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At least 55 records · Page 3Linked to original sources
PubMed1995

Assessing the shape of root canals: an in vitro method using microradiography.

The aim of this paper is to describe an in vitro method which provides clear and accurate details of root canal shape. The method utilizes the technique of contact microradiography to produce high resolution, two-dimensional, real-size images of canals in a longitudinal plane. Specimens can be accurately rotated through 90 degrees allowing images to be produced in a bucco-lingual and mesio-distal direction. The method is simple, relatively rapid and can process large numbers of teeth without the need for complicated and expensive mounting blocks or film holders. The technique can be used to produce pre- and post-operative images of canal shape which can be superimposed to delineate the dentine removed during canal preparation. The method is thus suitable for the evaluation of the shaping ability of endodontic instruments and preparation techniques.

Dental Pulp Cavity↗
PubMed1999

Discrimination of morphological findings in dentine from osteogenesis imperfecta patients using combinations of polarized light microscopy, microradiography and scanning electron microscopy.

OBJECTIVES: The aim of this study was to investigate the morphological appearance of dentine in teeth from individuals with osteogenesis imperfecta type I, III and IV using different histological techniques, and to correlate morphological findings to different types of osteogenesis imperfecta. SAMPLE AND METHODS: Extracted or exfoliated primary and permanent teeth were collected from 15 patients with the osteogenesis imperfecta diagnoses I, III or IV, with or without the additional diagnosis dentinogenesis imperfecta. Ground and decalcified sections were prepared from the teeth. Histo-morphological studies of the dentine were performed utilizing light and polarized light microscopy, microradiography and scanning electron microscopy. RESULTS: Characteristic findings were irregular tubules, remnants of capillary inclusions and obliterated pulps. All types of osteogenesis imperfecta exhibited similar types of dentine aberrations, but patients with type III or IV had a higher frequency of aberrations when compared to type I. CONCLUSIONS: The combination of either polarized light microscopy or micro-radiography, together with scanning electron microscopy, gave the most amount of morphological information from dentine samples. In addition, aberrations in dentine structure were more clearly observable. Light microscopy was not critical for the analyses.

Adolescent↗
PubMed1980

Correlated microradiography, X-ray microbeam diffraction and electron probe microanalysis of calcifications in an odontoma.

Using microradiography, X-ray microbeam diffraction and electron probe microanalysis, a correlated morphologic crystallographic study was performed on dysplastic enamel in a compound odontoma. The tumor was found in the lateral incisor-canine region of the left mandible of a 36-year-old woman. A conspicuous feature was the presence of hypomineralized areas, which were situated in the proximity of enamel surface and distinctly demarcated from the adjacent enamel. X-ray microbeam diffraction and electron probe microanalysis showed that these lesions have a lower crystallinity and a higher concentration of magnesium as compared with the adjacent enamel. In addition, the present study revealed the presence of two other types of calcifications: (1) calcified structures within the fissure or on the enamel surface, which include lacunae of varying size and which resemble a form of coronal cementum, and (2) spherical calcifications which may be an epithelial product.

Adult↗
PubMed1993

Microradiography and light microscopy of mineralization in the pulp of undemineralized human primary molars.

This study was undertaken to investigate the prevalence, location and histologic features of the different types of mineralization observed in the pulp of human primary molars. Microradiography and light microscopy of undemineralized material disclosed that 95% of primary molars contain pulp calcifications. Histologically, their structure may be classified into four different types: (1) pulp stones, (2) diffuse calcifications, (3) eburnoid tissue and (4) spherulitic calcifications.

Adolescent↗
PubMed1983

Observations on giant tubules in human coronal dentin by light microscopy and microradiography.

Human coronal dentin was studied by light microscopy and microradiography. The material comprised 50 permanent and 10 primary anterior teeth and microradiographs of 63 primary anterior teeth from a previous study. Both intact and worn teeth were examined. Ground sections in the long axes of the crowns in the buccolingual and mesiodistal planes were prepared, as well as transverse sections. A few crowns were also examined in toto. A system of giant tubules extending from the border of the pulpal cavity could be followed, though not continuously, through the secondary and primary dentin almost to the incisal dentinoenamel junction was observed. The lumina of the tubules were 5-40 microns wide and bordered by an approximately 10-microns-wide, usually hypermineralized rim of dentin in which only a few dentinal tubules were clearly discernible. The giant tubules were located along the mesiodistal axes of the teeth. The number of such tubules varied between 0 and 30.

