• Title/Summary/Keyword: Dental inlay

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CERAMIC INLAY RESTORATIONS OF POSTERIOR TEETH

  • Jin, Myung-Uk;Park, Jeong-Won;Kim, Sung-Kyo
    • Proceedings of the KACD Conference
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    • 2001.05a
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    • pp.235-237
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    • 2001
  • ;Dentistry has benefited from tremendous advances in technology with the introduction of new techniques and materials, and patients are aware that esthetic approaches in dentistry can change one's appearance. Increasingly. tooth-colored restorative materials have been used for restoration of posterior teeth. Tooth-colored restoration for posterior teeth can be divided into three categories: 1) the direct techniques that can be made in a single appointment and are an intraoral procedure utilizing composites: 2) the semidirect techniques that require both an intraoral and an extraoral procedure and are luted chairside utilizing composites: and 3) the indirect techniques that require several appointments and the expertise of a dental technician working with either composites or ceramics. But, resin restoration has inherent drawbacks of microleakage. polymerization shrinkage, thermal cycling problems. and wear in stress-bearing areas. On the other hand, Ceramic restorations have many advantages over resin restorations. Ceramic inlays are reported to have less leakage than resin restoration and to fit better. although marginal fidelity depends on technique and is laboratory dependent. Adhesion of luting resin is more reliable and durable to etched ceramic material than to treated resin composite. In view of color matching, periodontal health. resistance to abrasion, ceramic restoration is superior to resin restorationl. Materials which have been used for the fabrication of ceramic restorations are various. Conventional powder slurry ceramics are also available. Castable ceramics are produced by centrifugal casting of heat-treated glass ceramics. and machinable ceramics are feldspathic porcelains or cast glass ceramics which are milled using a CAD/CAM apparatus to produce inlays (for example, Cered. They may also be copy milled using the Celay apparatus. Pressable ceramics are produced from feldspathic porcelain which is supplied in ingot form and heated and moulded under pressure to produce a restoration. Infiltrated ceramics are another class of material which are available for use as ceramic inlays. An example is $In-Ceram^{\circledR}$(Vident. California, USA) which consists of a porous aluminum oxide or spinell core infiltrated with glass and subsequently veneered with feldspathic porcelain. In the 1980s. the development of compatible refractory materials made fabrication easier. and the development of adhesive resin cements greatly improved clinical success rates. This case report presents esthetic ceramic inlays for posterior teeth.teeth.

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A Study on the Physical Growth and Health Status in University Students (일부(一部) 대학생(大學生) 신체발육(身體發育) 및 건강상태(健康狀態)에 관(關)한 조사(調査))

  • Kwon, E-Hyock;Cha, Chul-Hwan
    • Journal of Preventive Medicine and Public Health
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    • v.1 no.1
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    • pp.67-78
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    • 1968
  • For the purpose of ascertaining the status of physical growth and health status of the University students, a intensive survey was conducted by the authors towards a total of 2,638(male; 2,228, female; 410) who passed the written entrance examination at the Seoul National University. The items included the measurements on physical growth, various physical indixes, visual acuity, tuberculosis and dental status. The findings and results can be summarized as follows: 1. Physical Growth No significant difference was found in the physical growth between classes(literature and science) and by ages. In males, the means of body height, body weight, chest-girth and sittingheight were $168.0{\pm}5.07cm,\;55.7{\pm}5.71kg,\;85.8{\pm}4.4cm\;and\;91.5{\pm}2.21cm$, respectively. In females, these were $157.4{\pm}4.57\;cm,\;00.4{\pm}5.75kg,\;80.3{\pm}4.51cm\;and\;86.1{\pm}3.30cm$, respectively. Basing on the above measurements several physical indixes were calculated as follows ; Relative body weight 33.15 in males and 32.02 in females. Relative chest-girth 51.07 and 51.01, relative sitting-height 54.46 and 54.70 $R\ddot{o}hrer$ index 1.00 and 1.02, Kaup index 1.97 and 2.04, Vervaeck index 83.63 and 83.03, and Pelidisi index 89.94 and 92.45. 2. Visual Acuity Among the students of science classes those of 0.8 and below in vision on left and right occupied 46.4% and 45.0%, those of 0.6 and below 39.1% and 41.2%, respectively. Among the students of literature classes those of 0.8 and below occupied 46.3% and 42.9%, and those of 0.6 and below occupied 41.4% and 39.0, respectively. In males those of 0.8 and below occupied 46.8% and 44.5% and 0.6 and below occupied 41.9% and 39.7%, while in females 0.8 and below occupied 43.9%, and 42.4%, and 0.6 and below occupied 38.3% and 37.3%, respectively. In males those of 0.8 and below in corrected vision occupied 12.1% and 10.3%, while in females 12.9% and 12.2%, respectively. More students of abnormal vision were found among science classes and the proportions of corrected vision were 38.9% and 37.4% in males, and 33.9% and 33.2% in females, respectively. 3. Tuberculosis Among the total, 55 students were diagnosed as tuberculosis, of whom 50 were minimal cases, 2 were moderately advanced cases and 3 were far advanced cases. 4. Dental Status Among the total, 81.2% were of decayed teeth, 20.8% filled, 9.5% missed, 5.0% extraction needed, 9.1% sunplatinum bridges, 3.3% golden bridges and 5.5% golden inlay. Regarding tartar on teeth moderate, heavy and light grades occupied 49.5%, 29.7% and 20.3%, respectively and 0.8% had none. 5. Comprehensive evaluation According to criteria 4 grades were applied to comprehensive evaluation as follows : A...excellent in physical status B...with some physical defects but no difficulties in study C...need treatment D...need treatiment and rest Out of the total, A grade occupied 21.6%, B 76.2% and C. and D 2.2.

