| 1. |
- Flygare, Lennart, et al.
(författare)
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Bone histomorphometry using interactive image analysis. A methodological study with application on the human temporomandibular joint.
- 1997
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Ingår i: European Journal of Oral Sciences. - : Wiley-Blackwell. - 0909-8836 .- 1600-0722. ; 105:1, s. 67-73
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to develop a reproducible method for bone histomorphometry with the aid of a computerized image analysis program, and to examine the variation when assessing the total and the trabecular bone volume. Histologic sections of 18 temporomandibular joint autopsy specimens were read interactively using a cursor. The two parameters total bone volume and trabecular bone volume, of the condyle and the temporal component respectively, were estimated 2 x by 1 observer using 3 different threshold settings: an automatic, a semi-automatic and a manual technique. The threshold was based on the gray-scale distribution of the image. 2 observers read the same sections with the aid of the semi-automatic technique. The intra-observer variation expressed as coefficient of variation ranged between 1.9% and 7.1% for the different parameters, when the automatic threshold setting technique was employed, and between 2.8% and 8.7% with the semi-automatic technique. The manual technique resulted in a high intra-observer variation with a coefficient of variation between 5.2% and 19.9%. There was a systematic difference between the estimates of the 2 observers. In general, intra- and inter-observer variation was higher in the temporal component than in the condyle. The inter-section variation was moderate, the coefficient of variation ranging from 3.8% to 11.1%. The automatic and semi-automatic techniques resulted in comparable intra-observer variation, with a lower bias in the estimates of the semi-automatic technique. By letting one observer apply the semi-automatic technique, it was possible to achieve fast and reproducible analysis of the total and trabecular bone volume.
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| 2. |
- Flygare, Lennart, et al.
(författare)
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Bone volume in human temporomandibular autopsy joints with and without erosive changes
- 1997
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Ingår i: Acta Odontologica Scandinavica. - : Informa Healthcare. - 0001-6357 .- 1502-3850. ; 55:3, s. 167-172
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to compare the trabecular bone volume (TBV) and the total bone volume (TOBV) of human temporomandibular joints (TMJ) with erosive changes with those of joints without erosive changes. We examined 35 TMJ autopsy specimens from 19 individuals aged 66 88 years. Sagittal sections of the joints were analyzed microscopically for erosive hard-tissue changes. The TBV and the TOBV of the sections were assessed with the aid of computerized image analysis. A significant increase in trabecular and total bone volume was found in condyles with erosive changes (TBV = 21%, TOBV = 54%) as compared with condyles without erosive changes (TBV = 15%, TOBV = 40%). The trabecular bone volume of the temporal component was also increased (TBV = 24%) in joints with erosive changes in the condyle as compared with joints with unaffected condyles (TBV = 16%). The findings indicate that the relative bone mass may play a role in the development of erosive changes in the TMJ.
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| 3. |
- Flygare, Lennart, et al.
(författare)
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Calcified cartilage zone and its dimensional relationship to the articular cartilage in the human temporomandibular joint of elderly individuals
- 1993
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Ingår i: Acta Odontologica Scandinavica. - : Informa Healthcare. - 0001-6357 .- 1502-3850. ; 51:3, s. 183-191
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to describe the appearance of the calcified cartilage zone (CCZ) and to determine its dimensional relationship to the articular cartilage thickness in the normal human temporomandibular joint. An autopsy material comprising 21 joints from 12 elderly individuals was examined microscopically. The appearance of the CCZ was examined, and the thickness of the CCZ and of the total articular cartilage was measured in 18 different positions in each joint. The CCZ was outlined by a flat or gently undulating tidemark and an irregular osteochondral junction. The cellularity of the CCZ varied extensively. The cells were numerous in the CCZ when the overlying articular cartilage displayed high cellularity. Statistical analysis of the measurements demonstrated a relationship (p < 0.001) between the thickness of the CCZ and of the articular cartilage. Our findings, both qualitative and quantitative, indicate a close relationship between the physiology of the CCZ and of the overlying articular cartilage.
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| 4. |
- Flygare, Lennart, et al.
(författare)
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Cartilage matrix macromolecules in lavage fluid of temporomandibular joints before and 6 months after diskectomy
- 1997
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Ingår i: European Journal of Oral Sciences. - : Wiley-Blackwell. - 0909-8836 .- 1600-0722. ; 105:4, s. 369-372
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to investigate if antigenic fragments of aggrecan and cartilage oligomeric matrix protein (COMP) are detectable by enzyme-linked immunosorbent assay in lavage fluids from the temporomandibular joint (TMJ) and to examine if the relative content of these cartilage markers changes during development of osteoarthrosis (OA) after diskectomy. Lavage fluid was obtained at surgery and 6 months postoperatively in 13 patients. Computed tomography or magnetic resonance imaging was without evidence of hard-tissue changes prior to surgery in all patients. In 9 of the patients, sufficient material for analysis was obtained at both examinations. Aggrecan and COMP were detectable in all but 2 fluids, in which the COMP levels were below detection limit. The aggrecan/COMP ratio increased in all 9 patients during the 6-month period, indicating increased release of aggrecan relative to COMP fragments. The changed aggrecan/COMP ratio possibly reflects increased cartilage turnover during development of OA. Changes compatible with OA were present on computed tomography in all cases at the 6-month follow-up. This study shows that the lavage procedure is feasible for obtaining synovial fluid from the TMJ for immunochemical analyses of tissue-derived macromolecules.
