Showing papers by "Allyson Nogueira Moreira published in 2020"

Effect of ethanol-wet bonding on porosity and retention of fiberglass post to root dentin.

Abstract: This in vitro study aimed to assess the effects of different pretreatments used to adapt glass-fiber posts cemented to root canals with different resin cements, regarding porosity percentage and bond strength. Twelve bovine incisor roots were prepared with Largo drills. After post space preparation, the specimens were randomized into two types of pretreatment groups (n = 3): water-wet bonding and ethanol-wet bonding. After the post were cemented, the roots were stored in 100% humidity at room temperature for 7 days. The samples were scanned by microcomputed tomography (micro-CT). Images were reconstructed by NRecon software, and CTAn software was used to analyze the porosity percentage (%) at the luting interface. Evaluation of the push-out bond strength was performed by serially cutting the roots, and submitting the slices to testing. Additionally, the resin cement post-gel shrinkage values (%) were measured using the strain-gauge method (n = 10). Data were analyzed by two-way ANOVA, Tukey's test and Student's t test (a = 0.05). The roots prepared with ethanol-wet bonding using RelyX™ U200 had significantly lower porosity in the coronal and apical thirds (p < 0.05). The group prepared with ethanol-wet bonding using RelyX™ ARC presented better bond strength results in the coronal and apical thirds (p < 0.05). RelyX™ ARC (0.97%) produced a higher post-gel shrinkage value than RelyX™ U200 (0.77%). Canals pretreated with ethanol-wet bonding presented better outcomes in regard to porosity percentage and push-out bond strength.

Development and assessment of an over-expanded engine to be used as an efficiency-oriented range extender for electric vehicles

Abstract: A range extender (RE) is a device used in electric vehicles (EVs) to generate electricity on-board, enabling them to significantly reduce the number of required batteries and/or extend the vehicle driving range to allow occasional long trips. In the present work, an efficiency-oriented RE based on a small motorcycle engine modified to the efficient over-expanded cycle, was analyzed, tested and simulated in a driving cycle. The RE was developed to have two points of operation, ECO: 3000 rpm, very high efficiency with only 15 kW; and BOOST: 7000 rpm with 35 kW. While the ECO strategy was a straightforward development for the over-expansion concept (less trapped air and a much higher compression ratio) the BOOST strategy was more complicated to implement and involved the need for throttle operation. Initially the concepts were evaluated in an in-house model and AVL Boost® (AVL List Gmbh, Graz, Austria), and proved feasible. Then, a BMW K75 engine was altered and tested on a brake dynamometer. The running engine proved the initial concept, by improving the efficiency for the ECO condition in almost 40% in relation to the stock engine and getting well over the required BOOST power, getting to 35 kW, while keeping an efficiency similar to the stock engine at the wide open throttle (WOT). In order to protect the engine during BOOST, the mixture was enriched, while at ECO the mixture was leaned to further improve efficiency. The fixed operation configuration allows the reduction, not only of complexity and cost of the RE, but also the set point optimization for the engine and generator. When integrated as a RE into a typical European light duty vehicle, it provided a breakthrough consumption reduction relatively to existing plug-in hybrid electric vehicles (PHEVs) in the market in the charge sustaining mode. The very high efficiency of the power generation seems to compensate for the loss of efficiency due to the excess electricity production, which must be stored in the battery. The results indicate that indeed it is possible to have an efficient solution, in-line with the electric mobility sustainability paradigm, which can solve most of the shortcomings of current EVs, notably those associated with batteries (range, cost and charging time) in a sustainable way.

Adaptable fiberglass post after 3D guided endodontic treatment: Novel approaches in restorative dentistry.

Abstract: Objective The rehabilitation of extensively damaged teeth with great structural loss and calcified root canals represents a challenge for dentistry. Classically, this restorative procedure of endodontically treated teeth involves intraradicular post placement. Retentive function post that can closely adapt to the root canal without the excessive wear of intraradicular dentin has a fundamental importance to ensure the longevity of the restoration. Clinical considerations This report presents a clinical case of 3D guided access to a severely calcified pulp canal followed by the cementation of a fiberglass post that is adaptable to the root canal and prosthetic rehabilitation with full ceramic crown. Conclusions 3D guided access allowed conservative and safe root canal treatment. The adaptable fiberglass post meets the specific needs of the described case and has a simple technique and low cost. Clinical significance Guided endodontics is a minimally invasive approach for teeth with calcified root canals. The post used in this study meets the demands of teeth endodontically treated with conservative techniques. The professional should not need to adapt the anatomy of the root canal to the anatomical reality of the post. This one adapts itself to the shape of the canal.

Metallization and Ar-O plasma effects on dental enamel roughness evaluated with SEM and MeX™ for 3D reconstruction

Abstract: The MeX™ software is a useful tool for tridimensional data collection for surface evaluation and could be relevant to evaluate the same specimen in different phases of the study, assuming repeated measures of dental enamel roughness. The aim of this study was to evaluate the influence of sample metallization for dental enamel roughness analysis with 3D images reconstructed using MeX™ software from Scanning Electron Microscopy (SEM) images. The influence of 74.98% (%mol/mol) argon-oxygen plasma for carbon layer removal on surface roughness of the metallized specimen was also evaluated. Dental enamel specimens were prepared for SEM analysis with and without carbon metallization using conventional or environmental modes. Argon-oxygen plasma for carbon layer removal was used and surface roughness was re-evaluated. Roughness obtained by SEM and MeX™ reconstructed images, with or without metallization, did not differ. No significant alteration on surface roughness after carbon layer removal using plasma was found. SEM baseline evaluation using conventional mode without sample preparation and in environmental mode were not comparable. Roughness of enamel 3D images reconstructed with MeX™ software from SEM images, with or without metallization was similar. The 74.98% (%mol/mol) argon-oxygen plasma removed the carbon layer with no effect on enamel roughness.

Koh group influence on titanium surfaces and pure sol-gel silica for enhanced osteogenic activity:

Abstract: Although, the excellent level of success of titanium surfaces is based on the literature, there are some biological challenges such as unfavorable metabolic conditions or regions of poor bone quali...

Maxillofacial Prosthetic Rehabilitation of Patients with Resection of Squamous Cell Carcinoma: A Report of Two Cases.

Abstract: Maxillofacial prosthetic rehabilitation is almost always indicated after surgical treatment of affected individuals with oral cavity and pharynx cancers. Few articles have described in detail the technical sequence of maxillofacial prosthesis fabrication. The first case is a 56-year-old woman who was rehabilitated with pharyngeal obturator prosthesis after a partial maxillectomy, including soft palate, tonsil, oropharynx, and retromolar space regions. The second case is an 83-year-old man who was rehabilitated with hard palatal obturator prosthesis after a maxillectomy, including hard palate and nasal floor. In both cases, the patients complained of oronasal regurgitation and difficulty in chewing, swallowing, and speaking. A multi-professional approach including oral rehabilitation should be part of the treatment plan for individuals with oral and pharyngeal cancer after tumor resection.