Method: Two mirror-version titanium surgical guides (Marotta Dental) were fit to the adult New Zealand white rabbit maxillary alveolar ridges and outlined a 3mm x 5mm four-wall bony defect. Scaffolds were designed to fit this defect to a depth of 3mm (scaffold1) and 4mm (scaffold2) and were printed with 15:85 HAP/β-TCP ink. Both scaffold designs provided 2mm of ridge augmentation. Bilateral alveolar ridge defects were made in 6 rabbits. On all rabbits, the left defect was left open as a control and the right defect was repaired with scaffold1 (n=3) and scaffold2 (n=3). Rabbits were fed a normal diet, and after 4 weeks, bony repair was analyzed by MicroCT and hard tissue histology.
Result:Two scaffolds from each group were lost, but overlying soft tissue was healed. The single remaining scaffold1 showed no infection or soft tissue dehiscence but was disengaged from bone. The single remaining scaffold2 had a soft tissue dehiscence occlusally but was engaged with 1mm of bone and provided 0.5mm of ridge augmentation.
Conclusion: Two of six scaffolds were retained by soft tissue closure (scaffold1) and parallel wall resistance (scaffold2). Scaffold loss was due to inadequate retention coupled with overloading by masticatory forces. Although further surgical model development is warranted, the single sample of scaffold2 which was engaged in bone shows that 3D-printed tricalcium phosphate scaffolds can repair and augment bone under loaded settings.