test (RSST), RSST accumulated time, oral mucosa wetness, and maximum tongue pressure were measured pre and post stimulation.

The RSST significantly improved in both the stretch and vibratory stimulus groups (P<0.05). The RSST accumulated time was measured up to the third time and was significantly shortened only in the stretch stimulus group (P<0.05). There were no significant differences in oral mucosal wetness and maximal tongue pressure.

Within the limitations of this study, it can be concluded that the swallowing reflex induction could be improved by stretch and vibratory stimulus to the oral mucosa. In the vibratory stimulus group, there was no significant difference in RSST accumulated time. Potential reason is receptor temporarily becomes desensitization right after the stimulus. For the future, it is recommended to examine the change of the RSST accumulated time after the fourth. Shika Igaku (J Osaka Odontol Soc) 2022; Mar; 85(1): 28-38.

Surgical orthognathic treatment is a large part of oral surgery. This paper is a clinical and statistical study of 1556 patients who underwent orthognathic surgery in our department over the past 26 year period from April 1993 to March 2019. We compared the sex, age at surgery, surgical technique, operation time, and intraoperative blood loss for each year. In our study, April 1993 to March 2006 was considered Period I, and April 2006 to March 2019 was considered Period II. The total number of patients in Period I was 735, and there were 821 in Period II. The male to female ratio was almost 1:2, with 466 males and 1090 females, and there was no significant difference between the two periods. The youngest patient was 15 years of age and the oldest was 64. The majority of patients were between 10 and 40, with the largest group in their 20s in both Periods I and II.

The most common surgical procedure was the sagittal split ramus osteotomy (SSRO) in both Periods I and II, followed by two-jaw osteotomy. Compared to Period I, Period II saw a threefold increase in two-jaw osteotomy. The operative time was about 10-20 minutes shorter in Period II than in Period I. The amount of intraoperative blood loss did not differ significantly between the two periods. The number of cases of surgical orthodontic treatment for jaw deformities has been increasing in our department due to the increase in awareness of esthethics, especially among patients in their 30s and 40s. In addition, the number of cases of two-jaw osteotomy and genioplasty increased proportionately with the increase in the number of cases, with a trend toward a diversification of cases. Furthermore, we found that as the level of skill of the surgeons increased, while the operation times and blood loss decreased. Shika Igaku (J Osaka Odontol Soc) 2022; Mar; 85(1): 39-44.

The purpose of this study was to clarify the impression that tooth color differences in female smiles imparts on dental students using the Semantic Differential Method. The subjects were 38 undergraduate dental students. The stimulus images used were the average faces of ten adult females with smiles processed to shade guides C4, A2 and NW0. The stimulus images were presented to the subjects, and they were asked to rate their impressions of each image on a Likert scale using fifteen adjective pairs. The semantic differential (SD) profiles were then created, and the ratings of C4, A2 and NW0 for each adjective pair were compared. We found that although NW0 gave more positive impressions, it lacked naturalness and realism. A2 gave the impression of being most natural and realistic, while C4 gave more negative impressions than NW0 or C4. These results indicate that the tooth color in female smiles imparts various impressions on dental students. Shika Igaku (J Osaka Odontol Soc) 2022; Mar; 85(1): 45-51.

Local community dental offices often do dental treatment for the disabled and those who need nursing care. This is done in smooth collaboration with university hospitals and general hospitals. As a higher medical institution, we are responsible for dealing with cases that are difficult for primary care facilities. We evaluated the charts of patients who came to our hospital for their first visit during the three years from January 1, 2018 to December 31, 2020. From the charts we recorded the patient's age, type of disease, disability certificate, residence, referral source, behavioral management method, and dental treatment. There was a wide distribution in the characteristics of the patients at their first visit. In particular, the number of patients under 30 and over 70 years of age trended to increase every year. The proportion of patients with severe disabilities was also high. This information should help in providing seamless medical collaboration to improve the oral hygiene and quality of life of disabled patients. Shika Igaku (J Osaka Odontol Soc) 2022; Mar; 85(1): 52-57.