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At least 73 records · Page 4Linked to original sources
PubMed1997

Electron probe microanalysis and transverse microradiography studies of artificial lesions in enamel and dentin: a comparative study.

In cardiology and research involving the interactions between restorative materials and dental hard tissues, it is important for small changes in tooth mineral content to be measurable. Currently, transverse microradiography (TMR) is the most accepted tool for the above purpose. Electron Probe Microanalysis (EPMA) can yield both qualitative identification of elements and quantitative compositional information. The purpose of this study was to compare the mineral distribution in well-defined artificial lesions, in dentin and enamel, by the use of both TMR and EPMA on the same sample. The good correlation between the two sets of data validates EPMA as a technique and helps in the interpretation of its results. The data from TMR analysis are expressed as vol% of mineral, while EPMA gives the levels of Ca and phosphate in wt%. The conversion between the two sets of data is complicated by the fact that local density is, as yet, unknown.

Analysis of Variance↗
PubMed1997

Caries development in fluoridated and non-fluoridated deciduous and permanent enamel in situ examined by microradiography and confocal laser scanning microscopy.

The aim of the study was to compare initial caries development in fluoridated and non-fluoridated deciduous and permanent enamel in situ. Enamel slabs were mounted in removable appliances and worn for 4 wks. Significantly larger lesions developed in deciduous than in permanent enamel when no topical fluorides were used. Fluoride mouthrinsing partly prevented lesion development in deciduous and completely in permanent enamel. Initial enamel caries not detected by microradiography can be visualized by CLSM (confocal laser scanning microscopy).

Dental Caries↗
PubMed1997

The caries-preventive effect of titanium tetrafluoride on root surfaces in situ as evaluated by microradiography and confocal laser scanning microscopy.

The aim of the present study was to investigate the cariostatic effect of titanium tetrafluoride (TiF4) on in situ-induced lesions on human root surfaces. Analysis of the samples was carried out by quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM). Pre-molar roots, sectioned into four pieces, were used for sample preparation. Before they were mounted into the recesses prepared in the acrylic intra-oral appliances, two root pieces from each tooth were treated with 4% TiF4 for 1 min, while the remaining two pieces served as controls. The appliances were worn by 12 volunteers for 4 wks. After 4 wks with no fluoride supplementation, the root pieces were removed and analyzed by TMR and CLSM. The TMR results showed that the TiF4 treatment reduced lesion depth and total mineral loss by 56% and 62%, respectively. CLSM images agreed well with the TMR measurements. A dense light-reflecting surface layer with almost intact subsurface structures was evident in the TiF4-treated samples.

Bicuspid↗
PubMed1996

Mineral loss in incipient caries lesions quantified with laser fluorescence and longitudinal microradiography. A methodologic study.

The laser fluorescence method (LAF) was validated with longitudinal microradiography (LMR) for assessment of mineral loss in incipient caries lesions in human enamel. Fluorescence radiance scans and LMR recordings were made of 36 enamel slabs with incipient lesions. Original sound values for fluorescence radiance and enamel amount (kg.m-2) at the lesion site were reconstructed by a computer algorithm. Changes in fluorescence radiance and amount of enamel in each measuring point were calculated. The reconstruction method was tested on 20 sound enamel surfaces. The differences between measured and reconstructed values were -0.13 +/- 0.17% with LAF and 0.002 +/- 0.005 kg.m-2 with LMR. The repeatability of the caries quantification was tested by measuring one lesion 20 times. The fluorescence loss in this lesion was 18.2 +/- 1.0%. The enamel loss was 0.09 +/- 0.02 kg.m-2. The correlation between measurements with the two methods was r = 0.73. The non-destructive laser fluorescence method was concluded to be a sensitive and valid method for quantification of mineral loss in enamel caries lesions.

Adolescent↗
PubMed1995

Microradiography and fluorescence microscopy of bone remodeling on the basal crypt of permanent mandibular premolars in dogs during eruption.

