Chlorhexidine´s interference on the dentin adhesion of glass ionomer cements

Objectives: The aim of this in vitro study was to evaluate the interference of the chorhexidine gel 2% on tensile and shear resistence of two glass ionomer cements (Ketac Molar – 3M/ESPE e Fuji IX – GC Corporation) to the dentin of primary molars. Methods: From 40 primary molars was obtained 80 specimens and divided in 8 groups. In the experimental groups the dentin was treated (cleaned) with chlorhexidine gel 2% during 20 seconds. After the tests all specimens were observed at an estereomicroscope and those with higher and lower values of adesive resitence were selected for analyse in the scanning eletron microscope. Results: Variance analyses determined differences estatistically significants between the cements , the Fuji IX presented higher adhesive resistence than did the Ketac Molar and the interaction test – group where the chlorexidine interfered increasing the shear resistence in both cements and decreasing the tensile resistence of the Ketac Molar. At the stereomicroscope 95% of the fractures were cohesives and at the MEV the cement presented a rugous aspect. The microanalyses with EDS determined presence of glass ionomer cement into the dentin tubuls. Conclusions: (1) chlorexidine interfered positivilly in the shear resistence in both cements and negativallly in the tensile resistence only for the Ketac Molar (2) it is possible that had an micro-mechanical adhesion of the glass ionomer cements tested to the detin of primary molars.