Nichidai koku kagaku = Nihon University journal of oral science最新文献

Morphological observation of cervical line of deciduous teeth has been studied in many ways. But there are few reports of research observed from a three-dimensional view point. Using twenty seven mandibular right second deciduous molars, we studied morphological observation of cervical line of physiologically sound deciduous teeth by three-dimensional measuring system. Three-dimensional coordinate values were obtained from the center pit and the mesiolingual cusp of mandibular right second deciduous molar. We used the three-dimensional measuring system (Microcode BX 303: MITUTOYO), and then the three-dimensional coordinate values obtained were transferred to a microcomputer for analysis. As a result the figure of cervical line of the mandibular right second deciduous molar observed from the XY-axis can be grouped into two, and the Z-axis can be classified two types, and we found one new method related to the morphological observation of cervical line.

The purpose of this study is to find out the most suitable expansion speed in the rapid palatal expansion method in the rat. A total of 96 male rats of Wistar strain were used. The midpalatal suture of the rat was expanded by means of distal displacement of two maxillary incisors. Circular metal wedges of different thickness were inserted between the two incisors. The animals were divided into three groups according to the expansion speeds applied; slow, intermediate and rapid groups, respectively. It took 5 days in the slow group, 3 days in the intermediate, and 1 day in the rapid to achieve 2 mm interval between the two incisors. 1. Although the body weight of the rats was temporarily lost when an interval reached 2 mm, but it turned to gain after 48 hrs in the slow group, 72 hrs in the intermediate, and 96 hrs in the rapid. 2. A cephalography revealed that the width of the midpalatal suture in the control rats was 0.13 mm on the average. On the 6th day of the experiment, the width of the suture increased into 0.26 mm in the slow group, 0.34 mm in the intermediate, and 0.55 mm in the rapid. On the 26th day, however, the width of the suture in the slow and the intermediate group recovered to normal, while the width remained at 0.46 mm in the rapid group. 3. The width of premaxilla increased in the intermediate and rapid group. 4. Histologically, in the slow group, most fibers in the sutural tissue ran along the force line, the osteoid seam was conspicuous, and a few Howship's lacunae were found on the 6th day of the experiment. On the 26th day, the fibers were recumbent, the osteoid seam decreased in width, and Howship's lacunae were not found. It was assumed that the restoration of the expanded suture was almost complete. 5. On the 6th day of the intermediate group, the osteoid seam was conspicuous and some Howship's lacunae were found. The cellular infiltration and the impletion of capillaries were also found in the sutural tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

The stress distributions in the porcelain laminates under various kinds loading are analysed numberically in order to make clean the reason of their exfoliation or fracture. The two-dimensional finite element method is used to determine the principal stresses developed in the porcelain laminated and the teeth substance of a restored maxillary central incisor. The thicknesses of enamel preparations are assumed to be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm and 0.8 mm in the analysis. As a result of this analysis, the following points are made clear: 1) The stress concentration are observed at the vicinity of a loading point and in the cervical regions, independently of the loading conditions on its location and direction. 2) In case of the vertical loading, the location of loading point has no effect on the overall stress magnitude and distribution. 3) In the case when the load is applied in the 45 degrees-direction to the vertical axis, the overall stress level is increased, as the location of loading point is far from the supporting regions. 4) In the case when the load is applied normal to the vertical axis at the incisal edge, the high stress is obtained in comparison with other loading conditions.

