Doutorado em Odontologia (FO)
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Navegando Doutorado em Odontologia (FO) por Por Orientador "Fonseca, Rodrigo Borges"
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Item Desempenho biomecânico de novos retentores intrarradiculares em dentes com ou sem férula(Universidade Federal de Goiás, 2020-02-28) Almeida, Letícia Nunes de; Fonseca, Rodrigo Borges; http://lattes.cnpq.br/8629552867290605; Fonseca, Rodrigo Borges; Lopes, Lawrence Gonzaga; Barata, Terezinha de Jesus Esteves; Kasuya, Amanda Vessoni Barbosa; Favarão, Isabella NegroThe aim of this study was to evaluate the influence of intrarradicular post system and the amount of coronary remnant (ferrule) on maximal fracture load, fracture pattern and stress distribution of endodontically treated teeth. Eight experimental groups were created: Pf-0 e Pf-2 - glass fiber post (GFP) no. 3 in teeth with and without ferrule respectively; GFP no. 1 relined with experimental composite (EC) with and without ferrule respectively; EC-0 and EC-2 - custom post made with the experimental composite (EC) with and without ferrule respectively, CAD-0 e CAD-2 - custom milled post with and without ferrule respectively. The EC was composed of 22.5 wt% of methacrylate resin (Bis-GMA, TEGDMA, Bis-EMA), 30% of glass fibers and 47.5% of filler particles. After endodontic treatment, post cementation and crowns with composite resin, the teeth were tested to verify the maximum fracture load (n = 10) in a universal testing machine (Instron 5965) a 0.5 mm/min. Subsequently, the fracture pattern was analyzed and stress distribution was evaluated by the finite element method using the modified von Mises criterion (MSC Marc & Mentat). The maximum fracture load results were subjected to factor analysis, and subsequently Kolmogorov-Smirnov, ANOVA, Tukey and T-Test for comparison between groups (α = 0.05). Interaction was observed between the factors under study (p = 0.046), and ANOVA and Tukey showed a statistically significant difference between the groups (p = 0.001). EC-0 (752.81N) and CAD-0 (728.84N) were similar and superior Pr-0 (545.16) and Pf-0 (498.01N). In ferrule groups, all retainers were similar (p>0.05) Pf-2 (791.85), Pr-2 (699.1), EC-2 (822,81), CAD-2 (779.89). Pf-0 showed a greater number of non-repairable failures and the Pr-2 posts promoted a greater number of favorable failures. Groups without ferrule showed higher number of non-repairable failures. The posts made with EC showed lower stress concentration and the posts made by CAD / CAM technique, the highest stress concentration. Retainer type and presence of ferrule influence on maximal load, fracture pattern and stress distribution of endodontically treated teeth. CE custom posts promote higher maximum fracture load and more favorable stress distribution.Item Comportamento biomecânico de pinos personalizados em remanescente dentário fragilizado(Universidade Federal de Goiás, 2017-03-02) Kasuya, Amanda Vessoni Barbosa; Fonseca, Rodrigo Borges; http://lattes.cnpq.br/8629552867290605; Fonseca, Rodrigo Borges; http://lattes.cnpq.br/8629552867290605; Torres, Érica Miranda de; Barata, Terezinha de Jesus Esteves; Marson, Fabiano Carlos; Carlo, Hugo LemesThe objectives of this work were to evaluate the stress distribution (SD), fracture resistance (RF), adhesive strength (AS) and their respective fracture patterns of weekeaned bovine roots, rehabilitated with customized pins with different resinous materials. In addition, the objective of this study was to evaluate the polymerization depth of the resinous materials by Knoop microhardness method (MH). Eight experimental groups were established (n = 10 for FR and AS; n = 5 for MH), with the factor under study: 1. The post type (industrialized glass fiber post relined (I) and personalized post (P), 2. the relining material only for industrialized glass fiber post (experimental composite (e) and composite resin (R)); 3. the material used only for personalized post (experimental composite (e) and bulk fill resin (b), and 4. the amount of remaining dentin (root embrittlement inner wear, in lengths of 5 mm or 10 mm). One hundred and forty bovine roots of similar size were selected and restored according to the group to which they belonged. For FR, Pperiodontal and alveolar bone were simulated and the specimens were placed in an Instron 5965 machine at a 135 ° angle to the long axis and loaded at a constant velocity of 0.5 mm/min in compression until the fracture. The fracture pattern was classified as: F1- crown; F2- root; F3- crown/root; F4- fracture with displacement of the crown/post. For AS, the specimens were sectioned in slices of 1 mm perpendicular to their long axis. Each specimen was placed in a test machine to received the load in the apical-coronal direction, at a constant velocity of 0.5mm / min, pushing the pin through the largest side of the sample until fracture. The fracture pattern was classified as: F1- cohesive of the pin and/or reline material; F2- cohesive of dentin; F3- adhesive of pin/reline material; F4 - Adhesive bonding cement/ eline material and F5 - mixed. For MH, the specimens were sectioned parallel to their long axis. The tests were performed with a Knoop penetrator under a static charge of 50 grams per 10 seconds. MH was calculated as the average value for each third. Finally, the finite element method was used to analyze the DT. 3D virtual models representative of each experimental group were created and analyzed under von Mises equivalent stresses criterion, simulating loading of 100N at a 45o angle with the long axis. The experimental composite proved to be an alternative for the rehabilitation of weakened roots when used to create personalized posts or when used as a relining material, with FR values similar to the traditional technique, but with more favorable stress distributions. Moreover, it presented excellent adhesive strength to the dentin structure, being comparable to conventional composite resin and bulk fill resin. The bulk fill resin resulted in low values of fracture resistance associated with the fracture and displacement of post/crown. Lower microhardness values were observed in the apical third for bulk fill resin.