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At least 343 records · Page 19Linked to original sources

PubMed1989

Structure and per-rectal ultrasonography of prostatic disease using cadaver specimens.

One hundred cadaver prostates were examined by per-rectal ultrasound and the findings correlated with the microradiographic and histopathological features of whole sections taken at the levels of scanning. The normal gland consists of both periurethral muscle and glands. The periurethral muscle has little structure on microradiography and is therefore hypoechoic (low amplitude echoes) on ultrasound scanning. The gland itself, both central and peripheral zones, has a lattice appearance on microradiography (reticular structure) and therefore produces mid-range amplitude echoes on ultrasound. Benign hypertrophy develops at the edge of the periurethral muscle and is microadenomatous in structure. This produces mid-range amplitude echoes which are coarser than in the normal gland. Associated calcification has a characteristic distribution around the adenomas. Cancer produces an amorphous structure resulting in loss of ultrasonic echoes (hypoechoic). In a few cancers irregular calcification is present, resulting in high echoes in the ultrasound scan (hyperechoic) which are not in the typical benign distribution. The internal structure of the prostate was therefore demonstrated in its histopathological states by the technique of microradiography and seen to relate to its representation by ultrasound.

Adolescent↗

PubMedDate not supplied

Microradiographic study of retrieved craniofacial osseointegrated implants.

In this study 18 screw-shaped extraoral osseointegrated implants retrieved from 10 patients were analyzed. The reasons for retrieval were: unexplained pain (n = 4); inability to cope with the implants (n = 2); fracture of the central screw (n = 2); skin penetration problems (n = 1), and trauma (n = 1). Retrieved implants were trephined with a border of surrounding bone, fixed, embedded in epon plastic, ground and processed for microradiography. The study group comprised 6 males and 4 females with a mean age of 53.4 (range 9-81) years. All implants were clinically stable at the time of removal, and the mean osseointegration time was 3 (range 1-5) years. Six implants were removed from the temporal bone, 5 from the frontal bone, and 7 from the maxilla. By microradiography, it was found that all retrieved implants were surrounded by a lamellar type of bone with haversian systems, vascular channels, osteocyte lacunae, and in some specimens regeneration and resorption areas. Bone metal contact was estimated to vary between 27 and 83%. Bone metal contact was lower in the frontal bone compared to the temporal bone or maxilla, and was further reduced after preoperative irradiation. Longer osseointegration time increased bone metal contact, as did increased age up to 60 years. It is concluded that extraoral osseointegrated implants in humans may integrate morphologically as well as clinically. By microradiography it was possible to define bone metal contact in the region of implant installation.

Adult↗

PubMed2001

[A possible criteria for diagnosis of early caries in pits and fissures].

OBJECTIVE: The aim of this study was to examine pits and fissures of occlusal surfaces with severe stains by both histological and clinical methods, and to evaluate the criteria for diagnosis of early caries in pits and fissures. METHODS: Thirty-one fresh extracted molars and premolars, severely stained but no detectable defects in the surfaces, walls and floors of occlusal fissures, were collected. The teeth were longitudinally sliced across the stained fissures and ground into sections of 100-140 microns. The sections were observed using microscopy and microradiography. RESULTS: All samples showed early carious lesions in pits and fissures under microscope. Demineralization in walls or floors was identified by microradiography in 30 samples. CONCLUSION: Although without detectable defects, severely stained pits and fissures showed demineralization by using microscopy and microradiography. Thus, early caries in pits and fissures may be identified by the severely stained appearance.

Adolescent↗

PubMedDate not supplied

The mineral composition and enamel ultrastructure of hypocalcified amelogenesis imperfecta.

Hypocalcified amelogenesis imperfecta is characterized clinically by a yellow-brown colored enamel that is prone to severe attrition, often leading to rapid destruction of the crown. While the enamel is thought to be poorly mineralized few studies have evaluated the mineral content, or the histological or microradiographic features of this specific AI type. The purpose of this investigation was to examine teeth affected with autosomal dominant hypocalcified AI histologically using light microscopy (LM), scanning electron microscopy (SEM), and to evaluate the degree of enamel mineralization chemically and with microradiography. Four AI teeth were obtained from an affected individual for comparison with age-matched teeth from normal healthy individuals. Thin sections approximately 100 microns were cut with a diamond disc for examination by LM and microradiography. Using SEM, fractured enamel samples were examined either untreated or after removal of organic material using NaOCl or urea. Normal and AI enamel particles were dissected from thin sections to evaluate the mineral per volume and carbonate content. The enamel was not uniformly affected in all areas of the teeth with the lingual surfaces of the mandibular central incisors appearing clinically and histologically normal. The affected enamel was porous and appeared opaque with LM. Both SEM and LM showed the enamel to be prismatic with relatively normal prism morphology. However, the enamel crystallites were rough and granular compared with those of normal enamel. Extraction to remove organic material did not change the appearance of the crystallites indicating their granular appearance was due to mineral and not residual organic material such as enamel protein. Microradiography showed the enamel was less radiodense and therefore poorly mineralized compared with normal enamel. This was confirmed by chemical determination of the mineral per volume, which showed some areas of the AI enamel had as much as 30% less mineral compared with normal enamel. The carbonate content was found to be similar in AI and normal enamel. Hypocalcified AI is associated with decreased mineralization as well as ultrastructural defects in the crystallite structure. The combined histological and biochemical features of hypocalcified AI seen in this investigation indicate that this AI type is distinctly different from the hypoplastic and hypomaturation AI types.