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| 5. |
- Flygare, Lennart, et al.
(författare)
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Macroscopic and microscopic findings of areas with radiologic erosions in human temporomandibular joints
- 1992
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Ingår i: Acta Odontologica Scandinavica. - : Informa Healthcare. - 0001-6357 .- 1502-3850. ; 50:2, s. 91-100
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to describe the macroscopic and microscopic findings of areas with radiologic erosions in the human temporomandibular joint. An autopsy material of 40 human joints, removed as blocks, was examined with tomography, and an erosion was found in 37 areas. A macroscopic and a microscopic examination focused on the presence of the calcified cartilage zone (CCZ) was performed in these areas. In the condyle 13 of 14 areas with a radiologic erosion showed denudation of bone macroscopically. Microscopically, these areas were covered by a thin fibrocellular tissue, and the CCZ was absent. In the temporal component, only 1 of the 23 areas showed bone exposure macroscopically. Microscopically, the soft tissue in these areas varied in thickness. The CCZ was missing in 13 of the 23 areas, even in some areas that appeared normal macroscopically and were microscopically covered by intact soft tissue. Thus, in areas with a radiologic erosion the macroscopic and microscopic appearance differed between the condyle and the temporal component. The nature of the findings is discussed.
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| 6. |
- Flygare, Lennart, et al.
(författare)
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Microscopy and tomography of erosive changes in the temporomandibular joint. An autopsy study.
- 1995
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Ingår i: Acta Odontologica Scandinavica. - : Informa Healthcare. - 0001-6357 .- 1502-3850. ; 53:5, s. 297-303
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-nine temporomandibular joint autopsy specimens were examined by microscopy and tomography for erosive changes. We found two types of erosive changes, an extensive type with complete loss of cartilage and a local type with retained articular cartilage. On microscopic examination nearly twice as many temporal components as condyles were eroded. The erosions were generally more extensive in the condyle. Erosions in the condyle were evenly distributed. In the temporal component there was a slight predominance of erosions located to the lateral part of the tubercle. The radiologic investigation underestimated both the presence and the extent of the erosions. Positive predictive values and negative predictive values were 0.70 and 0.83, respectively, for erosions in the condyle and 0.91 and 0.68 for erosions in the temporal component. It is suggested that the initial event in osteoarthrosis of the TMJ can occur as a subarticular hard-tissue change. The need for more accurate diagnostic tools than radiography should be stressed.
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| 7. |
- Johansson, Gun-Britt, 1954-, et al.
(författare)
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Svarvning och borrningi metallmatriskompositer (MMC)
- 1993
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fyra gjutna metallmatriskompositer (MMC) har bearbetats vid svarvning och borrning. De fyra MMC-materialen bestod av aluminiummatriser förstärkta med partiklar av kiselkarbid (Sirp) i volymshalter mellan 10 och 20 %.Målet med arbetet har varit dels att utreda arbetsmaterialets inverkan på bearbetningen, dels att klarlägga prestanda för PCD och andra verktygsmaterial.Svarvning har utförts med verktyg av polykristallin diamant (PCD), diamantbelagda skär av hårdmetall och kiselnitrid, belagd och obelagd hårdmetall samt keramisict skär. Vid borrförsöken användes borr med skruvade skär av hårdmetall (U-borr från Sandvik Coromant) och lödd spiralborr (Deltaborr från Sandvik Coromant), med variation av hårdmetallsort och slipning av borrgeometrierna.Vi har inte sett någon större skillnad mellan de olika matrismaterialen. Högre volymshalt SiC-partiklar ger som förväntat högre förslitning.Vid både svarvning och borrning i aluminiumbaserade MMC år PCD ett oslagbart verktygsmaterial. PCD ger en utslitningstid på 10 minuter vid en skärhastighet på 437 m/minut. Bra resultat visar också de diamantbelagda verktygen, så länge diamantskiktet är intakt. Bästa resultat bland övriga testade verktyg uppvisar whiskersförstärkt keramik (CC670), beroende på dess kombination av hårdhet i grundmaterialet och seghet genom whiskersförstärkningen.Vid borrning med U-borr, var skåren utslitna redan efter 10 mm borrad längd. Beläggning gav ingen förbittring i det extremt abrasiva materialet, ej heller slipad egg. Vid testerna med Deltaborr (vars geometri är gynnsammare för borrning i MMC) höll borrarna längre, ca 200 mm. Här erhölls lägre förslitning med specialslipad egg jämfört med standardegg. Vid borrning med spiralborr av PCD borrades 2500 mm utan att borrarna var utslitna.Skärkraftsmätning i olika arbetsmaterial visade ingen signifikant skillnad. Skärkrafterna stiger snabbare för de keramiska skären i jämförelse med PCD, vilket tyder på att de keramiska skären förslits under skärkraftsmätningen medan diamantens eggskärpa år intakt.
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