Cuspid↗
PubMed1983

In vitro study by fluorescence microscopy and microradiography of tetracycline-tooth interaction.

The administration of tetracycline to the growing child may cause discoloration and hypoplasia in developing teeth. Whether tetracycline may also cause changes in fully mineralized enamel and dentin, is still a matter of discussion. The present investigation examines the in vitro reaction between tetracycline chloride and enamel and dentin of extracted human teeth. Specimens were immersed in 0.5 mg/ml to 20 mg/ml aqueous tetracycline solutions. After 24 hr the specimens were sectioned and studied by fluorescence microscopy and microradiography. The tetracycline solutions, which were all very acidic, were found to cause 1) demineralization of enamel and dentin, 2) incorporation of fluorescent material in enamel and, notably, dentin; and 3) formation of yellow, rhombohedral crystals on dental surfaces, especially in the more concentrated solutions. No fluorescence was seen in totally demineralized dentin. The findings indicate that the incorporation of tetracycline into enamel and dentin is caused by physiochemical processes that may take place regardless of the developmental stage of the mineralized tissues.

Dental Enamel↗
PubMed1996

Microradiography and confocal laser scanning microscopy applied to enamel lesions formed in vivo with and without fluoride varnish treatment.

The aim of the present investigation was to combine 2 techniques suitable for lesion characterization: quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM) on in vivo induced lesions with and without a fluoride varnish (Duraphat) treatment. Orthodontic bands were attached to premolars to be extracted for orthodontic reasons to induce enamel caries on the buccal surfaces. In the caries development part of the study, 1 tooth of each pair received at the start 1 topical application with the fluoride varnish Duraphat, the contralateral tooth serving as untreated control. All teeth were extracted after 4 weeks. In the caries progression part, the premolars were banded for 4 weeks without any treatment to induce caries, 1 premolar in each pair was then extracted and analyzed. The contralateral tooth received one Duraphat application and was extracted after another 2 weeks. In the caries development part of the study, TMR analysis showed that the Duraphat treatment on sound enamel reduced lesion depth by 48% compared to the untreated control. In the caries progression part, no significant difference was found between the untreated teeth extracted after 4 weeks and the fluoride treated lesions extracted after another 2 weeks. CLSM images agreed well with the TMR measurements. In the fluoride treated lesions, the CLSM images showed more light scattering indicating precipitation of material.

Adolescent↗
PubMed1998

Use of transverse microradiography to quantify mineral loss by erosion in bovine enamel.

The aim of the present study was to develop transverse microradiography (TMR) in order to quantitatively assess the influence of artificial saliva and orange juice on the erosion of bovine enamel. Bovine incisors were sectioned sagittally into two equal halves. Each half was coated with acid-resistant nail varnish except for a rectangular enamel window on the labial surface of the tooth. While both halves of each tooth were immersed in pure orange juice 6 times daily for a period of 5 min at each occasion making a total of 30 min per day, one half was stored in artificial saliva and the other half in deionized distilled water between exposures to orange juice and for the remaining 12 h overnight, for 24 days making a total of 12 h of exposure to orange juice. Sections bearing intact and eroded enamel surfaces were cut from each specimen and ground to 80 microm thickness, and TMR of the sections was made. Mineral loss was quantified from the microradiographs using two-step image analysis. Mineral loss was significantly greater in those specimens cycled in orange juice and de-ionized distilled water. TMR was used successfully to quantify the mineral loss by erosion in vitro, and it is envisaged that it will be useful for specimens used in intra-oral appliances during in situ trials. Artificial saliva saturated with respect to calcium and phosphate salts can possibly remineralize an erosive lesion and may reduce the degree of erosion.

Analysis of Variance↗
PubMed1998

Measurement of enamel remineralization using microradiography and confocal microscopy. A correlational study.