Amelogenesis Imperfecta↗

PubMed2004

Differences in X-ray absorption due to cadmium treatment in Saponaria officinalis leaves.

A method for detecting cadmium uptake in leaves of Saponaria officinalis doped with a solution of cadmium acetate is described. The technique based on the exposure of dried leaves to X-rays of a wavelength close to that of the metal K-edge could be useful for phytoremediation studies as it could reveal the bioaccumulation in plants due to the treatment either in vivo or in vitro with heavy metals. X-ray microradiography measurements are in agreement with those from peroxidase enzyme assay utilized to follow the oxidative damage induced by heavy metals. At present, as we will see in this report, microradiography has still poorer sensitivity in comparison with enzyme assay, but it has the advantage of being faster, not destructive, and usable even at very high doping levels, where the enzyme assay technique results are fully saturated. Further analysis of the optical density values could lead to a quantitative measurement of the heavy metal in the sample. Thus, the technology developed in this article could be useful for tracing the intake in phytoremediation studies.

Absorption↗

PubMed1990

Measuring the volume fraction of bone ingrowth: a comparison of three techniques.

The need for quick, accurate, and reproducible methods to measure the amount of bone within porous metals has increased as the use of these materials has become more common within orthopedics. The purpose of this paper is to compare measurements of bone ingrowth using microradiography, stained histology, and backscattered electron imaging-scanning electron microscopy (BEI-SEM) in cementless, porous-coated acetabular components retrieved from human patients. BEI-SEM of bone ingrowth into porous metal provided excellent images for quantitative analysis. The stained sections and BEI-SEM images provided very comparable results, while microradiography consistently underestimated the porosity of the porous coating and overestimated the amount of bone ingrowth.

Acetabulum↗

PubMed1994

A procedure for the visualization of bone with hydroxyl-apatite coated implants.

A procedure for the histological visualization of the interface between implants coated with hydroxyl-apatite (HA) and bone, and the reaction of bones to the implants, has been developed. Thick sections of bones with HA-coated stainless-steel implants, were investigated with the implant still in situ with routine and (confocal) fluorescence microscopy. The prosthesis-HA-bone interface, bone cells, necrotic and vascularised bone, bone-ingrowth and bone remodelling could be visualised. After removal of the implant from the sections alternative sections were further processed for routine light microscopy, microradiography and detailed fluorescence studies. It appeared that the HA coating was still intact and the integrity of the HA-bone bond was very well preserved. The HA coating layer had the same appearance as after the first inspection with surface microscopy. However, more details were visible. Prosthesis-related and time-related changes in the appearance of the HA layer were detected. The advantage of the procedure is that observations can be made of bone reactions with the prosthesis still in situ, without previous embedding in plastics, and laborous sectioning and/or grinding procedures. Thereafter, sections can be processed for different histological techniques, e.g. immunocytochemistry, routine histology, microradiography, fluorescence microscopy, apparently without imparing the HA coating layer.

Animals↗

PubMed2005

PRP modulates expression of bone matrix proteins in vivo without long-term effects on bone formation.

