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PubMed1989

The penetration of smear material into dentinal tubules during instrumentation with surface-active reagents: a scanning electron microscopic study.

Thirty freshly extracted, single-rooted anterior teeth were used. They were divided into three groups and instrumented conventionally with #10 to 50 K files. During instrumentation, the K files in the first group were moistened with saline solution, in the second group with 50% sodium dodecylbenzenesulfonate solution, and in the third group with Sulfapon (sodium salt of sulfonated condensation product of ethylen oxide with a fatty acid) solution. After the experimental procedure the specimens were examined in a scanning electron microscope to observe packing of smear material into dentinal tubules. Results showed the surface-active reagents cause the deeper penetration of the smear material into the dentinal tubules. These findings support the hypothesis that the phenomenon of the packing of smear material into the dentinal tubules is by capillary action and fluid dynamics.

Benzenesulfonates↗

PubMed1985

Scanning electron microscope evaluation of wear of dental curettes during standardized root planing.

Root planing relies upon the quality of instrument cutting edges. This study evaluated the sharpness and wear of some dental curettes available in the market following standardized root planing procedures. Nine working edges of nine Gracey No. 1/2 DE curettes, three each from three different manufacturers, were used as controls. These unused factory-sharpened edges were examined by scanning electron microscope (SEM). Eighteen edges of nine curettes of the same brands were likewise examined after root planing procedures. Root planing was carried out on extracted one-rooted teeth mounted in natural positions in manikin jaws. Working areas measuring 3 X 5 mm were marked on root surfaces previously exposed by periodontitis. Root planing procedures included 15 vertical strokes done by either Side 1 or Side 2 of each instrument in relation to a single working area of a tooth, and the same procedure repeated 3 times using the opposite side of the curette. All working edges were examined at points 1 and 2 mm from the tip under 500 times magnification. Edge deformation increased significantly from the control group to the "15-stroke" group and from the "15-stroke" group to the "45-stroke" group. Factory-sharpened curettes (control) were sharp, with functional wire edges present on 55% of the specimens. After 15 strokes, nonfunctional wire edges and narrow edge deformations with bevels measuring less than 15 mu were present. After 45 strokes eight cutting edges (88.9%) showed bevels wider than 15 mu. The difference between the three brands was not significant in any group (i.e., controls, 15 strokes, 45 strokes). Further study is indicated to evaluate the relationships between bevel dimensions and root planing effectiveness.

Curettage↗

PubMed1989

Binding patterns of monoclonal anti-B, anti-H and anti-(Leb + Y) on erythrocytes, imaged in the scanning electron microscope.

Binding patterns of monoclonal IgM anti-B, anti-H and anti-(Leb + Y) antibodies on erythrocytes were visualized in the backscatter electron imaging (BEI) mode of a scanning electron microscope by indirect immunogold labelling. The results were independent of secretor status, supporting the view that type 2 oligosaccharides predominate on erythrocytes. There were considerable cell-to-cell variations of amounts of the antigens, presumably because of differences of antigen development. The amount of H antigens may have been overestimated in previous studies. B and H antigens seemed linked mostly to mobile structures, probably lipid, on the convex parts of the cells and to immobile structures, probably protein, on the concave parts. Y antigens appeared bound to mobile structures also on the concave part of the cell membrane. The results therefore confirm that B oligosaccharides on erythrocytes develop from both lipid- and protein-bound H, but suggest that Y develops mainly from lipid-bound H.

ABO Blood-Group System↗

PubMedDate not supplied

Clinical and scanning electron microscopic assessments of porcelain and ceromer resin veneers.

