The Caries Lesion Under the Scanning Acoustic Microscope

1987 ◽  
Vol 1 (1) ◽  
pp. 50-63 ◽  
Author(s):  
S.D. Peck ◽  
G.A.D. Briggs
Keyword(s):  
Elastic Properties ◽  
Focal Plane ◽  
Polarized Light ◽  
Acoustic Microscope ◽  
Caries Lesion ◽  
Human Enamel ◽  
Light Micrograph ◽  
Acoustic Images ◽  
Scanning Acoustic Microscope ◽  
Caries Lesions

The scanning acoustic microscope can be used to obtain images of caries lesions in longitudinal sections of human enamel. The contrast in the acoustic images is unique in that it arises from changes in the elastic properties across the surface of a specimen. The contrast depends sensitively on the distance between the specimen and the focal plane of the lens, and this can be exploited to reveal features of interest. Comparison of an acoustic micrograph, a polarized light micrograph, and a microradiograph of a caries lesion reveals that the elastic properties of enamel are strongly dependent on the level of mineralization within the tissue. Acoustic micrographs show regions similar to those seen with the other techniques, but with greater sensitivity to small changes in mineralization.

Studies on Sound and Carious Enamel with the Quantitative Acoustic Microscope

1989 ◽  
Vol 68 (2) ◽  
pp. 107-112 ◽  
Author(s):  
S.D. Peck ◽  
J.M. Rowe ◽  
G.A.D. Briggs
Keyword(s):  
Elastic Properties ◽  
Substantial Reduction ◽  
Elastic Stiffness ◽  
Acoustic Microscope ◽  
Area Of Interest ◽  
Human Enamel ◽  
Scanning Acoustic Microscope ◽  
Caries Lesions ◽  
Strong Contrast

The scanning acoustic microscope gives strong contrast from small caries lesions in sections of human enamel. The uniqueness of the acoustic microscope lies in its ability to image elastic properties. In addition to revealing the extent and the shape of lesions, the microscope may also be used to measure the elastic properties point by point across an area of interest. Since enamel is anisotropic, measurements of the Rayleigh velocity and attenuation were made as a function of direction on a section of sound enamel. The velocity was greatest parallel to the prism axis, and the attenuation was least in this direction. Measurements of V(z) across a section through a lesion are presented. The variation of attenuation can be interpreted in terms of the development of demineralization, initially along prism boundaries and then along cross-striations. The variation of velocity indicates a substantial reduction of elastic stiffness in the lesion.

scholarly journals Acoustic microscopy in orthodontology

2017 ◽  
Vol 98 (3) ◽  
pp. 452-456
Author(s):  
Z V Gasymova
Keyword(s):  
Tooth Enamel ◽  
Acoustic Microscopy ◽  
Acoustic Microscope ◽  
Medical Interventions ◽  
Time Points ◽  
Acoustic Images ◽  
Novel Method ◽  
Scanning Acoustic Microscope ◽  
Tooth Tissue

Aim. Assessment of the possibility to use the method of ultrasound acoustic microscopy to control the state of microstructure of hard tooth tissues under the brackets. Methods. The study was conducted with the use of scanning acoustic microscope ELSAM (Leitz, Germany) in Emanuel Institute of biochemical physics, Moscow. The studied material for acoustic microscopy corresponds to 34 teeth (premolars) with brackets fixed to them, which were removed due to orthodontic indications at different time points after brackets placement. Results. In most cases on acoustic images of the removed teeth there were no revealed changes of physical and mechanical enamel properties, fissures or excess porosity both directly under the brackets and in the areas adjacent to the sealer margin. But in some cases along with good enamel state after long-term brackets placement minor changes in the structure of hard tooth tissues were revealed. In particular, the method of acoustic microscopy allowed to detect in the tooth enamel such minor defects as fissures and areas of reduced mineralization and increased porosity. Conclusion. Acoustic microscopy as a novel method to obtain clear structural images of hard tooth tissue state allows detecting minimal changes of the structure of hard tissues and performing medical interventions based on them.

Scanning Acoustic Microscope Studies of the Elastic Properties of Osteons and Osteon Lamellae

1993 ◽  
Vol 115 (4B) ◽  
pp. 543-548 ◽  
Author(s):  
J. Lawrence Katz ◽  
Alain Meunier
Keyword(s):  
Elastic Properties ◽  
Pulse Mode ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Structural Studies ◽  
Microstructural Properties ◽  
Acoustic Microscope ◽  
Ultrasonic Signals ◽  
Comparable Level ◽  
Scanning Acoustic Microscope

Scanning acoustic microscopy (SAM) provides the means for studying the elastic properties of a material at a comparable level of resolution to that obtained by optical microscopy for structural studies. SAM is nondestructive and permits observation of properties in the interior of materials which are optically opaque. Two modes of ultrasonic signals have been used in a Model UH3 Scanning Acoustic Microscope (Olympus Co., Tokyo, Japan) as part of a continuing study of the microstructural properties of bone. The pulse mode, using a single narrow pulse in the range of 30 MHz to 100 MHz, has been used to survey the surface and interior of specimens of human and canine femoral compact cortical bone at resolutions down to approximately 30μm. To obtain more detailed information at significantly higher resolution, the burst mode, comprised of tens of sinusoids, has been used at frequencies from 200 MHz to 600 MHz. This has provided details of both human and canine single osteons (or haversion systems) and osteonic lamellae at resolutions down to approximately 1.7μm, well within the thickness of a lamella as viewed in a specimen cut transverse to the femoral axis.

