本学における歯科医学教育の意識調査

Recent dental curriculum consists of two columus, that is, basic science and clinical science in Japan. However, we regard current dental curriculum as important to comprise cultural sciences, social sciences and natural sciences under the present condition, such as the rapid development of science technology, the progress of dental health care quality, and the directivity of the community medical health care. We regard current dental curriculum as necessary to reform and fill up to satisfy the new academic development and social demand. Therefore we made this opinion survey for the purpose to make characteristic to examine dental surriculum. (The object and method of the survey) We selected 637 dental students in M.D.C. from the first grade to the sixth grade when students in finished clinical practice. Of 532 male students and 105 female students, opinion survey on dental curriculum was made. (Result) 1. As for the occupation of dental students\u27 parents, it is notified that "medical doctor" rank first (29.2%) and "dental doctor" rank second (24.2%) and together they form 53 percent of the total, and "Company executives" rank third, and "self-employed" rank fourth. Howerver "Office worker" form 7.4 percent of the total and "Government worker" form 4.2 percent. 2. As for the motivation to become a dental doctor, it is notified that "advice of parent" and "stabilization of livelihood" form about 70 percent of the total at the point of admission. After admission to school, "stabilization of livelihood" and "too much payment of school expenses" have a majority. 3. As for ideal dental doctor to be desired, it is notified that "dental doctor to be kind to the patients" rank first, and "dental doctor who has excellent technique" rank second. 4. As for cultural sciences in liberal arts, it is notified that the higher the school year, the higher the percentage of the students who regard cultural sciences as necessary and important. 5. As for linguistics, it is notified that about 90 percent of the students regard English as most necessary, and about 50 percent of the students regard German as necessary. 6. As for natural sciences, it is notified that the ratio of the students who deny to regard "mathematics" and "physics" as necessary is high and the ratio of the students who regard "chemistry" and "biology" as necessary is high

全身麻酔下集中治療児の環境調査

To investigate positive inhibitory measures against severe caries thought to develop in nursing infants, we examined the nursing environment of intensive care infants under general anesthesia at Matsumoto Dental College\u27s Department for dental treatment from January 1989 through December 1993

幼若歯へのEr: YAGレーザー切削の応用

To evaluate the usefulness and safety of Er: YAG laser for cavity preparation of immature teeth, we irradiated the tooth substance using Er: YAG laser in teeth of rats in the growth stage and human immature premolars showing an incomplete root and determined appropriate irradiation conditions, observed the irradiated surface by scanning electron microscopy (SEM), evaluated the thermal effects of irradiation, and performed histopathological examination. SEM of the irradiated surface revealed no smear layer or dentinal plug observed after cavity preparation using an air turbine, and the dentinal tubules were open. Neither carbonization nor cracks were observed after irradiation at 50, 100, or 150mJ/pulse. Evaluation of thermal effects showed a mean temperature of less than 5℃ in the dentin on the pulp side after irradiation by each combination of the following conditions: dentin thickness, 1.0 or 1.5mm irradiation time, 2, 5, or 10 seconds; and energy, 50, 100, or 150mJ/pulse. Histopathological examination showed circulatory impairment and disarrangement of odontoblasts immediately after irradiation but tendency to recovery after 1 week. These results suggest the applicability of YAG laser to irradiation of the tooth substance. Considering the effects on the pulp, irradiation at 50-100mJ/pulse may be useful and safe for irradiation of the tooth substance of immature teeth

三次元有限要素法を用いた臼歯陶材焼付鋳造冠におけるメタルコーピング形態の力学的検討

Objectives To find the ideal form of coping for metal molar ceramic crowns, we evaluated their stress distributions under various loading conditions using three-dimensional finite element analysis. Materials and methods A three-dimensional finite element model representing a lower first molar was constructed. The model was varied to include one of three types of coping, the standard, butterfly, and flat types. A load of 600N, simulating the maximum bite force, was applied vertically to the crowns at the central occlusal surface and mesio-oc-clusal marginal areas. Loads of 225N, simulating masticatory force, were applied at a 45° angle to the tooth axis. Results In three of the simulation load tests, the maximum stresses were concentrated around the loading points on the porcelain and coping. The minimum tensile stress value was placed on the butterfly coping crown in the test simulating maximum bite force, when the load was applied to the mesio-occlusal marginal areas. Conclusion The butterfly coping design optimizes the stress distribution within copings and porcelain and enhances the structural strength of porcelain in metal ceramic crowns