PURPOSE: Recently available Ceromer resin materials are promising for fabrication of esthetic anterior laminates and provices an alternative, cost effective treament modality to porcelain laminates for discolored anterior anterior teeth. It was proposed to study the esthetic quality and surface finish of veneers fbricated from ceromer resin and compare it with the standard porcelain veneers, both clinically as well as by scanning electron microscope (SEM) at baseline and at 12 months. If found comparable, ceromer resin veneer could provide an alternative to porcelain veneers which is an expensive technique for a developing country like India. MATERIALS AND METHODS: Seventy-two veneers, 36 porcelain and 36 ceromer were placed in 12 subjects who were studied at 0, 6 and 12 months for clinical acceptability, and at 0 and 12 months for SEM assessment. The restorations were luted with Opal luting composite and Scotchbond multipurpose system; polyvinyl siloxane was used as the impression material. The clinical assessment was made using modified United Public Health Services criteria, whereas the SEM assessment was made by quantitative analysis of the marginal fit and surface characteristics of the two veneering materials. RESULTS: Ceromer exhibited good anatomical form during the study period, but depicted changes in color, surface appearance, marginal adaptation, increased marginal discoloration, and tissue response. Inability to achieve a good finish with high gloss was a major drawback of the ceromer. Porcelain exhibited better esthetics, marginal adaptation, finish qualities, and tissue response. The SEM showed good to excellent marginal fit at baselinne in ceromer and porcelain veneers, but loss of luting resin at the margins was evident in both the materials after 12 months, leading to visible gaps in a number of veneer restorations. Ceromer veneers exhibited poor surface characteristics in several restorations, which further degraded in an oral conditions over 12 months. CONCLUSION: Veneering is an effective mode of treating discolored teeth. Ceromer veneers exhibited deterioration of surface finish and increased marginal discolouration over a period of 12 months. Clinically ceromer veneers were less acceptable to the patients than porcelain veneers. Porcelain out-scored ceromer as a permanent mode of treatment for discolored teeth, as over a period of 12 months it yielded good clinical results in comparison to ceromer.

Adolescent↗

PubMed1979

Wear striation direction on primate teeth: a scanning electron microscope examination.

Two experimental methods were used to produce wear striations in one direction on unworn teeth. These include: (1) sliding 22 American Indian (Juntunen site, Michigan; Late Woodland) newly erupted incisors, by hand, across a flat grass surface covered with fine loose sand; and (2) using a unidirectional motor driven mechanical wear machine to draw 56 modern human dental extractions across a flat glass surface covered with silicon carbide powder of different grit sizes. A scanning electron microscope examination of individual wear striation morphology indicates that these wear striations begin with broad pits and have extending grooves that become narrower; characteristics that indicate the motion of wear. Patterns of wear striations on the worn dentitions of American Indians (Juntunen site) and the paleocene primate Phenacolemur pagei show similar characteristics and correspond to the buccal phase of mastication when the mandible is drawn upward, forward and slightly medially into centric occlusion. The data provided by this study can be used to test competing hypotheses concerning the direction of mandibular movement during mastication and food preparation.

Animals↗

PubMed1975

Scanning electron microscopic investigation of thermal damage of the teeth.

Sound teeth were heated to 200 degrees C and 1300 degrees C and the gradually developing morphological changes have been studied. The cementum structure was destroyed at about 500 degrees C, the enamel structure between 700 and 900 degrees C, whereas dentine preserved its canalicular structure even after the inorganic salts had melted at 900 degrees to 1000 degrees C. At 1300 degrees C the mineral substances of the tooth were melting into atypical, globular formations. Scanning electron microscopic examination of dental residues damaged by high temperature seems valuable from forensic, criminological as well as anthropological aspects, since the origin of the finding can be determined, from a small fragment, the material can be identified with a tooth and conclusions can be drawn concerning the temperature inducing the damage.

Adult↗

PubMed1981

Mechanisms of nutritive endocytosis. I. Phagocytic versatility and cellular recognition in Chlorohydra digestive cells, a scanning electron microscope study.

The quantity of surface membrane internalized during phagocytosis by Chlorohydra digestive cells was estimated for a range of particle types. Challenge with 2 of these particles, freshly isolated symbiotic algae (FIS) and latex spheres (LS), resulted in a greater (2.5 X) quantity of surface membrane interiorized than with heat-treated symbiotic algae (HTS) and free living algae (FA), Chlorella vulgaris. This discriminatory process was investigated further by a scanning electron microscope (SEM) and transmission electron microscope (TEM) comparison of the surface events associated with phagocytosis of each of these 4 particles. Those particles that were avidly phagocytized, FIS and LS, were both enveloped by a tightly fitting extension of digestive-cell surface, and obtained a prominent surface coating after their injection into the gut of Chlorohydra. Phagocytic challenge with FIS resulted, furthermore, in the rapid formation of a dense microvillar cover on digestive-cell surfaces. HTS and FA, on the other hand, were enveloped by a less closely fitting extension of digestive-cell surface, did not obtain a prominent surface coating, and did not induce the formation of microvilli. In addition, SEM revealed that at least 3 morphologically distinct phagocytic modes were utilized by the versatile nutritive phagocyte of Chlorohydra: (I) envelopment by the progressive movement of numerous, overlapping tubular protrusions (microvilli) over the particle (FIS) surface, forming first a network of tubular interlocking members, and finally a continuous but rough enclosing surface; (2) envelopment by a single, smooth-surfaced, funnel-like extension of digestive-cell surface (FIS, LS, HTS, FA); and (3) envelopment by multiple, broad folds, often of unequal size, and with overlapping margins (Artemia particles).

