As there were no strict guidelines about the use of electric dental devices near patients with a cardiac pacemaker, the electro-magnetic interference by an electronic apex locator, a pulp tester and an iontophoresis apparatus to cardiac pacemakers were examined by using an experimental model. Although the electronic apex locator and pulp tester were found to give no interference to cardiac pacemakers, the iontophoresis apparatus altered the pacing waveform and changed the pacing interval. It is suggested that an iontophoresis apparatus should not be used for endodontic treatment of a patient with a cardiac pacemaker.

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There are few reports of the association between occlusal interference and the change of systemic symptoms which provide evidence of the relationship of the cause and the effect or crisis mechanism. This study attempted to analyze fundamentally the reciprocal relation of Activity (Act), Heart rate (HR), Systolic blood pressure (SBP) and Diastolic blood pressure (DBP), stress added to the oral region, and stress responses of Circulatory Hemodynamics (CH) in WKY and SHR with the use of a telemetry system. On the first day of implantation surgery of the transmitter, Act of WKYs and SHRs decreased remarkably, and HR increased significantly. A stable recovery from this surgery stress takes 7 to 10 days. In the stable recovery stage, circadian rhythms of Act and HR were observed in WKYs and SHRs, but the circadian rhythm of Blood pressure (BP) was not clear. There were no significant differences in HR between WKYs and SHRs at rest time. SBP and DBP at rest were significantly higher in SHR than WKY. It was followed by an increase of Act and HR with an increment rate of BP larger in SHRs. After the unilateral bite raising splints were set on the upper teeth, the primary value of Act and HR in WKYs and SHRs decreased remarkably and then recovered slowly. However, SBP and DBP tended to increase in WKYs and SHRs, and the variation range of BP was wide. The variation range was larger in SHRs. The result of the present study suggests that it is necessary to study the stress responses, considering the circadian rhythm and the variation of Act, HR and BP in an individual animal when continuously observing CH of WKYs and SHRs for a long term with the use of a telemetry system.

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Carisolv, a reagent for chemomechanical caries removal has been developed, authorized and used in clinical situations in Sweden. The purposes of this study were to examine the ability of Carisolv for carious dentin removal, compare the result to that by sodium hypochlorite (NaOCl) as an organic dissolution agent, and search the further possibility of caries removal by Carisolv with Root Canal Preparation Cream (RC-Prep^TM) as an inorganic dissolution agent. Thirty freshly extracted human teeth with chronic caries were used in this study. Gel A which contained a few kinds of amino acids and Gel B which was mainly composed of NaOCl were mixed and applied to carious dentin for 20 or 30 sec, and then carious dentin was removed with special excavators. This procedure was repeated twice. The efficiency of caries dissolution by Carisolv was compared to that by NaOCl (Experiment 1), and to that by RC-Prep and Carisolv (Experiment 2). The specimens were observed by stereoscopy and scanning electron microscopy (SEM) to assess the degree of caries removal after stained by 2% acid red in propylene glycol. Carious dentin was removed by Carisolv more than by NaOCl only in Experiment 1. There was no difference on the caries removal by order of Carisolv and RC-Prep applications, but the efficiency of the carious dentin removal by Carisolv with RC-Prep was almost same level or more than that by Carisolv only in Experiment 2. The stereoscope and SEM were used for the judgment on the remnant of carious dentin in this study, but it was problematic. These results show the ability of Carisolv for carious dentin removal and suggest that the usage of Carisolv with RC-Prep enhances the ability of caries removal, though it was problematic whether the caries was removed completely or not.

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The purpose of this study was to investigate the adaptation of premolar full cast crowns. Premolars extracted for orthodontic treatment were used for the in vivo study and premolar epoxy dies were used for the in vitro study. The cement thicknesses of the full cast crowns fabricated using three different impression methods were measured at five measuring points. The results were as follows :
1. All the mean cement thicknesses of the in vivo studies were twice those of the in vitro study.
2. The cement thicknesses of the crowns fabricated using the individual tooth tray method were thinner than those of the crowns fabricated using the other impression methods.
3. The cement thicknesses of the marginal and axial portions were thinner than those of the occlusal portions.
4. In this study, we concluded that the adaptation of the full cast crowns fabricated using the three impression methods was clinically acceptable in both the in vivo and the in vitro studies.

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Three-dimensional observation was performed to clarify sexual difference in the Japanese face configuration by analyzing the facial images of the frontal views using moiré topography.
Results : Analysis of the width of the face revealed that female had wider structures in the middle of the face than male. In the length of the face, the ratio of the structures in the middle of the face was higher in female than in male. These results may show that as seen in a baby's face, female have smaller masticatory apparatus than male. Regarding the depth of the face, projections were more apparent in male than in female. Analysis of laterality revealed that the figures were larger on the left side in most of the items. Moreover, there was a significant difference in the Alare height and stomion height, both of which show the length of the masticatory apparatus, in both male and female. These findings indicates that the masticatory apparatus was better developed on the left side than on the right side.

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The three-dimensional organization of collagen fibrils in the human temporomandibular joint disk was investigated by scanning electron microscopy. In the anterior band of the temporomandibular joint disk, collagen fibril bundles running in an anteroposterior and mediolateral directions were organized into a series of closely packed layers. The fibril bundles in the intermediate zone of the disk were predominantly oriented in an anteroposterior direction. The main bundles formed linear and wavy architectures exerting stiffness in tension. Roundish cells distinguished from spindle-shaped fibroblasts frequently occur in the intermediate zone. The roundish cells may be chondrocytes resulting from a corresponding change of mechanical stresses to which the disk is subjected. In the posterior band of the disk, the fibril bundles of various size were oriented in an anteroposterior direction in the articular surface and in an anteroposterior, mediolateral, and superoinferior directions directly bellow the surface. The fibril bundles of the central area were irregularly interlaced for absolving compressive stress. The main bundles composed of linear and wavy fibril architectures became less compact in the junction between the posterior band and bilaminar zone. The fibril bundles in the junction frequently present a spiral appearance. These distorted bundles seem to provide some elasticity under a tensile stress.

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The accuracy of square measure of regions of interest using an NIH Image was discussed. In this research, the area of circles, rhombuses and squares with various sizes which were digitally depicted on a display using Adobe Photoshop, were measured using an NIH Image. The errors between these measurements and the calculated values were examined. The areas of these figures were able to measure with accuracy below 1% above 20mm (57 pixels) in diameter or length of a side. Therefore, in order to make a measurement error smaller, it is necessary that a measuring object be indicated as largely as possible. In other words, the measuring objects must be input to a personal computer with high resolution and the number of pixels that compose a figure must be increased as much as possible.

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