This experimental study (domestic pig) examined the bone formation after filling defined defects of the frontal skull with autogenous bone or a deproteinized bovine bone matrix (DBBM) in combination with platelet-rich plasma (PRP). Six groups, both materials with and without PRP in two different concentrations (4.1x and 6.5x referring to untreated whole blood) were evaluated at 2, 4, 12, and 26 weeks by means of immunohistochemical staining for different bone matrix proteins, microradiography, light microscopy and polychromatic fluorescence labeling. The sequential expression of bone matrix proteins reflected the specific roles these proteins fulfil in the mineralization of hard tissue. Collagen I expression at 2 weeks was enhanced in all autogenous bone groups. No specific modification of the collagen I expression was found after use of DBBM with or without PRP. Osteopontin and especially osteonectin showed a remarkable enhancement at 4 weeks in nearly all autogenous bone and DBBM groups. These increased levels closely resembled the mineralization content evaluated by microradiography at that time. For the three autogenous bone groups, an expression peak for osteocalcin was demonstrated at 12 weeks, further reflecting the way of de novo bone formation. The microradiographic evaluation demonstrated a statistically significant enhancement in bone regeneration by PRP only after use of autogenous bone plus PRP at 2 weeks (P = 0.002). After 4 weeks, mineralization values after use of autogenous bone were significantly lower if PRP was added to the autogenous bone (P = 0.002). No long-term effects of the PRP administration were found in the mineralization process. In all DBBM groups, bone formation remained unchanged, confirming the lack of any osteoinductive capacity of PRP. PRP modulated the expression of bone matrix proteins in this experimental setting. However, an enhancement of bone formation was demonstrated only at 2 weeks after application of the higher PRP concentration in combination with autogenous bone. In conjunction with an anorganic bovine bone no effects of PRP on defect mineralization were discovered, demonstrating the lack of osteoinductive capacity in PRP as well as in DBBM.

Animals↗

PubMed2004

The use of in situ models and QLF for the study of coronal caries.

OBJECTIVES: The purpose of the paper is to review aspects of the systems available to model the caries process in enamel. METHODS: The in situ model developed in Liverpool, and the new method of quantifying mineral loss, Quantitative Light-induced Fluorescence (QLF), are described. QLF is a powerful new diagnostic tool which can be used to measure demineralisation and remineralisation in tooth surfaces in vivo; studies to optimise, validate and use QLF in different clinical situations are described. RESULTS: Examples of the use of in situ models show that they are particularly valuable for monitoring de and remineralisation of artificial lesions in relation to product testing as alternatives to clinical trials, and present significant advances over in vitro methods. Quantification of mineral loss by Transverse Microradiography (TMR) as in the traditional Liverpool model has produced much valuable information, but the destructive nature of the method limits experimental design, and removes the system from the clinical situation. As a possible alternative, QLF has been validated and optimised. Longitudinal measures can be made on the same surface, and examples of its use are for monitoring recurrent caries and demineralisation around orthodontic brackets. CONCLUSIONS: While current in situ models provide a major advance over earlier caries models, measurement of de and remineralisation by destructive methods such as transverse microradiography limits the design of experimental investigations. QLF offers significant time saving, reduces the cost of clinical studies, and because the measurements can be carried out longitudinally in vivo, can remove the need for intra-oral appliances carrying experimental tissues.

Dental Caries↗

PubMed2005

Acceleration of de novo bone formation following application of autogenous bone to particulated anorganic bovine material in vivo.

OBJECTIVE: This prospective animal study examined the de novo bone formation following application of deproteinized bovine bone matrix (DBBM) with or without autogenous bone (AB) to osseous defects. STUDY DESIGN: Defects of defined size were created in the frontal skull of domestic pigs and filled with DBBM alone (group A) and DBBM+25%AB (group B). De novo bone formation was analyzed qualitatively and quantitatively at 9 different times (0.5, 1, 2, 3, 4, 6, 8, 12, 26 weeks) by means of light microscopy, microradiography, and statistical analysis. RESULTS: Histological analysis indicated sufficient osseointegration of DBBM in both groups. Microradiography demonstrated a significant increase of bone formation in group B after 6 weeks (P = .0159) and 8 weeks (P = .0317). CONCLUSION: The addition of 25%AB to DBBM results in accelerated de novo bone formation in osseous defects. This effect is likely caused by osteoinductive properties of cellular elements transplanted with the autogenous bone.

Animals↗

PubMed1998

Scanning microradiographic studies of rates of in vitro demineralization in human and bovine dental enamel.

The aim was to measure frequently and with precision the local integrated mineral loss through small areas of the natural surface of human and bovine enamel during in vitro demineralization using an X-ray photon-counting system (scanning microradiography). The method used was an adaptation of photographic longitudinal microradiography in which the attenuation of X-rays through the enamel is measured in the direction of acid attack, i.e., normal to the enamel surface. The mass of mineral (assumed to be hydroxyapatite) per unit exposed area was measured over 15 microm dia. circles at a series of positions as a function of time in blocks of human and bovine enamel immersed in 0.1 mol/l acetic acid buffered to pH 4.0 with NaOH. There was an initial period (approx. 45 h for human, approx. 75 h for bovine enamel) during which the mineral loss with time was sigmoidal, followed by a nearly linear loss for the remainder of the experiment, in some cases up to 500 h. The initial sigmoidal period may be due to properties of surface enamel or be associated with the development of a surface layer overlying subsurface demineralization. The essentially constant rate of mineral loss after the surface layer has formed confirms earlier observations and is consistent with a rate-limiting process occurring at the dissolving enamel surfaces of the advancing front, and not by transport of ions within the lesion. Small perturbations from a linear loss were seen, which were approximately periodic for human enamel. The slope of the linear period was rather constant within one human or bovine block, but variable between blocks without a clear distinction between human and bovine enamel.

