[Research progress on the biomimetic remineralization of hard tooth tissues based on polyamide-amine dendrimer].

Polyamide-amine (PAMAM) dendrimer, a new hyperbranched macromolecular polymer, is considered an "artificial protein" by many scholars on account of its excellent chemical and biological characteristics. PAMAM has internal cavities and a large number of reactive terminal groups. These structures allow the polymer to be used as a bionic macromoleculethat could simulate the biomimetic mineralization of the natural organic matrix on the surface of tooth tissue. Specifically, PAMAM can beused as an organic template to regulate mineral nucleation and crystal growth; thus, the polymerisa more ideal dental restoration material than traditional allogenic materials. This article reviews research progress on thePAMAM-induced biomimetic mineralization of hard tooth tissues.

[The Effect of PAMAM Dendrimer on the Dentin Remineralization and Matrix Metalloproteinases Activity].

OBJECTIVE: The purpose of this study was to investigate the effect of G4.5 carboxyl-terminated poly dendrimer (PAMAM-COOH) on the dentin remineralization and the matrix metalloproteinases (MMPs) activity. METHODS: The dentine samples were averagely divided into four groups: 100 mg/mL PAMAM-COOH group (A group), 10 mg/mL PAMAM-COOH group (B group), 2% (wt) chlorhexidine (CHX) group (C group) and deionized water group (Control group). MMP Activity Assay Kit was used to detect the activity of dentin endogenous MMPs in the four groups. The loss of dry mass of dentin after 30 d were measured. In situ zymography analysis was performed to detect the effects of PAMAM dendrimer in each group (except A group) on gelatinase activity in dentin. After incubation in artificial saliva for 7 and 14 d incubated, the remineralization of each group (except A group) in dentin surfaces were examined using a field emission-scanning electron microscope (FESEM). RESULTS: Compared with the control group, the dentin endogenous MMPs activity in A, B and C groups were all decreased ( P<0.05). The activity of endogenous MMPs in C group was lower than that of A and B groups ( P<0.001), but the difference between A and B groups was not statistically significant. The loss of dry mass in A, B and C groups were lower than that in control group ( P<0.05), but there were no significant difference in A, B and C groups. The in situzymography analysis showed that 48 h later, the dentin gelatinase activity in B group was inhibited compared with the control group, but the inhibitory effect was weaker than that of CHX. After 7 d and 14 d, there were no obvious mineralization in the control group, while distinct mineralization were observed in B group. The mineralization effect in group B was better than group C. CONCLUSION: G4.5 PAMAM-COOH could introduce remineralizationin and demineralizeddentin by effectively inhibiting endogenous MMPs and gelatinase, thus contributes as novel material to enhancing durability of adhesion.