Bacteria display extraordinary variation in their metabolic properties, cellular structures, lifestyle and pathogenicities. Several mechanisms could be responsible for the differences evident among bacterial species. These phonotypic changes are mainly induced by the acquisition of foreign genetic material through horizontal gene transfer known as conjugation, transduction and transformation. However, because new genetic material may also cause damage, removal of imported genetic material and protection against selfish invading genetic elements are also important. Recently, a new counterattack system against foreign genetic material, CRISPR (clustered regularly interspaced short palindromic repeats)/Cas (CRISPR-associated) system was discovered as a prokaryotic adaptive immune system. In addition, recent evidences indicate that the CRSIRP/Cas system not only work for the immune system but also contribute to the bacterial evolution by controlling the acquisition and exclusion of foreign genetic materials. In this review, I mainly focus on new mechanisms of the CRISPR/Cas system for bacterial evolution in Streptococcus pyogenes and Porphyromonas gingivalis.

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I have been allowed to follow an educational fi eld for 11 years from new assignment to Showa University. The activities can be devided into three periods; immediately after new assignment, period of the head of educational comittee, period of head of graduate school management committee. The struggles for the improvement of education were stated divided into 4 categories; geriatric dentistry, the education of the whole department of dentistry, graduate education, and activity off campus. At last, a future subject was analyzed.

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Surprisingly little is known about how the structure and composition of tooth dentin varies between different areas of the tooth. This study was to investigate and compare the mineral density of coronal and radicular dentin using ten bovine incisor teeth. The mineral density of coronal and radicular dentin was quantifi ed at two locations per tooth using micro-computed tomography (micro-CT). The coronal area was 15.0 mm coronal to the cemento-enamel junction on the buccal side of the tooth, while the radicular area was 5.0 mm apical to the cemento-enamel junction, also on the buccal side. Mean mineral density value was compared statistically by the paired Student's t-test. The mineral density of coronal dentin was 1,628.8±34.0 mg/cm³, and that of radicular dentin was 1,406.1±38.7 mg/cm³, suggesting that the dentin mineral density is higher in the crown than in the root. Micro-CT intensity data is a useful method for quantitating dentin mineral density.

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In this study, the contents of the Respiratory Support Team (RST)'s activities, present status of the activities, and oral health problems were evaluated to standardize the management of patients using ventilators at Showa University Hospital. The RST consisted of medical doctors, nurses, medical engineers, physiotherapists, dentists, and dental hygienists. The aim of the team was to standardize the management methods of ventilators and promote early weaning from ventilators. Between April 2011 and March 2012, the RST performed interventions for a total of 184 inpatients. The number of interventions was highest for respiratory medicine, followed in order by gastrointestinal medicine, hematology, cranial nerve surgery, and cardiovascular surgery. During rounds and in training sessions, the members of the RST explained and demonstrated the management of ventilators and facemasks to the staffs of wards where ventilators were used. The results indicated that the management methods of ventilators at Showa University were partially standardized through knowledge transmission from the members of the RST to the staffs of the wards. Moreover, since the dental professionals participated in the RST, the ward staff had opportunities to improve methods of oral hygiene management. However, some future recommendations were provided on indication sheets that varied according to the type of ventilator, and there was no standardization in terms of ventilator settings and facemask selection.

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In comprehensive dentistry, management is considered as an important conservative treatment for dental caries. It is expected that light-induced fluorescence by visible blue light of about 400 nm wavelength could be applied to accurate diagnosis and management of dental caries lesion. In this paper, non-contact type caries diagnosis systems was explained, and related research which was done in comprehensive dentistry will be introduced.
Commercially available caries recognition system VISTACAM-P could not identify a C₀, C₁, and C₂. However, the measured value of VISTACAM-P was important for caries observation or determination of the dental intervention, as same as it of DIAGNOdent. When light source of about 400 nm wavelength was irradiated, a light-induced fluorescence spectrums with three peaks between 770 nm and 600 nm on caries dentin, with a single peak about 480 nm on sound dentin and was recognized. Currently, an experimental caries dentin recognition and removal system, an ultrasonic equipment with an LED light source of 405 nm wavelength was considered for clinical application.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Errata
Vol.33 No.1 (2013) p55
（false）References
8） Imamura T, Travis J, Potempa J: The biphasic virulence activities of gingipains: activation and inactivation of host proteins. Curr Protein Pept Sci, 4: 443‒450, 3003
（true）References
8） Imamura T, Travis J, Potempa J: The biphasic virulence activities of gingipains: activation and inactivation of host proteins. Curr Protein Pept Sci, 4: 443‒450, 2003

［CONTENTS］　Vol.33 No.2 (2013)
(false) Review
The Role of University Dentistry Education in an Aging Society
Tomio INOUE
(true) Review
Review of the Kamijo Grant Prize Lecture, 2012
The Role of University Dentistry Education in an Aging Society
Tomio INOUE

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