Animals↗

PubMed1995

Influence of disodium (1-hydroxythylidene) diphosphonate on bone ingrowth into porous, titanium fiber-mesh implants.

The influence of disodium (1-hydroxythylidene) diphosphonate on the bonding between bone and porous, titanium fiber-mesh implants was studied. Rectangular, porous, titanium fiber-mesh implant (15 x 10 x 2.4 mm) were implanted into the tibial bone of mature male rabbits. The rabbits were divided into six groups. Disodium diphosphonate was administered daily by subcutaneous injection to groups 1-5. Groups 1-4 received doses of 5.0, 2.5, 1.0, and 0.1 mg per kilogram of body weight per day for 8 weeks, respectively. Group 5 received a dose of 5 mg per kilogram of body weight per day for 4 weeks. Group 6 (control group) was given saline injections. At 8 weeks after implantation, the rabbits were killed. The tibiae containing the implants were dissected out and subjected to detachment tests. The failure load, when an implant became detached from the bone or when the bone itself broke, was measured. The interface of the bone and implant was investigated by Giemsa surface staining and contact microradiography. Giemsa surface staining and contact microradiography showed that porous implant bonding to bone tissue was inhibited by a high dose of disodium diphosphonate in groups 1, 2, and 5. Soft tissue was observed at the interface. In groups 3, 4, and 6, bone tissue ingrowth was observed at the interface between the porous implant and bone tissue. Growth of bone into the porous fiber-mesh implant of a cementless prosthesis is possible if a low dose of diphosphonate below 1.0 mg per kilogram of body weight is given subcutaneously.

Animals↗

PubMed1999

Corrosion on an internal spinal fixator system.

STUDY DESIGN: Thirteen spinal fixators with 26 stabilization bridges and 52 pedicle screws and a mean length of implantation of 10 months were prospectively examined for corrosion. OBJECTIVES: To determine the type of corrosion and the correlation between the construction of the spinal fixator and the type of corrosion. SUMMARY OF BACKGROUND DATA: Evidence of fretting and crevice corrosion is seen in many stainless steel implants in retrieval studies. Such reactions have not been described in the literature on spinal fixator systems. METHODS: Macroscopic and microscopic alterations in the adjacent tissue were examined, and the corrosive alterations were documented photographically using stereoscopic optical light microscopy. The chemical composition of the implants was determined spectrographically. Microradiography and x-ray fluorescence analysis of the soft tissue were performed. RESULTS: At surgery, tissue discoloration was found in four cases. Histologic examination showed extensive fibrosis, foreign body reaction and inflammation associated with a small number of metal particles, indicating metallosis in five cases. Corresponding particles were detected by microradiography. Corrosion was found on 13 telescopic rods and on two pedicle screws. The alterations on the telescopic rods could be interpreted as crevice corrosion and the alterations in the pedicle screws as fretting corrosion. The two monobloc fixator bridges did not show signs of corrosion. In these implants, the neighboring tissue was macroscopically inconspicuous, and histologic examination showed minimal fibrosis or presence of metal particles. Spectrographic examination of the spinal fixators showed no structural imperfection. CONCLUSIONS: The construction constraints of a spinal fixator make it prone to corrosion. New spinal implants should be examined not only in vitro but also in vivo to ascertain whether corrosion and adjacent tissue reaction occur. Corrosion is one reason to explant the internal fixation system after fusion of the spinal fracture.

Adult↗

PubMed1984

Dysplastic enamel in odontoma: a light microscopic, microradiographic and SEM study.

Dysplastic enamel and calcifications at the enamel surface in 7 odontomas were studied, using correlated light microscopy of decalcified and undecalcified material, microradiography and SEM. Much of the dentin in the odontomas was not covered with enamel. When present, the enamel was immature and assumed a prismatic structure. The prisms were irregular distributed and associated with spherical calcifications. The calcifications adhering to the enamel surface or separated from it presented variations in size, morphology, staining reactions and radiodensity. The correlated techniques of light microscopy, microradiography and SEM indicated that all the calcifications adhering to the enamel surface and part of those separated from it may be related to a pathological process of amelogenesis. Most of the calcifications separated from enamel and often formed around nidi of ghost cells, are the result of a dystrophic mineralizing process, definitely distinct from amelogenesis.