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Evaluation of Metal Volume and Proton Dose Distribution Using MVCT for Head and Neck Proton Treatment Plan (두경부 양성자 치료계획 시 MVCT를 이용한 Metal Volume 평가 및 양성자 선량분포 평가)

  • Seo, Sung Gook;Kwon, Dong Yeol;Park, Se Joon;Park, Yong Chul;Choi, Byung Ki
    • The Journal of Korean Society for Radiation Therapy
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    • v.31 no.1
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    • pp.25-32
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    • 2019
  • Purpose: The size, shape, and volume of prosthetic appliance depend on the metal artifacts resulting from dental implant during head and neck treatment with radiation. This reduced the accuracy of contouring targets and surrounding normal tissues in radiation treatment plan. Therefore, the purpose of this study is to obtain the images of metal representing the size of tooth through MVCT, SMART-MAR CT and KVCT, evaluate the volumes, apply them into the proton therapy plan, and analyze the difference of dose distribution. Materials and Methods : Metal A ($0.5{\times}0.5{\times}0.5cm$), Metal B ($1{\times}1{\times}1cm$), and Metal C ($1{\times}2{\times}1cm$) similar in size to inlay, crown, and bridge taking the treatments used at the dentist's into account were made with Cerrobend ($9.64g/cm^3$). Metal was placed into the In House Head & Neck Phantom and by using CT Simulator (Discovery CT 590RT, GE, USA) the images of KVCT and SMART-MAR were obtained with slice thickness 1.25 mm. The images of MVCT were obtained in the same way with $RADIXACT^{(R)}$ Series (Accuracy $Precision^{(R)}$, USA). The images of metal obtained through MVCT, SMART-MAR CT, and KVCT were compared in both size of axis X, Y, and Z and volume based on the Autocontour Thresholds Raw Values from the computerized treatment planning equipment Pinnacle (Ver 9.10, Philips, Palo Alto, USA). The proton treatment plan (Ray station 5.1, RaySearch, USA) was set by fusing the contour of metal B ($1{\times}1{\times}1cm$) obtained from the above experiment by each CT into KVCT in order to compare the difference of dose distribution. Result: Referencing the actual sizes, it was appeared: Metal A (MVCT: 1.0 times, SMART-MAR CT: 1.84 times, and KVCT: 1.92 times), Metal B (MVCT: 1.02 times, SMART-MAR CT: 1.47 times, and KVCT: 1.82 times), and Metal C (MVCT: 1.0 times, SMART-MAR CT: 1.46 times, and KVCT: 1.66 times). MVCT was measured most similarly to the actual metal volume. As a result of measurement by applying the volume of metal B into proton treatment plan, the dose of $D_{99%}$ volume was measured as: MVCT: 3094 CcGE, SMART-MAR CT: 2902 CcGE, and KVCT: 2880 CcGE, against the reference 3082 CcGE Conclusion: Overall volume and axes X and Z were most identical to the actual sizes in MVCT and axis Y, which is in the superior-Inferior direction, was regular in length without differences in CT. The best dose distribution was shown in MVCT having similar size, shape, and volume of metal when treating head and neck protons. Thus it is thought that it would be very useful if the contour of prosthetic appliance using MVCT is applied into KVCT for proton treatment plan.