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  • 1
    Electronic Resource
    Electronic Resource
    Munksgaard : Munksgaard International Publishers
    Journal of clinical periodontology 26 (1999), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract. The aim of the present study was to compare linear measurements of interproximal bone loss on digitized radiographic images after application of different filters to the gold standard of intrasurgical measurements. Immediately before surgery, 50 radiographs of 50 periodontally-diseased teeth exhibiting interproximal bone loss, were obtained by a standardized technique in 33 patients. Intrasurgically, the distances from the cementoenamel junction (CEJ) to the alveolar crest (AC) and from the CEJ to the deepest extension of the bony defect (BD) were assessed. All radiographs were digitized with a flatbed scanner (resolution: 600×1200 dpi). Using the FRIACOM-soft-ware, the linear distances CEJ to AC and CEJ to BD were measured at 50 interproximal lesions from the digitized but unchanged radiographic images and also after use of 7 different basic imageprocessing modes (enhancement of contrast [dynamics], inversion, high-pass, enhancement of gray-level differences, mean value, histogram correction, spreading of grey values) with 11-fold magnification. Neither the measurement of the distance CEJ to AC on the unchanged images nor assessments with any of the filters revealed significant differences from the gold standard. Multivariate analysis of variance showed the respective filter (p=0.009), intrasurgical and radiographic assessments (p〈0.0001), to statistically significantly, influence the difference between intrasurgical and radiographic measurements of the distance CEJ to BD. The underestimation of the intra-surgically assessed distance CEJ to BD by radiographic measurements ranged from 0.3±2.0 to 0.8±1.9 mm. The filter “mean value” underestimated interproximal bone loss statistically significantly more than the digitized but unchanged radiograph (p=0.05). In this study, basic digital manipulations (filters) of radiographic images failed to result in statistically significantly more valid measurements of interproximal bone loss when compared to the unchanged but digitized images. All radiographic assessments on the digitized images except for use of one filter (mean value) came close to the intrasurgical gold standard.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Journal of clinical periodontology 28 (2001), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: (I) Introducing an intraoral camera system with a special positioner to allow computer-based analysis of reproducible images on lingual tooth surfaces and (II) comparing plaque removal by three manual toothbrushes with different brushhead designs (convex, multilevel and flat trimmed) on lingual mandibular tooth surfaces.Method: In a clinical single-blind, crossover, 24-h plaque-regrowth study on 25 subjects, a computer-based index (PPI) was used to evaluate pre- and postbrushing plaque on lingual surfaces of mandibular premolars and molars. Subjects brushed their teeth under standardized conditions at three visits, each time with a different, randomly assigned toothbrush.Results: The intraoral camera system allowed a reproducible and relatively convenient access to the lingual surfaces of the mandibular teeth and provided an increase in objectivity. Overall, each brush achieved statistically significant plaque removal, however, none reached clinical relevance. The multilevel brush was superior at specific sites, but failed to show statistically significant superiority in terms of overall plaque reduction. Without regard of the toothbrush used, the right handed subjects were less efficient in removing plaque from the right side compared to the left.Conclusions: The method is able to detect even small differences in plaque reduction. None of the different brushhead designs was able to compensate an insufficient brushing techniques.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Journal of clinical periodontology 28 (2001), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aim: The aim of the present study was to assess the reproducibility and validity of linear measurements of interproximal bone loss in intrabony defects on digitized radiographic images after application of different filters and magnifications.Methods: Immediately before surgery 50 radiographs of 50 periodontally diseased teeth exhibiting interproximal intrabony defects were obtained by a standardized technique in 50 patients. Intrasurgically the distances from the cementoenamel-junction (CEJ) to the alveolar crest (AC) and from the CEJ to the deepest extension of the bony defect (BD) were assessed. All radiographs were digitized by a flatbed scanner (resolution: 600×1200 dpi). Using the FRIACOM-soft ware, the linear distances CEJ to AC and CEJ to BD were measured at 50 intrabony defects on digitized but unchanged radiographic images and also after use of 2 different basic image processing modes (filters: enhancement of grey level differences, spreading of grey values) with 7-fold and 14-fold magnification by 2 different examiners.Results: Repeated measures MANOVA revealed reproducibility of the measurement of the distance CEJ to AC to be significantly influenced by examiner (p=0.027) and filter in combination with the height of 2 wall component of the intrabony defect (p=0.066). For the distance CEJ to BD filters had significant influence on reproducibility in correlation with vertical angulation difference (p=0.001). On the average in this study radiographic measurements tended to overestimate the amount of bone loss as assessed by intrasurgical measurements (CEJ-AC: 0.74–1.91 mm; CEJ-DB: −0.04–0.77 mm). Validity of measurement of the distance CEJ-AC was shown to be significantly influenced by the depth of the intrabony defect (p〈0.003). Validity of the distance CEJ-BD was significantly influenced by intrasurgically assessed bone loss (p=0.029), horizontal angulation (p=0.066). Filters influenced the validity only in combination with examiner (p〈0.001).Conclusions: In this study, the chosen digital manipulations (filters: spreading, structure) of radiographic images failed to result in statistically significantly more reproducible or valid measurements of interproximal bone loss within intrabony defects when compared to the digitized but unchanged images. All radiographic assessments on the digitized images except for use of enhancement of grey level differences (structure) came close to the intrasurgical gold standard.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Clinical oral implants research 16 (2005), S. 0 
