This article reviews the current situation of CBCT in terms of the indications, the exposure dose to the patient and its reduction, and quality assurance in the use of CBCT. Plenty of articles related to these topics including several guidelines based on the scientific evidence have been published and these cover essentials for consideration in these tasks. Such evidences are helpful for clinicians when considering the application of CBCT, and suggest that clinicians should keep abreast of recent advances in CBCT technology.

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Several international standards in maintaining the safety and quality of oral health practice are important, but many dentists may be unaware of the role of such standards. This article outlines the current activities for the dental products/materials by the ISO/TC106, the dental X-ray machines by the IEC/TC62, the communications of clinical information by the DICOM Committee and other standards committee, and the medical/dental terminology by the ICD related committee. In addition it highlights how standards pervade nearly every dental procedure.

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Recently, there has been growing interest in food and eating in Japanese society, including public health and medical care. One of the topics that has emerged is functional development in eating. In child health, there have been many interdisciplinary studies between medicine and dentistry on mothering such as breastfeeding and weaning. In addition, many authors reported on eating function training in developmentally retarded children. In this article, we reviewed this area that has emerged over the last three decades. The analyses involved both public health and medical care, especially studies in Japan in the 1980’s and 1990’s. The importance of dental interventions on eating for normal physical and mental development in children might be increasing, irrespective of having a developmental disability regarding eating.

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Due to Japan’s rapidly aging population, patients with some kind of severe systemic disease are increasingly going to the dental office. As such, society’s need of dentists who can treat these types of patients is higher than before. Unfortunately, sometimes general practitioners are unable to give these patients appropriate care because of the high risk of their treatment. So, a community dental network between dental offices and the hospital is becoming necessary. I have received many referrals to treat such high-risk patients for many years while work at several hospitals. I would like to talk about my history and the achievements I made in creating a community dental network, and make some suggestions based on my experiences.

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Chronic kidney disease (CKD) is one of the wide prevalent disease, and it is not negligible that a dentist have a chance to prescribe an antibiotics for a CKD patient with a low kidney function. Beta-lactam antibiotics, such as penicillin antibiotics or cephem antibiotics, are most frequently prescribed drugs in dental office. Most dentists will be careful about allergic adverse effects of beta-lactam antibiotics, but only a few dentists will recognize that beta-lactam antibiotics are excrete mainly from kidney, and that these drugs are recommended to adjust the dosing schedule for the patient with a low kidney function. If you administer a renally-eliminated drug repeatedly for the CKD patient with an elongated half-life, the mean plasma drug concentration in stable phase will increase to toxic concentration. Pharmacokinetically-guided correction coefficient will be helpful to get an adequate dosing schedule for the patient with a low kidney function. The reference chart of recommended dosing schedule for the CKD patients will also be helpful.

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Since joining Showa University, I have been studying the regulatory mechanisms related to differentiation and functions of hard-tissue-constituting cells. Here I present two topics that have recently received out attention. The first is monocarboxylate transporter-1, a molecule involved in cellular energy metabolism, which controls the expression of phagocyte-type NADPH oxidase and cell death in chondrocytes. The other is lysine gingipain, a protease produced by Porphyromonas gingivalis that promotes osteoclast differentiation.

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Streptococcus mutans uses two-component signal transduction systems (TCSs) to monitor and respond to the fluctuating pH levels to survive the human oral cavity. The TCSs modulate the expression of genes encoding products crucial to cell survival. CiaRH is one of TCSs that is thought to be responsible for the acid tolerance of this pathogen; however, the target molecules modulated by the CiaRH have been still unclear. In this study, we identified that a lipoprotein OpcC contributes to the acid tolerance of S. mutans. The opcC-deficient mutant showed higher acid sensitivity than the wild-type 109c. In addition, deletion of the gene encoding prolipoprotein diacylglyceryl transferase (Lgt) eliminated OpcC on the cell surface of S. mutans. These results suggest that OpcC is an acid-tolerance related lipoprotein that is lipid anchored in the cell membrane by Lgt. Relationship between opcC and CiaRH was assessed by transcriptional analysis of S. mutans in the acidic or neutral conditions. The opcC expression was increased in the wild type and ciaR mutant in the acidic environment. However, the opcC expression was not increased in the ciaH mutant by the acidic stress. These results suggest that acidic stress sensing by CiaH is essential for the increased expression of opcC. Collectively, S. mutans OpcC is an acid tolerance-related lipoprotein whose gene-expression is enhanced via CiaH by sensing the acidic stress. In this study, we clarify the partial mechanism mediating S. mutans survival in acidic environments by showing the link between CiaRH and OpcC.

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To clarify 1) how the signal fading effect occurs and 2) the diagnostic quality of the signal fading image in caries diagnosis. The Digora Optime (Soredex, Helsinki, Finland) system was used. Aluminum step wedges of 1 to 10 mm thickness and 1-mm-thick lead were used. Exposed photo-stimulated phosphor imaging plates (PSP-IPs) were scanned at six different intervals: immediately, 3, 6, 24, 72, and 144 h. Two kinds of scanning modes were used: with and without auto enhancement correction (AEC). The gray value difference between the immediate and delayed scanning images in the same objective area was calculated as the signal fading effect value (FEV). Thirty extracted upper premolar teeth (carious: 42 surfaces) were used. Immediate, 3, 24, and 72 h delayed scan images were created. Four observers assessed them. The Friedman test was used for statistical analysis and statistical significance was p<0. 05. Analysis of the without AEC image revealed that the signal fading had the same gray value change. This change was not related to the initial gray value. In the processing of AEC, the middle part of the gray value tended to be more enhanced. Significant differences in gray value changes were observed after 3 h, but no statistically significant difference was seen in the caries diagnosis. The area under the receiver operating characteristic (ROC) curve (Az) from immediate, 3, 24, and 72 h delayed images was 0. 61±0. 17, 0. 56±0. 04, 0. 67±0. 04, and 0. 58±0. 06.

