Giuseppe Lizio^1,*; Gerardo Pellegrino²; Agnese Ferri¹; Pietro Felice¹

¹Biomedical & Neuromotor Sciences; ²Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy

Background: Extended alveolar defects are challenging for the irregularity of their shape and the lack of supporting bone. A virtually planned GBR with customized scaffold-meshes to shape and contain particulate autologous bone can optimize and standardize the treatment. The rationale is to plan the minimal entity of bone reconstruction needed according to the prosthetic evaluation, not to stress the impaired soft tissues, reducing the risk of exposure that heavily affects GBR procedures.

Aim/Hypothesis: To verify if virtual planning with a customized scaffold could improve the predictability of a complex bone reconstruction evaluating the device exposure and the superimposition of the obtained results to what was digitally planned regarding mesh fitting, bone volumes, and complications.

Material and Methods: 19 complex defects were digitally reconstructed according to the prosthetically guided project. A scaffold mesh was designed and printed to fit each defect during surgery with autologous and bovine bone as a particulate graft based on the calculated bone reconstruction. After six months at least, a new CBCT was taken for the phase of implant placement. The pre-and postoperative CT datasets were converted into 3D models and digitally aligned for the overlap of the treated regions. Afterward, the planned bone volumes (PBV), calculated under the mesh, were compared with the lacking bone volumes (LBV) to calculate the real reconstructed ones (RBV). These data were inferentially correlated with the numbers of exposures, the timing of their appearance, the presence of infection and the precocious removal of the mesh, the entity of VPBV (virtually planned bone volume). Other considered variables were the location of the atrophies and the entity of the planned volumes

Results: No significant difference resulted between the VPBVs and postoperative volumes under the mesh (p = 0.217), with a mean 82 ± 13.4% of mesh fitting. 52.3% exposures (40 % early and 60% late) of the mesh for soft tissue dehiscence were observed with 15.8% infection and 26.3% complete failures. The amount of reconstructed bone volume (RBV) regarding PBV was 65 ± 40.5% and 88.2 ± 8.32 % with and without considering the failures, respectively. The exposure event only resulted statistically significant (p = 0.006) in conditioning the bone volume regenerated, independently from the timing of happening, the association with infection, and the mesh removal; no relevance of other variables resulted.

Conclusion and Clinical implications: The virtual planning of GBR in extended 3d defects and its reproduction in reality with customized meshes reached a prediction level of 88 % in about 74 % of the cases. Early exposures and infection ultimately compromised the outcomes in 5 sites out of 19 ones. The relevance of anatomic features, surgical management, and digital flowchart should be clarified in further investigations.

Disclosure of Interest: None Declared

Keywords: CAD/CAM, digital workflow, guided bone regeneration

朱塞佩·利齐奥^1,* ; 杰拉尔多·佩莱格里诺² ; 艾格尼丝·费里¹ ; 彼得罗费利斯¹

¹生物医学和神经运动科学；²生物医学和神经运动科学，博洛尼亚大学，意大利博洛尼亚

背景：扩展的牙槽骨缺损因其形状不规则和缺乏支撑骨而具有挑战性。具有定制支架网的虚拟计划 GBR 可以塑造和包含微粒自体骨，可以优化和标准化治疗。其基本原理是根据假肢评估计划所需的最小骨重建实体，而不是对受损的软组织施加压力，从而降低严重影响 GBR 程序的暴露风险。

目的/假设：验证使用定制支架的虚拟规划是否可以提高复杂骨骼重建的可预测性，评估设备暴露并将获得的结果叠加到有关网格拟合、骨骼体积和并发症的数字规划中。

材料与方法：根据修复引导项目，对 19 个复杂缺陷进行了数字化重建。基于计算出的骨重建，设计和打印支架网以适应手术过程中的每个缺陷，自体骨和牛骨作为颗粒移植物。至少六个月后，在种植体植入阶段进行了新的 CBCT。术前和术后 CT 数据集被转换为 3D 模型，并针对治疗区域的重叠进行数字对齐。然后，将在网格下计算的计划骨体积 (PBV) 与缺失骨体积 (LBV) 进行比较，以计算出真正的重建骨体积 (RBV)。这些数据与暴露的次数、出现的时间、感染的存在和网状物的早熟去除有推论相关，VPBV（虚拟计划骨量）的实体。其他考虑的变量是萎缩的位置和计划体积的实体

结果： VPBV 和术后网格下体积之间没有显着差异（p = 0.217），网格拟合的平均值为 82±13.4%。观察到 52.3% 的软组织裂孔暴露（40% 早期和 60% 晚期），15.8% 的感染和 26.3% 的完全失败。PBV 的重建骨体积 (RBV) 量分别为 65 ± 40.5% 和 88.2 ± 8.32%，包括和不考虑失败。暴露事件仅在调节骨量再生方面具有统计学意义（p = 0.006），与发生的时间、与感染的关联和网片去除无关；结果没有其他变量的相关性。

结论和临床意义：扩展 3d 缺陷中的 GBR 虚拟规划及其使用定制网格在现实中的再现在大约 74% 的案例中达到了 88% 的预测水平。早期暴露和感染最终影响了 19 个站点中 5 个站点的结果。解剖特征、手术处理和数字流程图的相关性应在进一步研究中阐明。

利益披露：无申报

关键词：CAD/CAM，数字化工作流程，引导骨再生