189,219 research outputs found
Carbon fibre versus metal framework in full-arch immediate loading rehabilitations of the maxilla - a cohort clinical study
No full textFrameworks made of carbon fibre-reinforced composites (CFRC) seem to be a viable alternative to traditional metal frameworks in implant prosthodontics. CFRC provide stiffness, rigidity and optimal biocompatibility. The aim of the present prospective study was to compare carbon fibre frameworks versus metal frameworks used to rigidly splint implants in full-arch immediate loading rehabilitations. Forty-two patients (test group) were rehabilitated with full-arch immediate loading rehabilitations of the upper jaw (total: 170 implants) following the Columbus Bridge Protocol with four to six implants with distal tilted implants. All patients were treated with resin screw-retained full-arch prostheses endowed with carbon fibre frameworks. The mean follow-up was 22 months (range: 18â24). Differences in the absolute change of bone resorption over time between the two implant sides (mesial and distal) were assessed performing a MannâWhitney U-test. The outcomes were statistically compared with those of patients rehabilitated following the same protocol but using metal frameworks (control group: 34 patients with 163 implants â data reported in Tealdo, Menini, Bevilacqua, Pera, Pesce, Signori, Pera, Int J Prosthodont, 27, 2014, 207). Ten implants failed in the control group (6·1%); none failed in the test group (P = 0·002). A statistically significant difference in the absolute change of bone resorption around the implants was found between the two groups (P = 0·004), with greater mean peri-implant bone resorption in the control group (1 mm) compared to the test group (0·8 mm). Carbon fibre frameworks may be considered as a viable alternative to the metal ones and showed less marginal bone loss around implants and a greater implant survival rate during the observation period
Fattori chirurgici-protesici nell’inserimento implantare postestrattivo immediato in area estetica:caso clinico
No full textL’inserimento degli impianti in una posizione ideale, protesicamente guidata, può essere osta-colato dall’insufficiente disponibilità di volumi ossei nei siti postestrattivi di aree ad alta valenza estetica. Negli ultimi anni è stato proposto da diversi autori un approccio chirurgico, noto come preservazione dell’osso alveolare (Alveolar Ridge Preservation, ARP), allo scopo di ridurre al minimo le variazioni dimensionali successive all’avulsione dentale. L’ARP comprende un’ampia varietà di procedure, che consistono principalmente nell’impiego di materiali d’innesto per il riempimento dell’alveolo, da soli o in combinazione con membrane riassorbibili-non riassorbibili e l’allestimento di lembi chirurgici a copertura del difetto. Dall’analisi delle revisioni sistematiche e meta-analisi attualmente disponibili in letteratura, le tecniche ARP sembrano offrire vantaggi piuttosto limitati rispetto alla guarigione spontanea dell’alveolo. Inoltre, resta ancora acceso il dibattito su quale fra le varie tecniche di ARP mostri maggior efficacia nel mantenimento delle dimensioni dell’osso alveolare residuo e sul ruolo dell’ARP in merito al miglioramento dei risultati clinici di sopravvivenza implantare. In questo articolo viene riportato un caso clinico di inserimen-to implantare immediato nell’alveolo postestrattivo di un incisivo centrale senza utilizzo di innesti ossei, allo scopo di mostrare come la corretta gestione dei fattori chirurgici (posizionamento implantare palatino con mantenimento dell’integrità della corticale ossea vestibolare) e protesici (condizionamento dei tessuti molli attraverso il provvisorio immediato) sia determinante per il successo clinico delle riabilitazioni implantari nei siti postestrattivi di aree estetiche.The implant placement in the ideal prosthetic position could be complicated if insufficient bone volumes are available in post-extractive sites of highly aesthetic areas. In recent years a surgical approach, known as alveolar ridge preservation (ARP), has been proposed to reduce the dimensional changes of the bone following tooth loss. ARP includes a large amount of techniques, mainlyconsisting in the use of graft materials to fill the socket alone or in combination with resorbable/not resorbable barriers and/or surgical flaps aimed to cover the bone defect. According to available meta-analysis andsystematic reviews of the Literature, ARP techniques do not seem to offer limited advantagescompared to socket spontaneous healing. Moreover, there is still a debate concerning which among the various ARP techniques shows higher efficacy in keeping residual alveolar bone volumes, as well as the ARP role in improving implant-related outcomes. In the present paper it is reported a clinical case of immediate implant placement in central incisor post-extractive socket without the use of bone graft, in order to show how the proper management of surgical factors (implant placement in palatine position with the maintenance of buccal cortical bone integrity) and prosthodontic factors (soft tissues conditioning with the relining of the acrylic resin provisional crown) is essential for the clinical success of implant-supported rehabilitations in post-extractive sites of aesthetic area
Adhesive strength of the luting technique for passively fitting screw-retained implant-supported prostheses: an in vitro evaluation.
