Juvenile periodontitis (1977, AAP) was renamed as aggressive periodontitis at the International Workshop for a Classification of Periodontal Diseases and Conditions in 1999. In 2017, the AAP and EFP (European Federation of Periodontology) jointly reached the consensus that invasive periodontitis, which had been distinguished from “chronic periodontitis,” could not be proven to be a pathophysiologically distinct disease, and the category of periodontitis was unified to periodontitis and classified according to its severity, rate of progression and extent. The new classification is characterized by (1) the definition of the disease at the patient level rather than at the local condition, (2) the stage (severity) and the extent to assess the complexity in respect to disease control as well as management and maintenance of dentition, and (3) the grade (rate of progression) to estimate the future risk of periodontitis progression and the likely responsiveness to standard therapeutic principles. This resolved the paradox that tooth loss was included in the index of severity and that extraction reduced the severity of the disease. Grades may have become useful as therapeutic indicators because they assess not only the status of bone resorption, but also the risk of progression and responsiveness to treatment, but no biomarker has been established to distinguish between the grades.

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It has been shown that influenza is influenced by increasing bacteria in the oral cavity. Oral infectious diseases and poor oral hygiene are risk factor for aspiration of oral microorganisms to enter the lower respiratory tract and thus cause respiratory infectious disease. Recent clinical studies revealed that co-infection of SARS-CoV-2 with oral bacteria aggravated pneumonia by interacting with immune responses. Oral health by dentistry and oral care is significantly effective to reduce risk of respiratory virus infections.

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Hypophosphatasia (HPP) is a genetic disorder of bone system with the main symptoms of “impaired bone calcification” and “early deciduous tooth drop-off under 4 years of age”. In 2012, the Department of Pediatric Dentistry, Osaka University Dental Hospital opened an outpatient department specializing in dentistry for bone system diseases, and has been managing the oral cavity of HPP patients in collaboration with the Department of Pediatrics. In addition, since 2015, we have been aiming to build a system that leads to early diagnosis by referring suspected cases to the medical field through screening at dental facilities. The present paper summarizes our activities so far by conducting a fact-finding survey of HPP patients who visited our department and an analysis focusing on odontohypophosphatasia with little knowledge acquired to date. Searching for HPP patients who visited our department in the last 5 years from April 2015, about 24 cases were extracted, and more than 1/3 of them were diagnosed after being referred to our department from a nearby dental clinic. This suggests that an early screening system has been constructed in the area around our hospital. It was also revealed that dental symptoms were the first to be detected in more than half of the cases. In addition, there were some cases in which problems with growth and development were noticed but no diagnosis was given. It was revealed that 11 cases of the odonto HPP had significantly more autosomal dominant inheritance than cases of other hypophosphatasia. Additionally, it was shown that the ALP value at the time of diagnosis was significantly high and close to the normal value. Since the reports of the mild cases are scarce, it is considered that dissemination of the findings obtained in this study may contribute to the development of the conventional early diagnosis system.

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A follow-up study of autologous tooth transplantation A follow-up study was conducted to determine the current status of autologous tooth grafting performed at author’s institution and to identify areas for improvement. The scope of the survey was set as autologous tooth transplantation performed during the period from April 2005 to March 2018 and the subjects included 52 people and 52 teeth received autologous tooth transplantation. The average age was 44.6 years and the average duration of observation 4.1 years. Most of the reasons for tooth extraction in the recipients that required autografting were due to caries lesions. Most of the donors were mandibular third molars (69.2%) and most of the recipients were mandibular molars (78.8%). The 5-year survival rate by the Kaplan-Meier method was 89.2%: 6 teeth were lost. The state of engraftment at the time of tooth grafting had the greatest impact on the postoperative course, including the loss of teeth. In the analysis of risk factors, a significant difference (p＜0.05) was found for smoking in the log-rank test results. On the other hand, there were no significant differences in gender, age (＞50 years and ＜50 years), or root morphology (single root and double root). In our hospital, 77 autologous teeth were transplanted during the same period, which averaged 1.5 teeth per year per dentist. Autologous tooth grafting is a less common procedure in dentistry.

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The strongest evidence for smoking as a risk factor for periodontal disease has been established, and in order to scrutinize their relevance we analyzed real-world clinical data on periodontal tissue examination and smoking habit collected at the member clinics of the Japan Health Care Dental Association (JHCDA). The results showed that smoking status at the initial periodontal tissue examination was more strongly related to the number of remaining teeth and the number of missing teeth than smoking status at the re-evaluation, and that smoking cessation during the study period had not a significant impact on the number of remaining teeth. When the degree of periodontal disease progression was taken into account, but smoking status was significantly correlated with the number of remaining teeth and the number of missing teeth in cases of periodontal disease at moderate or severe stages, suggesting that smoking cessation may save teeth when the progression of periodontal disease was in its moderate or severe stages.

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The Japan Health Care Dental Association has established a system to certify clinics that meet the requirements of “health care practice” (e.g., setting preventive care as the basis of treatment, sharing information with patients, treating patients as a team, establishing a maintenance system, etc.) as “dental clinics that protect and nurture health” to be conditioned on a questionnaire asking for patients’ ratings of the treatment. The results of this anonymous mail-based questionnaire survey (57 clinics, 8,567 responses) were secondarily used to investigate implementation status of the following examinations: (1) intraoral photography, (2) dental X-ray, (3) caries risk examination, and (4) periodontal tissue examination. For the four tests, (a) the test implementation rate and (b) the comprehension rate of the test results were evaluated, and (c) the comprehension rate of the need for regular maintenance was also investigated. After anonymizing 57 dental clinics, (a), (b), and (c) of each clinic were calculated, and the clinics were plotted against the coordinates of (a) and (b) as well as (b) and (c), and the correlation between (a), (b), and (c) was examined with the distribution of the clinics (correlation coefficient). As a result, no correlation was found between (a) the test implementation rate and (b) the comprehension rate of the test results while a correlation was found between (b) and (c) the comprehension rate of the need for regular maintenance. All of (a), (b) and (c) are medical services carried out by dental hygienists, and the importance of their roles was confirmed.

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This survey was conducted to investigate oral health status of new patients at dental clinics practicing routine maintenance. Subjects were collected in anonymised digital format from Japan Health Care Dental Association (JHCDA) member clinics. The subjects of this 13th survey included 13,654 new patients (5,889 male and 7,765 female patients) who visited the 56 member clinics (across 25 prefectures) during the period between January 1st and December 31st, 2018. For children and minors, the DMFT scores were recorded, and for adults the DMFT scores, the number of remaining teeth, the condition of periodontal tissues and smoking status were recorded. As a result, the DMFT index continued to decrease across all age groups above 12 years old; the prominent decrease of male smoking population across all age groups continued; and the number of remaining teeth continued to increase across age groups above 65 years old in both male and female population.

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