摘要:

SummaryThe aim of this research was to examine the effects of metals used in dentistry upon magnetic resonance imaging (MRI). Ten disk‐shaped samples of metals have been used in this study. Each sample has been set into a volunteer who had produced a normal MR image when tested. The subject was imaged in the sagittal, frontal and coronal plane with a 0.1T MRI device and results examined for MR defects.Au, Ag, Au‐Ag‐Pd and amalgam produced no defect. Ni‐Cr, Co‐Cr and SUS304 expressed small amounts of MR defects, but SUS405, Pd‐Co‐Ni and Sm‐Co expressed large defects. Those metals which create MR image degradation must not be used for fixed prosthesis or orthodontic devices both of which could easily be made from other metals. If the MR image degrading metals are to be used in dentistry, their application should be restricted to remov

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1993.tb01519.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryThe purpose of this study was to analyze theoretically and experimentally the relations between the horizontal and the vertical changes of impressions taken with a mandibular stock tray. According to the theoretical analysis the ratio between the horizontal (ΔX) and the vertical changes (ΔX) can be expressed as:where μ is the Poisson's ratio and Lx and Lz are the horizontal and vertical dimensions of the die, respectively. With regard to the experimental findings the Poisson's ratio calculated by this expression was μ=0.44 which fits the range of Poisson's ratio for rubber materials. In addition it was shown that the ratio between the vertical and horizontal strains is constant for a particular impression techni

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1993.tb01520.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY