An evaluation of master cast techniques for multiple abutment implant prostheses

Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1991 (Prosthodontics)Bibliography: leaves 54-62.This study evaluates the accuracy of three different techniques used to obtain a master cast for the construction of a prosthesis that will fit passively onto osseointegrated implants. A machined metal model with six fixtures and abutments and a matching template were fabricated. Impressions of this master model were taken and poured in stone. The master casts were divided into three groups of fifteen as follows: 1. Solid 2. Pindex-sectioned 3. Zeiser-sectioned Each master cast was evaluated for the accuracy with which the template passively fit the abutment replicas. Clinical judgment was assisted by the use of an optical comparator. Only those master casts sectioned with the Zeiser system allowed an accurate passive fit of the template. This conclusion is attributable to the predetermination of die positions prior to pouring impressions that is the distinguishing feature of the Zeiser system

Bonding Effectiveness of Two Adhesive Luting Cements to Glass Fiber Posts: Pull-Out Evaluation of Three Different Post Surface Conditioning Methods

The purpose of this study was to evaluate the bond strength at the post/resin-cement interface with 3 different surface treatments of glass fiber posts and with 2 different luting resin cements. Sixty glass fiber posts (RelyX Fiber Post) were randomly divided into 3 groups (n=20) and were luted with a dual-polymerizing self-adhesive universal resin cement (RelyX Unicem) and with a dual-polymerizing resin cement (RelyX ARC). This was carried out in association with a dual-polymerizing adhesive (Scotchbond Multi-Purpose Plus) in simulated plexiglass root canals after receiving three different pretreatment procedures. A pull-out test was performed on each sample to measure bond strengths. Data were analyzed with two-way ANOVA. Two samples from each group were processed for SEM observations in order to investigate the morphologic aspect of the post/cement interface. Both resin cements demonstrated significant different bond strength values (P<0.0001). The surface treatment result was also statistically significant (P=0.0465). SEM examination showed a modification of the post surface after pretreatment with methyl methacrylate. The dual-polymerizing self-adhesive universal resin cement achieved higher MPa bond strength values. The use of methyl methacrylate as a surface treatment of glass fiber posts provided a significant increase in bond strengths between the posts and both luting materials

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Study of the corpora lutea's echotexture in buffaloes

openQuesta tesi tratta l'utilizzo del software imageJ per la caratterizzazione dell'ecotessitura dei corpi lutei nelle bufale. Delle ecografie analizzate sono stati individuati i corpi lutei, dei quali tramite il software si è andati a misurare le dimensioni e l'intensità dei pixels. In aggiunta, sono state analizzate anche cisti luteiniche per chiarire le differenze di ecotessitura tra queste e i corpi lutei funzionali

Clinical evaluation of marginal bone level change around multiple adjacent implants restored with splinted and nonsplinted restorations: a 10-year randomized controlled trial

The management of occlusal forces on implant restorations may influence their long-term prosthetic success. The purpose of this randomized controlled trial was to compare marginal bone level changes around adjacent splinted and nonsplinted implants, functionally loaded with cemented restorations, up to 10 years in maxillae

An in vitro evaluation of impression techniques for multiple internal- and external-connection implant prostheses

This in vitro study evaluated the accuracy of three different impression techniques, using polyether impression material, to obtain a precise definitive cast for a multiple-unit implant restoration with internal- or external-connection implants

Tracheal matrices, obtained by a detergent-enzymatic method, support in vitro the adhesion of chondrocytes and tracheal epithelial cells

Several attemps have been performed to achieve a suitable tracheal replacement for the treatment of different conditions characterized by a lack of sufficient tissue for surgical reconstruction. Actually, tracheal homografts can induce long-term stenosis and their growth potential is not known. Thus, in this work porcine tracheal matrices have been obtained by a detergent-enzymatic method. The treatment decreased the antigenicity of matrices which were able to support the in vitro adhesion of both chondrocytes and tracheal epithelial cells. On the contrary, only few cells were observed in tracheal matrices prepared with formalin, Thimerosal, and acetone, suggesting that the long-term stenosis occuering in vivo is probably because of an insufficient cell ingrowth. In summary, our results indicate that the detergent-enzymatic method allows us to obtain tracheal matrices which can function as a promising support to achieve an in vitro tissue-engineered cell-matrix construc