下顎第3大臼歯の萌出程度と下顎骨の形態について

Recent studies have indicated that even in cases in which the existence of tooth germs are observed, third molars cannot perfectly erupt because there is too little space for eruption in the distal end of the 2nd molar, and that cases of impaction or semi-impaction are increasing. The purpose of this study was to compared the morphological variation of the mandible as the mandibular corpus and the mandibular ramus among three groups: a group of full impaction of the third molar in the mandibular dental arch (A group), a group of semi-impaction (B group), and a group of full eruption (C group). The following results were obtained. 1) Concerning the measurements representing distance: R (the width of the mandibular ramus), was significantly longer in group A while it was shorter in group C. M (total length of the mandible), C (length of the mandibular corpus) and the distance between Cd and Gn were all significantly longer in group C than in group A. 2) Concerning the measurements representing angles, the Go angle was significantly larger in group C than in group A. 3) All the measurements in group B approached the median value of those of group A and group C. It was suggested that there was no impaction of the mandibular third molar observed due to the reduction of the mandible, and that the eruption of the mandibular third molars appears to be affected by the growth and change in the mandibular corpus and the mandibular ramus and/or the change in the Go angle

幼若永久歯小窩裂溝の清掃に関する研究 第2報 EMPAによる裂溝内の元素分析について

The application of fissure sealants have been highly appreciated to prevent the development of caries in immature permanent teeth such as first molars immediately after their eruption. However, the sealant often breaks and peels off due to the insufficient cleansing of the surface and pits and fissures of the teeth. We newly developed diamond fixed scratch point (DFSP) for the cleansing of pits and fissures of immature permanent teeth. In this study we aimed to have good prognosis of the condensation of fissure sealant and to suppress the progress of early fissure caries, and made a comparison of this method with conventional methods using brushcone and air-flow in term of the components of fissure debris after cleansing. The effects of cleaning for the three cleaning methods were examined comparatively by usting EMPA. The results obtained were as follows: 1. It was difficult to remove the contents in deep narrow fissures of types I and IK by the methods using brushcone or air-flow. Cleansing effect could not be recognized in the narrow base, for debris and organic residue were found. 2. DFSP developed by authors removed all of the organic debris in the fissures to result in excellent cleansing effect. 3. It was confirmed that extremely mild mechanical cleansing by use of DFSP brought good cleansing effect in deep narrow fissures which seemed to be unable to be cleansed sufficiently by the conventional methods

Protein kinase A enhances lipopolysaccharideinduced IL-6, IL-8, and PGE2 production by human gingival broblasts

Objective: Periodontal disease is accompanied by inflammation of the gingiva and destruction of periodontaltissues, leading to alveolar bone loss in severe clinical cases. Interleukin (IL)-6, IL-8, and the chemical mediatorprostaglandin E2 (PGE2) are known to play important roles in inflammatory responses and tissue degradation.Recently, we reported that the protein kinase A (PKA) inhibitor H-89 suppresses lipopolysaccharide (LPS)-inducedIL-8 production by human gingival fibroblasts (HGFs). In the present study, the relevance of the PKA activity andtwo PKA-activating drugs, aminophylline and adrenaline, to LPS-induced inflammatory cytokines (IL-6 and IL-8) andPGE2 by HGFs were examined.Methods: HGFs were treated with LPS from Porphyromonas gingivalis and H-89, the cAMP analog dibutyryl cyclicAMP (dbcAMP), aminophylline, or adrenaline. After 24 h, IL-6, IL-8, and PGE2 levels were evaluated by ELISA.Results: H-89 did not affect LPS-induced IL-6 production, but suppressed IL-8 and PGE2 production. In contrast,dbcAMP significantly increased LPS-induced IL-6, IL-8, and PGE2 production. Up to 10 μg/ml of aminophylline didnot affect LPS-induced IL-6, IL-8, or PGE2 production, but they were significantly increased at 100 μg/ml. Similarly,0.01 μg/ml of adrenaline did not affect LPS-induced IL-6, IL-8, or PGE2 production, but they were significantlyincreased at concentrations of 0.1 and 1 μg/ml. In the absence of LPS, H-89, dbcAMP, aminophylline, andadrenaline had no relevance to IL-6, IL-8, or PGE2 production.Conclusion: These results suggest that the PKA pathway, and also PKA-activating drugs, enhance LPS-induced IL-6,IL-8, and PGE2 production by HGFs. However, aminophylline may not have an effect on the production of thesemolecules at concentrations used in clinical settings (8 to 20 μg/ml in serum). These results suggest thataminophylline does not affect inflammatory responses in periodontal disease

