Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-10-10T14:17:09Z No. of bitstreams: 1 magnolinharesdamotta.pdf: 787435 bytes, checksum: f1496aa1318e46521eaae35e86890c8d (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-10-11T15:53:30Z (GMT) No. of bitstreams: 1 magnolinharesdamotta.pdf: 787435 bytes, checksum: f1496aa1318e46521eaae35e86890c8d (MD5) / Made available in DSpace on 2016-10-11T15:53:30Z (GMT). No. of bitstreams: 1 magnolinharesdamotta.pdf: 787435 bytes, checksum: f1496aa1318e46521eaae35e86890c8d (MD5) Previous issue date: 2009-05-21 / Este trabalho avaliou a microinfiltração marginal em materiais restauradores provisórios utilizados em Endodontia, em diferentes períodos de tempo (3 e 7 dias). Foram utilizados 120 dentes humanos unirradiculares, que após tratamento endodôntico foram separados aleatoriamente em 6 grupos (n=20), de acordo com o material restaurador provisório utilizado: Grupo 1: Vidrion R, Grupo 2: IRM, Grupo 3: Provisory, Grupo 4: Dentalville,, Grupo 5: guta percha e Super Bonder (controle positivo) e Grupo 6: apenas bolinha de algodão (controle negativo). Após a restauração os dentes foram impermeabilizados com esmalte de uso cosmético e submetidos à termociclagem por 500 ciclos (0+/- 5 º C e 55 +/- 5º C). Em seguida foram imersos em solução de azul de metileno 2% por 3 e 7 dias, sendo seccionados longitudinalmente e examinados por lupa estereoscópica com aumento de 40x. Os resultados foram submetidos ao testes estatísticos Mann Whitney e Kruskal Wallis, mostrando resultados significativos quando se utilizou o material Dentalville por um período de 3 dias (p<0,001). Após 7 dias, apenas o grupo 5 (controle positivo) não apresentou microinfiltração marginal, não havendo diferenças estatisticamente significativas entre os demais grupos. Pode-se concluir que o material restaurador provisório Dentalville apresentou menores índices de microinfiltração quando utilizado por um período de 3 dias, comparado aos demais materiais avaliados. / This study evaluated the marginal microleakage in temporary filling materials used in Endodontics, in different time intervals (3 and 7 days). One hundred and twenty uniradicular human teeth comprised the sample of this study. After endodontic treatment they were randomly divided into 6 groups (n=20) according to the temporary restoring material used: Group 1: Vidrion R, Group 2: IRM, Group 3: Provisory, Group 4: Dentalville, Group 5: Gutta percha and Super Bonder (positive control), and Group 6: cotton balls (negative control). After restoration the teeth were were impermeabilized with a nail varnish and submitted to thermocycling with 500 cycles (0+/- 5°C e 55 +/- 5°C). Subsenquently, the teeth were immersed in 2% blue methylene solution for 3 and 7 days, longitudinally sectioned and examined by means of a stereoscopic lens with magnification of 40x. The Mann Whitney and Kruskal Wallis tests were applied for statistical analysis. The results were statistically significant for the Dentalville material at the time interval of 3 days (p<0.001). After 7 days only group 5 (positive control) did not show marginal microleakage, and there was no significant differences between the other groups. It may be concluded that Dentalville temporary restoring material showed the smallest indexes of microleakage at time interval of 3 days when compared to the other materials evaluated.

Indiana University-Purdue University Indianapolis (IUPUI) / A provisional restoration must fulfill biologic, mechanical, and esthetic requirements. These prostheses should provide comfort, pulp protection, positional stability, occlusal function, hygiene access, esthetics, strength and retention. Methyl-methacrylate acrylic has assumed many appli¬cations in the field of restorative dentistry. However, the material still has deficiencies, such as polymerization shrinkage, pulpal damage associated with exothermic polymerization and susceptibility to fracture. Bis-GMA composites, Bis-acryl composites and visible light-cured urethane dimethacrylate resins have been developed to address these issues. The purpose of this study was to compare the mechanical properties of provisional restorations made from composite resins (Protemp Plus, Luxatemp Solar, Radica, Protemp Crown) to those made of the traditional methacrylate resins (Jet, Snap, High Impact). Six groups of samples, two groups from methacrylate and four groups from composite based materials, were fabricated. Samples from each group were evaluated for microhardness (n=10), flexural strength and flexural modulus (n=20) according to ISO 4049, and fracture toughness (n=20) according to ISO 13586. From each of the six groups, ten samples were tested for flexural strength, flexural modulus and fracture toughness and 5 samples were tested for microhardness. These tests were done after storing at 37°C in a distilled water solution for 7 days followed by thermal cycling (2500 cycles, 5-55°C, 45 s. dwell). Identical sets of samples from each group were used as controls; these were tested after storing for 24 hours in dry conditions. The results were analyzed by two-way ANOVA with material type and aging conditions as the two main variables. Significance level was set at p=0.05. For flexural strength and flexural modules, the higher values were obtained for Radica. Protemp plus (7 days) and Radica (24h) had the highest fracture toughness value. Protemp crown showed the highest surface hardness. The mechanical properties of composite resin were superior.

Indiana University-Purdue University Indianapolis (IUPUI) / Background: Interim restoration for a lost anterior tooth is often needed for temporary esthetic and functional purposes. Materials for interim restorations usually have less strength than ceramic or gold and can suffer from fracture. Several approaches have been proposed to reinforce interim restorations, among which fiber reinforcement has been regarded as one of the most effective methods. However, some studies have found that the limitation of this method is the poor polymerization between the fibers and the composite resin, which can cause debonding and failure. 64 Purpose: The purpose of this study was to investigate the effects of different polymerization methods as well as fiber types on the mechanical behavior of fiberreinforced composite resin. Material and Methods: A 0.2-mm thick fiber layer from strip fibers or mesh fibers embedded in uncured monomers w as fabricated with polymerization (two-step method) or without polymerization (one-step method), on top of which a 1.8-mm composite layer was added to make a bar-shape sample, followed by a final polymerization. Seventy-five specimens were fabricated and divided into one control group and four experimental groups (n=15), according to the type of glass fiber (strip or mesh) and polymerization methods (one-step or two-step). Specimens were tested for flexural strength, flexural modulus, and microhardness. The failure modes of specimens were observed by scanning electron microscopy (SEM). Results: The fiber types showed significant effect on the flexural strength of test specimens (F = 469.48; p < 0.05), but the polymerization methods had no significant effect (F = 0.05; p = 0.82). The interaction between these two variables was not significant (F = 1.73; p = 0.19). In addition, both fiber types and polymerization steps affected the flexural modulus of test specimens (F = 9.71; p < 0.05 for fiber type, and F = 12.17; p < 0.05 for polymerization method). However, the interaction between these two variables was not significant (F = 0.40; p = 0.53). Both fiber types and polymerization steps affected the Knoop hardness number of test specimens (F = 5.73; p < 0.05 for polymerization method. and F = 349.99; p < 0.05 for fiber type) and the interaction between these two variables was also significant (F = 5.73; p < 0.05). SEM images revealed the failure mode tended to become repairable while fiber reinforcement was 65 existed. However, different polymerization methods did not change the failure mode. Conclusion: The strip fibers showed better mechanical behavior than mesh fibers and were suggested for use in composite resin reinforcement. However, different polymerization methods did not have significant effect on the strength and the failure mode of fiber-reinforced composite