Alveolar bone of erupting teeth was studied in order to define the types of calcified tissues deposited as well as the rate of tooth growth. The third (P3) and fourth (P4) mandibular premolars of 30 dogs aged 12-24 weeks were analyzed by microradiography and microscopy in fluorescent and ordinary light. The bone plate separating P3 and P4 from the mandibular canal presented a complex arrangement of lamellar and woven bone, and even of chondroid tissue. During the pre-eruptive phase, this plate shifted towards the base of the mandible by means of selective resorption and apposition activities. As soon as the furcation was formed, bone apposition appeared on the alveolar side and became the main activity under P3 at the outset of eruption. Under the roots of P4 it occurred 4 weeks later. Dynamic morphometry in fluorescence microscopy showed that eruption progressed faster than the radicular growth. The formation of interradicular bone underwent the same acceleration as the eruption. However, though the tissues were formed at a high rate, it cannot be inferred therefrom that they are responsible for tooth shifting. They might just fill the space left by the erupting tooth.

Alveolar Process↗
PubMed2004

Quantification of root caries using optical coherence tomography and microradiography: a correlational study.

PURPOSE: The use of transverse microradiography (TMR) to quantify the amount of mineral lost during demineralization of tooth tissue has long been established. In the present study, the use of an en-face Optical Coherence Tomography (OCT) technology to detect and quantitatively monitor the mineral changes in root caries was investigated and correlated with TMR. MATERIALS AND METHODS: We used an OCT system, developed initially for retina imaging, and which can collect A-scans, B-scans (longitudinal images) and C-scans (en-face images) to quantitatively assess the development of root caries. The power to the sample was 250 microW, wavelength lambda = 850 nm and the optical source linewidth was 16 microm. RESULTS: Both the transversal and longitudinal images showed the caries lesion as volumes of reduced reflectivity. Quantitative analysis using the A-scan (reflectivity versus depth curve) showed that the tissue reflectivity decreased with increasing demineralization time. A linear correlation (r = 0.957) was observed between the mineral loss measured by TMR and the percentage reflectivity loss in demineralized tissue measured by OCT. CONCLUSION: We concluded that OCT could be used to detect incipient root caries, and that the reflectivity loss in root tissue during demineralization, measured by OCT, could be related to the amount of mineral lost during the demineralization.

Analysis of Variance↗
PubMed1985

Osteochondritis dissecans of the femoral condyles. A histological study with pre-operative fluorescent bone labelling and microradiography.

A review of the literature in osteochondritis dissecans of the femoral condyles reveals that the aetiopathology is still unclear and that relatively few histopathological studies have been carried out. The authors describe a method of study based on microradiography and on preoperative fluorescent labelling of the osteogenetic area followed by examination of the bone remodelling under ultraviolet light microscopy. The results in 12 adult cases are reported in relation to a topographical scheme which divides the lesions into four separate zones.

Adult↗
PubMed1980

Hypophosphatemic vitamin D resistant rickets (phosphate diabetes): bone mineral problems studied by 125I-computed tomography and microradiography.

125I-computed tomography (CT) for the bone mineral analysis of the radius was performed on 9 children with vitamin D resistant hypophosphatemic rickets (VDRR) treated with vitamin D in pharmacological doses. Trabecular bone density was increased in 1 patient and normal in all others. The cortical width of the diaphysis of the radius was decreased, and the cross sectional area of the bone increased, but the total amount of compat bone mineral in the cross section was normal. Measurements of the second metacarpal bone on X-rays of the hand revealed similar findings. Microradiographic and histological examinations of the fibula on 9 different patients also treated with vitamin D showed grossly abnormal mineralization of bone tissue with a perilacunar mineral deficit. It is concluded, that the amount of compact bone and trabecular bone is not decreased in children with VDRR. The normal mineral content determined by CT and the impaired mineralization of the bone material examined by microradiography indicate an over-abundance of incompletely mineralized bone.

Adolescent↗
PubMed1984

Microradiography of in vivo remineralized lesions in human enamel. II.

The purpose of this work was to investigate mineral deposition and redistribution in subsurface human artificial enamel lesions during in vivo remineralization period of 3 months. The enamel lesions were placed in lower prostheses of 30 patients, divided in 3 groups. Group A brushed daily with H2O; group B brushed with H2O and rinsed with a neutral 50 ppm F solution and group C brushed with a neutral 1500 ppm F toothpaste. The technique employed was microradiography. Initially the average vol % of mineral in the lesion body was 47%. After 3 months remineralization in vivo the vol % of mineral in the lesion body was for group A, B and C: 50.7, 48.7 and 53.1 vol %, respectively. The average lesion depth decreased for groups A, B and C 18, 13 and 25 microns respectively over 3 months. The original lesion depth was +/- 100 microns. The microradiographic data show conclusively that mineral is deposited "de novo" inside subsurface lesions. The remineralization percentages are for the control, rinse and brush group 20%, 15% and 31%, respectively.

