Shin Kasahara

An Approach to Medical Knowledge Sharing in a Hospital Information System Using MCLink

Clinicians often need access to electronic information resources that answer questions that occur in daily clinical practice. This information generally comes from publicly available resources. However, clinicians also need knowledge on institution-specific information (e.g., institution-specific guidelines, choice of drug, choice of laboratory test, information on adverse events, and advice from professional colleagues). This information needs to be available in real time. This study characterizes these needs in order to build a prototype hospital information system (HIS) that can help clinicians get timely answers to questions. We previously designed medical knowledge units called Medical Cells (MCs). We developed a portal server of MCs that can create and store medical information such as institution-specific information. We then developed a prototype HIS that embeds MCs as links (MCLink); these links are based on specific terms (e.g., drug, laboratory test, and disease). This prototype HIS presents clinicians with institution-specific information. The HIS clients (e.g., clinicians, nurses, pharmacists, and laboratory technicians) can also create an MCLink in the HIS using the portal server in the hospital. The prototype HIS allowed efficient sharing and use of institution-specific information to clinicians at the point of care. This study included institution-specific information resources and advice from professional colleagues, both of which might have an important role in supporting good clinical decision making.

Tooth shape reconstruction from ct images using spline Curves

It is desired to obtain three-dimensional shapes of teeth without extracting them physically in order to construct teeth database. In this paper, we propose a method for reconstructing three-dimensional shape of a tooth from the images acquired by a dental micro CT. First, initial contour of a tooth is obtained from an image in which the tooth is not buried in the bone and does not touch another tooth. A contour is determined in the adjacent image by searching the positions where the edge is strong. The shape of the tooth is obtained by recursive detection of the contours. Active contour model is used to obtain the contour where the edge is strong, and closed spline curve is used to represent the contour. Experimental results show that the shape of a tooth can be reconstructed from actual CT images by the proposed method.

Characterization and mode of action of exo-1,3-β-D-glucanase from Aspergillus saitoi

Abstract An acid exo-β-1,3- d -glucanase was isolated from the commercial digestive enzyme Molsin prepared from Aspergillus saitoi. The enzyme had a molecular weight of 57,000, isoelectric point of pH 4.1, optimum pH of 3.8 and an optimum temperature of 50°C. Major amino acid components of the enzyme were Asx, Ser, Thr and Gly which comprised more than 60% of the molecule, while 11% was carbohydrates. The N-terminal amino acid was determined to be Gly. The enzyme acted on the β-1,3- d -glucan (Pachyman) or laminaritetraose in an exo-type manner and the hydrolysis product was α- d -glucose.

Cloning and Expression of the Exo-β- D -1,3-glucanase Gene (exgS) from Aspergillus saitoi

A gene of exo-1,3-β-D-glucanase (exgS) was cloned from a koji mold, Aspergillus saitoi, genomic DNA using PCR. The exgS has an ORF comprising 2832 bp, which contains one intron of 45 bp, and encodes 945 amino acids. The deduced amino acid sequences showed that the ExgS has a non-homologous linker region consisting of 180 amino acids, which encompassed highly conserved regions observed in Exg homologues from filamentous fungi. A recombinant protein (ExgS) has been recovered from the cultural filtrate of an Aspergillus oryzae strain that carried an expression vector containing full length of the exgS. The N-terminal amino acid sequences of the recombinant exo-1,3-β-D-glucanase (ExgS) were identical to that of native ExgS from A. saitoi.

Tooth shape reconstruction from dental CT images with the region-growing method.

OBJECTIVES The three-dimensional shape information of teeth provides useful information. However, obtaining accurate three-dimensional shapes of teeth is difficult without extracting them physically. In this study, we aimed to develop a method for automatically extracting accurate three-dimensional shapes of teeth from dental CT images. METHODS The proposed method includes pre-processing and region extraction. Pre-processing is a combination of image-processing techniques that enhances tooth regions. In the region-extraction process, the region-growing method is introduced for extracting a region of each tooth. Constraint conditions determined by considering the characteristics of the structure of teeth are introduced for accurate extraction. Finally, morphological image processing is applied for eliminating discontinuous points. RESULTS We carried out an experiment in which the three-dimensional shapes of teeth were reconstructed from dental CT images. Quantitative evaluation was performed by measuring the three-dimensional spatial accordance rates between the region obtained by the proposed method and the manually extracted region. The proposed method was significantly more accurate than an existing method at the 5% level. CONCLUSIONS The experimental results showed that the proposed method reconstructs the shapes of teeth with high precision. However, an unextracted region remained at the surface of the enamel. Solving this problem and improving the extraction accuracy are important topics for future work.