Tooth minerals are lost and regained constantly in a normal, human oral environment. Different methods have been developed to measure this gain and loss in enamel minerals; however, these methods deal with different problems, such as being time consuming or involving the use of X-rays. The aim of this study was to determine if remineralization measured in a thin enamel section (TS) by transversal microradiography (MR) can be reliably monitored by measuring lesion parameters (area, total and average dye fluorescence) on the same TS or on half a tooth (HT) with confocal laser scanning microscopy (CLSM). Thirty-six human enamel specimens were demineralized for 96h, and then half of each specimen was covered with an acid-resistant nail varnish. Specimens were divided into three groups (12/group) and subjected for 20 days to a cyclic remineralization regimen with consisted daily of a 4-hour acid challenge, four 1-min treatment periods with 0, 250 or 1,100 ppm F dentifrice slurries (1:2; dentifrice:water) and 20 h in pooled, human saliva, at room temperature. Specimens were cut and analyzed by MR, then stained with a fluorescent dye (0.1mM rhodamine B) for 1 h and analyzed using CLSM. Both MR and CLSM detected significantly greater remineralization (p<0.05) in the specimens treated with the fluoride-containing dentifrices than in the specimens treated with 0 ppm F. Significant differences were detected between specimens treated witht the fluoride-containing dentifrices by MR and CLSM (HT area and total fluorescence). Statistically significant (p<0.05) Pearson correlation coefficients were calculated between the MR and CLSM data: difference in MR mineral content (DeltaM) versus HT lesion area = 0.71; DeltaM versus HT total fluorescence = 0.70; DeltaM versus HT average fluorescence = 0.61; DeltaM versus TS lesion area = 0.88; DeltaM versus TS total fluorescence = 0.63, and DeltaM versus TS average fluorescence = 0.40. It is concluded that confocal microscopy in either TS or HT may provide valid surrogates (area and total fluorescence) for MR measurements in enamel remineralization studies.

Analysis of Variance↗
PubMed1998

Influence of nail varnish on the remineralization of enamel single sections assessed by microradiography and confocal laser scanning microscopy.

Single-section techniques are attractive in enamel de- and remineralization investigations because they allow longitudinal studies in which mineral changes can be assessed by microradiography (TMR). Nail varnish (NV) is in general applied to coat the cut thin-section sides. The aims of this study were to investigate: (1) NV penetration depth in cut surfaces of demineralized enamel, (2) the influence of NV on cut surfaces of demineralized enamel on TMR, (3) the influence of NV penetration on a following remineralization. Cut surfaces of thin sections of demineralized enamel were NV coated; the NV was peeled off and the penetration depth assessed by confocal laser scanning microscopy. The NV penetration was 18+/-5 micrometer (mean+/-SD) in demineralized enamel. To evaluate the possible influence of NV on TMR, cut surfaces of thin sections of demineralized enamel were coated (twice) and microradiographed before and after nail varnishing. The NV effect (total effect of penetrated and surface NV) on the main parameters of TMR, Ld and DeltaZ, was less than 5% of the mean values. In the remineralization experiment (remineralization with 1.5 mM Ca2+, 0.9 mM phosphate, pH 7, 1 ppm F for 1 and 2 weeks), lesions in bulk samples, lesions in thin sections with NV-coated cut surfaces and lesions in thin sections in a PMMA (polymethylmethacrylate) holder were compared. (1) The remineralization of bulk samples and of NV-coated thin sections is different in one aspect. The amounts of mineral deposited in the lesions expressed as DeltaZ are comparable after 1 week. But because the NV penetrates part of the lesion outside, there was an Ld difference. The lesion depth difference between bulk lesions and NV-coated lesions in thin sections was statistically significant and was about 19% less in NV-coated lesions after 1 week; after 2 weeks of remineralization there was no difference in Ld between bulk- and NV-coated lesions any more. (2) There was no difference in remineralization efficacy between lesions in bulk samples and lesions in thin sections in the PMMA holder.

Adolescent↗
PubMed2007

A comparison of terahertz pulsed imaging with transmission microradiography for depth measurement of enamel demineralisation in vitro.