松本歯科大学病院における小児全身麻酔下集中歯科治療の検討 : 過去11年間の環境要因の変遷について

We investigated the actual child-rearing environment, considering factors such as hygiene training, among 177 children (102 boys, 75 girls) ranging from 1 year and 9 months to 7 years and 2 months in age who underwent intensive dental treatment under general anesthesia in the Department of Pediatric Dentistry, Matsumoto Dental University Hospital between January 1990 and December 2000. The following results were obtained. 1) The annual number of patients slightly increased between 1992 and 1994. Thereafter, the annual number of patients decreased slightly each year. 2) The mean age attreatmentwas 3 years and 7 months (44.5±12.9 months). 3) Concerning the regional distribution, more than 50% of the children came from Nagano Prefecture areas other than Shiojiri City, where our university is located. 4) With respect to feeding methods during infancy, most children were breast fed or mixed breast and bottle fed. Furthermore, any feeding irregularity was noted. 5) The mean interval from birth until the start of weaning was 7.5±4.1 months. The mean interval until completion of weaning was 16.0±6.3 months. 6) 95.5% of the children habitually brushed their teeth. The frequency of tooth brushing was "once a day" or "sometimes" in 69.5% of the children. 7) Overall, 46.9% of the children had received fluoride application

臼歯陶材焼付鋳造冠におけるメタルフレーム形態の力学的検討(英文)

Objectives: The purpose of this study was to find an ideal shape of the metal frame (coping) in the porcelain fused to metal (PFM) crown. The stress distribution was assessed by the load-to-fracture values and a three-dimensional finite element analysis. Methods: Three kinds of coping designs were tested; Design I: Conventional type as control (traditional frame). Design II: 1.0 mm lower than occlusal surface of coping (butterfly frame). Design III: Straight type (flat frame). The load-to-fracture value consisted of three groups (Design I, II and III) of five samples each. The loading location is selected at the area where mesial and distal of the metal frame will coincide with the projection of the occlussal surface. All samples were loaded to fracture at the rate of 0.1 mm/min using a universal-testing machine. The stress distribution was assessed in a three-dimensional finite element model, which consisted of the abutment tooth, cement, metal coping and porcelain. The loading position is the projection point ofbuccal-lingual transitional part of the frame mesial and distal proximal surface on the occlusal surface towards the median, in which the load is in constant value. Loading direction is vertically downward along tooth axis with a load of 2000 N. Results: The mean load-to-fracture value for each group is as follows: Group A (Design I)=1823.0 N±132.7 (S.D.), Group B (Design II)=1940.4 N±147.4 (S.D.), Group C (Design III)=2333.9 N±180.9 (S.D.). The results of the three-dimensional finite element analysis showed that the maximum tensile stress of 84.5 MPa occurred in Design I. The maximum tensile stress in design II and III were 53.8 MPa and 53.3 MPa, respectively, which were the lower than Design I. Conclusions: The results indicated that the butterfly and flat frame designs will increase metal support on proximal porcelain, thus effectively change the stress distribution within the coping and porcelain, optimizing stress distribution in PFM crown under perpendicular load, and enhance structural strength of porcelain of PFM crown

中国上海市小児における乳歯列形態の検討 : 正常咬合児72例の模型から

To obtain the dimensional data of the dental casts of growing and developing Chinese children, and to compare the data to the Japanese, we have performed dental examinations on children in the kindergarten attached to Shanghai Teachers\u27 University in Shanghai since 1996. As study materials, dental casts obtained between 1996 and 1999 from 72 Chinese children aged 3 to 6 years with normal primary occlusion were used to evaluate the mesio-distal crown diameters of the primary teeth, the sizes of the primary dental arch, and the standard values and frequency distributions of primary occlusion. 1. Males showed higher values in mesio-distal crown diameters in deciduous teeth, and the size of dental arch than females. 2. In regard to the interdental spaces both in the maxilla and mandible, primate and developmental spaces together were most frequently observed. 3. In regard to the occlusal relationship, the incidence of terminal planes was higher in the order of Vertical type > Mesial step type > Distal step type, and the incidence of primary canine occlusal relationship was higher in the order of type I>type III>type II. 4. The items that were thought to be characteristic of Chinese children were the frequency of only primate spaces, and the incidence of the Mesial step type of terminal plane and type III primary canine occlusal relationship