Cell Membrane↗

PubMed2004

Scanning electron microscope and energy dispersive X-ray spectrometry studies on the material surface of extruded Polycel ossicular prostheses.

BACKGROUND: The cause of ossicular prosthesis extrusion remains an issue of interest to many otologists. This study evaluated the change in material surfaces and chemical elements of extruded total ossicular replacement prostheses (TORPs) and partial ossicular replacement prostheses (PORPs). METHODS: A total of nine extruded Polycel ossicular prostheses (four TORPs, five PORPs) from nine patients was investigated using scanning electron microscope and energy dispersive X-ray spectrometry (EDX). Three prostheses (TORPs) obtained during revision surgery for hearing restoration were used as control subjects for EDX study. RESULTS: All subjects from the study group showed loss of fibrous capsule at both platform and shaft in the extruded prostheses. In comparison with the control group, the extruded prostheses had a lower level of carbon element (Wilcoxon signed-rank test, p < 0.05). CONCLUSION: Loss of fibrous capsule and micro-degradation are probably two of the many factors that contribute to the extrusion of ossicular prostheses.

Carbon↗

PubMed2002

[Scanning electronic microscope observation of elastic fiber of anastomosed artery].

OBJECTIVE: To observe the architecture of elastic fiber of anastomosed artery. METHODS: The right femoral arteries of 60 Wistar rats were cut off transversely and end-to-end anastomosis were performed. On the 3rd, 7th, 14th, 21st, 30th and 90th days after operation, the anastomosed artery segments were harvested and fixed by 10% formalin. After routine processed, the architecture of elastic fiber of anastomosed artery was observed under scanning electronic microscope and was compared with that of normal artery. RESULTS: On the 3rd and 7th days after anastomosis, there was no the elastic fiber in the middle of the anastomosed area. From 14 to 90 days after anastomosis, the newborn elastic fiber connected the anastomosed area. The reconstruction of elastic fiber could be divided into quiescent stage, proliferation stage, and rebuilding stage. CONCLUSION: The reconstruction of elastic fiber occurs after arterious anastomosis and newborn elastic fiber originates from endoarterious layer. The structure of elastic fiber can return to normal 30 days after anastomosis.

Anastomosis, Surgical↗

PubMed1988

A scanning electron microscope study of monkey maturation-stage ameloblasts.

The maturation-stage enamel organs of Macaca arctoides and Macaca mulatta were examined in order to determine whether the cells were similar to those of the continuously erupting rat incisor. Tooth buds of the permanent dentition were fixed in formaldehyde-glutaraldehyde and post-fixed in OsO4. The enamel organs were separated from the enamel during dehydration, critical-point-dried, metal-coated, and examined in a scanning electron microscope. The results showed that there were few differences in the morphology of maturation-stage ameloblasts of these primates compared with those of other species reported in the literature. The apical plasma membranes were either smooth- or ruffle-ended, while the later membranes had maze, microvillous, or ridge configurations, also seen in rats, and an additional configuration of interdigitating bulbous extensions. The blood vessels of the papillary layer in monkeys were about 7 micron in diameter, considerably larger than those of the rat.

Ameloblasts↗

PubMed1979

Removal of amalgam overhangs. A profilometric and scanning electron microscopic evaluation.

Forty recently extracted teeth with Class II amalgam restorations with overhangs were divided into four groups of 10 teeth each. The overhangs were removed using one of the following instruments in each group: trimmer, chisel, surgical blade and reciprocating motordriven diamond tip. Instrumentation was performed until no irregularity could be detected clinically with a No. 3 explorer. The tooth-amalgam interfaces were examined by combined use of a surface measuring instrument and a scanning electron microscope. Four tracings from each specimen were recorded and the discrepancy at the tooth-restoration interface was measured. The mean score for each tooth was determined, and the results were analyzed statistically. The tooth-restoration interfaces were photographed at 140 magnification with the SEM. The results indicated that all instruments tested were effective in removing overhangs, since none of the mean discrepancies registered after instrumentation exceed 4 micron. The surgical blade, and especially the reciprocating motor-driven diamond tip eliminated overhangs better than the chisel. Both SEM photographs and the profilometric tracings revealed gaps or voids at the toothamalgam interface, ranging from 10 to 50 micron.

