Avaliação da união composito/dentina em função do tempo de condicionamento acido e sistema de união em dentes deciduos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The aim of this study was to evaluate the micro-tensile bond strength, the failure sites obtained after the test, and the resin/dentin interface, in different etching times (7, 15, and 20s) and with different bond systems (Single Bond-SB; Prime &Bond 2.1- P&B2.1; One Up Bond F-OUP e Clearfil SE Bond-CSE). 138 sound extracted primary teeth were selected. For the micro-tensile bond strength, 48 teeth were selected and randomly distributed into 3 groups, according to etching time, and subdivided into 4 subgroups, according to bond systems as follows (n=20): G1- 7s + SB; G2- 15s + SB; G3- 20s + SB; G4- 7s + P&B2.1; G5- 15s + P&B2.1; G6- 20s + P&B2.1; G7- 7s + OUP; G8- 15s + OUP; G9- 20s + OUP; G1Q- 7s + CSE; Gll- 15s + CSE; G12- 20s + CSE. The teeth were obliquely cut on the occlusal surface and flatenned until dentin area was reached. The bonding procedures were carried out according to groups, and the restorative procedure was carried out using the resin composite Filtek Z250. Next, the samples were sectioned in buccal-lingual and mesio-distal orientations, to obtain samples of about lmm2. The samples were stored in distilled water at 3-rC for 24h, and then submitted to micro-tensile bond strength in a Universal Testing Machine (Instron) with a crosshead speed of 0.5mm/min. The data were submitted to ANOV A and Tukey s test (p<0.05). The failure sites obtained after the test were observed, for failure type, in stereoscope microscopy of 25X magnification, and the representative failures of each group were observed in Scanning Electron Microscopy (SEM). 90 teeth were selected for the analysis of resin composite/dentin. The teeth were distributed and treated as previously described, except that just one. The photomicrographs were analyzed according to scores: o - absence of hybrid layer and resin tags; 1- absence of hybrid layer and presence of resin tags; 2 - presence of hybrid layer present and absence of resin tags, and 3 -presence of hybrid layer and resin tags. The data obtained were submitted to Kruskal-Wallis s testo According to the results it could be concluded that: 1 -the decrease in etching time (7s) did not interfere in bond values, for ali bond systems used; 2- there was negative correlation, solely, between P&B2.1*etching time interaction; 3 - the pattern of failure analysis showed major predominance of mixed failures for ali groups tested, except P&B 2.1, where failures for 7 and 15s were adhesives and for the 20s were composite cohesive; 4 - the resin composite/dentin area showed that the formation of hybrid layer and resin tags showed direct relation with the bond system used

ASSUNTO(S)

odontopediatria microscopia eletronica de varredura materiais dentarios

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