Calcinosis↗

PubMed1985

Natural root caries: a histologic and microradiographic evaluation.

The purpose of this study was to obtain information about the detailed histopathology of naturally occurring root caries. Fifty extracted human teeth exhibiting some degree of root caries were sectioned longitudinally and examined with transmitted light, polarized light and microradiography. The occurrence of the histological zones of dentinal caries was tabulated and revealed a lesion body in all cases. Light microscopy showed the same basic features as microradiography and was most useful when the sections were imbibed in quinoline. A structureless area below the main body of the lesion was observed in 77% of the cases when using quinoline. This fluid more clearly defined the extent of the lesion and may show a "phenolic reaction" when using polarized light microscopy. Partial radiopaque surface layers were observed in almost 80% of the sections. This study has described the detailed histopathology of root caries, and aids in the development of model systems to evaluate this emerging dental health problem.

Dental Caries↗

PubMed1981

Effect of cyclophosphamide on dentinogenesis in the rat incisor: fluorescence microscopic and microradiographic investigations.

Previously described dentin reactions to cyclophosphamide (CPhA) were studied by means of fluorescent labeling and microradiography. Ten adult rats received 20 mg/kg calcein i.p. on days 0, 4, 7, 10, and 40 mg/kg CPhA 30 min after the first calcein injection. Two animals served as controls. The observation time was 14 d. Fluorescence microscopy and microradiography of the maxillary incisors revealed 1)niche-like defects in dentin starting in mineralize 1-4 d after the CPhA administration labially, while lingually the niches developed later and were completed earlier, 2)localized reduced and increased growth lingually, 3)continuous but reduced apposition of a hypomineralized dentin in the niches, and 4)niche osteodentin produced by pulp cells.

Animals↗

PubMedDate not supplied

The validity and repeatability of three light-induced fluorescence systems: An in vitro study.

New optical systems are being developed that aim to determine the extent of demineralization in enamel. In our laboratory we have compared three such systems: a ring illuminator equipped with a laser, a beam splitter also equipped with a laser and an intra-oral camera equipped with a white-light arc lamp. The aim of the study was to compare the ability of the different optical systems to detect small enamel lesions with microradiographic analysis and to determine the repeatability of these systems. Forty human enamel specimens (3mm in diameter) were mounted in acrylic and polished. The specimens were kept moist throughout the study. Each specimen of the four groups was individually exposed to 14 ml of Carbopol demineralizing solution for 24, 48, 72 and 96 h, respectively. The mineral loss of the 40 specimens was assessed with blue-violet light- induced fluorescence. Each image was captured with a video camera and analysed with dedicated software. The measurements were repeated 3 times with complete shut-down of the system in between the measurements. The same measurements were performed with the ring illuminator, the beam splitter and the arc lamp. The specimens were then cut into thin sections and analysed with microradiography. Similar high correlations between microradiography and the light-based analysis systems were found for the beam splitter and the clinical caries camera set-up. The repeatability was best for the beam splitter set-up. This indicates that the light-induced fluorescence measurement technique can be used in different configurations and that the repeatability of the measurements is influenced by the physical stability of the set-up.

Dental Caries↗

PubMedDate not supplied

Distribution of exogenous proteins in caries lesions in relation to the pattern of demineralisation.

While it is believed that proteins may protect enamel from demineralisation, recent work has indicated that such material may also hinder remineralisation. For example, albumin will inhibit apatite crystal growth in vitro and is present in carious enamel in vivo. However, it is not clear whether (1) the distribution of proteins within lesions is restricted to specific lesion zones or (2) the origin of such proteins is endogenous (i.e. as a remnant of the developmental process) or exogenous, originating in the saliva or gingival crevicular fluid. The present study used a combination of immunohistochemistry and microradiography to determine the distribution of two proteins, serum albumin and salivary amylase, within natural white-spot carious lesions in relation to specific levels of demineralisation. The results indicated that albumin is found primarily in a region of between 10 and 20% demineralisation (an area of transition between the 'dark' zone and lesion 'body'), with smaller quantities occurring in the region between 0 and 10% demineralisation and trace amounts in the zone indistinguishable from sound enamel by microradiography. A similar distribution was found for amylase in that the heaviest labelling was within the 10-20% demineralisation zone, although little if any was present in the 0-10% zone. The presence of these molecules in a region of the lesion where some potential for reprecipitation may exist will have important implications with respect to lesion progression.

Albumins↗