Dental Amalgam↗

PubMed2001

Novel approach to analysis of in vitro tumor angiogenesis with a variable-pressure scanning electron microscope: suppression by matrix metalloproteinase inhibitor SI-27.

Degradation of basement membrane by metalloproteinases (MMP) is a critical step in tumor angiogenesis. To evaluate in vitro angiogenesis, several models have been employed, including bovine cornea, fenestrated rat brain, Matrigel, and others. These models did not provide quantitative analysis of capillary formation. The current study aimed for a novel approach to in vitro assay of angiogenesis with a "wet scanning electron microscope (SEM)" to investigate suppression of tumor angiogenesis by the MMP inhibitor, SI-27. The effects of noncytotoxic concentrations of SI-27 (1-100 microM) were determined on nonmitogenic vascular endothelial growth factor (VEGF) (10 ng/ml)-mediated cell motility and in vitro angiogenesis of human umbilical vein endothelial cells (HUVECs). Activities of MMP and tissue inhibitor of metalloproteinase (TIMP) were determined by enzyme-linked immunosorbent assay (ELISA). Subsequently, the inhibitory effect of SI-27 was examined on in vitro angiogenesis stimulated by supernatants of human glioma cell lines (U87MG, U251MG, or U373MG). In vitro angiogenesis was quantitatively analyzed with a variable-pressure SEM. Cell motility and in vitro angiogenesis by HUVECs were significantly increased by VEGF along with elevated MMP-1 and -2 activity, whereas SI-27 significantly suppressed VEGF-mediated in vitro angiogenesis and inactivated both MMP-1 and MMP-2, but not inhibited cell motility. The angiogenesis promoted by glioma supernatants showed a significant reduction in the presence of SI-27. SI-27, a novel MMP inhibitor, inhibited tumor angiogenesis in vitro. It can be anticipated to prevent tumor growth through its angiosuppressive effect. Quantitative analysis with a variable-pressure SEM is a novel approach to in vitro angiogenesis assay.

Angiogenesis Inhibitors↗

PubMed1987

The influence of various bacteria on the cecal mucosa of monoflora chickens infected with Eimeria tenella. A scanning electron microscopic study.

Monoflora chickens were established at the age of 2 days by an oral inoculation of one of six species of bacteria (Lactobacillus acidophilus, Bifidobacterium thermophilum, Bacteroides vulgatus, Clostridium perfringens, Escherichia coli, or Streptococcus faecalis). Two days later the chickens were infected with Eimeria tenella (5 X 10(4) oocytes per bird). There were four groups: uninfected birds as controls, the birds infected with either bacteria or E. tenella alone, and the birds infected with bacteria and E. tenella. As observed under the scanning electron microscope (SEM) seven days after E. tenella infection, damage of the cecal mucosa in all groups infected with bacteria + E. tenella was more severe than in that infected with E. tenella alone. Most severe damage to the cecal mucosa was found in the birds infected with either C. perfringens or B. thermophilum combined with E. tenella.

Animals↗

PubMed1993

An introduction to process visualization capabilities and considerations in the environmental scanning electron microscope (ESEM).

Process visualization can be a very powerful tool for understanding dynamic processes. Process visualization requires a non-destructive technique that can be monitored in real time. In this paper various methods of non-destructive inspection will be described and compared. The applicability of these non-destructive inspection methods to process visualization will be compared and contrasted. Particular attention will be paid to a recent development in this area, the environmental scanning electron microscope (ESEM) which is inherently a non-destructive inspection technique with the advantages of electron microscopy for superior magnification and depth of field capability. The ESEM offers a unique platform for process visualization studies. The majority of process visualization is currently done using optical microscopes with hot stages for observing morphological effects top down (optical microscopes) or from the side (contact angle). Major limitations of these optical methods include lack of magnification, poor depth of field, and clouding of optics. Process visualization is best carried out utilizing a non-destructive technique, such as the ESEM, since invasive sample preparation techniques such as conductive coatings alter the sample and make interpretation more difficult. Common process variables such as thermal profiling and the effect of ambient conditions have been examined using the ESEM. Other process variables that could be of interest in the future will be discussed. There are limitations in the ability of the ESEM to reproduce actual process conditions, such as pressure and mass flow rate trade-offs. The ESEM can also be combined directly and indirectly with other analytical techniques to determine the composition of the sample and/or byproducts of a reaction that is being monitored.(ABSTRACT TRUNCATED AT 250 WORDS)

Humidity↗

PubMed1983

Early changes in venous arterial autografts: a scanning electron microscope study.

