DOI: 10.3290/j.jad.a29513, PubMed ID (PMID): 23560253Pages 137-144, Language: EnglishSousa, Ana Beatriz Silva / Silami, Francisca Daniele Jardilino / Garcia, Lucas da Fonseca Roberti / Naves, Lucas Zago / Pires-de-Souza, Fernanda de Carvalho Panzeri
Purpose: To evaluate the effect of two adhesive systems and different aging protocols on the bond strength of a -repaired microhybrid composite.
Materials and Methods: Eighty test specimens (n = 20) and 10 control specimens measuring 8 x 4 mm were fabricated of a microhybrid composite (4 Seasons, shade A2) and grouped according to time/aging protocol: G1: 24 h in artificial saliva; G2: 7 days in artificial saliva; G3: 30 days in artificial saliva; G4: artificial accelerated aging (AAA) for 384 h; G5: control. After aging, samples were submitted to three types of surface treatment: SB2: Adper Single Bond 2, a two-step adhesive (3M ESPE); SB3: Adper Scotchbond Multi-Purpose, a three-step adhesive (3M ESPE); C: without application of adhesive (control). After this, test specimens were repaired with the same composite of a different shade (C3), and submitted to the microtensile test at a crosshead speed of 0.5 mm/min. Failure modes were analyzed by scanning electron microscopy (Jeol JSM 7500). Statistical analysis was performed using ANOVA and Tukey's test (p < 0.05).
Results: G2/SB2 presented significantly lower bond strength values in comparison with the other groups (p < 0.05). The control group presented the highest bond strength values, which differed statistically significantly from SB3, G3/SB2, and G4/SB2 (p < 0.05). Fractographic analysis demonstrated that most samples presented predominantly cohesive failures, excepting GI/SB2, which presented mixed and cohesive failures, and G4/SB2 and G1/SB3, which showed adhesive failures.
Conclusion: The repair was more effective when performed after a short period of time and when the 3-step adhesive system (SB3) was used.
Keywords: dental materials, composites, bond strength, artificial aging