Avaliação da resistência de união e da adaptação interna entre cavidade dentinária e adesivos aplicados em uma e duas camadas

• Autor(a) principal: Soares, Clarissa Grassi
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional PUCRS
• Texto Completo: http://hdl.handle.net/10923/391
• topic: ODONTOLOGIA; DENTÍSTICA; ADESIVOS DENTÁRIOS; DENTINA

This research evaluated the influence of the adhesive layers of three adhesive systems on: 1) the microtensile bond strength (μTBS) to dentine and the fracture pattern; 2) the dentine/composite resin interfacial adaptation (DIA). Two cavities measuring 4 x 4 x 2 mm in samples for DIA, and 3,5 x 3,5 x 1,5 mm in samples for μTBS (factor C=3), 2 mm distant among themselves, were made at the vestibular surfaces of 30 incisive bovine. Scotchbond Multi-Purpose (MP), Single Bond 2 (SB) (3M/ESPE) and Clearfil SE Bond (CF) (Kuraray) were applied in one layer (MP-I, SB-I and CF-I) and in two layers (MP-II, SB-II and CF-II), being light-cured separately for 20 s. The composite resin Z250 (color A3) was inserted in four increments. Ten teeth for each adhesive system were used, being five for each test. After 48 h, resin/dentin sticks were made (n=15/group), with 0. 53 mm2 of adhesive area mean for μTBS test, and slices containing the two restorations with thickness among 0,15 - 0,20 mm (n=15/group) for DIA analysis. The sticks were submitted to the μTBS test using the universal testing machine EMIC DL-2000 and, after the test, the extremities were analyzed by SEM to classify the fracture pattern. The slices were analyzed in a Leica DMR optical microscope at x10, using polarized light and differential interference contrast microscope images. The restorations images were captured by a Nikon Coolpix 990 digital camera and the types and amounts of flaws (gap, crack, rupture) were classified. The mean values of μTBS were submitted to ANOVA Factorial and Turkey’s test (á=0. 05). The factors adhesive (p=0,001) and layers (p=0,025) presented significant difference, but the interaction among them did not have significant difference (p=0. 189). The mean values of μTBS were the following: MP-II: 56. 92; MP-I: 52:23; CF-II: 47:71; CF-I: 42. 25; SB-I: 35. 12; SB-II: 34. 69. The predominant fracture pattern was mixed failure. For DIA analysis, the Kruskal-Wallis test (á=0. 05) showed statistics differences for cracks and ruptures between the adhesives systems. SB-I and II had the highest values of cracks, and MP-I, the lowest value. SB-II showed significantly greater values for rupture. The application of two layers did not favor the results of μTBS and of DIA.