Statement of problem

The fit of a 3D printed surgical template will directly influence the accuracy of guided implant surgery. Various 3D printing technologies are currently available with different levels of resolution and printing accuracy; however, how the different systems affect accuracy is unclear.

Purpose

The purpose of this in vitro study was to assess the effect of using various 3D printers for the fabrication of implant surgical templates and its effect on the definitive implant position compared with the planned implant position.

Material and methods

A cone beam computed tomography scan from a partially edentulous patient and an extraoral digital scan of a dental cast obtained from the same patient were used. The digital imaging and communications in medicine and standard tessellation language (STL) files were imported to an implant planning software program and merged, and an implant was digitally positioned in the mandibular right first molar region. A surgical template was designed and exported as an STL file. Ten surgical templates were printed for each of the following groups: stereolithography (SLA) printing, PolyJet, and MultiJet. The region where the implant was planned was cut away from the cast onto which the surgical templates were seated, allowing a passive positioning of the implant through the template, which was held in place with polyvinyl siloxane material. A scan body was inserted in the implant, and the cast was scanned with a laboratory scanner. The STL files obtained from the definitive implant position were imported into an implant planning software program and registered with the planned implant position, allowing for a comparison between the planned and actual implant position. Mean deviations were measured for angle deviation, entry point offset, and apex offset. Data normality was tested by using the Shapiro-Wilk test. The Kruskal-Wallis test was used to determine whether the outcomes of angle deviation, apex offset, and entry offset were statistically different between groups (α=.05).

Results

The median and interquartile range for the angle deviation (degrees) were 1.30 (0.62) for SLA; 1.15 (1.23) for Polyjet; and 1.10 (0.65) for Multijet. No statistically significant differences were found in the angular deviation among groups (χ2(2)=3.08, P=.21). The median and interquartile range for the entry offset and apex offset (mm) were 0.19 (0.16) and 0.36 (0.16) for SLA, respectively; 0.20 (0.13) and 0.34 (0.26) for Polyjet, respectively; and 0.23 (0.10) and 0.32 (0.08) for Multijet, respectively. Similarly, nonsignificant differences were found for entry point offset (χ2(2)=0.13, P=.94) and apex offset (χ2(2)=1.08, P=.58).

Conclusions

The different types of 3D printing technology used in this study did not appear to have a significant effect on the accuracy of guided implant surgery.

中文翻译：

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使用各种 3D 打印机制造的 CAD-CAM 手术模板放置植入物的准确性比较：一项体外研究

问题陈述

3D 打印手术模板的贴合度将直接影响引导种植手术的准确性。目前可用的各种 3D 打印技术具有不同级别的分辨率和打印精度；然而，不同的系统如何影响准确性尚不清楚。

目的

这项体外研究的目的是评估使用各种 3D 打印机制造种植手术模板的效果，以及与计划的种植位置相比，其对最终种植位置的影响。

材料与方法

使用来自部分缺牙患者的锥形束计算机断层扫描和从同一患者获得的牙模型的口外数字扫描。医学中的数字成像和通信以及标准曲面细分语言 (STL) 文件被导入种植体规划软件程序并合并，并在下颌右第一磨牙区域数字化定位种植体。手术模板被设计并导出为 STL 文件。为以下各组打印了 10 个手术模板：立体光刻 (SLA) 打印、PolyJet 和 MultiJet。计划植入物的区域从手术模板所在的铸件上切掉，允许植入物通过模板被动定位，模板用聚乙烯硅氧烷材料固定到位。将扫描体插入植入物，并使用实验室扫描仪扫描模型。从确定的种植体位置获得的 STL 文件被导入种植体规划软件程序并与计划的种植体位置进行注册，从而可以比较计划的种植体位置和实际的种植体位置。测量角度偏差，入口点偏移和顶点偏移的平均偏差。使用 Shapiro-Wilk 检验测试数据正态性。Kruskal-Wallis 检验用于确定角度偏差、顶点偏移和入口偏移的结果在组间是否存在统计学差异 (α=.05)。从确定的种植体位置获得的 STL 文件被导入种植体规划软件程序并与计划的种植体位置进行注册，从而可以比较计划的种植体位置和实际的种植体位置。测量角度偏差，入口点偏移和顶点偏移的平均偏差。使用 Shapiro-Wilk 检验测试数据正态性。Kruskal-Wallis 检验用于确定角度偏差、顶点偏移和入口偏移的结果在组间是否存在统计学差异 (α=.05)。从确定的种植体位置获得的 STL 文件被导入种植体规划软件程序并与计划的种植体位置进行注册，从而可以比较计划的种植体位置和实际的种植体位置。测量角度偏差，入口点偏移和顶点偏移的平均偏差。使用 Shapiro-Wilk 检验测试数据正态性。Kruskal-Wallis 检验用于确定角度偏差、顶点偏移和入口偏移的结果在组间是否存在统计学差异 (α=.05)。

结果

SLA 的角度偏差（度）的中位数和四分位距为 1.30 (0.62)；1.15 (1.23) 对于 Polyjet；Multijet 为 1.10 (0.65)。组间角度偏差差异无统计学意义（χ2(2)=3.08，P =.21）。SLA 的入口偏移和顶点偏移 (mm) 的中位数和四分位间距分别为 0.19 (0.16) 和 0.36 (0.16)；Polyjet 分别为 0.20 (0.13) 和 0.34 (0.26)；Multijet 分别为 0.23 (0.10) 和 0.32 (0.08)。类似地，切入点偏移（χ2(2)=0.13，P =.94）和顶点偏移（χ2(2)=1.08，P =.58）的差异不显着。

结论

本研究中使用的不同类型的 3D 打印技术似乎对引导种植手术的准确性没有显着影响。