Chlorhexidine does not improve but preserves bond strength to eroded dentin

Purpose: To evaluate the effect of aqueous solutions of chlorhexidine digluconate (CHX) in different concentrations on bond strength to eroded dentin up to 6 months, using normal dentin as a control. Methods: Exposed flat dentin of extracted third molars was only ground with 600-grit SiC paper/1 minute (normal dentin - N), or subsequently eroded by a regular-cola soft-drink (eroded dentin - E). N and E were acid-etched, washed, dried and rehydrated with 1.5 uL, respectively, of distillated water (control - NC / EC); of 0.004% CHX (NO.004% / EO.004%); or of 2% CHX (N2% / E2%). Adper Single Bond 2 was applied in all specimens and resin composite buildups were constructed with Filtek Z350. Specimens were sectioned in beams, which were tested (uTBS) immediately or after 6 months of aging. Results: Microtensile bond strength to eroded dentin was always significantly lower than that to normal dentin. Application of tested CHX solutions did not exert a significant effect immediately; however, after aging, the 2% CHX prevented abrupt bond strength loss both to eroded and normal dentin.