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objectives: The accuracy of two commercially available systems for image-guided dental implant insertion based on infrared tracking cameras was compared with manual implantation.Material and methods: Phantoms of partially edentulous mandibles were used. In a master phantom, pilot boreholes for dental implants were placed. These boreholes were reproduced in slave phantoms using either of the two image-guided systems and manual implantation. The resulting positions were determined using a coordinate measurement machine and compared with the master model.Results: In comparison with manual implantation, the difference of borehole positions to the master phantom was significantly lower using either of the systems for image-guided implant insertion.Conclusion: Image-guided insertion of dental implants is significantly more accurate than manual insertion. However, the accuracy that can be achieved with manual implantation is sufficient for most clinical situations.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Mund-, Kiefer- und Gesichtschirurgie 4 (2000), S. 324-329 
    ISSN: 1434-3940
    Keywords: Schlüsselwörter Elektrochirurgie ; Spülpinzette ; Koagulation ; Keywords Electrosurgery ; Irrigation forceps ; Coagulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Problem: During most surgeries, tissues are coagulated by a high-frequency current in order to stop the bleeding. Usually, bipolar forceps are used for this procedure. Until now it could not be avoided, however, that the biotissue would adhere to the forceps ends making hemostasis more difficult to achieve. Can this negative effect possibly be avoided? Material and method: A newly developed bipolar irrigation forceps spilling out a 0.9% sodium chloride solution during the coagulation process has been designed to avoid this disadvantage. The irrigation forceps has been tested and evaluated experimentally in surgery as well as clinically. Results: The irrigation liquid selected is a 0.9% sodium chloride solution. Thermal imaging during biotissue coagulation has shown that the tissue heats up more and faster with flushed coagulation, and that the tip of the forceps heats up less than with unirrigated coagulation. In both experimental-surgical as well as in clinical tests it was possible to stop the biotissue sticking to the ends of the forceps. This effect was also confirmed histologically. Conclusion: Since other methods of avoiding the sticking effect during tissue coagulation by a high-frequency current have not been successful until now, the bipolar irrigation electrode is a promising new development. It helps the surgeon to work more efficiently and safely without having to adapt to big changes, and, at the same time, it reduces the risk of complications.
    Notes: Zusammenfassung Fragestellung: Im Rahmen der meisten operativen Eingriffe wird Gewebe zum Zweck der Blutstillung mittels Hochfrequenzstrom koaguliert. In der Regel werden hierfür bipolare Pinzetten verwendet. Bisher konnte jedoch ein durch die Koagulation hervorgerufenes, mehr oder weniger starkes Ankleben von Biogewebe an den Pinzettenbranchen nicht vermieden werden, wodurch eine suffiziente Blutstillung erschwert wurde. Es sollte untersucht werden, ob dieser unerwünschte Effekt möglicherweise vermieden werden kann. Material und Methode: Eine neu entwickelte bipolare Spülpinzette, bei der während des Koagulationsvorgangs 0,9%ige NaCl-Lösung aus den Pinzettenbranchen austritt, soll diese Nachteile vermeiden. Die Spülpinzette wurde sowohl experimentell-chirurgisch als auch klinisch getestet und bewertet. Ergebnisse: Spülflüssigkeit der Wahl ist 0,9%ige NaCl-Lösung. Thermographieaufnahmen während der Koagulation von Biogewebe konnten zeigen, dass sich das Gewebe bei gespülter Koagulation schneller und stärker erwärmt sowie die Pinzettenspitze weniger erhitzt wird als bei ungespülter Koagulation. Sowohl bei experimentell-chirurgischer als auch bei klinischer Testung konnte das Ankleben von Biogewebe an den Pinzettenbranchen praktisch vollständig vermieden werden. Dieser Effekt bestätigte sich auch histologisch. Schlussfolgerungen: Nachdem sich andere Methoden zur Vermeidung des Klebeeffekte bei Gewebekoagulation mittels Hochfrequenzstrom bisher nicht bewährt haben, erwies sich die bipolare Spülelektrode als eine viel versprechende Neuentwicklung, die dem Operateur ohne größere Umstellung ein zügigeres und sichereres Arbeiten ermöglicht und das Risiko von Komplikationen senken kann.
    Type of Medium: Electronic Resource
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  • 6
    Title: Rechnerunterstützte Planung und intraoperative Instrumentennavigation in der Mund-, Kiefer-, und Gesichtschirurgie : eine experimentelle und klinische Studie. Zugl. Heidelberg, Univ., Habil.-Schr., 2000
    Author: Haßfeld, Stefan
    Publisher: Berlin :Quintessenz,
    Year of publication: 2000
    Pages: 116 S.
    Series Statement: Habilitationsschriften der Zahn-, Mund- und Kieferorthopädie
    Type of Medium: Book
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