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Posterior atrophic jaws rehabilitated with prostheses supported by 5 x 5 mm implants with a novel nanostructured calcium-incorporated titanium surface or by longer implants in augmented bone. One-year results from a randomised controlled trial
No full textPURPOSE:
To evaluate whether 5 × 5 mm dental implants with a novel nanostructured calciumincorporated titanium surface could be an alternative to implants at least 10 mm long placed in bone augmented with bone substitutes in posterior atrophic jaws.
MATERIALS AND METHODS:
A total of 40 patients with atrophic posterior (premolar and molar areas) mandibles having 5 to 7 mm of bone height above the mandibular canal and 40 patients with atrophic maxillae having 4 to 6 mm below the maxillary sinus, were randomised according to a parallel group design to receive one to three 5 mm implants or one to three at least 10 mm-long implants in augmented bone at two centres. All implants had a diameter of 5 mm. Mandibles were vertically augmented with interpositional bovine bone blocks and resorbable barriers. Implants were placed after 4 months. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers and implants were placed simultaneously. All implants were submerged and loaded after 4 months with provisional prostheses. Four months later, definitive screw-retained or provisionally cemented metal-ceramic or zirconia prostheses were delivered. Patients were followed up to 1 year post-loading and the outcome measures were prosthesis and implant failures, any complications and peri-implant marginal bone level changes.
RESULTS:
One maxillary grafted patient dropped out before the 1-year evaluation. In mandibles, 1 grafted patient did not want to go ahead with the treatment because of multiple complications and graft failure, and another grafted patient did not receive his prostheses due the loss of 2 implants. In maxillae, one 5 × 5 mm implant failed with its provisional crown 3 months post-loading. There were no statistically significant differences in prostheses and implant failures. Significantly more complications occurred at both mandibular and maxillary grafted sites: 17 augmented patients were affected by complications versus 8 patients treated with short implants in the mandible (P = 0.0079; difference in proportion = -0.45; 95% CI -0.67 to -0.15), and 5 sinus-lift patients versus none treated with maxillary short implants (P = 0.047; difference in proportion = -0.25; 95% CI -0.44 to -0.06). Patients with mandibular short implants lost on average 0.94 mm of peri-implant bone at 1 year and patients with 10 mm or longer mandibular implants lost 1.03 mm. Patients with maxillary short implants lost on average 0.87 mm of peri-implant bone at 1 year and patients with 10 mm or longer maxillary implants lost 1.15 mm. There were no statistically significant differences in bone level changes up to 1 year between short and longer implants in maxillae (mean difference -0.28 mm, 95% CI -0.56 to 0.01, P = 0.051) and in mandibles (mean difference -0.09 mm, 95% CI -0.26 to 0.08, P = 0.295).
CONCLUSIONS:
One year after loading, 5 × 5 mm implants achieved similar results compared to longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity, however 5 to 10 years of post-loading data are necessary before making reliable recommendations.
CONFLICT-OF-INTEREST STATEMENT:
MegaGen partially supported this trial and donated implants and prosthetic components used in this study, whereas Tecnoss donated the biomaterials. The data belonged to the authors and by no means did the manufacturers interfere with the conduct of the trial or the publication of its results
Un nuovo impianto per i siti post estrattivi di elementi plururadicolati gravemente compromessi: l’impianto “RESCUE”.
No full textProcedura di rialzo del seno monofasica verso bifasica: risultati ad 1 anno dal carico di uno studio controllato randomizzato multicentrico.
No full textOBIETTIVO: Confrontare l’efficacia della procedura di rialzo del seno mascellare laterale monofasica verso quella bifasica.
MATERIALI E METODI: Sono stati inclusi 60 pazienti parzialmente edentuli che necessitavano da 1 a 3 impianti e con un’altezza ossea residua di 1- 3 mm e uno spessore di almeno 5 mm al di sotto del seno mascellare, misurata su tomografie computerizzate. I pazienti sono stati randomizzati secondo un disegno di studio a gruppi paralleli in 2 gruppi per essere sottoposti a procedura di rialzo del seno in un unico intervento (monofasica) mediante apertura di una finestra laterale e contestuale posizionamento degli impianti oppure ad una procedura di rialzo del seno in 2 interventi (bifasica) con posizionamento degli impianti a distanza di 4 mesi dal rialzo di seno con sostituto d’osso. Gli interventi sono stati eseguiti in 3 centri diversi. Gli impianti sono rimasti sommersi per 4 mesi e in seguito caricati con protesi provvisorie rinforzate, che sono state sostituite dopo 4 mesi con protesi definitive. I parametri di successo, valutati da valutatori in cieco sono stati: fallimenti delle procedure di aumento, fallimenti protesici e fallimenti implantari; complicazioni; e variazioni dei livelli ossei marginali peri-implantari. I pazienti sono stati seguiti fino ad 1 anno dal carico. Sono qui riportati solo i dati relativi agli impianti posizionati in un’altezza ossea subantrale fra 1 e 3 mm.
RISULTATI: Nel gruppo della procedura monofasica ci sono stati 2 drop-out verso nessuno per il secondo gruppo. Non c’è stato nessun fallimento delle procedure di rialzo nel gruppo monofasico verso un fallimento nel gruppo bifasico, ma la differenza non è stata statisticamente significativa (P = 1,00). Ci sono stati 2 fallimenti protesici (o casi in cui non è stato possibile posizionare le protesi nel tempo previsto) nel gruppo monofasico e uno nel gruppo bifasico, ma la differenza non è stata statisticamente significativa (P = 0,51). Sono falliti 3 impianti in 3 pazienti nel gruppo monofasico verso 1 nel gruppo a bifasico, ma la differenza non è stata statisticamente significativa (P = 0,28). Si sono verificate 2 complicazioni nel gruppo monofasico e 1 nel gruppo bifasico, ma la differenza non è stata statisticamente significativa (P=0,61). Ad 1 anno dal carico, i pazienti trattati con procedura monofasica hanno perso di media -1,01 mm (DS: 0,56) di osso peri-implantare verso -0,93 mm per i siti del gruppo bifasico (DS: 0,40). Non sono state riscontrate differenze statisticamente significative a livello di variazioni dei livelli ossei tra i 2 gruppi a distanza di 1 anno dal carico (-0,08 mm IC 95%: da -0,33 a 0,18, P = 0,56).
CONCLUSIONI: Non è stata osservata nessuna differenza staticamente significativa tra le 2 procedure di rialzo del seno. Tuttavia, il presente studio potrebbe suggerire che in pazienti con un’altezza ossea residua compresa tra 1 e 3 mm al di sotto del seno mascellare, il rischio di fallimento implantare è leggermente superiore per la procedura monofasica
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
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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