A semiautomated image analysis procedure for the quantification of dental microwear II

Paleontologists often examine microscopic scratches and pits that form on teeth for indications of the diets of past animals. Most researchers count and measure scratches and pits from photomicrographs to identify microwear patterns for comparison among samples. This paper describes an affordable, available semiautomated image analysis procedure for microwear quantification. An image is downloaded from a scanning electron microscope frame buffer to a microcomputer, and the user identifies microwear features with a mouse-driven pointer. Microwear feature density, dimensions, and orientations are then computed and stored as ASCII files for subsequent data analysis.     

Comparative study of dental enamel loss after debonding braces by analytical scanning electron microscopy (SEM)

Clinical procedures when shear forces are applied to brackets suggest adhesion forces between 2.8 and 10.0 MPa as appropriate. In this study dental enamel was evaluated by scanning electron microscopy (SEM) before and after removing the brackets. Thirty bicuspids (previous prophylaxis) with metallic brackets (Roth Inovation 0.022 GAC), Transbond Plus SEP 3M Unitek adhesive and Transbond XT 3M resin were used. The samples were preserved to 37°C during 24 hr and submited to tangential forces with the Instron Universal machine 1.0 mm/min speed load strength resistance debonding. Also the Adhesive Remanent Index (ARI) test was made, evaluating the bracket base and the bicuspid surface. All the bracket SEM images were processed with AutoCAD to determine the enamel detached area. The average value was 6.86 MPa (SD ± 3.2 MPa). ARI value 1= 63.3%, value 2= 20%, value 3= 13.3% and 33% presented value 0. All those samples with dental enamel loss, presented different situations as fractures, ledges, horizontal, and vertical loss in some cases, and some scratch lines. There is no association between the debonding resistance and enamel presence. Less than half of the remanent adhesive on the dental enamel was present in most of the samples when the ARI test was applied. When the resin area increases, the debonding resistance also increases, and when the enamel loss increases, the resin free metallic area of the bracket base decreases in the debonding.     

Quantification of dental microwear by tandem scanning confocal microscopy and scale-sensitive fractal analyses

Dental microwear analysis is among the most commonly used approaches to reconstructing the diets of extinct animal species and past peoples. The usual procedure involves imaging tooth wear surfaces by scanning electron microscopy (SEM). Surfaces are characterized quantitatively by measurement of individual wear features (pits and scratches) on photomicrographs. Recent studies of living animals have shown associations between diets on one hand and patterns of dental microwear on the other. Furthermore, patterns on fossil teeth have been used to reconstruct diets in extinct forms. However, conventional methods for microwear analysis are limited. Scanning electron microscopy does not provide a true representation of these surfaces in three dimensions, and identification and measurement of individual features is time consuming, subjective, and subject to high interobserver error. This paper describes a new approach to the analysis of dental microwear using tandem scanning confocal microscopy and scale-sensitive fractal analyses. The instrument used in this study provides three-dimensional coordinates representing surfaces at a resolution equivalent to that employed by most SEM microwear studies. Fractal analyses offer objective, repeatable, quantitative characterization of surfaces. This approach eliminates major sources of error and increases power to resolve differences between species. Moreover, rapid surface characterization will allow examination of large samples to assess within species variation and to make finer distinctions between species.     

3D analysis of SEM images of corrosion casting using adaptive stereo matching

The corrosion casting method represents one of the most widely used technique to study the 3D microvascularization of many tissues, both in their normal and pathological conditions. For a long time this technique was used only to perform a qualitative evaluation of the images obtained by scanning electron microscopy (SEM). A quantitative evaluation of vascular parameters (e.g., interbranching and intervascular distances, angle measurements, lengths and diameters) was lacking, mainly because of the difficulties found in the measurement performed on 2D SEM images. Then, some authors reported a quantitative method based on the analyses of stereo-pair images that allowed precise morphometric measurements. To visualize the specimens in 3D, it was necessary to use red-green glasses. In this article we describe a new approach by which we can automatically obtain a 3D reconstruction of vascular cast specimen's surface directly from stereo-images. Moreover, we developed a software that performed micrometric measurements on the 3D construct generated from the stereo-pictures. In conclusion, implementing together these two softwares and applying them to corrosion casting samples made it possible to render in 3D the surface of corrosion cast as well as make quantitative measurements on the corrosion casts.     

