3D printing titanium grid scaffold facilitates osteogenesis in mandibular segmental defects.

"Competing interests The authors declare no competing interests."

"This work was funded by the National Key Research and Development Program of China (Grant Number: 2017YFB1104103), the Beijing Science and Technology Project (Grant No. D131100003013001), and the Key R&D Program of Shaanxi Province (Grant No. 2020SF-023). We also thank Yan Gao and Nuo Cheng for their assistance with the sample evaluation. We acknowledge Shanghai Reborn Sci. & Tech. Co. Ltd., Beijing Zhong An Tai Hua Technology Co., Ltd. Shen Zhen Excellent Technology Co., Ltd., for supporting scaffold manufacturing during the study."

"Animal experiment procedures were conducted according to the guidelines of the Ethical Review of Laboratory Animal Welfare (GB/T358922018) and approved and supervised by the Institutional Animal Care and Use Committee of the Chinese PLA General Hospital (Beijing, China. approval no. 2017-D13–15). The clinical trial was approved and supervised by the Medical Ethics Committee of the Chinese PLA General Hospital on March 28th, 2019 (Beijing, China. approval No. S2019–065–01), and registrated in the clinical trials registry platform (registration number: ChiCTR2300072209). Written informed consent was obtained from all patients or their guardians, and the authors affirmed that human research participants provided informed consent for publication of the images in Figs. and , as well as Supplementary Figs. , , , and .Fig. 5The procedures of scaffold implantation in case 1.Surgical incision design. a Exposure to neoplasm. b Neoplasm excision. c Scaffold implantation and fixation. d, e Autogenous bone fragment filled into the pore of the scaffold. f Suture.Fig. 6The procedures of scaffold implantation in case 3.a Exposure of fractured Ti plate. b Autogenous bone fragment preparation by the bone mill. c, d Scaffold implantation and fixation. e, f Autogenous bone fragments filled into the pore of the scaffold. Bone fusion of defect broken ends is the basis of the functional reconstruction of critical maxillofacial segmental bone defects. However, the currently available treatments do not easily achieve this goal. Therefore, this study aimed to fabricate 3D-printing titanium grid scaffolds, which possess sufficient pores and basic biomechanical strength to facilitate osteogenesis in order to accomplish bone fusion in mandibular segmental bone defects. The clinical trial was approved and supervised by the Medical Ethics Committee of the Chinese PLA General Hospital on March 28th, 2019 (Beijing, China. approval No. S2019–065–01), and registered in the clinical trials registry platform (registration number: ChiCTR2300072209). Titanium grid scaffolds were manufactured using selective laser melting and implanted in 20 beagle dogs with mandibular segmental defects. Half of the animals were treated with autologous bone chips and bone substances incorporated into the scaffolds; no additional filling was used for the rest of the animals. After 18 months of observation, radiological scanning and histological analysis in canine models revealed that the pores of regenerated bone were filled with titanium grid scaffolds and bone broken ends were integrated. Furthermore, three patients were treated with similar titanium grid scaffold implants in mandibular segmental defects; no mechanical complications were observed, and similar bone regeneration was observed in the reconstructed patients’ mandibles in the clinic. These results demonstrated that 3D-printing titanium grid scaffolds with sufficient pores and basic biomechanical strength could facilitate bone regeneration in large-segment mandibular bone defects."