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Magnifying Lens (magnifying + lens)
Selected AbstractsA comparison between clearing and radiographic techniques in the study of the root-canal anatomy of maxillary first and second molarsINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2004O. E. Omer Abstract Aim, To compare a clearing technique with conventional radiography in studying certain features of the root-canal system of maxillary right first and second molars. A secondary aim was to assess interexaminer agreement for these features using radiographs. Methodology, Eighty-three recently extracted permanent maxillary right first molars and 40 recently extracted maxillary right second molars from an Irish population were included. Standard periapical radiographs were taken from a buccolingual and mesiodistal direction. The specimens were then decoronated, demineralized in 10% hydrochloric acid for 8 days and then cleared using methyl salicylate. The cleared teeth were examined using a dissecting microscope (×20), and data relating to number of roots, canal type following Vertucci's classification, presence of lateral canals, presence of transverse anastomoses and position/number of apical foramina were collected. The radiographs were examined by two independent trained endodontists using an X-ray viewer and a magnifying lens (×2) in a dark room for the same features studied using the clearing technique. Results, The Kappa values for the agreement between the radiographic examiners A and B and the clearing technique and between the two examiners for the number of roots were 0.60, 0.64 and 0.53; for the root-canal type, 0.37, 0.41 and 0.42; for the number of roots with lateral canals, 0.21, 0.18 and 0.14; and for the transverse anastomoses, 0.29 for radiographic Examiner A. Radiographic Examiner B did not feel capable of accurately recognizing transverse anastomoses from the radiographs. For the position/number of apical foramina, the Kappa values were 0.33 and 0.24, respectively. In general, the Kappa values were low to modest for all comparisons. Conclusions, It is concluded that the agreement between the two radiographic examiners and the agreement between either radiographic examiner and the clearing technique were poor to moderate, indicating the limited value of radiographs alone when studying certain aspects of the root-canal system. [source] Observations on feed size and capture success in the larval butterfly splitfin (Ameca splendens Miller & Fitzsimons, 1971, Pisces: Goodeidae) reared on zooplanktonJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2007F. Peña-Aguado Summary In this study, we quantified the feeding behaviour (encounter, attack, capture. and ingestion) of larval A. splendens on micro-crustacean prey [cladocerans: Alona rectangula, Simocephalus vetulus (separately neonates and adults), Ceriodaphnia dubia, Daphnia pulex (juveniles), Moina macrocopa and ostracods: Heterocypris incongruens]. Although we initially (first 4 weeks) offered rotifers (Brachionus calyciflorus and B. patulus), they were not consumed by the larvae and hence observations with these prey were discontinued. Feeding behaviour was observed during the first 10 weeks. Fifteen observations were made with each prey species (seven diets × four replicates). Experiments were conducted in 50 ml transparent containers with 20 ml fish-conditioned water into which one fry was introduced. Before introducing the fish, 20 individuals of a given cladoceran prey species or 50 individuals of a rotifer prey species were introduced. Until the fourth week, we used 20 ml of medium and thereafter 30 ml, but the prey density used remained constant (1 ind. ml,1). Observations (10 min per fry per cladoceran replicate) were taken under a stereomicroscope (20×) for the first 2 weeks and later with a lamp and a magnifying lens. The number of encounters (E), attacks (A), captures (C) and ingestions (I) were recorded. During the study period, there was a 60% increase in gape size but only a 30% increase in body length. The number of encounters of larval A. splendens was highest (192) on M. macrocopa and lowest (29) on ostracods and adult S. vetulus (59). The inverse relationship between capture success and prey size was more pronounced during the latter half of the study period. Compared with all the other prey types offered, A. splendens fed maximally on M. macrocopa, which therefore could be a suitable diet for the larval rearing of this fish species. [source] Extent of peri-implantitis-associated bone lossJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 4 2009Christer Fransson Abstract Objective: The purpose of the present study was to describe the extent of peri-implantitis-associated bone loss with regard to implant position. Material and methods: Patient files and intra-oral radiographs from 182 subjects were analysed. Among the 1070 examined implants, 419 exhibited peri-implantitis-associated bone loss. The position of each implant within the jaw and fixed reconstructions was determined. In the radiographs the distance between the abutment-fixture junction and the most coronal position of bone to implant contact was assessed at the 419 "affected" implants using a magnifying lens (× 7) with a 0.1 mm graded scale. Results: About 40% of the implants in each subject was affected by peri-implantitis-associated bone loss. The proportion of such implants varied between 30% and 52% in different jaw positions and the most common position was the lower front region. In