Qualitative evaluation of the effects of professional oral hygiene instruments on prosthetic ceramic surfaces

During professional hygiene procedures, different instruments used may cause various damage to dental prostheses. Deplaquing and scaling with curettes and ultrasonic instruments may inadvertently increase the surface roughness of the material and the risk of future bacterial adhesion and/or also compromise the marginal seal of the prosthesis. Hence, the aim of this study was to assess the qualitative effects of two types of curettes and one piezoelectric instrument with a stain-less-steel tip on three types of metal-free samples. After treating the samples with different instru-mentations, they were analyzed using the scanning electron microscope and then underwent a qualitative microanalysis by using a spectroscopy machine. All the materials tested in this study have undergone significant changes of their superficial structure after instrumentation both with mechanical and manual instruments. Plastic curettes appeared to be less aggressive than the other in-struments. Disilicate samples show a significantly lower degree of surface glazing erosion com-pared to the zirconia sample with all the instruments used

Assessment of Preload Loss after Cyclic Loading in the OT Bridge System in an “All-on-Four” Rehabilitation Model in the Absence of One and Two Prosthesis Screws

The aim of this study was to evaluate the stability of prosthetic screws after applying cyclic loadings in an “all-on-four” rehabilitation model with the OT Bridge system. The model was tested both with and without anterior screws. Four implant analogues following the “all-on-four” concept were inserted in an edentulous mandibular resin model. An OT Bridge system with a Cr–Co prosthetic framework was fabricated. Depending on the presence or absence of one or two anterior screws on the implant analogues, three groups were created, i.e., Gr.1: three tightening screws, Gr.2: two tightening screws, Control Group: four tightening screws. Each single group underwent subsequent 400,000 cyclic loads, simulating approximately a year of chewing by using a dynamometer machine. This cycle was repeated five times for each group, and preload loss values were evaluated on each prosthetic screw after each cycle. All the data obtained were analyzed by one-way ANOVA and Student’s t-test. No statistically significant differences after intragroup analysis were found. A statistically significant difference within the Gr.1 between the screws in positions 33 and 36, equal to 15.2% (p-value = 0.0176), was found. The OT Bridge seems a useful system to maintain the retention of a prosthesis during mechanical stress conditions even in the absence of one screw in an “all-on-four” rehabilitation. This could represent a good solution to solve the esthetic problem of the screw buccal access hole for fixed solutions

High-order accurate p-multigrid discontinuous Galerkin solution of the Euler equations

Discontinuous Galerkin (DG) methods have proven to be perfectly suited for the construction of very highorder accurate numerical schemes on arbitrary unstructured and possibly nonconforming grids for a wide variety of applications, but are rather demanding in terms of computational resources. In order to improve the computational efficiency of this class of methods a p-multigrid solution strategy has been developed, which is based on a semi-implicit Runge–Kutta smoother for high-order polynomial approximations and the implicit Backward Euler smoother for piecewise constant approximations. The effectiveness of the proposed approach is demonstrated by comparison with p-multigrid schemes employing purely explicit smoothing operators for several 2D inviscid test cases

Caratterizzazione sensoriale di prosciutto cotto pre-affettato e percezione della freschezza

Il principale obiettivo dell’attività di ricerca ha riguardato lo studio dell’evoluzione della qualità di prosciutto cotto pre-affettato nel corso della shelf-life, attraverso la valutazione sensoriale del prodotto condotta all’inizio della vita commerciale (Ti) e dopo 10 giorni la data indicata come termine minimo di conservazione (Tf). In via preliminare, è stato necessario eseguire una caratterizzazione del profilo sensoriale di prosciutti cotti pre-affettati, al fine di identificare gli attributi significativi capaci di descrivere e discriminare la qualità sensoriale del prodotto in esame. E’ stata, così, messa a punto una scheda di valutazione contenente 10 descrittori, selezionati tra quelli proposti dal panel (costituito da 10 giudici) durante le fasi iniziali di addestramento con il metodo del “consensus profiling”. Per ogni attributo sono state concordate e stabilite: definizione semantica e modalità di valutazione. Sono stati preparati degli appositi materiali o standard di riferimento, ad intensità definite, per gli attributi valutati dal panel con maggiore variabilità di risposta e che risultavano quindi difficoltosi in fase di attribuzione dell’intensità. I risultati ottenuti dall’analisi quantitativa descrittiva hanno confermato la rilevanza degli attributi selezionati dal panel e fornito informazioni utili per la definizione sensoriale e la percezione della freschezza del prodotto. Alcuni termini utilizzati per descrivere il prodotto potrebbero essere impiegati come descrittori nella stesura di un disciplinare di qualità o come leve per la comunicazione al consumatore delle caratteristiche sensoriali del prodotto

A sensory and metabolomic approach for the "zonation" of typical extra virgin olive oils: an Italian case study

Metabolites found in the extra virgin olive oils can be tracers for some enzymatic activity. The presence and activity of enzymes is strictly related to genetic factors (as olive cultivar) and environmental conditions. The characterization of minor components of extra virgin olive oil, in particular volatile compounds and phenolic molecules, may contribute to the identification of the cultivar\u2013environment interaction. Many of these compounds can be considered to be direct metabolites produced by intracellular biogenic pathways. In this work different analytical approaches were applied for the characterization of extra virgin olive oils produced from autochthon varieties of olives from Brisighella area which has been sampled specifically to carry on a study of zoning, by sampling oils obtained in the same product geographical district, but from different agronomic (types of soils) and agricultural practices (as irrigation). According to the Reg. UE 61/2011, basic quality parameters and additional determinations (free acidity, peroxide number and spectrophotometric indices) has been carried on to be able to discriminate the quality of the samples. The sensory evaluation of the products, conducted by a panel of fully trained judges, and the comparison of the volatile analyses by SPME/GC-MSD and E-Nose as well as the determination of phenolic compounds by HPLC-DAD/MSD were conducted together with the aim to highlight the peculiarities that constitute an important element of typicality valorization. In this way an in-depth study of the samples has been carried out in order to detect all the specific characteristics that could contribute to discriminate between samples to underline their typicality attributes. The research was carried out with the financial contribution of the TERRA DI BRISIGHELLA\uae - CAB

Peculiar sensory notes, related volatile profiles and origin of extra virgin olive oils. The case of the so called “boxwood” attribute

In this work, the volatile profile of selected extra virgin olive oils has been studied, in order to characterize them and to find an eventual relation with the secondary notes described by a sensory Panel. The link between volatile compounds and the secondary sensory notes, with particular attention to the so-called attribute of "boxwood", has been taken into consideration; the aim is to tag the compounds manly responsible, or represented, when the perception of “boxwood” is referred by the Panel and to investigate if this secondary sensory notes can be related to one or more possible geographical origins