1,720,988 research outputs found
The use of a non-absorbable membrane as an occlusive barrier for alveolar ridge preservation: A one year follow-up prospective cohort study
Full text linkThe aims of this study were to obtain preliminary data and test the clinical efficacy of a novel nonporous dense-polytetrafluoroethylene (d-PTFE) membrane (permamem®, botiss) in alveolar ridge preservation (ARP) procedures with a flapless approach. A traumatic extraction was performed in the premolar maxillary area, and a d-PTFE membrane was used to seal the alveolar cavity: no biomaterial was used to graft the socket and the membrane was left intentionally exposed and stabilized with sutures. The membrane was removed after four weeks and dental implants were placed four months after the procedure. The primary outcome variables were defined as the dimensional changes in the ridge width and height after four months. A total of 15 patients were enrolled in this study. The mean width of the alveolar cavity was 8.9 ± 1.1 mm immediately after tooth extraction, while four months later a mean reduction of 1.75 mm was experienced. A mean vertical reduction of 0.9 ± 0.42 mm on the buccal aspect and 0.6 ± 0.23 mm on the palatal aspect were recorded at implant placement. Within the limitations of this study, the d-PTFE membrane proved to be effective in alveolar ridge preservation, with the outcomes of the regeneration not affected by the complete exposure of this biomaterial
The effects of wearing a removable-partial-denture on the bite forces: a cross-sectional study
Full text linkBackground: Removable partial dentures are a frequently used prosthetic treatment in the elderly population, but different types or RPDs might guarantee different chewing capabilities. In many studies, the relationship between chewing and aging has been reported and it has been shown that efficient chewing can improve the overall quality of life. Objectives: In the present study, the relationship between maximum bite force (MBF) and RPDs was studied. A relationship between the body mass index (BMI) and the type of prosthesis was also analyzed. Methods: 240 elderly patients, 120 males and 120 females, with bilateral posterior edentulism (class 1 of Kennedy classification) who had been wearing an RPD for at least a year, were recruited. Patients were divided into two groups: Group 1: male (n = 60) and female (n = 60) patients with bilateral edentulous areas located posterior to the remaining natural teeth and natural teeth in the opposite dental arch. Group 2: male (n = 60) and female (n = 60) patients with maxillary and mandibular bilateral edentulous areas located posterior to the remaining natural teeth. Their Body Mass Index (BMI) and Maximum bite force (MBF) were measured and compared according to the material and design of their RPD. Re-sults: In both Groups, patients wearing cobalt-chrome alloy RPDs (Co-Cr-RPD) (Group 1: 20.25 ± 6.7 MBF, p < 0.001; Group 2: 16.0 ± 5.7 MBF, p < 0.001) had an increased MBF when compared to polymethylmethacrylate RPD (PMMA-RPD) (Group 1: 12.9 ± 3.36 MBF; Group 2: 10.4 + 2.8 MBF), and Valplast RPD (V-RPD) (Group 1: 14.3 ± 4.7 MBF; Group 2: 11.3 ± 3.4 MBF) users. There were no significant differences in bite force between patients wearing PMMA-RPD and V-RPD in both Groups. Patients in Group 2 showed a lower MBF than those in Group 1 (Group 1: 16.05 ± 6.13 MBF; Group 2: 12.6 ± 4.84 MBF; p < 0.001). Conclusions: A reduction in chewing force can lead to choosing softer foods for nutrition, which can lead to an increase in BMI. Our results show that only CoCr-RPD wearers were able to chew consistent food, whereas PMMA-RPD and V-RPD, due to the properties of the materials, their instability, and the possibility of causing pain during mastication, de-termined a limitation in the choice of food for many of the participants
Long-term clinical and radiographic analysis of platform matching and platform switching implants in the esthetic zone: a retrospective cohort study
