Influence of the organic matrix on root dentine erosion by citric acid

This investigation was conducted in an attempt to clarify the role of the organic matrix in bovine dentine demineralisation by 1% citric acid. Dentine slabs (n = 15) were treated for 2 min with 10% sodium hypochlorite (NaOCl, a strong protein solvent), 2% glutaraldehyde (GDA, a protein fixative) or deionised water (DIW, as negative control) prior to each of 5 demineralisation periods of 30 min. The mineral loss (DeltaZ), lesion depth (LD) and surface loss (SL) were determined after each period of demineralisation, by transverse microradiography. The NaOCl-treated group showed higher DeltaZ and LD than the GDA- and DIW-treated groups. No differences between GDA and DIW groups were found. The DeltaZ and LD profiles were explained by quadratic fits (r(2) >0.80; p = 0.001) in all groups. SL was detected only in the NaOCl-treated group. The data suggested that the maintenance of the organic matrix in the lesion might be important to reduce the erosion progression rate.