RESUMO
To evaluate the ethanol wet-bonding protocol with a universal adhesive in etch-andrinse and self-etch modes on microleakage and microtensile bond strength (µTBS) of resin composite to different dentin depth. Molars were distributed into groups according to protocol and dentin depth: universal adhesive (C - control), ethanol + universal adhesive (E), and phosphoric acid etch + ethanol + universal adhesive (PA+E). All protocols were applied to dentin at superficial, middle and deep depths. The specimens (n = 10) were submitted to microleakage and µTBS tests. Half of specimens were submitted to thermocycling (10,000 cycles; 5∘C/55∘C). Data were submitted to Spearman correlation (µTBS x microleakage) and three-way ANOVA (protocol, aging and depth), followed by Bonferroni post hoc test (α=0.05). PA+E group showed highest µTBS and lowest microleakage mean values in 24h. All groups presented similar µTBS mean values after thermocycling. The deep dentin showed less stable µTBS results. PA+E group presented highest microleakage mean values after thermocycling. Spearman's correlation showed a strong correlation between microleakage and µTBS. The PA+E group improved immediate adhesion and E group promoted a more stable µTBS in the long-term adhesion of universal adhesive. The aging for all protocols jeopardized the stability of the hybrid layer. The ethanol wet bonding technique associated with universal adhesive has enhanced the immediate result of the resin composite adhesion.
Assuntos
Colagem Dentária , Cimentos Dentários , Cimentos Dentários/farmacologia , Adesivos Dentinários/química , Colagem Dentária/métodos , Cimentos de Resina/química , Resistência à Tração , Dentina , Resinas Compostas/química , Teste de MateriaisRESUMO
AIM: To test the hypothesis that the composition of endodontic sealer cements and the time elapsed between root filling and fibreglass post fixation interferes with adhesion to root canal dentine. METHODOLOGY: Sixty bovine incisor roots were divided into five groups (n = 12): CI, unfilled; SI, filled with a calcium hydroxide-based cement-Sealer 26, and immediate post fixation; S7, Sealer 26 and post fixation after 7 days; EI, filled with a zinc oxide and eugenol-based cement-Endofill and immediate fixation; and E7 Endofill and post fixation after 7 days. The posts were cemented with adhesive system and dual resin cement. Ten roots were cross-sectioned to obtain two 1-mm-thick discs for each cervical (TC), middle (TM) and apical (TA) third of the prepared root portion. The posts were submitted to a micropush-out test. The other two teeth were evaluated using scanning electron microscopy to analyse the bond interface. Data were analysed using anova, Tukey and Dunnett tests (P < 0.05). RESULTS: Group EI was associated with a significant reduction in bond strength values irrespective of the root region; TC = 3.50 MPa (P = 0.0001); TM = 2.22 MPa (P = 0.0043) and TA = 1.45 MPa (P = 0.003). Region of canal had an influence on the values for the cement used in group E7, in which only the TA presented differences from the CI. CONCLUSIONS: Endofill interfered negatively with the bond to root dentine along its full length and in the TA when post fixation was delayed for 7 days. Bond strength decreased from crown to apex in all groups.