Terahertz pulsed imaging (TPI) is a relatively new, non-ionising and non-destructive imaging technique for studying hard tissues which does not require tooth section preparation, unlike transmission microradiography (TMR). If TPI can measure the depths of caries/demineralisation lesions accurately the same tooth samples could be reused and remeasured during in vitro and in situ studies on de- and/or re-mineralisation. The aim of this study was to compare TPI and TMR for measuring the depths of a range of artificially induced bovine enamel demineralised lesions in vitro. Bovine slabs with artificial caries, induced to different levels of demineralisation by two different but standard demineralisation techniques ('acid gel' and 'carbopol') were measured by TPI and TMR and the readings compared. The set of TPI/TMR measurements obtained on the gel-demineralised slabs showed an extremely high coefficient of determination (r(2) = 0.995). Detailed analysis of the results and theoretical considerations (involving the relationship between refractive index profiling and mineral loss profile) are used to explain the findings and show that for acid gel lesions TPI is measuring demineralisation in the range of 47% of that of TMR depth plus an intercept of 16 microm, with further calculations allowing the TMR depths to be determined to within 5% using TPI.

Acids↗
PubMed1988

Determination of mineral changes in human dental enamel by longitudinal microradiography and scanning optical monitoring and their correlation with chemical analysis.

Both longitudinal microradiography (LMR) and scanning optical monitoring (OM) are non-destructive methods for measuring mineral changes in dental tooth enamel slices with time at 169 locations on the slice. Average calcium losses from four human tooth enamel slices (300-400 micron thickness), etched in HClO4, were determined by LMR and chemical analysis (C). As predicted from theory, LMR and C correlate very well (r = 0.99), but the appearance of a systematic error of unknown source of 30% made with LMR, C, or both could not be avoided. Another, more complex, experiment concerned six human tooth enamel slices of the same thickness which were demineralized in an aqueous buffered acid solution containing Ca and PO4. From this experiment it was found that average calcium loss as measured by C and LMR correlated well with the optical scattering as measured with scanning OM (Spearman rank correlation rs approximately equal to 0.79). It was also found that three-dimensional plots of local calcium loss by LMR and scanning OM as a function of tooth slice surface position show a well-defined tooth-dependent increase due to local demineralization and rather similar behaviour with time. From the experiments it follows that LMR and scanning OM are reliable methods to determine the mineral change in a tooth tissue as a function of local tooth slice surface position and of time and that with LMR and scanning OM time- and position-dependent measurements with an oral device become feasible.

Acid Etching, Dental↗
PubMed1992

Comparison of laser fluorescence and longitudinal microradiography for quantitative assessment of in vitro enamel caries.

A new quantitative, non-destructive method using laser-induced fluorescence (LAF) was compared with longitudinal microradiography (LMR) for assessment of mineral changes in enamel slices using an in vitro caries model. Ten enamel slices, cut longitudinally from sound natural smooth surfaces of human teeth, were exposed to de- and remineralization in a pH-cycling model. The enamel slices were subjected to LAF and LMR measurements before and at 2, 4, 7, and 9 days of demineralization. For LAF, the average fluorescence radiance decreased during the demineralization period with 11% by day 2 and 49% by day 9. For LMR, the corresponding average loss of mineral content changed with 0.01 and 0.10 kg.m-2 over the same time period. The mineral losses in each individual enamel slice measured with the two techniques were strongly correlated, r = 0.97. The Spearman rank correlation coefficient for all LAF and LMR demineralization results was 0.86. The precision (coefficient of variation) for LAF was 3.1%, corresponding to 0.005 kg.m-2, and the repeatability error for LMR was 0.02 kg.m-2, indicating a lower discrimination threshold for LAF compared to LMR. It was concluded that the new, sensitive, non-destructive LAF method provides possibilities for further improvement in the quantification of initial caries lesions in natural smooth enamel surfaces for use in in vitro studies. Furthermore, it offers potential in in situ caries studies as well as a tool in the diagnosis of early enamel caries in vivo.

Contrast Media↗
PubMed1994

The video camera compared with the densitometer as a scanning device for microradiography.

