Abstract: Objective A clinical retrospective study was proposed to compare the bone augmentation effect of GBR based on 3D printing individualized titanium mesh (3D-PITM) with onlay block autogenous bone grafting in the reconstruction of complex alveolar bone defects. Methods This study included 39 patients with alveolar bone defects who attended the Implant Department of the Affiliated Stomatological Hospital of Chongqing Medical University from May 2018 to January 2022. According to bone grafting methods, they were divided into 3D-PITM+GBR group (19 patients) and Onlay group (20 patients). Preoperatively, Cone-Beam Computed Tomography (CBCT) images of the patients were imported into Mimics Research and 3-Matic Software for 3D reconstruction and digital design. 3D-PITM was fabricated by CAD/ selective laser melting (SLM) technology. Intraoperatively, bone augmentation surgery was completed with fixed 3D-PITM or autologous bone block. CBCT imaging data were collected preoperatively, immediately postoperatively, 6~9 months postoperatively and after implant placement. Based on the digital radiographic data, the gained bone height on the implant axis and the gained bone width at 0 mm, 2 mm and 4 mm under the implant platform were measured. Results The 3D-PITM+GBR group had higher vertical bone increments [2.68 mm (0.45,4.23), 2.27 mm (0.49,3.27)] than onlay group [1.60 mm (0.33,1.62), 1.74 mm (0.53,1.60)] before/after bone grafting and before/after implant placement respectively. The 3D-PITM+GBR group had higher mean bone width increments at 0 mm, 2 mm, and 4 mm below the alveolar ridge before and after bone grafting [(1.97±0.97) mm, (2.59±1.22) mm, (2.94±1.50) mm)] than that of onlay group [(1.06±0.99) mm, (1.45±1.25) mm, (2.32± 1.23) mm]. In the 3D-PITM+GBR group, the mean bone width increments at 0 mm, 2 mm, and 4 mm below the implant platform before and after implantation [(2.34±1.09) mm, (2.53±1.48) mm, (2.85±2.20) mm)] were lower than those of onlay group [(2.51±1.34) mm, (3.04±1.73) mm, (3.38±1.94) mm]. The 3D-PITM+GBR group had higher osteogenesis rates in both horizontal and vertical directions (66.8%, 68.8%) than the Onlay group (64.6%, 62.6%).3D-PITM for reconstruction of complex alveolar bone defects was able to significantly increase the height and width of alveolar bone reconstruction compared with onlay block autogenous bone grafting, but the implant exposure rate (21%) was still higher than that of the onlay group (5%). Conclusion 3D-PITM+GBR technique can be used instead of block autogenous bone grafting for reconstruction of complex alveolar bone defects, obtaining ideal bone augmentation results and stable bone contours, but titanium mesh exposure is still a common complication in its application.

Key words: 3D printing individualized titanium mesh, Guided bone regeneration, Block bone grafting, Alveolar bone defects