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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Immediate, non-submerged, root-analogue direct laser metal sintering (DLMS) implants: a 1-year prospective study on 15 patients
No full textThis study evaluated the 1-year survival and success rate of root-analogue direct laser metal sintering (DLMS) implants, placed into the extraction sockets of 15 patients. DLMS is a technology which allows solids with complex geometry to be fabricated by annealing metal powder microparticles in a focused laser beam, according to a computer-generated three-dimensional (3D) model; the fabrication process involves the laser-induced fusion of titanium microparticles, in order to build, layer-by-layer, the desired object. Cone-beam computed tomography (CBCT) acquisition and 3D image conversion, combined with the DLMS process, allow the fabrication of custom-made, root-analogue implants (RAIs). CBCT images of 15 non-restorable premolars (eight maxilla; seven mandible) were acquired and transformed into 3D models: from these, custom-made, root-analogue DLMS implants with integral abutment were fabricated. Immediately after tooth extraction, the RAIs were placed in the sockets and restored with a single crown. One year after implant placement, clinical and radiographic parameters were assessed: success criteria included absence of pain, suppuration, and exudation; absence of implant mobility and absence of continuous peri-implant radiolucency; distance between the implant shoulder and the first visible bone-to-implant contact <1.5 mm from initial surgery; and absence of prosthetic complications. At the 1-year follow-up, no implants were lost, for a survival rate of 100 %. All implants were stable, with no signs of infection. The good conditions of the peri-implant tissues were confirmed by the radiographic examination, with a mean DIB of 0.7 mm (±0.2). The possibility of fabricating custom-made, RAI DLMS implants opens new interesting horizons for immediate placement of dental implants
Trueness and precision of 5 intraoral scanners in the impressions of single and multiple implants: a comparative in vitro study
No full textBackgroundUntil now, a few studies have addressed the accuracy of intraoral scanners (IOSs) in implantology. Hence, the aim of this in vitro study was to assess the accuracy of 5 different IOSs in the impressions of single and multiple implants, and to compare them.MethodsPlaster models were prepared, representative of a partially edentulous maxilla (PEM) to be restored with a single crown (SC) and a partial prosthesis (PP), and a totally edentulous maxilla (TEM) to be restored with a full-arch (FA). These models were scanned with a desktop scanner, to capture reference models (RMs), and with 5 IOSs (CS 3600 (R), Trios3 (R), Omnicam (R), DWIO (R), Emerald (R)); 10 scans were taken for each model, using each IOS. All IOS datasets were loaded into a reverse-engineering software where they were superimposed on the corresponding RMs, to evaluate trueness, and superimposed on each other within groups, to determine precision. A statistical analysis was performed.ResultsIn the SC, CS 3600 (R) had the best trueness (15.20.8m), followed by Trios3 (R) (22.3 +/- 0.5m), DWIO (R) (27.8 +/- 3.2m), Omnicam (R) (28.4 +/- 4.5m), Emerald (R) (43.1 +/- 11.5m). In the PP, CS 3600 (R) had the best trueness (23 +/- 1.1m), followed by Trios3 (R) (28.5 +/- 0.5m), Omnicam (R) (38.1 +/- 8.8m), Emerald (R) (49.3 +/- 5.5m), DWIO (R) (49.8 +/- 5m). In the FA, CS 3600 (R) had the best trueness (44.9 +/- 8.9m), followed by Trios3 (R) (46.3 +/- 4.9m), Emerald (R) (66.3 +/- 5.6m), Omnicam (R) (70.4 +/- 11.9m), DWIO (R) (92.1 +/- 24.1m). Significant differences were found between the IOSs; a significant difference in trueness was found between the contexts (SC vs. PP vs. FA). In the SC, CS 3600 (R) had the best precision (11.3 +/- 1.1m), followed by Trios3 (R) (15.2 +/- 0.8m), DWIO (R) (27.1 +/- 10.7m), Omnicam (R) (30.6 +/- 3.3m), Emerald (R) (32.8 +/- 10.7m). In the PP, CS 3600 (R) had the best precision (17 +/- 2.3m), followed by Trios3 (R) (21 +/- 1.9m), Emerald (R) (29.9 +/- 8.9m), DWIO (R) (34.8 +/- 10.8m), Omnicam (R) (43.2 +/- 9.4m). In the FA, Trios3 (R) had the best precision (35.6 +/- 3.4m), followed by CS 3600 (R) (35.7 +/- 4.3m), Emerald (R) (61.5 +/- 18.1m), Omnicam (R) (89.3 +/- 14m), DWIO (R) (111 +/- 24.8m). Significant differences were found between the IOSs; a significant difference in precision was found between the contexts (SC vs. PP vs. FA).Conclusions The IOSs showed significant differences between them, both in trueness and in precision. The mathematical error increased in the transition from SC to PP up to FA, both in trueness than in precision
