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

Erythritol is a sugar alcohol which is obtained through a cultivation of glucose and Aureobasidium sp. The sugar is about 70-80% as sweet as sucrose and is also non-hygroscopic. The effect of erythritol on cariogenicities of mutans streptococci (serotype a-h) and certain oral microorganisms was studies. Erythritol was not utilized as a substrate for the growth, lactic acid production and plaque formation of mutans streptococci (serotype a-h). It did not serve as a substrate for cellular aggregation of mutants streptococci (serotype d, g, h) and was not utilized water-insoluble glucan synthesis and cellular adherence by glucosyltransferase from S. mutans PS-14 (c) or S. sorbrinus 6715 (g). Erythritol was not also utilized for the growth and lactic acid production of certain oral microorganisms although some growth was seen with Actinomyces viscosus. SPF SD rats infected with S. sobrinus 6715 were fed a diet containing 26% erythritol or 26% sucrose for 53 days. A significantly (p less than 0.01) lower caries score (mean +/- SE; 3.1 +/- 0.5) was observed in the rat fed a diet containing erythritol than the control (60.5 +/- 2.0). The caries inhibition rate is 94.9%. Also, rats infected with S. mutans PS-14 were fed a diet containing 56% erythritol chocolate or 56% sucrose chocolate for 58 days. The mean total caries score of rats fed a diet containing 56% erythritol chocolate was 6.7 +/- 0.8, while the mean total caries score of rats fed a diet containing 56% sucrose chocolate was 82.8 +/- 2.8. The value between both groups was significant at 0.01 level, and the caries inhibition rate is 91.9%.

Upper canine protects molar teeth from occlusal trauma by controlling lateral movement of mandible and discluding. Hence, it is expressive to find relative position between lingual contour of upper canine and lower canine. The authors have investigated relative position between clinical crown of upper and lower canine with rectangular coordinates system established on the trace in a labiolingual section of clinical crowns of upper and lower canine. As a result, the authors arrived at the following conclusion: 1. Significant difference between right and left side wasn't found in relative position between upper and lower canine clinical crown (p less than 0.05). 2. Items of upper canine hadn't relevance to items of lower canine. 3. Over bite had significant relevance to 4, 6, and 7. But overjet hadn't relevance to the other items.

We set out a questionnaire for 400 participants of the seminar, to investigate the thoughts of dental practitioners and dentists on duty with regard to the post-graduation study and training in particular, to dental anesthesiology. The results obtained were as follows. 1. Almost all of the dental practitioners felt necessary to receive the post-graduation study and training to brush up their techniques. 2. The dental practitioners felt defective in actual techniques prepared by post-graduation trainings now under way, and they desired a particular training in an actual technique specific to an emergency therapy. 3. Seminars for re-education they desired to attend were those related to anesthesia in majority, followed by prosthetics, maintenance and periodontosis, orthodontics, and surgery, implantodontics, and pedodontics. 4. Major curriculums of anesthesiology they desired to receive were systemic management, resuscitation, how to apply the first-aid medicine, and treatment for shock states. The number of those participants who desired to receive these curriculums was help or above of all members, followed by those in dental psychosomatic disease, treatment for senile patients and acupuncture anesthesia. 5. It was unexpected that those who had been aware of the concept of authorized dental anesthesiologist were confined to 54% of the participants. This led us to consider that clinical dentist should be re-educated regarding the system for authorized anesthesiologist. 6. Major participants answered nothing with regard to the advocated curriculums we questioned, so that it was postulated that none felt unsatisfactory of the advocated curriculums at present.

A PSPC (Position Sensitive Proportional Counter)-MDG (Micro Diffract Goniometer) system was applied to show the crystal orientation in the rat linugal dentin. The X-ray diffraction from a specimen was recorded by usual chart recorder instead of the classical film method. Specimens were about 150 microns wide and 100 microns thick of pillar form with the long axis of specimen parallel to the dentinal tubules. When the X-ray was irradiated in the labiolingual dicection, the peak intensity of (002) was stronger than that of the combined peak of (211) and (112). The more it rotated from the first position along the long axis of specimen, the more the peak intensity of (002) weakened, and after it rotated at 90 degrees the peak of (002) completely disappeared. The results indicated that the crystals were well-oriented in the lingual dentin. The axis of crystal orientation was almost parallel to the tooth axis, but swayed within the range of about 30 degrees.