Metallization and Ar‐O plasma effects on dental enamel roughness evaluated with SEM and MeX™ for 3D reconstruction

The MeX? software is a useful tool for tridimensional data collection for surface evaluation and could be relevant to evaluate the same specimen in different phases of the study, assuming repeated measures of dental enamel roughness. The aim of this study was to evaluate the influence of sample metallization for dental enamel roughness analysis with 3D images reconstructed using MeX? software from Scanning Electron Microscopy (SEM) images. The influence of 74.98% (%mol/mol) argon?oxygen plasma for carbon layer removal on surface roughness of the metallized specimen was also evaluated. Dental enamel specimens were prepared for SEM analysis with and without carbon metallization using conventional or environmental modes. Argon?oxygen plasma for carbon layer removal was used and surface roughness was re‐evaluated. Roughness obtained by SEM and MeX? reconstructed images, with or without metallization, did not differ. No significant alteration on surface roughness after carbon layer removal using plasma was found. SEM baseline evaluation using conventional mode without sample preparation and in environmental mode were not comparable. Roughness of enamel 3D images reconstructed with MeX? software from SEM images, with or without metallization was similar. The 74.98% (%mol/mol) argon?oxygen plasma removed the carbon layer with no effect on enamel roughness.     

A new approach for improving the birefringence analysis of dental enamel mineral content using polarizing microscopy

The main problem in interpreting birefringence of dental enamel under polarizing microscopy is the lack of physical constants able to allow the Wiener equation to be applied directly to the composition of such tissue. The present study introduces a new approach to circumvent this constraint. Because the nonmineral phase of enamel is heterogeneous, its refractive index can be computed in terms of its components (namely, water, which is partially replaced by the immersion medium, and organic matter), thereby providing a more acceptable refractive index to be used in the Wiener equation. Furthermore, the enamel mineral volume is ordinarily calculated on the basis of the density 3.15 g cm^?3. The density 2.99 g cm^?3 has been, however, reported to be more accurate for enamel hydroxyapatite, so enamel mineral volumes from selected published data were converted using such a density. The birefringence of mature enamel computed by the Wiener equation, taking into account the above refinements, matched, for the first time, published experimental birefringence values. The theoretical water and organic contents were also consistent with published experimental data. Thus, a direct application of the Wiener equation to the enamel composition has now been achieved. It is speculated that quantitative data on the mineral, the water and the organic contents of mature dental enamel can be derived from interpretation of birefringence in two immersion media (obtained before and after extraction of the organic matter) with this new approach.     

Morphological and mineral analysis of dental enamel after erosive challenge in gastric juice and orange juice

This study evaluated and compared in vitro the morphology and mineral composition of dental enamel after erosive challenge in gastric juice and orange juice. Human enamel specimens were submitted to erosive challenge using gastric juice (from endoscopy exam) (n = 10), and orange juice (commercially-available) (n = 10), as follows: 5 min in 3 mL of demineralization solution, rinse with distilled water, and store in artificial saliva for 3 h. This cycle was repeated four times a day for 14 days. Calcium (Ca) loss after acid exposure was determined by atomic emission spectroscopy. The presence of carbonate (CO) and phosphate (PO) in the specimens was evaluated before and after the erosive challenge by FT-Raman spectroscopy. Data were tested using t-tests (P < 0.05). Morphology of enamel was observed in scanning electron microscopy (SEM). The mean loss of Ca was: 12.74 ± 3.33 mg/L Ca (gastric juice) and 7.07 ± 1.44 mg/L Ca (orange juice). The analysis by atomic emission spectroscopy showed statistically significant difference between erosive potential of juices (P = 0.0003). FT-Raman spectroscopy found no statistically significant difference in the ratio CO/PO after the erosive challenge. The CO/PO ratios values before and after the challenge were: 0.16/0.17 (gastric juice) (P = 0.37) and 0.18/0.14 (orange juice) (P = 0.16). Qualitative analysis by SEM showed intense alterations of enamel surface. The gastric juice caused more changes in morphology and mineral composition of dental enamel than orange juice. The atomic emission spectroscopy showed to be more suitable to analyze small mineral loss after erosive challenge than FT-Raman.     