Full text linkBackground: The aims of this study are to retrospectively compare the clinical, radiographic and esthetic outcomes of platform switching (PS) and platform matching (PM) dental implants in the anterior maxilla after ≥ 10 years of functional loading. Methods: Marginal bone loss (MBL) levels were recorded; furthermore, peri-implant clinical parameters (PPD, BOP, PI) were collected and the Pink and White Esthetic scores (PES/WES) were used to evaluate the esthetic outcomes. Wilcoxon signed rank tests were performed to compare collected parameters among the two groups, with a p-value < 0.05. Results: A final sample of 58 patients was enrolled in this study (PM implants = 29; PS implants = 29). PS implants showed lower MBL levels (1.02 ± 0.81 mm vs. 1.67 ± 0.99 mm, p = 0.028) and PPD values (3.69 ± 1.1 vs. 5.16 ± 1.09 mm, p < 0.001) compared to PM implants. Mean PES values were higher in the PS group compared to the PM group (8.46 ± 0.69 vs. 7.89 ± 0.78, p < 0.005), while there were no differences for WES values (7.82 ± 1.09 vs. 7.71 ± 0.85, p > 0.05) and peri-implant diseases’ prevalence (p > 0.05). Conclusions: After 10 years, PS implants showed statistically significant lower MBL and PPD values and higher PES values compared to PM implants
Porcine Cortical Bone Lamina as a Predictable Technique for Guided Bone Regeneration: Histomorphometric and Radiographic Evaluation
No full textThe stability of bone regenerated through Guided Bone Regeneration (GBR) around implants is crucial for long-term success. In this case series, changes in marginal bone levels (MBL) around implants placed in a regenerated bone using heterologous cortical lamina technique were radiographically measured. In addition, bone samples were obtained and submitted to histological and histomorphometric analysis. Thirty implants were placed in regenerated bone sites 8 months after the regenerative surgery; in the same surgical stage, a hard tissue biopsy was taken using a trephine bur and submitted to histologic and histomorphometric analysis. Changes in the marginal bone level, mesial and distal to the implant shoulder, were measured between prosthetic loading and the last follow-up, 2 years later. No implants were lost, and all could be deemed successful at the last follow-up. Only a minimal mean variation in the position of the marginal bone level was observed, both at the mesial (0.11 ± 0.49 mm) and at the distal level (0.03 ± 0.19 mm). The bone lamina had been resorbed after 8 months, and new bone had developed in close connection to the biomaterial. The average percentage of newly formed bone was 28%, while only 10% of the samples were composed of residual biomaterial; bone marrow and connective tissue composed the remaining part of the samples. This regeneration technique allowed, thanks to the rigidity of the lamina, the regeneration of new bone, which is stable after the prosthetic load. Further studies are needed to compare this procedure with those adopting non-resorbable, titanium-supported membranes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
Hard and Soft Tissue Evaluation of Different Socket Preservation Procedures Using Leukocyte and Platelet-Rich Fibrin: A Retrospective Clinical and Volumetric Analysis
No full textPurpose: The extraction of a tooth is followed by hard and soft tissue changes that can compromise implant placement. The aim of the present retrospective study was to compare the clinical and radiographic outcomes of different ridge preservation procedures based on the use of leukocyte and platelet-rich fibrin (L-PRF). Materials and Methods: The study population consisted of all patients who had undergone surgery from January 1, 2017 to January 1, 2018 for alveolar ridge preservation on single posterior teeth using 3 clinical protocols: L-PRF alone, L-PRF mixed with a bone xenograft, and bone xenograft alone. Clinical and radiographic measures were recorded preoperatively and at 6 months postoperatively to determine the horizontal and vertical ridge resorption. Results: A total of 45 patients were included in the present study. All the surgeries were performed successfully, and no intraoperative complications developed. The L-PRF group experienced significantly greater horizontal and vertical bone resorption. The L-PRF plus bone xenograft group had less vertical and horizontal bone resorption than the bone xenograft alone group. Statistically significant differences in postoperative pain and wound healing were observed, with the bone xenograft alone group, in particular, having higher values for pain and experiencing delayed wound healing. Conclusions: Within the limitations of the present retrospective study, the use of a bone xenograft alone or L-PRF combined with a bone xenograft to perform alveolar ridge preservation procedures significantly limited bone resorption
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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