Mandibular Defect Reconstitution: A Contaminated Caprine Model of Bone Regeneration.

Purpose: Mandibular reconstitution with bioabsorbable scaffolds seems feasible with the application of 3-dimensional printing combined with bioactive proteins. As yet, previous studies have been limited in number of animals and have avoided a contaminated defect. We present a caprine model of mandibular defect bone regeneration with a 3-dimensionally printed bioabsorbable scaffold contaminated with oral secretions and explore the impact of bone morphogenic protein in mandibular bone reconstitution.

Methods: A 3-cm, contaminated mandibular defect was generated in 18 goats and stabilized with 2 mandibular reconstruction plates. An uncoated scaffold was placed in 6 goats, and in the final 6 goats, the scaffold was coated with bone morphogenic protein-2. In 6 goats, the defect was left empty. After 12 weeks, the operative site, scaffold, and adjacent mandible were plasticized, sectioned, and evaluated histologically to assess for bone regeneration.

Results: The specimens revealed only focal (average of 5.8% of the scaffold pores) and early bone formation in the scaffold-only group. In the scaffold + bone morphogenic protein-2 group, there was more (average of 51.4% of the pores) bone formation. In the periosteum-only group, the ratio of the bone thickness of the defect to that of the normal bone ranged from 0.16 to 0.78. No major infections occurred.

Conclusions: This caprine model serves as an excellent method to assess reconstructive options for contaminated mandibular deficits. Bone regeneration was documented in a 3-cm contaminated caprine mandibular defect reconstructed with a 3-dimensionally printed synthetic scaffold with or without the addition of bone morphogenic protein-2. Bone morphogenic protein-2 significantly augments bone generation in the synthetic scaffold. Residual mandibular periosteum generated bone. Future studies will focus on optimizing vascularization.