Hydroxyapatite (HAP) is regarded as a useful material for grafting in procedure aimed at bone replacement. The purpose of this investigation, as a basic experiment, was to demonstrate bone formation in the dental extraction sockets during orthodontic movement of the neighboring teeth in the initial wound healing phase, and to clarify effects of indirect forces through alveolar bone on repairing bone in extraction sockets. Secondary we examined changes in the bone formation in the sockets during the tooth movement which were plugged with HAP granules and compared with the repairing bone without HAP. For this study seven dogs were used and were scarificed according to a schedule yielding observation periods up to 6 weeks. The animals were injected continuously with tetracycline during the experimental period. Undecalcified mesio-distal specimens 65-100 microns of thickness were prepared at first for microradiogram and then subjected to fluorescence microscopy. The observations indicated that the bone formation seemed to be accelerated with HAP implantation, however the alveolar trabeculae around HAP were developed during the tooth movement less than the control. The tooth movement in implanted sites was faster than in the sites without HAP implantation. The decreased response on alveolar bone formation, incident to experimental tooth movement into extraction sockets, was found in the pressure area, mesial part of socketswall. It might be induced by excessive stress during the tooth movement, amplified by the change of bone repairing due to the HAP implantation.

Root fractures in the teeth under or after the crown prosthetic treatment after occur intra-alveolary. In the many cases, these teeth will be diagnosed to be extracted. Therefore, root fracture is one of the clinical problems for clinicians. There are many clinical and descriptive reports on root fractures after crown prosthesis. But more fundamental studies should be done for the prevention of root fractures. We observed the sampled tooth with scanning electron microscopy and analytical electron microscopy. The tooth with root fractures after the treatment of crown prosthesis was used in this study. The following were the results of this investigations: 1) The cohesional substances, which are regarded as oral bacteria and organic materials, were observed in the definite section on the surface of fracture. 2) The line of the root fracture ran parallel with the canaliculus dentalis. 3) The cracks were observed to run through the face of crosscutting of canaliculus dentalis. 4) Ca and P on the surface of the fracture is 32.75 and 27.70 (atomic %), respectively (Ca/P 1.18). These values are lower than these of control group. In the same surface of the root fractures, the values of Ca and P in the middle parts were less than those of the outside. Reversely, the more deep parts have a little higher values than those of the middle parts. 5) The values of Zn increased on the surface of the fracture than those of the control. 6) The values of S was not detected on the control surface. On the other hand, S was detected in the relatively higher density (15.04) on the surfaces of the root fractures.

Changes in respiratory function were compared. The results obtained were as follows. Subjects selected were 462 normal healthy male adults with no disorders in respiratory and circulatory systems, of whom forced expiratory volume in 1 second (FEV1.0%) and peak flow (PF), forced expiratory volume in 75% (V75), forced expiratory volume in 50% (V50) and forced expiratory volume in 25% (V25) were determined. 1. Results of each measured value FEV1.0%, PF, V75, V50 and V25 decreased with age. But V50/V25 increased with age Minimum and maximum values were 6.86 and 36.46 in FEV1.0% and V25. 2. Relationship between FEV1.0% and V50/V25. Both FEV1.0% and V50/V25 did not show marked relation till 34 years. Individual variation occurs in 35 to 39 year old group. This current was famous in 40 to 49 year old group. But no individual variations were found over 50 year old. This suggested that aging affects not only large airways but also small airways, and which is accompanied with enlarged peripheral air way resistance and decreased expiratory flow volume

