Immediate precision of the digital osteotomy template in the digital stackable template: a clinical study

Abstract

Objectives: This study aimed to evaluate the immediate accuracy of the digital osteotomy template in the digital stackable template.

Methods: From November 2018 to January 2020, 4 patients with dentition loss were selected from the Prosthodontics Department, West China Stomatological Hospital. All patients met the conditions for immediate planting and immediate restoration. Owing to the lack of vertical target-restoration space, the implantation plan included intraoperative osteotomy. According to the preoperative cone beam CT (CBCT) data, combined with aesthetic digital smile design (DSD) analysis, virtual wax design, and so on, the ideal bone plane design was performed. According to the virtual osteotomy plane, the virtual implantation plan was designed, and then the digital stackable template assuming osteotomy template, implantation guide, and temporary restoration were made and 3D printed. Osteotomy was performed under the guidance of digital osteotomy template during the operation. The preoperative CBCT and postoperative CBCT of all patients overlapped, the deviation between the actual osteotomy and the ideal osteotomy was calculated, and the angle deviation between the postoperative bone plane and the ideal bone plane was measured.

Results: The ave-rage volume deviation between the postoperative design and the ideal one was 492.94 mm³, accounting for 21.21% of the preset osteotomy volume. The average deviation between the postoperative osteotomy and the ideal osteotomy in four patients was 0.024 8 mm. The average angle between the postoperative bone plane and the ideal bone plane was 6.03°.

Conclusions: The displacement deviation of virtual osteotomy design and the actual osteotomy one under the guidance of digital osteotomy template in the digital stackable template are highly consistent with the original design. Thus, this clinical technique is worth popularizing, accurate, and quantifiable.

Keywords: digital stackable template; implant supported fixed dental prothesis; vertical target restoration space.

图 1. 数字化堆积导板的设计

Fig 1 Digital stackable templane design A、D：数字化堆积导板的截骨导板的虚拟设计和三维打印截骨导板；B、E：数字化堆积导板的种植导板的虚拟设计和三维打印种植导板；C、F：数字化堆积导板的临时修复体的虚拟设计和三维打印临时修复体。

图 2. 数字化截骨导板的设计

Fig 2 Preoperative alveolar bone reduction guide design A：CBCT重建下颌三维图像；B：Exo-cad设计的下颌虚拟蜡型与下颌三维CBCT拟合；C：设计种植体植入位点；D：根据种植体位点和B-VTRS设计截骨平面；E、F、G：根据确定的数字化截骨平面设计数字化截骨导板；H：三维打印的数字化截骨导板。

图 3. 数字化截骨导板的临床应用

Fig 3 Clinical usage of alveolar bone reduction guide A、D、G、J：数字化堆积导板的截骨导板口内试戴；B、E、H、K：数字化堆积导板的种植导板口内试戴；C、F、I、L：数字化堆积导板的临时修复体的口内粘接；A~F：数字化三维树脂打印导板；G~L：数字化三维金属打印导板。

图 4. 虚拟截骨与实际截骨拟合偏差测量图

Fig 4 The discrepancy measurement between virtual bone reduction and real bone reduction A：虚拟截骨与实际截骨拟合图像正面观；B：虚拟截骨与实际截骨拟合图像的侧面观；C：虚拟截骨与实际截骨的体积差；D：虚拟截骨与实际截骨的角度偏差测量。

图 5. 截骨位移偏差量的散点图、回归曲线及箱状图

Fig 5 Scatter plot, boxplot and regression line of the discrepancy deviation between virtual bone reduction and real bone reduction A：截骨位移偏差量的散点图及回归曲线；B：截骨位移偏差量的箱状图，其中RU位移偏差值均值及标准差为（0.503 3±0.774 6）mm，RL为（−0.073 3±0.433 0）mm，MU为（−0.539 4±0.593 7）mm，ML为（0.010 4±0.986 3）mm。

图 6. 预设截骨与实际截骨的体积偏差、位移偏差和角度偏差的平均值的柱状图

Fig 6 Histogram of the mean values of the volume, displacement, and angle deviations of virtual osteotomy from actual osteotomy RU：上颌三维树脂打印导板病例；RL：下颌三维树脂打印导板病例；MU：上颌三维金属打印导板病例；ML：下颌三维金属打印导板病例。左：体积偏差；中：位移偏差；右：角度偏差。