Accuracy of four intraoral scanners in oral implantology: A comparative in vitro study
No full textBackground: Until now, only a few studies have compared the ability of different intraoral scanners (IOS) to capture high-quality impressions in patients with dental implants. Hence, the aim of this study was to compare the trueness and precision of four IOS in a partially edentulous model (PEM) with three implants and in a fully edentulous model (FEM) with six implants. Methods: Two gypsum models were prepared with respectively three and six implant analogues, and polyether-ether-ketone cylinders screwed on. These models were scanned with a reference scanner (ScanRider®), and with four IOS (CS3600®, Trios3®, Omnicam®, TrueDefinition®); five scans were taken for each model, using each IOS. All IOS datasets were loaded into reverse-engineering software, where they were superimposed on the reference model, to evaluate trueness, and superimposed on each other within groups, to determine precision. A detailed statistical analysis was carried out. Results: In the PEM, CS3600® had the best trueness (45.8 ± 1.6μm), followed by Trios3® (50.2 ± 2.5μm), Omnicam® (58.8 ± 1.6μm) and TrueDefinition® (61.4 ± 3.0μm). Significant differences were found between CS3600® and Trios3®, CS3600® and Omnicam®, CS3600® and TrueDefinition®, Trios3® and Omnicam®, Trios3® and TrueDefinition®. In the FEM, CS3600® had the best trueness (60.6 ± 11.7μm), followed by Omnicam® (66.4 ± 3.9μm), Trios3® (67.2 ± 6.9μm) and TrueDefinition® (106.4 ± 23.1μm). Significant differences were found between CS3600® and TrueDefinition®, Trios3® and TrueDefinition®, Omnicam® and TrueDefinition®. For all scanners, the trueness values obtained in the PEM were significantly better than those obtained in the FEM. In the PEM, TrueDefinition® had the best precision (19.5 ± 3.1μm), followed by Trios3® (24.5 ± 3.7μm), CS3600® (24.8 ± 4.6μm) and Omnicam® (26.3 ± 1.5μm); no statistically significant differences were found among different IOS. In the FEM, Trios3® had the best precision (31.5 ± 9.8μm), followed by Omnicam® (57.2 ± 9.1μm), CS3600® (65.5 ± 16.7μm) and TrueDefinition® (75.3 ± 43.8μm); no statistically significant differences were found among different IOS. For CS3600®, For CS3600®, Omnicam® and TrueDefinition®, the values obtained in the PEM were significantly better than those obtained in the FEM; no significant differences were found for Trios3®. Conclusions: Significant differences in trueness were found among different IOS; for each scanner, the trueness was higher in the PEM than in the FEM. Conversely, the IOS did not significantly differ in precision; for CS3600®, Omnicam® and TrueDefinition®, the precision was higher in the PEM than in the FEM. These findings may have important clinical implications
Wide-diameter locking-taper implants: A prospective clinical study with 1 to 10-year follow-up
Get PDFAim Wide-diameter implants (WDIs, diameter ≥4.5 mm) are increasingly being used in patients with poor bone quality and reduced bone height. The aim of this study was to evaluate the survival rate, peri-implant bone loss, biological and prosthetic complications of wide-diameter (4.8 mm) lockingtaper implants used in the restoration of partially and fully edentulous patients.Materials and methods Between January 2002 and December 2011, all patients referred to a private clinic for treatment with WDIs were considered for inclusion in the study. At each annual follow-up session, clinical and radiographic parameters were assessed: the outcome measurements were implant failure, peri-implant bone loss (distance between the implant shoulder and the first visible bone-to-implant contact: DIB), biological and prosthetic complications. The cumulative survival rate (CSR) was assessed using the Kaplan-Meier estimator; Log-rank was applied