It is important for pediatric dentists to find effective means of communicating oral hygiene instructions to their patients. The purpose of this study was to investigate the current status of fluoride toothpaste use by child patients in order to promote its proper use. The subjects were 383 children under 13 years old who visited the Pediatric Dentistry Department of Chiba Dental Center, Tokyo Dental College, from May 2018 to April 2020. The use of fluoride toothpaste was surveyed by questionnaire, with the following results:

1. The rate of fluoride toothpaste usage of all subjects was 88.6% and 91.0% among 6 to 12 year-old children.

2. When asked about the fluoride concentration of the toothpaste they used, most subjects answered that they did not know. Furthermore, only 9.5% of the subjects aged 0 to 2, 1.0% of those aged 3 to 5, and 10.5% of those aged 6 to 12 years selected toothpaste containing an appropriate fluoride concentration for their age and used an appropriate amount.

3. As for the effect of fluoride, 81.8% of the subjects answered that they understood it to some extent, while 220 indicated that they had obtained such knowledge “from a dentist and/or dental hygienist.”

4. The most common reasons given for selection of a specific toothpaste were “dental caries prevention” and “contained fluoride.”

We conclude that accurate and adequate information regarding fluoride toothpaste is important for effective caries prevention. Additionally, it is recommended that the fluoride concentration be indicated on the toothpaste package to promote appropriate age-specific use of fluoride toothpaste.

The Heisei Era ended at the end of April 2019 and the Reiwa Era began.

For about 30 years in the Heisei era after the Showa era, the environment surrounding children changed rapidly, including the economic downturn, the acceleration of late marriage and declining birthrate, and progress in information and communication technology. As a result, individual households have diversified and a large polarization has become apparent. As pediatric dentists, we need to deal with and support children with all kinds of problems. Therefore, to clarify the transition of the first-visit patients in our clinic, we categorized the 30 years from 1989 to 2018 by five-year groups: early (1989-1993), middle (1997-2001) and late (2013-2018) stages, with a total of 5,892 patients, and then investigated and analyzed their properties. As a result, the number of new patients decreased from 2,477 in the early stage to 1,301 in the late stage. The male-female ratio was approximately 1:1 in each period. As for age, school age was the highest at about 40%, and there was no significant change in the age composition in each period. The most common chief complaint during each period was tooth decay, but it decreased from 44% in the early stage to 27% in the late stage. The proportion of children who brought a letter of referral increased from 23% in the early stage to 83% in the late stage, and the proportion of children with disabilities and illness increased from 13.8% in the early stage to 33% in the late stage. Compared to the early days, the chief complaints have diversified, and it has become clear that the functional differentiation of general dental clinics and university hospitals is progressing. Furthermore, it was suggested that the importance of medical and dental cooperation will increase in the future.

Following the revision of dental fees in 2012, oral function management for the perioperative period was newly established for the purpose of comprehensive management. We investigated the current status of oral function management for the perioperative period in children at designated hospitals for pediatric cancer from 2012 to 2018 (7 years).

Of the 568 patients referred by the medical department of our hospital to the department of pediatric dentistry during the study period, 259 (45.6%) underwent perioperative oral function management. Of these, more than half, that is 142 (54.8%) patients, were preschoolers aged 1–6 years. Management associated with surgery and hematopoietic stem cell transplantation was performed in 124 (47.9%) patients, and the remaining 135 (52.1%) underwent radiation therapy or chemotherapy. The latter has increased, particularly since 2015. Acute lymphocytic leukemia (44 cases, 17.0%) was the most common systemic disease, followed by neuroblastoma (19 cases, 7.3%), chronic granulomatous disease (19 cases, 7.3%), acute myeloid leukemia (18 cases, 7.0%), and osteosarcoma (18 cases, 7.0%). The average number of times of providing care per patient was 13.1 and the maximum was 80 (management period: approximately 1 year and 2 months). There were many cases in which care was required beyond the number of times that insurance could be calculated.

Oral management from a long-term perspective is required not only during the perioperative period but also for late-stage disorders that occur after radiation therapy, chemotherapy, and hematopoietic stem cell transplantation.

A method for predicting the proximal coronal width of permanent teeth from panoramic X-rays and dentition models during the deciduous stage was devised. The subjects were 24 orthodontic patients (5 boys and 19 girls) who had panoramic X-rays and dental models taken during the deciduous dentition and who had dental models of the permanent dentition in the completed dentition, and their average age was 5 years and 8 months (4 years and 3 months to 6 years and 9 months).

The results showed that the predicted diameters of the proximal crown widths obtained from panoramic X-rays had a magnification rate of 1.00±0.08 and an error of 0.38-1.00 mm compared to the measured values. There was a correlation between all of the predicted and measured values.

These results suggest that the diameter of the crown proximal width of a permanent tooth can be predicted by the crown proximal width of a successor permanent tooth (panoramic X-ray) / ((crown proximal width of a deciduous tooth (panoramic X-ray) / crown proximal width of a deciduous tooth (deciduous tooth row model)).

Metal allergy is an allergic reaction that occurs when metal touches the skin or mucous membranes, and eluted metal ions are taken into the body. Here we report a case of metal allergy caused by the mouthpiece of a musical instrument. The patient was a girl of 10 years and 8 months. Since joining the brass band club of her elementary school, gingival swelling and inflammation in the oral cavity had appeared. Therefore, a patch test and a blood test were performed by a local clinic, but both metal allergies and autoimmune diseases were denied. At the first visit to our hospital, the labial and buccal gingiva and buccal mucosa presented mild spontaneous pain and diffuse swelling with redness. The gingiva bled easily, and had grown over, forming false pockets. The periodontopathic bacteria were below reference values in the periodontopathic bacteria test. Histopathological examination revealed that the gingival overgrowth was periodontitis. Although we started to provide professional oral care, her condition did not improve. Eleven months later, the inflammation in the oral cavity drastically improved. We found that the musical instrument (tuba) had been changed to a new one. After that, the condition of the oral mucosa was healthy. The old mouthpieces had some spots where the plating had peeled off. Energy dispersive X-ray fluorescence spectrometry was carried out for an element analysis of the mouthpieces, and a metal patch test was also performed. The results showed that she may have had an allergic response to Cr. Finally, we diagnosed oral mucositis caused by metal allergies. The patient made steady progress after the mouthpiece was changed.

In recent years, there have been reports that the incidence of juvenile temporomandibular disorders is on the rise. However, few studies have involved taking quantitative measurements over time. In this study, we conducted magnetic resonance imaging (MRI) on an 11-year-old girl with a chief complaint of crepitus in the left temporomandibular joint region and trismus due to left masseter pain, at her initial consultation, then again at 6, 12, and 36 months. We conducted follow-ups over time, and took quantitative measurements of the mandibular condyle anterior functional surface area and mandibular fossa area. While there was no bone deformation in the right mandibular condyle and the mandibular condyle anterior functional surface area had increased over time, bone deformation was found in the left mandibular condyle, with no increase in the mandibular condyle anterior functional surface area. Jaw exercises and correction of her tooth contact habits (TCH) resulted in a good outcome, so we report here on this case.