Systematic inquiry in tests of negative/positive replica combinations for SEM

High resolution replica materials are routinely used in scanning electron microscopy. A systematic evaluating procedure for replica combinations is proposed which details fourteen points to be recorded. These points include quantitative and qualitative information useful when assessing a replica combination for a particular research problem. A case study employing one silicone-based impression material and one epoxy resin is performed as an example of the procedure.     

Microstructure and mineral composition of dental enamel of permanent and deciduous teeth

Purpose: This study evaluated and compared in vitro the microstructure and mineral composition of permanent and deciduous teeth's dental enamel. Methods: Sound third molars (n = 12) and second primary molars (n = 12) were selected and randomly assigned to the following groups, according to the analysis method performed (n = 4): Scanning electron microscopy (SEM), X‐Ray diffraction (XRD) and Energy dispersive X‐ray spectrometer (EDS). Qualitative and quantitative comparisons of the dental enamel were done. The microscopic findings were analyzed statistically by a nonparametric test (Kruskal‐Wallis). The measurements of the prisms number and thickness were done in SEM photomicrographs. The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS investigation. Chemical phases present in both types of teeth were observed by the XRD analysis. Results: The mean thickness measurements observed in the deciduous teeth enamel was 1.14 mm and in the permanent teeth enamel was 2.58 mm. The mean rod head diameter in deciduous teeth was statistically similar to that of permanent teeth enamel, and a slightly decrease from the outer enamel surface to the region next to the enamel‐dentine junction was assessed. The numerical density of enamel rods was higher in the deciduous teeth, mainly near EDJ, that showed statistically significant difference. The percentage of Ca and P was higher in the permanent teeth enamel. Conclusions: The primary enamel structure showed a lower level of Ca and P, thinner thickness and higher numerical density of rods. Microsc. Res. Tech., 2010. © 2009 Wiley‐Liss, Inc.     

FIB preparation and SEM investigations for three-dimensional analysis of cell cultures on microneedle arrays

We report the investigation of the interfaces between microneedle arrays and cell cultures in patch-on-chip systems by using Focused Ion Beam (FIB) preparation and Scanning Electron Microscopy (SEM). First, FIB preparations of micro chips are made to determine the size and shape of the designed microneedles. In this essay, we investigate the cell-substrate interaction, especially the cell adhesion, and the microneedle's potential cell penetration. For this purpose, cross-sectional preparation of these hard/soft hybrid structures is performed by the FIB technology. By applying the FIB technology followed by high-resolution imaging with SEM, new insights into the cell-substrate interface can be received. One can clearly distinguish between cells that are only in contact with microneedles and cells that are penetrated by microneedles. A stack of slice images is collected by the application of the slice-and-view setup during FIB preparation and is used for three-dimensional reconstruction of cells and micro-needles.     

