Abstract: PURPOSE: Micro-arc oxidation (MAO) of titanium alloy was implemented, then GRGDSP polypeptide was loaded by coupling of dopamine (PDA) to form a composite active coating，in order to enhance esteointegration. METHODS: Eighteen adult New Zealand white rabbits were selected to establish a unilateral mandibular model. Ti-MAO (group A), Ti-MAO-PDA (group B) and Ti-MAO-PDA-GRGDSP (group C) were implanted into the mandible of rabbits. The mandibular bone on one side was selected at 2, 4, 8 weeks to harvest sample. Bone allografts were observed on cone-beam CT (CBCT). The interface of sample at 4w was observed under scanning electron microscopy (SEM), laser scanning confocal microscope was used to observe the degree of osteoblast activity, torsion test was applied to observe osseointegration. The date were compared between groups with one-way ANOVA using SPSS19.0 software package. RESULTS: For osseointegration at contact region, group C was better than group A and group B, and group B was better than group A on CBCT. SEM showed that group C had more new bone aggregated in the contact area between implant and bone. Laser confocal microscopy showed that the fluorescence intensity of group C was significantly higher than that of group B at the junction. The torsional force of group B and C at 8w was 2 times of that of group A, and group C was 8 N·cm greater than group B. The difference was statistically significant between group C and group B, comparing to group A(P<0.05). CONCLUSIONS: Ti-MAO-PDA and Ti-MAO-PDA-GRGDSP coatings can promote osseointegration, of which Ti-MAO-PDA-GRGDSP coating has the strongest osseointegration effect.

Key words: Titanium implant, Micro-arc oxidation, Dopamine, GRGDSP polypeptide, Osseointegration