A basic study was conducted utilizing a thermoelastic stress imaging method for stress analysis of model of simplified artificial molars based on an interocclusal contact relationship. This involved examining the effect of artificial saliva application on a stress field in a situation where occlusal pressure was applied in a dynamic sliding movement. As a result, the following conclusions were obtained. 1. The thermoelastic stress imaging method allowed the stress field to be determined artificial saliva application at distributed load due to plane contact in dynamic sliding movement. 2. Compared with the case of non-saliva application, in a squaremodel having a sliding movement and to which artificial saliva was applied, the pattern of the high compressive stress area was found to be a circle or an ellipsoid. This showed a slight dispersion trend at 10 degrees, with the contact plane as the boundary, and the dispersion of stress concentration began to become clearer at 20; stress concentration on the contact plane tended to disappear at 30 degrees, and sliding was conspicuous and determination impossible at 45 degrees. 3. Results showed that 10 degrees was a transition angle at which a different aspect was shown, representing a trend in a stress field pattern change accompanying an increase in the facet bevel angle when artificial saliva was applied. 4. From the results of stress analysis using the square-shape sliding movement model to which artificial saliva was applied, 10 degrees to 20 degrees of facet bevel of artificial molars was considered preferable in consideration of the presence of saliva.

Polyphenol compound (designated Sunphenon) from leaf of Camellia sinensis have been partially purified by extraction of the boiling water with ethyl acetate. The effect of Sunphenon on cariogenic Streptococcus mutans groups (serotype c and g) was studied in both in vitro and in vivo. The summary of results were described as follows; 1) Addition of Sunphenon to S. mutans JC-2 (c) caused a decrease in cell viability. The activity of Sunphenon showed that multiple application are required for killing and maximum effect was seen between 60 and 90 min treatment. However, treatment of S. mutans with Sunphenon did not induce complete cell death after 90 min incubation. 2) When S. mutans JC-2 (c) was pretreated with Sunphenon, the cellular attachment on saliva-treated hydroxyapatite surface was significantly reduced. 3) When saliva-treated hydroxyapatite surface was pretreated with Sunphenon, the cellular attachment of S. mutans JC-2 (c) was also markedly inhibited. 4) Sunphenon had no inhibitory effect on lactic acid production by S. mutans JC-2 (c). 5) Sunphenon showed a strong inhibitory effect against water-insoluble glucan synthesis by glucosyltransferase from S. mutans JC-2 (c) or S. sobrinus 6715 (g). 6) specific pathogen-free rats infected with S. mutans JC-2 (c) and fed a cariogenic diet containing 0.5%. Sunphenon developed significantly fewer carious lesions than controls infected with S. mutans and fed the same diet without Sunphenon. Furthermore, feeding of the drinking water containing 0.1% Sunphenon reduced caries incident in S. mutans in infected animals.

Two test teeth, anteriors with greater than or equal to 6 mm deep periodontal pockets from each of 10 patients with advancing periodontitis were included in this study. The clinical signs of advancing periodontitis, generalized moderate to deep pockets and to severe loss of alveolar bone, were observed in young adult. There have been several reports on factors, which reflect the conversion clinically from infection by highly pathogenic plaque bacteria to a from of periodontitis displaying relatively rapid loss of clinical attachment. The purpose of this investigation was to detect parameters in fluid, which could leak from the underlying inflamed connective tissue into the gingival crevice, and which could shown correlatively the progressive variations of periodontal disease by recurrent acute stage. In order to determine active disease sites and to monitor guantitatively response to therapy or to measure degree to susceptibility of future breakdown. Examinations on following parameters at pre- and post- periodontal treatment stages were carried out. Endotoxin, collagenase, alkaline phosphatase, beta-glucuronidase, interleukin-1 alpha, IgG antibody levels to Bacteroides gingivalis, Bacteroides intermedius were measured in gingival exudate samples, which were collected by the microtips technique from periodontal pockets. The following results were obtained: 1) Considering the effect of periodontal therapy, pathogenic responses on total colony forming unit (CFU), interleukin-1 alpha and changes of endotoxin and beta-glucuronidase levels after the treatment have indicated that specific changes in humoral responses. 2) There was not significant relation between alkaline phosphatase, collagenase, IgG antibodies level to Bacteroides gingivalis, Bacteroides intermedius and responses in active and also inactive disease sites. 3) This study has been resulted in the development of diagnostic techniques which requires strict criteria on the disease activity of the periodontal disease very specific in order to permit a more scientific approach to the care of periodontitis patients and to speculate the prognosis of the patients after the treatment.

