Souza, Rodrigo Othavio de Assunção eSena, Lorena Marques Ferreira de2019-01-172019-01-172018-11-13SENA, Lorena Marques Ferreira de. Efeito de diferentes estratégias de colagem de bráquetes ortodônticos na resistência de união ao esmalte e no grau de conversão dos monômeros. 2018. 60f. Tese (Doutorado em Saúde Coletiva) - Centro de Ciências da Saúde, Universidade Federal do Rio Grande do Norte, Natal, 2018.https://repositorio.ufrn.br/jspui/handle/123456789/26525Objective: To evaluate the effect of different surface treatments and polymerization protocols on the bond strength of brackets to enamel, and the degree of conversion of the bonding agents. Methods: 120 bovine crowns were embedded in acrylic resin blocks and sanded. Next, the blocks were randomly assigned into 12 groups. Metal brackets were bonded to enamel according to the "surface treatment" factor (A: Phosphoric Acid; ATxt: Phosphoric Acid + Transbond XT Primer®; Tse: Transbond Plus Self Etching Primer®; and SBU: Scotchbond Universal®) and "polymerization" factor (R20: Radii-Cal®/20 seconds; V20: Valo Cordless®/20 seconds; and V3: Valo Cordless®/3 seconds). All samples were stored for 6 months (water, 37ºC) and then subjected to a shear bond strength test (SBS). Using the same factors, 120 resin discs were made to assess the degree of conversion (DC) of the monomer. Data from the SBS (MPa) and DC (%) were analyzed by analysis of variance (2 factors) and Tukey's test (5%). Bond failures were classified according to the Adhesive Remnant Index (ARI) and analyzed with the Kruskal-Wallis and Mann-Whitney tests (5%). Results: For the SBS, the factors "polymerization" (R20=8.1B ; V20=13.2A ; V3=5.2C , p=0.0001) and “surface treatment” (A=3.1C ; ATxt=13.6A ; Tse=12.3A ; SBU=6.3B , p=0.0001) were statistically significant among groups. The highest adhesion value were found for the ATxtV20 group (22.2A ) and the lowest value for the A/R20 group (1.2E ). Regarding ARI, score 2 was the most prevalent in groups A, ATxt, V20 and V3, while score 4 was the most prevalent in the Tse, SBU and R20 groups, with no significant difference between them (p=1.0). Regarding DC, the factors "polymerization" (R20=66.6A ; V20=58.4B ; V3=45.1C , p=0.0001) and "surface treatment" (A=52B , ATxt=59.7A , Tse=51.4B , SBU=63.8A , p=0.0001) were statistically significant. Conclusions: Tse was more sensitive to the variations in polymerization protocols than the other surface treatments. Treatment A did not present suitable bond strength or degree of conversion.Acesso AbertoAdesividadeEsmalte dentárioBraquetesdoctoralThesisCNPQ::CIENCIAS DA SAUDE::SAUDE COLETIVA