Evaluation of the effect of food and beverages on enamel and restorative materials by SEM and Fourier transform infrared spectroscopy

Objectives To examine different types of restorative materials used in children as well as primary and permanent teeth enamel when affected by erosive foods. Materials and Method Buttermilk, fruit yoghurt, Coca‐cola, fruit juice, Filtek Z‐250, Dyract Extra, Fuji II LC, and Fuji IX and tooth enamel were used. Measurements were performed on 1‐day, 1‐week, 1‐month, 3‐month, 6‐month time periods by using ATR‐FTIR technique and surface of the specimens were examined with SEM. Results Permanent tooth showed the least change among human tooth samples when compared to restorative materials. Among filler materials, the most change was observed in Fuji IX. In terms of beverages the most changes on absorption peaks obtained from spectra were seen on the samples held in Coca‐Cola and orange‐juice. Conclusion The exposure of human enamel and restorative materials to acidic drinks may accelerate the degradation process and so reduce the life time of filler materials at equivalent integral exposure times longer than three months. Clinical Relevance Erosive foods and drinks having acidic potential destroy not only tooth enamel but also restorative materials. Microsc. Res. Tech. 77:79–90, 2014. © 2013 Wiley Periodicals, Inc.     

Comparative analysis on measuring performances of dental intraoral and extraoral optical 3D digitization systems

Implementation of the methods of 3D digitization in dental practice is a modern and sophisticated alternative to the method of conventional impressions. Among many different methods of 3D digitization applied in dentistry, optical methods can be considered as today mostly applied, especially in the field of prosthodontics. The developments of this kind of systems have converged in two main directions – extraoral and intraoral systems. The main quality parameters for evaluating measuring performances of 3D digitization methods and systems include accuracy and precision. By introducing LED blue light in intra- and extraoral cameras, the Cerec system has significantly improved the quality of 3D digitization results. As the technical features of cameras in both types of systems are identical and the difference of the digitization methods is connected only to operating environments, the main goal of the research was to analyze whether different digitization conditions significantly influence the systems’ measuring performances. Analyzes were focused on investigating accuracy and precision of two mentioned specialized dental optical systems on the basis of CAD inspection, with special attention on evaluating statistically significant differences within the obtained results. Statistically significant difference was not found in systems’ precision, while the extra oral system was found as of significantly higher accuracy.     

Direct preparation of particles from liquid suspension for ESEM or SEM analysis

A simplified method for the preparation of particles from liquid suspensions has been developed. Particles are deposited directly on carbon planchets for rapid analysis by environmental scanning electron microscopy or by conventional scanning electron microscopy after an additional drying step. This is accomplished by filtering the liquid through thin carbon planchets. Three different grades of graphite were investigated for their suitability as the source material for these planchets. The high quality isomolded graphite is recommended for the filtration and direct observation of particles by electron microscopy. This technique is demonstrated for particles in hydraulic fluid and aquatic suspended particulate material from a natural water source.     

Tillandsia stricta Sol (Bromeliaceae) leaves as monitors of airborne particulate matter—A comparative SEM methods evaluation: Unveiling an accurate and odd HP‐SEM method

Airborne particulate matter (PM) has been included among the most important air pollutants by governmental environment agencies and academy researchers. The use of terrestrial plants for monitoring PM has been widely accepted, particularly when it is coupled with SEM/EDS. Herein, Tillandsia stricta leaves were used as monitors of PM, focusing on a comparative evaluation of Environmental SEM (ESEM) and High‐Pressure SEM (HPSEM). In addition, specimens air‐dried at formaldehyde atmosphere (AD/FA) were introduced as an SEM procedure. Hydrated specimen observation by ESEM was the best way to get information from T. stricta leaves. If any artifacts were introduced by AD/FA, they were indiscernible from those caused by CPD. Leaf anatomy was always well preserved. PM density was determined on adaxial and abaxial leaf epidermis for each of the SEM proceedings. When compared with ESEM, particle extraction varied from 0 to 20% in air‐dried leaves while 23–78% of particles deposited on leaves surfaces were extracted by CPD procedures. ESEM was obviously the best choice over other methods but morphological artifacts increased in function of operation time while HPSEM operation time was without limit. AD/FA avoided the shrinkage observed in the air‐dried leaves and particle extraction was low when compared with CPD. Structural and particle density results suggest AD/FA as an important methodological approach to air pollution biomonitoring that can be widely used in all electron microscopy labs. Otherwise, previous PM assessments using terrestrial plants as biomonitors and performed by conventional SEM could have underestimated airborne particulate matter concentration.     