Dental Caries↗
PubMed1983

[Bone structure in aseptic necrosis of the femoral head by light microscopy, contact microradiography, and fluorescent microscopy --comparing with osteoarthritis and rapidly destructive coxarthrosis].

In order to obtain further information of the pathological changes and bone structure of aseptic necrosis (AN), the present author carried out histological investigation on 20 femoral heads removed by prosthesis or total hip replacement from 18 patients. Both decalcified and undecalcified sections were investigated by microscopy, contact microradiography (CMR) and fluorescent microscopy. Schemata of individual cases were drawn to know the relationship between femoral head deformity and bone reactivity. Moreover, 19 femoral heads with secondary osteoarthritis (OA) removed from 18 patients and 7 with rapidly destructive coxarthrosis (RDC) from 6 patients were similarly investigated to compare with AN. The following results were obtained; Histologically, there are four different areas in AN. From the top of the femoral head, the lesion consisted of (1) subchondral necrosis, (2) granulation tissue, (3) an area of variable bone formation, and (4) normal bone tissue. As the advancement of the head deformity, fibrous component in the granulation increases and seems to divide the femoral head into necrotic and living areas, which by fibrous as well as enchondral ossifications become more prominent in the edge of the demarcation. As for the bone formation, four different types of bone tissues are discernible by CMR; (1) low calcified appositional bone and its absorption, (2) low calcified, appositional bone on wide trabeculae, (3) low calcified appositional bone on narrow trabeculae, and (4) irregularly calcified woven bone. Although during the comparatively early stage, the bone formation is seen in almost all of the living area, as the advancement of the head deformity, its activity decreases and results in overt head deformity to resemble that of OA which would be caused by mechanical factor. Increase of fibrous component in the granulation along with decrease of the bone formation would reduce the repairing activity of the femoral head. In the femoral heads with OA, a wedge-shaped area of bone formation is formed of which peak is located on the medial thickened cortex. In the femoral heads with RDC, a large amount of woven bone with irregular calcification is found in the bone formation area, in the upper part of a femoral head.

Adult↗
PubMed1980

Polarizing microscopy and microradiography of sound enamel.

Plano-parallel longitudinal sections from 19 sound human premolars were imbibed in water and in air. The total birefringence of the occlusal, the midcoronal and the cervical region of the buccal sound enamel cap was then determined. The volume percentage mineral was measured in the same areas using semi-quantitative microradiography. The results show that when the mean values of both water and air imbibed occlusal and midcoronal enamel are considered, there is a positive correlation between the observed total birefringence and the mineral content. The cervical, fissure and cuspal regions showed a poor correlation between mineral content and total birefringence. In longitudinal sections, the influence of the structural organization and the organic matrix is not marked in the occlusal and midcoronal regions although the cervical, fissure and cuspal regions are probably influenced to the greatest extent by these factors.

Air↗
PubMed1981

[Microradiography of gallstones (author's transl)].

Success or failure of an attempted dissolution of gallstones depends--among other factors--on the nature, the quantity and the distribution of the different components. This paper presents an investigation of the distribution of the various components by X-ray microradiography. Due to their different absorption behaviour the following three classes of components could be distinguished: I. Components with low absorption: Cholesterol, II. Components with moderate absorption: Calcium palmitate monohydrate, calcium bilirubinate, III. Components with high absorption: Vaterite, aragonite, calcite, carbonate apatite. The distribution patterns of these classes of components showed that in all probability 12 out of the 27 gallstones which were examined would have resisted a dissolution.

Cholelithiasis↗
PubMed1997

Colocalization of hyaluronan and water in rabbit corneas after photorefractive keratectomy by specific staining for hyaluronan and by quantitative microradiography.

PURPOSE: Endogenous hyaluronan (HA) has previously been shown to be a part of corneal wound healing after photorefractive keratectomy (PRK). HA is known to bind considerable amounts of water. This study aimed to show whether HA colocalized with water in the wound area after PRK. METHODS: Five New Zealand White rabbits were subjected to PRK in one eye each. After 4 weeks, the rabbits were killed and the corneas were freeze-sectioned. The freeze-dried sections were exposed to soft x-rays generated at 3 kV and the microradiographs were evaluated densitometrically. The same sections were then stained for the presence of HA using the HA-binding region of bovine nasal cartilage proteoglycans linked to biotin. RESULTS: The microradiographs showed, in a zone underlying the epithelium, that the water content was increased. In the corresponding zone, the cornea stained positive for HA. CONCLUSION: HA that is reactively formed in the corneal wound after PRK colocalized to the hydrated area of the corresponding location as revealed by quantitative microradiography. The findings suggest that HA causes local shifts in water content in the corneal wound and thereby also local shifts in transparency.