Three-dimensional finite element analysis of zirconia all-ceramic cantilevered fixed partial dentures with different framework designs

The purpose of this study were: to perform stress analyses using three-dimensional finite element analysis methods; to analyze the mechanical stress of different framework designs; and to investigate framework designs that will provide for the long-term stability of both cantilevered fixed partial dentures (FPDs) and abutment teeth. An analysis model was prepared for three units of cantilevered FPDs that assume a missing mandibular first molar. Four types of framework design (Design 1, basic type; Design 2, framework width expanded buccolingually by 2 mm; Design 3, framework height expanded by 0.5 mm to the occlusal surface side from the end abutment to the connector area; and Design 4, a combination of Designs 2 and 3) were created. Two types of framework material (yttrium-oxide partially stabilized zirconia and a high precious noble metal gold alloy) and two types of abutment material (dentin and brass) were used. In the framework designs, Design 1 exhibited the highest maximum principal stress value for both zirconia and gold alloy. In the abutment tooth, Design 3 exhibited the highest maximum principal stress value for all abutment teeth. In the present study, Design 4 (the design with expanded framework height and framework width) could contribute to preventing the concentration of stress and protecting abutment teeth.

Clinical Chipping of Zirconia All-Ceramic Restorations

Advancements in CAD/CAM systems employed in dentistry have made possible the application of yttria tetragonal zirconia polycrystal (Y-TZP) in zirconia-based all-ceramic restorations. Y-TZP has excellent flexural strength and fracture toughness and is used in molar crowns as well as frameworks of fixed partial dentures (FPDs). The use of Y-TZP in clinics has increased over the past several years, and it is now used in implant abutments and denture frameworks. While the demand for Y-TZP is increasing, chipping of porcelain used in the zirconia framework has been noted as a problem in zirconia-based all-ceramic restorations from a clinical point of view. We have previously used Cercon® smart ceramics with Y-TZP frames in clinics but have noticed the chipping of porcelain in a large number of cases over time. This review article focuses on the chipping of zirconia all-ceramic restorations by taking into account the following aspects: (1) clinical performance of zirconia all-ceramic restorations, (2) influence of frame thickness and porcelain firing schedules, and (3) reduction in porcelain chipping.

Measurement of human cerebral function caused by oral pain

Pain is one of the most important factors in dentistry. Objective measurement of pain may be useful for dental diagnosis and therapy. However, until now, we have had no modality to measure the location and degree of pain objectively. The purpose of this study is to measure reactions to pain in cerebral cortex during dental treatment using Cerebral functional mapping of Oxygen Exchange (COE), and to assess the application of COE in the field of dentistry. We obtained the following results: (1) reactions in cerebral cortex apparently related to dental pain were measured at Brodmann’s area 10, (2) COE measurement responses were sensitive and reactions could be shown within a few seconds during an event, and (3) the reactions also disappeared quickly after the pain disappeared.

Evaluation of the Accuracy of CAD/CAM Crowns Fabricated Using CT Images

In this study, from the standpoint of prevention of infection for dental technicians, we show the fabrication methods of crowns without impressions and dental model. We showed fabrication method of CAD/CAM crown using CAD data, and investigated the accuracy of the crowns. The discrepancies between the dies and crowns ranged from 50–95 μm at the margin and 15–40 μm at the shoulder in crowns fabricated from CT images of an abutment tooth. This present study showed a clinical utility of CAD/CAM crown that fabricated using CT images.

Educational effect on tooth preparation of visual feedback using computer graphics

This review article describes the educational effect on tooth preparation of visual feedback using computer graphics. The result is that in the feedback group, the average occlusal reductions showed significant differences at the three cusps, and the axial wall taper showed significant differences in the three regions. A series of studies indicates that visual feedback using computer graphics was effective for tooth preparation practices.