Palyno‐morphological characteristics of gymnosperm flora of pakistan and its taxonomic implications with LM and SEM methods

The present study is intended to assess gymnosperms pollen flora of Pakistan using Light Microscope (LM) and Scanning Electron Microscopy (SEM) for its taxonomic significance in identification of gymnosperms. Pollens of 35 gymnosperm species (12 genera and five families) were collected from its various distributional sites of gymnosperms in Pakistan. LM and SEM were used to investigate different palyno‐morphological characteristics. Five pollen types (i.e., Inaperturate, Monolete, Monoporate, Vesiculate‐bisaccate and Polyplicate) were observed. Six In equatorial view seven types of pollens were observed, in which ten species were sub‐angular, nine species were Traingular, six species were Perprolate, three species were Rhomboidal, three species were semi‐angular, two species were rectangular and two species were prolate. While five types of pollen were observed in polar view, in which ten species were Spheroidal, nine species were Angular, eight were Interlobate, six species were Circular, two species were Elliptic. Eighteen species has rugulate and 17 species has faveolate ornamentation. Eighteen species has verrucate and 17 have gemmate type sculpturing. The data was analysed through cluster analysis. The study showed that these palyno‐morphological features have significance value in classification and identification of gymnosperms. Based on these different palyno‐morphological features, a taxonomic key was proposed for the accurate and fast identifications of gymnosperms from Pakistan.     

Modelling and analysis of FMS productivity variables by ISM,SEM and GTMA approach

Productivity has often been cited as a key factor in a flexible manufacturing system (FMS) performance, and actions to increase it are said to improve profitability and the wage earning capacity of employees. Improving productivity is seen as a key issue for survival and success in the long term of a manufacturing system. The purpose of this paper is to make a model and analysis of the productivity variables of FMS. This study was performed by different approaches viz. interpretive structural modelling (ISM), structural equation modelling (SEM), graph theory and matrix approach (GTMA) and a cross-sectional survey within manufacturing firms in India. ISM has been used to develop a model of productivity variables, and then it has been analyzed. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) are powerful statistical techniques. CFA is carried by SEM. EFA is applied to extract the factors in FMS by the statistical package for social sciences (SPSS 20) software and confirming these factors by CFA through analysis of moment structures (AMOS 20) software. The twenty productivity variables are identified through literature and four factors extracted, which involves the productivity of FMS. The four factors are people, quality, machine and flexibility. SEM using AMOS 20 was used to perform the first order four-factor structures. GTMA is a multiple attribute decision making (MADM) methodology used to find intensity/quantification of productivity variables in an organization. The FMS productivity index has purposed to intensify the factors which affect FMS.     

Pollen micromorphological analysis of tribe Acacieae (Mimosaceae) with LM and SEM techniques

The morphology of pollen grains of the 06 species of tribe Acacieae (Mimosaceae) belonging to one genus were investigated using scanning electron microscopic (SEM) and light microscopic (LM) approach. Lactic acid acetolysis method was used for (LM) while non‐acetolysis for (SEM). The species were examined for the both qualitative and quantitative palynological features. Qualitatively the pollen was studied for the shape, exine sculpturing, pollen shape, and pollen type. Oblate spheroidal shape of pollen was observed in Accacia modesta. Subprolate shape in Accaca nilotica. In Accacia farnesiana, prolate pollen was examined while prolate spheroidal in Acacia tortilis and spheroidal pollen grains were studied in Acacia catechu, respectively. Pollen exine sculpturing of the studied tribe possesses novel variation. Foveolate, reticulate, foveolate‐psilate, faint reticulate, fossulate, perforate, and scrabate exine sculpturing were noticed. Colpi were absent in all species. Excessive variation was observed in both qualitative and quantitative character of pollen. SPSS software was use for the quantitative measurement of the pollen grains. The current study will be helpful for the identification of the problematic species and phylogenetic studies of family Mimosaceae.