In the recent past image analysis systems, comprising a video (CCD) camera and dedicated software, have replaced densitometer-based systems to analyze mineral content profiles using transversal microradiography (TMR). The main reasons for the introduction of the CCD camera were the ease and speed at which it can be operated. The densitometer, as a scanning device for TMR, has in the recent years been validated and is in this study considered as 'gold standard'. Comparisons of the two scanning devices for measuring the optical density of microradiograms have never been reported in the literature. The focus of this study was on accuracy and reproducibility of the scanning devices with the emphasis put on possible limitations of the CCD camera relative to the densitometer. These include resolution, number of gray levels and homogeneity of illumination of the scan area. The microscope was arranged in such a way that the same area on the microradiogram could be assessed by both scanning devices. Three different types of lesions were analyzed: a subsurface lesion, a surface-softened lesion and a laminated lesion. Paired t tests showed no significant difference between the mineral content profiles produced by the two scanning devices. The integrated mineral loss values were calculated and compared with analysis of variance and showed no significant differences. It is therefore concluded that mineral content profiles and integrated mineral loss obtained by the CCD camera are as accurate and reproducible as those obtained by the densitometer.

Analysis of Variance↗
PubMed1995

Stereomicroscopy, film radiography, microradiography and naked-eye inspection of tooth sections as validation for occlusal caries diagnosis.

In establishing a trustworthy validation for occlusal caries lesions, various methods have been used after sectioning teeth. The aim of the present study was to compare the accuracy of four such methods: stereomicroscopy (SM), film radiography (FR), microradiography (MR) and naked-eye inspection (NEI) for the detection of caries in occlusal tooth surfaces. Further, the interobserver agreement between three observers' registrations of occlusal caries by these methods was evaluated. The material consisted of 18 unerupted third molars known to be sound with respect to caries, as they were embedded in bone prior to removal, and 20 erupted third molars with an unknown 'true state of disease'. The teeth were serially sectioned, coded and examined blindly for occlusal caries by three independent observers by the four validation methods under study. SM was demonstrated to be the only method by which all observers correctly identified all 18 unerupted teeth as sound, resulting in a specificity of 1.00. By the other three methods, 1 or more of the unerupted teeth were falsely classified as carious. In the erupted teeth, 73, 58, 52 and 32%, respectively, of the teeth were determined carious by SM, MR, NEI and FR. As it was possible by SM to detect caries in nearly three quarters of the erupted teeth and at the same time to identify all unerupted teeth as sound, this method seemed to be the most trustworthy of the validation methods under study.

Dental Caries↗
PubMed1982

The pattern of mineralization of traumatically-induced developmental defects of sheep enamel assessed by microhardness and microradiography.

An earlier study showed that some of the variation in appearance of defects of enamel in sheep incisor teeth induced by trauma during tooth development was related to the phase of activity of the ameloblasts at the time of injury. In the present study, sixteen selected defects were examined by microhardness and microradiography. It was found that in some of the fully formed teeth, the defects had retained the pattern of mineralization present at the time of trauma, i.e., mineralization had ceased. In other teeth, further mineralization of the defects occurred after trauma, resulting in well-mineralized enamel, although sometimes of incomplete thickness. It was concluded that the trauma, depending on its severity, leads to either permanent or temporary dysfunction of the ameloblasts, which also influences the appearance of the resulting lesions.

Ameloblasts↗
PubMed1984

Comparison of artificial white spots by microradiography and polarized light microscopy.

This work compared lesions produced by three artificial caries systems with natural white spot lesions using both polarized light microscopy and microradiography. The three systems employed were the acidified gelatin gel, diphosphonate surface dissolution inhibitor, and a partially saturated buffer system. When we compared the natural white spot lesions with the artificial caries-like lesions, we found that the acidified gel system reproduced the classical histological zones most frequently. All systems showed a radiopaque surface layer overlying a radiolucent body of the lesion. This radiopaque layer could not be equated with the negatively birefringent surface zone seen in polarized light.

Decalcification Technique↗
PubMed1985

Application of an x-ray image magnifier to the microradiography of dental specimens.

A highly parallel incident x-ray beam combined with x-ray image magnification was used to obtain high-resolution microradiographs of dental specimens. Preliminary results obtained using a rotating anode x-ray generator show that limitations associated with conventional contact microradiography regarding spatial resolution, sample thickness, and sample orientation, relative to the film, were significantly reduced.

Dental Caries↗