Ceramic materials have been clinically utilized as artificial biomaterials in the stomatognathic ffeld today. Among the materials bioinert alumina ceramics was selected in this study to investigate the fundamental aspect of bony ingression into porous ceramics and influence of pore diameter on the ingression. Tubes made of alumina ceramics of respective pore diameters of 200, 300 and 500 microns were embedded in the mandibular bones of rabbits, and the aspect was observed with the passage of time. The osseous area in the tube was measured through image analysis system of contact microradiogram (CMR) of cross sections and the following conclusions were obtained: 1. Bony ingression was observed in all the porous diameter in 2 weeks after the embedding, and increased during the subsequent period up to 6 months. The alumina ceramics used in this study showed high histological affinity. 2. The respective diameters of 200, 300 and 500 microns were suitable for the pore of the alumina ceramic tooth root materials. The embedding period without any burden was estimated to be better for 6 months. 3. The adequate pore diameters of porous alumina ceramics, when used as osseous prosthetic materials, were 200 and 300 microns, because in these cases new bones proliferated well into the tube up to the depth of 5mm.

Unlabelled: At the present stage of drug interactions, little has been studied on food-drug interactions. Excess intake of sucrose is well known to cause arteriosclerosis, obesity, diabetes mellitus, toxicity to blood cells, dental caries, and accumulations of metabolic products in blood. Under the such conditions, it is possible that the ulcerogenic drugs, such as synthetic anti-inflammatory drugs, may cause severe gastric lesions by oral administration. The present investigation was undertaken to study the influences of sucrose on the gastric lesions induced by aspirin (aspirin ulcer) in rats maintained with 10% sucrose solution. Thus, the effect of sucrose on aggressive and protective factors, proposed by Shay and Sun, was studied.

Method: Sixty rats were maintained with 10% sucrose solution ad libitum as drinking solution for 4 weeks (10% sucrose group). As control, purified water was given ad libitum to 60 rats (control group). Rats were starved for 24 hours, but allowed free access of water before the experiment, and then were subjected to the following experiments: (1) Twenty rats from each group were treated to prepare pylorus-ligated rats. Aspirin in 1% CMC (100mg/kg body-weight) was given in 10 rats from each group immediately after the ligation. Gastric juice excreted during 6 hours was collected and its supernatant (1,500 x g) was used for determinations of pH, acidity, acid output, pepsin activity, and pepsin output. Aspirin and salicylic acid contents in gastric juice were also determined by HPLC. (2) The mucosa of the stomach of (1) were subjected to the analysis of hexosamine. Twenty rats from each group without pylorus-ligation were also used for the analysis. Among them, 10 rats from each group were given aspirin in 1% CMC with the dose of 300 mg/kg body-weight. (3) Ten rats from each group were given aspirin with the dose of 300 mg/kg body-weight and the stomach (n = 10 for each group) was extracted 30 minutes after the aspirin administration for histochemical study to obtain covering mucus index, epitherial mucus index, total mucus index, and rate of mucous injury. (4) Aspirin in 1% CMC was given to 10 rats of each group with the dose of 300 mg/kg body-weight. Rats were sacrificed 6 hours after the administration of aspirin, and then stomachs were extracted and treated with 10% neutral formalin. The length of lesions was measured under a microscope (x 10), and then Ulcer Index was obtained.(ABSTRACT TRUNCATED AT 400 WORDS)

The frequency of occurrence of anomalous cusps or tubercles on human lower first molars was investigated in three racial populations: Japanese, Australian Aboriginals and Dutch white. The technique used was moiŕe contourography, which permits the three-dimensional measurement of minute cusps. Four tubercles investigated were 6th cusp, 7th cusp, deflecting wrinkle and transverse ridge. The frequencies of four traits were all highest in Australian Aboriginals among three, especially those of 6th cusp and deflecting wrinkle were significantly higher than other two populations. Japanese and Dutch showed comparatively low frequencies of four traits, but the 6th cusp in the former occurred significantly higher than that in the latter. There was no significant differences of the frequency in all the traits between sexes. It was suggested that high frequency of these traits in Australian Aboriginals demonstrates the primitive morphology of the lower molar of this population.