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To avoid excessive excavation of carious dentin, we developed a caries-detecting agent composed of polypropylene glycol to stain caries-affected dentin. The purpose of this study was to evaluate the new agent by examining the characteristics of the dentin surface after removal of carious dentin. Eight extracted human teeth with dentin caries were used. The teeth were longitudinally sectioned through the center of the caries and micro Vickers hardness (MVH) was measured from the pulpal wall to the caries cavity every 200 μm. Carious dentin was then removed using a steel bur following Caries Check (Nishika, Yamaguchi, Japan) staining. After removal of the stained dentin, the MVH of the dentin was determined by observing the indentation on the dentin; the DIAGNOdent value (D-value) was measured using DIAGNOdent (Kavo, Biberach, Germany). Then a new caries-staining agent (Discover RED, Phoenix Dental, Inc., Fenton, MI, USA) was applied in the cavity, the stained dentin was removed, and the MVH and D-value were measured. Finally, such procedures were repeated using Caries Detector (Kuraray, Tokyo, Japan). After the final measurements, the microstructure of the dentin cavity wall was observed by scanning electron microscopy. The differences in the MVH and D-value between using Caries Detector and Discover RED were not significant. However, the differences in the MVH and D-value between the Caries Check and the other two methods were significant. Caries Check may be the most useful modality for the more precise excavation of carious dentin and preservation of sclerotic dentin.

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With super aged society in Japan, the death rate from choking due to blockage of the oropharynx has increased; it is now greater than that from traffic accidents and it is believed that this rate will continue to increase. The shape and function of the oropharyngeal crossing with the respiratory tract are most influential in ensuring that food is carried from the oral cavity to the pharynx and the esophagus. We sought to clarify the changes in the shape and features of the oropharyngeal airway from teenagers to those in their 70 s. A total of 57 patients were grouped by age (teenagers, 20s, 30s, 40s, 50s, 60s and 70s), and all underwent cone beam computed tomography (CBCT) to measure the oropharynx volume, height, cross-sectional area, and length of the superior and inferior extremities. Kruskal-Wallis analysis indicated that the volume and height of the oropharynx did no significant difference among age groups, but there was a different tendency when cross-sectional areas of the superior and inferior extremities were compared between younger and older patients. Further, the shape of the inferior extremity was also different features between younger and older patients. In humans, the oropharyngeal airway plays an important role in carrying food through the esophagus and facilitating phonation. Ideally, it is important for this airway to maintain a constant volume and height. Recently, there has been an increase in the incidence of oropharyngeal airway blockage accidents among the elderly. Declines in feeding and swallowing functions and changes in the form of the oropharynx are major factors in these accidents.

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Many aspects of the coordination of lip and mandibular movements in the process of eating have not yet been clarified. This time, aiming to objectively evaluate lip and mandibular movements when chewing, the movements of the corners of the mouth and the mandible during mastication were measured three-dimensionally and analyzed. The subjects were 20 healthy women with individual normal occlusion. The test food was a commercially-available biscuit with a weight of 1 g. With six measuring points set for the lips and pogonion, the movements at those measuring points were captured with two CCD cameras during mastication, and the resulting images were analyzed with a three-dimensional motion analysis system. The analysis result showed that X- and Z-axis movements occurred on the working-side corner of the mouth, with Z-axis movements preceding X-axis movements, while on the balancing-side corner of the mouth, X- and Z-axis movements occurred simultaneously. Data on the amount, time taken, and speed of movements measured at each anatomical landmark showed that the working-side corner of the mouth moved a greater distance at a faster pace and, therefore, in less time than that of the balancing-side corner of the mouth. This is conceivably due to the aforementioned differences in X- and Z-axis movements of the working-side and balancing-side corners of the mouth. Further comparisons and studies with expansion of the subjects to include children will be necessary.

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We examined the effects of fructooligosaccharide (FOS) consumption on gastrectomy-evoked osteopenia in rats. Forty-two 35-day-old male Sprague Dawley rats were equally divided into two groups and a sham operation group or a total gastrectomy group was performed. Four weeks after each surgery, 14 rats were killed in each group (BaseSH and BaseGX groups). Thereafter, the remaining rats were equally divided into two sub-groups; with or without 7.5% FOS (1.35 g/day)-feeding (SH, SH+FOS, GX and GX+FOS groups) for six weeks. Backscattered electron images of the tibial cross-sections were taken to calculate the cortical bone area (CBA). The CBA in BaseGX rats was markedly decreased. Thereafter, FOS-feeding significantly counteracted this reduction, but not to the level seen in SH rats. These results suggest that FOS consumption partially restored osteopenia in cortical bone following the gastrectomy.

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In the Showa University Dental Hospital, we start free oral cancer consultation for those who have uneasiness in suffering from the oral cancer at oral and maxillofacial surgery visitors from October, 2007.
It responds to the consultation on Saturday by the reservation system every week.
It is the clinical statistics for 264 patients that consulted our hospital for the past four years from 2007 to 2011. We reported it about the number of patients according to by year, sex and age, the clinical diagnosis, the address, and the medium that got to know free oral cancer consultation. The average number of patients who visit free oral cancer consultation was 64 per years, and the clinical diagnosis for consultations was stomatitis. It followed with leukoplalia, benign tumor, palatal and mandibular torus and dentistry disease next to it. Oral cancer was diagnosed in 2 patients.

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[in Japanese]

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[in Japanese]

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