Clinical evaluation of 3D printing bone block hydroxyapatite for large alveolar defect prior to implant placement: a clinical pilot study

In this clinical pilot study, custom 3D printed nanohydroxyapatite (3 DHA) graft was specially fabricated to fit a patient’s defects for primary bone augmentation before implant placement. This tailored design block graft was obtained from each patient’s cone beam computed tomography (CBCT) which was converted into stereolithography (STL) file format. Computer-aided design (CAD) software was used to design the graft by imitating natural bone structure with cortex and trabecular patterns. Overall, 3 DHA block graft was successful in 10 out of 1 2 patients. By incorporating concentrated growth factors (CGFs) and platelet-rich fibrin (PRF) membrane with 3 DHA can reduced graft failure from early membrane exposure at the grafted site. No adjustment of the graft was needed. All 3DHA adapted and fit well in all the defect sites. Maximum mean horizontal bone gains were 3.05 ± 0.72 and 3.45 ± 0.41 mm from DICOMs and STL data set respectively. The volume gain was 223.8 ± 80.46 mm3. Low pain score after surgery was reported as 1.41 ± 0.51, while the healing index score was increased with a maximum mean of HI = 4.7 ± 0.67. Thirteen implants were placed with good primary stability (ISQ = 65 ± 4.08) without additional GBR. Histomorphometric analysis revealed new bone formation, bone tissue, residual grafts and connective tissue were 28.6 ± 1.88, 30.48 ± 4.81, 19.82 ± 4.07, and 20.81 ± 4.41%.本临床预试验研究中，我们定制制备了3D打印纳米羟基磷灰石（3DHA）移植物，用于适配患者骨缺损，以在种植体植入前完成一期骨增量。该定制化块状移植物基于每位患者的锥形束计算机断层扫描（CBCT）数据生成，并转换为立体光刻（STL）文件格式。研究采用计算机辅助设计（CAD）软件，通过模拟天然骨的皮质骨与骨小梁结构设计该移植物。 总计12例患者中，10例的3DHA块状移植物植入成功。联合应用浓缩生长因子（CGFs）与富血小板纤维蛋白（PRF）膜包裹3DHA移植物，可降低移植物区域膜早期暴露引发的移植物失效风险，且无需对移植物进行额外调改。所有3DHA移植物均能良好适配各骨缺损位点。 基于医学数字成像与通信（DICOM）及STL数据集测得的最大平均水平骨增量分别为3.05±0.72 mm与3.45±0.41 mm，体积增量为223.8±80.46 mm³。术后患者疼痛评分较低，均值为1.41±0.51；同时愈合指数评分显著提升，最高平均愈合指数为HI=4.7±0.67。 本研究共植入13枚种植体，均获得良好的种植体稳定性系数（Implant Stability Quotient，ISQ=65±4.08），无需额外实施引导骨组织再生（Guided Bone Regeneration，GBR）术。组织形态计量学分析显示，新生骨形成、骨组织、残留移植物及结缔组织占比分别为28.6±1.88%、30.48±4.81%、19.82±4.07%及20.81±4.41%。