A two-dimensional imaging theory of surface discontinuities with the scanning acoustic microscope

1985 ◽  
Vol 401 (1820) ◽  
pp. 29-51 ◽  
Keyword(s):  
Elastic Properties ◽  
Reflection And Transmission ◽  
Acoustic Microscope ◽  
Relative Value ◽  
Different Types ◽  
Contrast Mechanism ◽  
Imaging Theory ◽  
Scanning Acoustic Microscope ◽  
Surface Discontinuities ◽  
Quantitative Account

This paper discusses theoretical aspects of the V ( z ) response of the scanning acoustic microscope (s. a. m.) when used to examine specimens with lateral discontinuities. The problem is introduced in terms of a simple ray model to establish a physical picture of the processes involved. An approximate Green function is then developed which enables use of a modified form of the Fourier optical formulations to calculate V ( z ) for a cylindrical lens. These calculations explain two different types of contrast observed when imaging specimens in the reflection s. a. m., such as (i) the ability to image fine discontinuities and display them with enhanced contrast and an apparent width determined by the acoustic wavelength; and (ii) to give a quantitative account of the amplitude of periodic ripple often observed running parallel to cracks on acoustic micrographs. Both these types of contrast may be predicted by using the same model and arise naturally from variation of the reflection and transmission properties of the discontinuity, the relative value of these parameters determines which type of contrast predominates. At an interface between media with different elastic properties, the contrast is affected not only by the scattering properties of the boundary but also by the very fact that surface waves must propagate in media with different elastic properties. This effect alone can provide a powerful contrast mechanism which enables one to understand the light to dark contrast reversals often observed at grain boundaries in polycrystalline specimens at different values of defocus.

Signature Analysis of Package Delamination Using Scanning Acoustic Microscope

1996 ◽  
Author(s):  
S.X. Li ◽  
K. Lee ◽  
J. Hulog ◽  
R. Gannamani ◽  
S. Yin
Keyword(s):  
Failure Analysis ◽  
Early Stage ◽  
Signature Analysis ◽  
Acoustic Microscope ◽  
Reflow Soldering ◽  
Moisture Expansion ◽  
Scanning Acoustic Microscope ◽  
Package Reliability

Abstract Package delaminations are often associated with electrical and package reliability problems in IC devices. Delaminations caused by electrical-over-stress (EOS) and moisture expansion during reflow soldering have shown different delamination patterns. A Scanning Acoustic Microscope (SAM) can be used to detect package delaminations. Understanding these delamination signatures can help us quickly identify the failure cause at an early stage of the failure analysis.

Failure Analysis of Flip-Chip Interconnections Through Acoustic Microscopy

1996 ◽  
Author(s):  
O. Diaz de Leon ◽  
M. Nassirian ◽  
C. Todd ◽  
R. Chowdhury
Keyword(s):  
Failure Analysis ◽  
Large Scale ◽  
Flip Chip ◽  
Ultrasonic Waves ◽  
Acoustic Microscopy ◽  
Acoustic Microscope ◽  
Chip Technology ◽  
Ball Joints ◽  
Non Destructive ◽  
Scanning Acoustic Microscope

Abstract Integration of circuits on semiconductor devices with resulting increase in pin counts is driving the need for improvements in packaging for functionality and reliability. One solution to this demand is the Flip- Chip concept in Ultra Large Scale Integration (ULSI) applications [1]. The flip-chip technology is based on the direct attach principle of die to substrate interconnection.. The absence of bondwires clearly enables packages to become more slim and compact, and also provides higher pin counts and higher-speeds [2]. However, due to its construction, with inherent hidden structures the Flip-Chip technology presents a challenge for non-destructive Failure Analysis (F/A). The scanning acoustic microscope (SAM) has recently emerged as a valuable evaluation tool for this purpose [3]. C-mode scanning acoustic microscope (C-SAM), has the ability to demonstrate non-destructive package analysis while imaging the internal features of this package. Ultrasonic waves are very sensitive, particularly when they encounter density variations at surfaces, e.g. variations such as voids or delaminations similar to air gaps. These two anomalies are common to flip-chips. The primary issue with this package technology is the non-uniformity of the die attach through solder ball joints and epoxy underfill. The ball joints also present defects as open contacts, voids or cracks. In our acoustic microscopy study packages with known defects are considered. It includes C-SCAN analysis giving top views at a particular package interface and a B-SCAN analysis that provides cross-sectional views at a desired point of interest. The cross-section analysis capability gives confidence to the failure analyst in obtaining information from a failing area without physically sectioning the sample and destroying its electrical integrity. Our results presented here prove that appropriate selection of acoustic scanning modes and frequency parameters leads to good reliable correlation between the physical defects in the devices and the information given by the acoustic microscope.

Stacked Die Analysis Using C-mode Scanning Acoustic Microscope

2005 ◽  
Author(s):  
Li Na ◽  
Jawed Khan ◽  
Lonnie Adams
Keyword(s):  
Data Acquisition ◽  
Image Interpretation ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Acoustic Microscope ◽  
Analysis Mode ◽  
Scanning Acoustic Microscope

Abstract For stacked die package delamination inspection using C-mode acoustic microscope, traditional interface and thorough scan techniques cannot give enough of information when the delamination occurs in multi-interfaces, and echoes from adjacent interfaces are not sufficiently separated from each other. A thinner thickness in the stacked-die package could complicate C-mode scanning acoustic microscopy (CSAM) analysis and sometimes may lead to false interpretations. The first objective of this paper is to briefly explain the CSAM mechanism. Based on that, some of the drawbacks of current settings in detecting the delamination for stacked-die packages are presented. The last objective is to introduce quantitative B-scan analysis mode (Q-BAM) and Zip-Slice technologies in order to better understand and improve the reliability of detecting the delamination in stacked-die packages. Therefore, a large portion of this paper focuses on the Q-BAM and Zip-Slice data acquisition and image interpretation.

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