Analysis of Slot Height Accuracy and Precision of Stainless Steel Orthodontic Brackets Manufactured by Metal Injection Molding and Computer Numerical Control Milling Using Stereomicroscopy

Objective: It is the objective of this study to determine the dimensional accuracy and precision that is achievable by two manufacturing methods of stainless steel orthodontic brackets, CNC milling and metal-injection molding. To determine this, we propose the following specific aims: 1) to determine the actual dimensions of the slots in both milled and MIMed orthodontic bracket and standard deviations. 2) Using mathematical models to determine if the dimensional difference, if one exists, between milled and MIMed brackets will result in a difference in third order tooth movement (torque) realization (effective torque vs nominal torque). The actual bracket slot dimensions from both manufacturing techniques will be used in the mathematical model, which determines effective torque produced by a rectangular archwire within a rectangular slot. And 3) to determine if there is a statistical difference in the precision of the two different manufacturing methods. Materials and Methods: In this study ten brackets of two different types of 0.022 in (0.559 mm) slot maxillary right central incisor stainless steel conventional brackets were investigated: GAC OmniArch (GAC, Bohemia, NY, USA) and OPAL Avex (OPAL Orthodontics, South Jordan, UT, USA), both brackets with MBT prescription, which is 17° torque for the maxillary central incisors. The GAC stainless steel brackets are produced by the MIM process. The OPAL stainless steel brackets are produced by the CNC milling process. The mesial profiles of the brackets were imaged using ZEN imaging software through a Carl Zeiss Stemi508 microscope (Carl Zeiss MicroImaging GmbH, Jena, Germany), at 45x magnification. The brackets were carefully aligned so that the slots were photographed perpendicular to the slot. The images were calibrated and evaluated using the GNU Image Manipulation Program (GIMP) software. Using the software, points were selected and transferred for analysis into an Excel spreadsheet. In each photo 3 points were selected on the left (gingival) wall, the right (incisal) wall, and the floor. The points were all plotted on a 2-dimensional Cartesian (x,y) coordinate system, which was given by the GIMP software. Using Excel, a trend-line was generated for the walls and the floor, using linear regression. This analysis allowed for the determination of the bottom and top slot height as well as the angle between the slot walls. In addition to these measurements, the torque play for each bracket was determined for five different, commonly used rectangular wires. Nominal values for the archwires were used to determine torque play. The archwire dimensions used were: 0.016in × 0.022in, 0.017in × 0.025in, 0.018in × 0.025in, 0.019in × 0.025in, and 0.021in × 0.025in. The torque play is the more clinically applicable information. Furthermore, all of the brackets evaluated in the study were additionally imaged using scanning electron microscopy (SEM) allowing for more precise subjective evaluation of the bracket slots, in addition to the objective forms of evaluation previously mentioned. The SEM images revealed any surface inconsistencies within the bracket slots, that could affect bracket-wire interaction, and therefore tooth movement. Results: The bottom slot dimension for the OPAL sample had a mean of 0.0216in, with a standard deviation of 0.0002in, and a maximum of 0.0219in. The entire sample being below the nominal slot height of 0.022 in. The GAC bracket slots on the other hand had a mean of 0.0230in, with a standard deviation of 0.0003in, and a maximum of 0.0234in. The entire sample of GAC brackets evaluated had a bottom slot height above 0.022in. On average, the AVEX OPAL bracket slot heights were 2% below the nominal value, whereas the GAC OmniArch brackets were 4.5% oversized. All of the brackets in each sample were divergent, meaning that the top height of the bracket slot was greater than the bottom height, and there was no difference between the two groups when considering divergence angle. There was a statistical difference found for the deviation angles for wires of commonly used nominal sizes. Furthermore, comparison of the two groups was performed to test the deviation from the mean for each individual sample. This essentially would test the precision of the manufacturing techniques. It was determined that there was a statistical difference in the precision of the bracket slot heights between the two groups. The SEM images offer more insight into the shape of the bracket slot and surface appearance of the brackets. Conclusions: In conclusion, it was determined that there was a statistically significant difference between the two samples of brackets, GAC OmniArch and AVEX OPAL, in the outcome variables of bottom slot height, top slot height, and deviation angle for the five nominally sized archwires used in the mathematical model, which effects torque realization. In addition, it was determined that there is a statistically significant difference between the two samples, in terms of deviation from the mean, for those outcome variables. Therefore it can be concluded that there is a statistically significant difference between the two samples in terms of both accuracy and precision

LA DIGITALIZZAZIONE PER LA DOCUMENTAZIONE, LO STUDIO E LA FRUIZIONE DI UN SITO ARCHEOLOGICO. LA VR EXPERIENCE DEL TEATRO DI RICINA