to evaluate correlations between the study variables. The statistical analysis was performed at the patient and at the implant level.Results A total of 438 WDIs were placed in 411 patients. Four implants failed, for a CSR of 99% (patient-based) and 99.1% (implant-based) at 10-year follow-up. The CSR did not differ significantly with respect to patients' gender, age, smoking or parafunctional habit, implant location, position, length, bone type or prosthetic restoration. A mean DIB of 0.34 mm (± 0.23), 0.45 mm (± 0.27) and 0.75 mm (± 0.33) was shown at the 1-, 5- and 10-year follow-up examination.Conclusions Wide-diameter, locking-taper implants can be a good treatment option for the rehabilitation of partially and fully edentulous patients over the long term
Dimensional changes of the gingival tissues induced by clear aligners and fixed orthodontic appliances
Get PDFObjective: The aim of this study was to evaluate gingival tissue adaption induced by orthodontic tooth movement, in terms of clinical crown height (i.e., attachment loss), and thickness of the keratinized gingiva at the margin level. Methods: Pre- and post-treatment intraoral models/scans of 100 orthodontically treated patients (50 treated with clear aligners and 50 treated with fixed appliance) were acquired. Models were digitally scanned. Each couple of pre- and post-treatment scans were superimposed using the Compare© software (Medit, Seoul, South Korea) taking the same reference landmarks in all cases, that were the palatal rugae for the upper arch, and the labial median frenulum for the lower arch. Only teeth that had undergone vestibulo-palatal (or vice versa) movement, greater than 1 mm were included in the analyses. The change from pre-treatment to post-treatment, in the clinical crown height and thickness of the keratinized gingiva at the margin level were digitally measured and compared between the two groups. Statistical analysis included paired t-tests, and unpaired t-tests with significance set at p<0.05. Results: There was a statistically significant change in clinical crown height and gingival thickness in both groups. However, a clinically relevant attachment loss was found only within the fixed appliance group. Whereas, regarding the change in gingival thickness, there was no clinically relevant changes between the two groups. Conclusions: Orthodontic tooth movement with fixed appliance is associated to a clinically relevant attachment loss. Clear aligners seem to be associated with a more discrete attachment loss than the one observed with fixed appliances. Clinical relevance: Orthodontists should pay attention and monitoring the clinical crown height (i.e., attachment loss) during orthodontic movement, mostly when using fixed appliances
Accuracy of 6 Desktop 3D Printers in Dentistry: A Comparative In Vitro Study
No full textPURPOSE: To compare the accuracy of 6 desktop 3D printers in dentistry. METHODS: A parallelepiped (PP) with known geometry and holes of different diameters was designed and printed with 6 desktop 3D printers (Sheraprint 40®; Solflex 350®; Form 2®; MoonRay D75®; Vida HD®; XFAB 2000®). For each printer, 9 PPs were printed with proprietary materials; these PPs were not cured and underwent dimensional analysis by optical microscopy and precision probing. A file representative of a dentate model (DM) was also printed with the aforementioned printers. For each printer, 3 DMs were printed with the proprietary materials. These DMs were cured and after 1 month, scanned with a desktop scanner and superimposed on the virtual reference model, to investigate trueness. RESULTS: Dimensional analysis by optical microscopy and precision probing highlighted the reliability of the 3D printed models; errors were compatible with clinical use. However, both linear and diameter measurements revealed statistically significant differences between the machines. The trueness of the DMs 1 month after printing was low, suggesting that they underwent dimensional contraction over time, albeit with differences between the printers. CONCLUSIONS: The 3D printed models showed acceptable accuracy, although statistically significant differences were found among them
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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