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.
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.