This paper presents a workflow developed thanks to the collaboration between archae- ologists and engineers, aimed at the documentation, representation and virtual fruition of an archaeological site. The purpose is to exploit the data acquired through digital solutions and the consequent elaboration of a reality 3D model to support archaeological studies and to effectively disseminate their results. The presented case study is the Roman Theatre of Ricina (Villa Potenza, MC). The building has preserved much of its masonry, but it is very different from that which could be appreciated by the audience of theatrical performances in Roman times. The work has been developed according to three steps: 1) digital documentation of the site and elaboration of a reality-based 3D model; 2) study of the archaeological finds thanks to the reality-based 3D model and design of a possible reconstruction, represented through a second 3D model elaborated by anastylosis; 3) development of a Virtual Reality environment for the fruition and the interaction with the two 3D models. The final output is therefore an immersive VR application that offers the possibility to access to the theatre both in its current form and in the original one. An experience that is not limited to a simple visualization rather presenting itself as a guided tour across the centurie

Antioxidant and Anti-Inflammatory Profiles of Spent Coffee Ground Extracts for the Treatment of Neurodegeneration

Spent coffee grounds (SCGs), waste products of coffee beverage production, are rich in organic compounds such as phenols. Different studies have demonstrated phenol beneficial effects in counteracting neurodegenerative diseases. These diseases are associated with oxidative stress and neuroinflammation, which initiates the degeneration of neurons by overactivating microglia. Unfortunately, to date, there are no pharmacological therapies to treat these pathologies. The aim of this study was to evaluate the phenolic content of 4 different SCG extracts and their ability to counteract oxidative stress and neuroinflammation. Caffeine and 5-O-caffeoylquinic acid were the most abundant compounds in all extracts, followed by 3-O-caffeoylquinic acid and 3,5-O-dicaffeoylquinic acid. The four extracts demonstrated a different ability to counteract oxidative stress and neuroinflammation in vitro. In particular, the methanol extract was the most effective in protecting neuron-like SH-SY5Y cells against H2O2-induced oxidative stress by upregulating endogenous antioxidant enzymes such as thioredoxin reductase, heme oxygenase 1, NADPH quinone oxidoreductase, and glutathione reductase. The water extract was the most effective in counteracting lipopolysaccharide-induced neuroinflammation in microglial BV-2 cells by strongly reducing the expression of proinflammatory mediators through the modulation of the TLR4/NF-kappa B pathway. On these bases, SCG extracts could represent valuable nutraceutical sources for the treatment of neurodegeneratio

Relaxation of Vibrational Excitons in Molecular-Ionic Crystal s Measured by Picosecond Time-Resolved CARS

The decay times of the internal vibrations in K2S04, KCl04, NaN03 and CaC03 single crystals have been measured at different temperature s by picosecond time-resolved CARS. The low temperature experimental data and their temperature dependence are interpreted on the basis of an energy relaxation mechanism, involving two-phonon and higher order decay processes

Evaluation of polygenic determinants of non-alcoholic fatty liver disease (NAFLD) by a candidate genes resequencing strategy

NAFLD is a polygenic condition but the individual and cumulative contribution of identified genes remains to be established. To get additional insight into the genetic architecture of NAFLD, GWAS-identified GCKR, PPP1R3B, NCAN, LYPLAL1 and TM6SF2 genes were resequenced by next generation sequencing in a cohort of 218 NAFLD subjects and 227 controls, where PNPLA3 rs738409 and MBOAT7 rs641738 genotypes were also obtained. A total of 168 sequence variants were detected and 47 were annotated as functional. When all functional variants within each gene were considered, only those in TM6SF2 accumulate in NAFLD subjects compared to controls (P = 0.04). Among individual variants, rs1260326 in GCKR and rs641738 in MBOAT7 (recessive), rs58542926 in TM6SF2 and rs738409 in PNPLA3 (dominant) emerged as associated to NAFLD, with PNPLA3 rs738409 being the strongest predictor (OR 3.12, 95% CI, 1.8-5.5, P 0.28 was associated with a 3-fold increased risk of NAFLD. Interestingly, rs61756425 in PPP1R3B and rs641738 in MBOAT7 genes were predictors of NAFLD severity. Overall, TM6SF2, GCKR, PNPLA3 and MBOAT7 were confirmed to be associated with NAFLD and a score based on these genes was highly predictive of this condition. In addition, PPP1R3B and MBOAT7 might influence NAFLD severity

Symbiotic Stars in OGLE Data I. Large Magellanic Cloud Systems

Symbiotic stars are long-orbital-period interacting-binaries characterized by extended emission over the whole electromagnetic range and by complex photometric and spectroscopic variability. In this paper, the first of a series, we present OGLE light curves of all the confirmed symbiotic stars in the Large Magellanic Cloud, with one exception. By careful visual inspection and combined time-series analysis techniques, we investigate for the first time in a systematic way the photometric properties of these astrophysical objects, trying in particular to distinguish the nature of the cool component (e.g., Semi-Regular Variable vs. OGLE Small-Amplitude Red Giant), to provide its first-order pulsational ephemerides, and to link all this information with the physical parameters of the binary system as a whole. Among the most interesting results, there is the discovery of a 20-year-long steady fading of Sanduleak's star, a peculiar symbiotic star known to produce the largest stellar jet ever discovered. We discuss by means of direct examples the crucial need for long-term multi-band observations to get a real understanding of symbiotic and other interacting binary stars. We eventually introduce BOMBOLO, a multi-band simultaneous imager for the SOAR 4m Telescope, whose design and construction we are currently leading.Comment: 16 pages, 4 Tables, 12 Figures. Accepted for publication in MNRA