[Study on bonding strength of TF adhesive compounded with nanograde hydroxyapatite]

TF no-mix orthodontic adhesive was compounded in different weight proportion of nanograde hydroxyapatite as 10%, 20% and 30%, for use in this comparative study on composites. 80 orthodontic brackets were cemented and divided into 8 experimental groups, and TF adhesive was set as the control group. The tensile strength and shear strength were tested respectively. The results showed that the group of 10% nanograde hydroxyapatite obtained the greatest bonding strength (9.668 +/- 1.0649 MPa in tensile strength and 11.991 +/- 1.4135 MPa in shear strength), and there was significant difference between the 10% group and the other groups (P < 0.05, one-way ANAOV). It is concluded that the bonding strength can be enhanced when TF adhesive is compounded in suitable proportion of nanograde hydroxyapatitie.