addition, affected implants were found in larger proportions among "mid" than "end" abutments irrespective of supporting fixed complete or fixed partial dentures. Conclusion: It is suggested that peri-implantitis occurs in all jaw positions and that an "end"-abutment position in a fixed reconstruction is not associated with an enhanced risk for peri-implantitis. [source] Knee pain reduces joint space width in conventional standing anteroposterior radiographs of osteoarthritic kneesARTHRITIS & RHEUMATISM, Issue 5 2002Steven A. Mazzuca Objective A suspected, but heretofore undemonstrated, limitation of the conventional weight-bearing anteroposterior (AP) knee radiograph, in which the joint is imaged in extension, for studies of progression of osteoarthritis (OA) is that changes in knee pain may affect extension, thereby altering the apparent thickness of the articular cartilage. The present study was undertaken to examine the effect of changes in knee pain of varying magnitudes on radiographic joint space width (JSW) in the weight-bearing extended and the semiflexed AP views, in which radioanatomic positioning of the knee was carefully standardized by fluoroscopy. Methods Fifteen patients with knee OA underwent a washout of their analgesic/nonsteroidal antiinflammatory drug (NSAID) agents (duration 5 half-lives), after which standing AP and semiflexed AP knee radiographs of both knees were obtained. Examinations were repeated 1,12 weeks later (median 4.5 weeks, mean 6.0 weeks), after resumption of analgesic/NSAID therapy. Knee pain was measured with the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index (Likert scale). JSW was measured with a pair of calipers and a magnifying lens. Mixed model analyses of variance were used to test the significance of changes in pain and JSW within and between 2 groups of knees with mild-to-moderate radiographic severity of OA: (a) "flaring knees," in which the patient rated standing knee pain as severe or extreme after the washout and in which pain decreased to any degree after resumption of analgesics and/or NSAIDs (n = 12) and (b) "nonflaring knees," in which standing knee pain was absent, mild, or moderate after the washout or did not decrease after resumption of treatment (n = 15). Results After reinstitution of treatment, WOMAC pain scores decreased significantly in both flaring and nonflaring knees (,44%; P < 0.0001 and ,18%; P < 0.01, respectively). After adjustment for the within-subject correlation between knees, mean JSW (±SEM) in the extended view of the flaring OA knee increased significantly from the first to second examination (0.20 ± 0.06 mm; P = 0.005). In contrast, the change in adjusted mean JSW in the extended view of the nonflaring OA knee was negligible (,0.04 ± 0.04 mm) and significantly smaller than that observed in flaring knees (P < 0.01). Mean JSW in the semiflexed AP view was unaffected by the severity or responsiveness of standing knee pain in flaring and nonflaring OA knees. Conclusion JSW in weight-bearing extended-view radiographs of highly symptomatic OA knees can be altered significantly by changes in joint pain. In clinical trials and in epidemiologic studies of OA progression that use this radiographic technique, longitudinal variations in pain may confound changes in the apparent thickness of the articular cartilage. [source] Marginal Bone Level around Implants Assessed in Digital and Film Radiographs: In Vivo Study in the DogCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2000Eva Borg DDS ABSTRACT Background: One of the objectives of postoperative radiographic examinations of implants is to evaluate the marginal bone height and its changes over time. Purpose: The purpose of this study was to assess the influence of digital image processing on measurements of the marginal bone level around implants. Material and Methods: Implants in beagle dogs, used to study the development of peri-implantitis and subsequent healing following treatment, were monitored with conventional radiography and a digital image plate system. Five observers measured the distance between a reference point and the bone level. Measurements in conventional radiographs were made with the use of an x-ray viewer (2X) and a magnifying lens (7X). For the digital images, the system's built-in measuring function was used together with five image processing techniques: edge enhancement (matrixes set on 5 and 25), inverted grey scale, single color highlight, and color intensity mapping together with the brightness and contrast control. From the time of maximum breakdown and the end of the experiment, histologic values were available. Results: Differences between techniques and observers increased toward the end of the healing period. Measurements made at maximum breakdown did not differ significantly from the histologic value. Measurements made after healing all methods, except that using edge enhancement and a 25 × 25 kernel, differed significantly from the histologic value by underestimating the bone level. Conclusions: Measurements of bone level around implants from digital radiographs are as accurate and precise as those from film images. In particular cases, the use of specific image processing algorithms may improve both accuracy and precision. After healing, the histologic specimens showed an incomplete bone fill in the crater with a remaining thin layer of connective tissue in contact with the fixture, and in such situations, the morphology of the bone will give a more complicated diagnostic task. [source] | ||||||||||