The effects of local and intraperitoneal zinc treatments on maxillofacial fracture healing in rabbits

Abstract

ObjectiveThis study aimed to determine whether administration of topical and intraperitoneal zinc for maxillofacial fractures has any impact on the bone healing process. Material and methodThirty-two New Zealand rabbits were randomly assigned to four groups of eight each. The first group was the control group; fracture lines were fixed using titanium microplates and no medication was administered. The second group received fixations using zinc-coated titanium microplates. A single dose of 3 mg/kg zinc was administered intraperitoneally to the third group following fixations with titanium microplates. A single dose of 3 mg/kg zinc was administered intraperitoneally to the fourth group following fixations with zinc-coated titanium microplates. Zinc coating on to the titanium microplates was achieved using the physical vapor deposition technique. A fracture line was created in the nasal bones of all subjects and fixed with five-hole flat microplates and three 5-mm micro screws. All work groups were sacrificed at the end of the sixth week. ResultsHistological examination showed that the number of osteoblasts were significantly higher in zinc-coated group (Group 2) than zinc uncoated, control group (Group 1), (415.6 ± 46.7 vs 366.3 ± 11.8) (p < 0.001). It was observed that intraperitoneal zinc treatment alone (Group 3) did not significantly increase in the osteoblast count compared to zinc un-coated group (Group 1), (390.6 ± 83.2 vs 366.3 ± 11.8), (p = 0.341). The immunoreactivity scores for IGF-1 were significantly higher in the zinc-coated group compared to control group (Group 2 vs 1), (9.3 ± 2.8 vs 3.7 ± 1.9) (p < 0.05). It was observed that intraperitoneal zinc treatment did not cause a significant difference in the aspect of IGF-1 for zinc-coated groups (Group 2 vs 4) (9.3 ± 2.8 vs 9.6 ± 2.2) (p = 0.791). The difference in the immunoreactivity score among whole groups for TGF-β was not statistically significant (Group 1 vs 2, 3.2 ± 1.7 vs 4.4 ± 2.3, p = 0.256; Group 1 vs 3, 3.2 ± 1.7 vs 3.8 ± 2.8, p = 0.524; Group 1 vs 4, 3.2 ± 1.7 vs 2.8 ± 1.3, p = 0.717; Group 2 vs 3, 4.4 ± 2.3, vs 3.8 ± 2.8, p = 0.610; Group 2 vs 4, 4.4 ± 2.3, vs 2.8 ± 1.3, p = 0.124; Group 3 vs 4, 3.8 ± 2.8, vs 2.8 ± 1.3, p = 0.311). ConclusionThe local use of titanium microplates coated with zinc by PVD technique was found effective for fracture healing. Zinc coating of titanium microplates used in fracture treatment can accelerate fracture healing. It may be concluded that clinical studies should be performed now in order to explore if comparable results can be achieved in humans.