The use of autogenous vein as an arterial substitute has been advocated for many years. Methods of harvesting generally cause spasm of the vein and it has been shown that preventing the spasm by applying papaverine improves long-term patency. The present study was undertaken to see if the reported long-term patency of such grafts was associated with improved short-term appearance of the venous endothelium as viewed with the scanning electron microscope. Two groups of dogs were studied; those sacrificed at 3 hours and those at 24 hours after replacing excised segments of the carotid and femoral arteries with cephalic veins. One of the veins was removed in the standard manner allowing spasm followed by distension back to its pre-spasm state; in the other, spasm was prevented by the topical application of papaverine before removal. The study shows that venous endothelial integrity is preserved by the use of papaverine and this improved appearance of the endothelium persists for the first 24 hours after insertion into an arterial milieu. But the study also demonstrated that there was extensive activity of polymorphonuclear leukocytes associated with the endothelium in the early hours after arterialization and that they appeared to have a deleterious effect on the endothelium.

Animals↗

PubMed1990

Scanning electron microscope study on the action of endodontic irrigants on bacteria invading the dentinal tubules.

Three groups of 10 maxillary anterior teeth each, which had been exposed to oral media, were flushed with 9 ml of tap water, physiologic saline solution, and alternating irrigation with NaOCl and hydrogen peroxide respectively. Residual caries, necrotic tissue remnants, intertubular cavitation, and dentinal tubule invasion by bacteria were searched for by means of the scanning electron microscope. Cuboidal sodium chloride crystals were very frequently found deposited in the main root canal, in lateral canals, and inside the dentinal tubules. This study discusses the important role NaOCl may play as a solvent of dental plaque and necrotic tissue remnants in the clinical endodontic treatment of infected teeth that had been exposed to oral media.

Adolescent↗

PubMed1984

Scanning electron microscope study of the development of the human respiratory acinus.

Plastic corrosion casts were made of lungs from fetuses aged from 19 weeks' gestation to term and of lungs from a child and two adults to study the development of the respiratory acinus. To achieve reliable infusion of the most peripheral airspaces a high viscosity plastic was used that is not known to have been employed previously for corrosion casting of lungs. The casts were examined in the scanning electron microscope and showed the increase both in number and in length of the airways distal to the terminal bronchiole and also the change in shape and complexity of the most peripheral airspaces as the lung matures. The terminal airspaces change from short, simple, tubular endings at 19 weeks' gestation to short, shallow saccules from around 30 weeks' gestation to full term and contrast with the deep cup shaped alveoli in the adult. Measurements of the size of the terminal airspace at various stages of development are presented. This new approach, allowing three dimensional study of the peripheral airspaces of the developing lung, will be useful for investigating the lung pathology of neonates.

Adult↗

PubMed2000

Effects of diode and Nd:YAG laser irradiation on titanium discs: a scanning electron microscope examination.

BACKGROUND: Dental lasers have been recommended for uncovering submerged implants as well as decontaminating implant surfaces when treating peri-implantitis. The aim of this study was to show the possible alterations in titanium disc surfaces using an Nd:YAG or a diode laser. METHODS: Three different titanium discs were used (sandblasted, titanium plasma-sprayed [TPS], and hydroxyapatite [HA] coated) to determine the effects of laser irradiation on these surfaces using a scanning electron microscope (SEM). The discs were either irradiated with a pulsed Nd:YAG laser with a contact handpiece and power settings of 2.0, 4.0, and 6.0 W or with a diode laser at 5.0, 10.0, and 15.0 W power settings and continuous wave (cw) in the contact handpiece. Irradiated areas were compared with control titanium sites which were not lased. The specimens were prepared for SEM examination after the disc irradiation. RESULTS: The SEM examination demonstrated extensive melting in all of the Nd:YAG laser irradiated areas. Damage was seen in all TPS- and HA-coated discs even at the lowest power setting. Loss of porosity, coating microfractures, and a relatively smooth surface were observed. In contrast, the diode laser did not cause any damage or modify the disc surface. Regardless of the power setting, there was no visible difference between lased and non-lased surfaces after cw irradiation with the diode laser. CONCLUSIONS: From these findings, it was concluded that the diode laser (980 nm) does not damage titanium surfaces, which should be of value when uncovering submerged implants and treating peri-implantitis.

Lasers↗