The change of respiratory function in senile persons was studied by determining timed vital capacity and flow volume curve, using 183 male subjects in age of 60-86 years old (66 subjected for 60-64 years old, 43 for 65-69 years, 45 for 70-74 and 29 for 75 years old or above) who are non-smoking persons and have no anamnesis of circulatory disorders. The results are as follows: 1. Each determination result by age; 1) Timed vital capacity; Both forced vital capacity (FVC) and % forced vital capacity (% FVC) were decreased with aging, where as forced expiratory volume in 1 second (FEV1.0%) remained unchanged. 2) Flow volume curve; Peak flow (PF), V75 and V50 were decreased with aging, but hardly any change was seen in V25.V50/V25 showed a tendency toward decrease with aging, but the level was 3.0 or above in each age group. It is postulated in respiratory function of senile persons aged 60 years or above that restrictive ventilation impairment goes to aggravate with age, but the severity of obstructive ventilation impairment is slight. 2. Each determination value by ventilation impairment groups; All subjects (183) were classified into 4 groups, i.e., 70 (38.3%) for normal healthy group, 43 (23.5%) for restrictive ventilation impairment group, 48 (26.2%) for obstructive ventilation impairment group and 22 (12.0%) for mixed ventilation impairment group. Normal healthy group and obstructive ventilation impairment group showed a tendency toward decrease with aging, but restrictive ventilation impairment group and mixed ventilation impairment group showed a tendency toward increase with aging. However, there were no significant differences in determination items of age and V50/V25 among the groups tested. These results suggest that ventilation impairment develops in senile persons in age of 60 years old or above regardless of their age distribution, along with the decrease in sensitivity to V50/V25. 3. Relationship among FEV1.0% and V75, V50, V25 and V50/V25 In age of 60-69 years old, there were correlations between FEV1.0% and V25, i.e., r = 0.377 (P less than 0.05) in normal healthy group; among FEV1.0% and V50 and V25, i.e., r = 0.505 and r = 0.479 (P less than 0.05) in obstructive ventilation impairment group. In senile persons in age of 70 years old, there were correlations between FEV1.0% and V50 and V25, i.e., r = 0.789 and r = 0.716 (P less than 0.01) in obstructive ventilation impairment group.(ABSTRACT TRUNCATED AT 400 WORDS)

The recent cell-biological research have been reported the usefulness of extracellular matrix, such as collagen and fibronectin, in cell culture techniques and in vitro experiments. These matrix began to applied in medical treatments and brought many success. Fibroblast and osteoblast have characteristics to promote stabilization of implant materials in vivo. These cells revealed the additional effects to control mending and healing of surgical invasion. The role of extracellular matrix and serum components for cellular adhesion and growth have been discussed extensively. The recent studies reported that collagen and other materials promoted the cellular behavior. The author discussed the effect of extracellular matrix and serum components or the established cell lines on cellular adhesion and growth, which were performed in vitro and in vivo. The following cell lines were employed in this study, fibroblastic cell lines from mouse (3T12-3) and human (SF-TY), osteogenic cell line from mouse (MC3T3-E1) and osteogenic cell lines from human (SAOS-2, NY), osteoblastic cell line (HuO-3N1) and rabbit cell line. Different types of collagen were used as the coating material on glass surface by the method of collagen-gel culture method. Fetal calf serum, bovine serum albumin, fibronectin and proteoglycan were also employed in this study. After the cultivation, adherent cells were stained by Gimsa's method and counted microscopically. In cellular-adhesion test, the most cell number was found on the collagen type I coated glass surface to compare with the other materials, such as fetal calf serum, bovine serum albumin, proteoglycan, employed in all the tested cell lines. Growth of the defined cell-number on glass surface was compared among used materials, and all the osteogenic cell lines and fibroblastic cell lines were found to grow well on collagen type I-fibronectin, collagen type I, and fibronectin coated glass surface to compare with other materials employed in this study. Collagen-fibronectin and collagen-coated alumina ceramic tubes were embedded in the mandibular bones of rabbits, and the aspect was observed with the passage of time. These treatments promoted the osseous area in the tubes. These findings strongly indicated that surface-coated biomaterial by collagen and collagen-fibronectin enhanced cellular adhesion, and promoted the growth of fibroblast and osteoblast in vitro and in vivo.

