Phosphorylated pullulan coating enhances titanium implant osseointegration in a pig model

Purpose: To investigate the effect of coating a titanium implant surface with a phosphorylated exopolysaccharide, pullulan, on the peri-implant bone formation and implant osseointegration. Materials and Methods: Implants were placed in the skull bone of 12 domestic pigs and healed for 1 or 3 months. Osseointegration of (un)coated implants was evaluated by quantitative histology (peri-implant bone fraction [BF] and bone-to-implant-contact [BIC]). The Wilcoxon-Mann-Whitney test with α = .05 was used to statistically compare BF and BIC of the coated and uncoated implants. Results: Significantly more BF was observed surrounding pullulan-coated implants compared with uncoated implants (P < .05) and for both healing periods (P < .05). BIC was positively affected by the exopolysaccharide coating, with significantly more BIC after the 3-month healing period compared with the uncoated implant (P < .05). Furthermore, BIC remained stable over time for the coated implants, while it significantly decreased for the uncoated ones (P < .05). Conclusion: These findings reveal the capacity of functionalizing the titanium implant surface with phosphorylated pullulan to improve the mineralization of the implant-bone interface.