Polyaspartic acid enhances dentine remineralization bonded with a zinc-doped Portland-based resin cement.

ABSTRACT

AIM: To ascertain whether biomimetic phosphoprotein analogues (polyaspartic acid (PAS) and sodium trimetaphosphate (TMP)) improve bonding efficacy and dentine remineralization ability of a novel zinc-doped Portland-based resinous sealing cement. METHODOLOGY: Bonding procedures were performed on phosphoric acid-etched dentine, and several groups were established regarding biomimetic analogue application (1) no application, (2) PAS-treated dentine and (3) dentine treated with a mixture of PAS and TMP. Raman spectroscopy and microtensile bond strength (MTBS) with fracture analysis by scanning electron microscopy were carried out. MTBS values were compared by anova, Student-Newman-Keuls and Student's t-tests (P < 0.05 and P < 0.01, respectively). RESULTS: Twenty-four hour MTBS values were not affected by the different bonding procedures. After 6 months, MTBS decreased in those groups in which the phosphoproteins analogues were not applied (P < 0.05). When PAS was applied, MTBS was maintained after 6 months (P > 0.05). The novel material bonded without primer application induced bioactive crystal (calcium carbonate and Ettringite) precipitation onto the etched dentine and augmented the degree of crystallinity at the hybrid layer. Mineral-to-matrix ratio was increased at the hybrid layer of the PAS-treated specimens; this primer was also able to catalyse dentine remineralization, without an increase in crystallinity. CONCLUSIONS: PAS application onto demineralized dentine produced an inhibition or delay of mineral phase crystallization, enhancing the remineralization potential of the Portland microfillers at the resin-dentine bonded interface.