No full textPURPOSE: This in vitro study evaluated the adhesive strength of a technique to lute implant cylinders to metal frameworks in implant-supported prostheses and ensure a good passive fit. MATERIALS AND METHODS: Different height samples were tested: In group 1, implant cylinders were 5 mm long; in group 2, they were 10 mm long. A universal testing machine (Instron) was used to perform pullout tests. RESULTS: The luting technique provided enough adhesive strength for clinical use with greater adhesive strength in group 2 (mean pull-out strength: 2.85 kN in group 1 versus 3.79 kN in group 2). CONCLUSIONS: The luting technique provides enough adhesive strength for clinical use. Moreover, specimens with a larger surface for adhesion demonstrated higher adhesive strength compared with shorter specimens
INFLUENZA DI DIVERSE SUPERFICI IMPLANTARI SULL'ACCUMULO DI PLACCA E IL COMPORTAMENTO DEI TESSUTI PERIIMPLANTARI. Studio clinico a 12 mesi
No full textOBIETTIVI: Valutare l’accumulo di placca e la risposta dei tessuti periimplantari a contatto con impianti con superficie sottoposta a doppia mordenzatura acida (DAE) (test) e con impianti con superficie DAE e una porzione coronale macchinata (controllo), simulando la loro esposizione nel cavo orale
Una nueva especie de Pera (Euphorbiaceae) de Colombia Una nueva especie de Pera (Euphorbiaceae) de Colombia
No full textSe describe una nueva especie del género Pera Mutis, Pera colombiana, basada en material colombiano y en láminas inéditas de la Flora de la Real Expedición Botánica del Nuevo Reyno de Granada (1783-1816). Se incluye una reseña sobre el género Pera en Colombia, y se comentan los manuscritos de la Expedición Botánica que aluden a este género y a la nueva especie. A new species of the genus Pera Mutis is described, Pera colombiana, based on Colombian material and on unpublished plates of the Flora de la Real Expedición Botánica del Nuevo Reyno de Granada (1783-1816). A summary about the genus Pera in Colombia is included, and the manuscripts of the Botanical Expedition which refer to this genus and the new species are commented on.</p
Normalized eigenvectors of a perturbed linear operator via general bifurcation
No full textLet X be a real Banach space, A:X → X a bounded linear operator, and B:X → X a (possibly nonlinear) continuous operator. Assume that λ = 0 is an eigenvalue of A and consider the family of perturbed operators A + εB, where ε is a real parameter. Denote by S the unit sphere of X and let SA = S ∩ KerA be the set of unit 0-eigenvectors of A. We say that a vector x0 ∈ SA is a bifurcation point for the unit eigenvectors of A + εB if any neighborhood of (0, 0, x0) ∈ × × X contains a triple (ε, λ, x) with ε = 0 and x a unit λ-eigenvector of A + εB, i.e. x ∈ S and (A + εB)x = λx.
We give necessary as well as sufficient conditions for a unit 0-eigenvector of A to be a bifurcation point for the unit eigenvectors of A + εB. These conditions turn out to be particularly meaningful when the perturbing operator B is linear. Moreover, since our sufficient condition is trivially satisfied when KerA is one-dimensional, we extend a result of the first author, under the additional assumption that B is of class C
SINUS FLOOR ELEVATION USING OSTEOTOMES AND PIEZOELECTRIC SURGERY. A new approach
No full textAim The aim of this paper is to describe a new technique for sinus floor augmentation with a 1-step crestal approach where the residual
bone is ≤ 7.5 mm
Un WebGIS sul centro storico di Roma.
No full textIl saggio, dopo aver sviluppato il tema inerente la cartografia storica su Roma, espone i risultati di una lunga ricerca, coordinata da Paolo Micalizzi, finalizzata alla realizzazione e messa in rete di un sofisticato sistema informativo geografico sul centro storico di Roma, denominato Descriptio Romae WebGIS.The essay, having developed the theme concerning the historical maps of Rome, expounds the results of an extensive research, coordinated by Paolo Micalizzi, aimed at the creation and networking of a sophisticated geographic information system on the historic center of Rome, called Descriptio Romae WebGIS
Gastric and masticatory performances in full-arch immediate loading rehabilitated patients
No full textFull-arch immediate loading implant rehabilitations provide patients with compromised dentition an effective treatment to improve their aesthetic and function. Aim of this prospective cohort study was to investigate the correlation between masticatory ability and gastric emptying rates among these patients. Ten subjects (five men and five women) with compromised dentition were tested in two occasions: before treatment and 30 days after the immediate loading rehabilitation. Masticatory ability was evaluated using the sieves test, and the gastric half emptying time (T(1/2)) was assessed by means of the 13C-octanoic acid breath test. A statistically significant increment (P < 0.005) in masticatory ability was found only in reference to the particles smaller than or equal to 4.75 mm, whereas the gastric emptying rate showed a statistically significant reduction between pre- and post-treatment (P = 0.003). A moderate negative correlation (rho = 0.64, P = 0.048) between the percentage change in masticatory ability and the percentage change in gastric emptying rate was evidenced. Patients with compromised dentition rehabilitated with full-arch immediate implant prostheses present a significant improvement of the gastric process
DNA binding of different PerA mutants.
No full text<p>EMSA experiments with wild type (A and B) and mutated MBP-PerA fusions (C–K) showing the interaction with DNA fragments spanning either the <i>bfpA</i> or <i>perA</i> promoter regions (indicated above each panel). Increasing amounts in µM concentrations of each protein were used as indicated above each individual gel. Free DNA and protein-DNA complexes were resolved in 6% polyacrylamide gel electrophoresis at 120 V in 0.25X TBE gels and stained with ethidium bromide. For presentation purposes the color of all images was inverted from the original image. A similar result was obtained for the <i>perA</i> promoter region with mutants PerA<sub>Y29A</sub>, PerA<sub>S194A</sub> and PerA<sub>Y255A</sub> (data not shown).</p
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