Animals↗
PubMed1997

Morphostructural relationships between bone and implant: comparative analyses by optical microscopy and microradiography.

This study assessed the relationship between the surfaces of a hollow cylindrical titanium implant and the consequent bone organization around it. A human bone maxillary specimen was taken that enclosed an implant which had lasted 28 months under prosthetic loading. The implant was removed because of fracture that prevented the implant from being used as a supporting element for new prosthetic aims. The bone block-section was fixed and embedded, several sections were obtained, and each section was analyzed using three different histologic analyses: optical microscopy under ordinary light and polarized light, and microradiography. Comparative analyses were required on every single section to provide a complete morphostructural analysis of the peri-implant bone. Data retrieved by this research showed the presence of woven bone in the bone layer facing the external implant surface several months after its surgical fitting and functionalization. This finding demonstrates the importance of woven bone, first as holding sheath in the immediate postsurgical stage, and second as a mold for the subsequent centripetal accrementition of secondary lamellar bone.

Dental Implantation, Endosseous↗
PubMed1988

Recurrent bone regeneration in titanium implants. Experimental model for determining the healing capacity of bone using quantitative microradiography.

An experimental technique for quantitative assessment of bone repair was tested. The recurrent regeneration capacity of cortical bone was analyzed in consecutive 3 wk periods, using an osseointegrated titanium implant, the Bone Harvest Chamber (BHC), in the proximal tibial metaphysis of the rabbit. The BHC is a divisible implant penetrated by a canal into which newly formed bone tissue will grow during a 3 wk healing period. The newly formed bone tissue may easily be collected (harvested) without the animal being killed. After 3 wk, bone tissue can again be harvested, in principle, indefinitely. Intact harvested specimens were quantified by microradiography-videodensitometry, yielding a total specimen mass in mg aluminium equivalent. This unit correlated very well to a specimen dry weight (r = 0.996) and an average mineralized bone density (r = 0.937). The specimens were also examined by correlative histology. Three weeks after implant insertion, the chambers had become integrated in the bone tissue but the average bone mass varied widely, influenced by the surgical insertion trauma. Six weeks after insertion, the greatest average bone mass was found, indicating an intense ongoing osseointegration. The amount of bone regenerated at later harvests was fairly equal, indicating a stabilization of the implant bed to the repeat stimulus, i.e. harvesting. Bone regeneration differed significantly between animals, but also intraindividual variations, i.e. different amounts of bone formed in the same chamber, were observed.

Animals↗
PubMed2004

Real-time observation of dendrite coarsening in Sn-13%Bi alloy by synchrotron microradiography.

An improved synchrotron microradiography technique is being used to study dendrite growth and coarsening in Sn-13%Bi alloy in real time. The morphology of growing dendrites can be well resolved with reasonable image contrast. Dendrite arm remelting, coalescence, and fragmentation have been observed in a real alloy and in real time during solidification under controlled thermal gradients and cooling rates. This research opens a different window to the study of alloy solidification and enables unambiguous understanding of solidification processes in optically opaque, metallic alloys.

Journal Article↗
PubMedDate not supplied

Comparison of calcium/phosphorus analysis, longitudinal microradiography and profilometry for the quantitative assessment of erosive demineralisation.

The study is a comparison of methods for the quantitative measurement of erosive mineral loss including longitudinal microradiography (LMR), profilometry (PM), and analysis of calcium (CA) and phosphorus (PA) in the erosion solution. Polished human enamel samples were taped, covered with nail varnish and the edges of the resulting enamel window marked with drilled holes as a reference. All samples were subjected to baseline LMR. Sixty samples each were eroded with citric acid (0.05 M; pH 2.3; 10 ml per sample) for 30, 60, 90, or 120 min. Erosive loss of each sample was estimated by the four methods. All methods revealed a linear erosive loss over time and showed good linear correlation. Values calculated from PM and LMR were both approximately 20% lower than those from CA and PA. After 30 min erosion, LMR showed no significant correlation with the other three methods. With LMR, erosive loss below 20 microm should be interpreted with care.

Calcium↗