In order to observe morphological features and distribution density of melanocytes in infantile gingival epithelium, 52 cases of clinically normal gingiva on 4-12 years old were examined by using sections prepared by paraffin dopa method and combined dopa-premelanin reaction and extended specimens prepared by dopa reaction and splitting method. The following information was obtained: 1) Melanocytes were observed among keratinocytes of the basal layer and especially abundant on the side of the epithelial peg, but rare on the tip of the epithelial peg. 2) Shapes of cell body of melanocytes were predominantly elliptical and spindle-type and their size was as large as or a little larger than the neighboring keratinocytes, with its nuclear portion remaining unstained and clear. 3) Dendritic processes were making complicated traveling while repeating branching and were extending to several neighboring cell. 4) Distribution density of melanocytes in infantile gingival epithelium was 813/mm2 as determined using extended specimens. Distribution density as determined in the ratio of basal cell count to melanocyte count was 40.7 for activated type melanocytes, and 27.3 for 'activated+inactivated' type melanocytes, respectively. 5) No difference in distribution density was noted by age, sex and site of collection. 6) The ratio of activated type to inactivated type melanocytes in infantile gingival epithelium was 2:1, the latter representing 32.6% of the whole.

Pertinent information used in radiographic diagnosis consists mainly of abstract abnormal findings. Experience has show that the reasoning process required to interpret this information is the most important element of a proper diagnosis. Thus, it is important to combine the results of radiograms with information obtained through actual observation of oral cavities. To reveal the thinking process required while reading radiograms, it is important to have an objective study in which visual action is followed as a reference. For this reason, studies on visual action have been conducted in the fields of medicine and dentistry using eye movement recording systems. In the field of medicine, Kundel and Nodine reported on visual actions while subjects were engaged in reading chest radiograms. In the field of dental medicine, and especially in oral diagnostics, Yamano et al. introduced an eye mark recorder which quantitatively analyzed the visual action of dentists during radiographic diagnosis. This device may lead to important information which can be used in making diagnoses, especially quantitative information. They concluded that the eye mark recorder is effective for quantitative evaluation of the thinking process during radiographic diagnoses. Thus, we focused our attention on visual action in analyzing the thinking process during radiographic diagnosis and by means of such analytical techniques, studied how information obtained from oral diagnostics can affect the thinking process during radiographic diagnosis. (1) The equipment used was the visual action analysis system. (2) Seventy-five dentists were engaged in reading radiograms for this study. (3) The radiograms we used included two pictures of marginal periodontitis and periapical periodontitis. (4) Diagnostic information given. Group A: none, group B: chief complaints, and group C: chief complaints, present symptoms and history of the present illness. We investigated how prior presentation of such information would affect visual action during radiographic diagnosis, and obtained the following results. 1. Newly-developed correction system. The newly-developed correction system made it possible to detect the fixation point more precisely by correcting head movement in real time. 2. Effect of prior oral diagnostic information on visual action during radiographic reading. 1) Effect on total fixation time. For both marginal periodontitis and periapical periodontitis, the total fixation time was shorter in group C than in groups A and B. 2) Effect on the total fixation time spent on decayed teeth. For both marginal periodontitis and periapical periodontitis, the total fixation time spent on decayed teeth was longer in group B than in groups A and C.(ABSTRACT TRUNCATED AT 400 WORDS)