打印方向对 3D 打印正畸保持器尺寸精度的影响。

Effect of print orientation on the dimensional accuracy of orthodontic aligners printed 3-dimensionally.

机构信息

Department of Orthodontics, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, Tex.

出版信息

Am J Orthod Dentofacial Orthop. 2021 Nov;160(5):732-742.e1. doi: 10.1016/j.ajodo.2021.01.018.

DOI:10.1016/j.ajodo.2021.01.018

PMID:34752256

Abstract

INTRODUCTION

Fabrication of orthodontic aligners directly via 3-dimensional (3D) printing presents the potential to increase the efficiency of aligner production relative to traditional workflows; however tunable aspects of the 3D-printing process might affect the dimensional fidelity of the fabricated appliances. This study aimed to investigate the effect of print orientation on the dimensional accuracy of orthodontic aligners printed directly with a 3D printer.

METHODS

A digitally designed aligner of 500 μm thickness was printed in 3D in Grey V4 (Formlabs, Somerville, Mass) resin at 8 angulations at 45° intervals (n = 10 per angulation) using a stereolithography 3D printer. Each aligner was scanned with an optical scanner, and all but the intaglio surface of each scan was digitally removed. Each resultant scan file was superimposed onto the isolated intaglio of the designed master aligner file. The dimensional deviation was quantified with Geomagic Control software (3D Systems, Rock Hill, SC), and data were analyzed using R statistical software (version 2018; R Core Team, Vienna, Austria) (P <0.05).

RESULTS

Print angle showed a statistically significant effect on standard deviation, average positive deviation, absolute average negative deviation, and percentage of points out of bounds (tolerance bounds defined as ±250 μm) (P <0.05). Qualitative analysis of the 3D surface deviation maps indicated that the 0° and 90° groups showed less deviation and appeared to be the most accurate in the anterior regions. Overall, the majority of the print angle groups studied were not printed within clinically acceptable tolerance ranges, with the major exception being the 90° group, which printed nominally within clinically acceptable tolerance ranges.

CONCLUSIONS

With the workflow applied, print orientation significantly affects the dimensional accuracy of directly 3D-printed orthodontic aligners. Within the limitations of this study, printing at the 90° angulation would be advised as it is the group with the most accurate prints relative to the 7 other orientations investigated, although not all differences were statistically significant.

摘要

引言

通过 3 维（3D）打印直接制作正畸矫治器具有提高矫治器生产效率的潜力，与传统工作流程相比；然而，3D 打印过程中的可调方面可能会影响所制作的器具的尺寸精度。本研究旨在探讨打印方向对直接使用 3D 打印机打印的正畸矫治器尺寸精度的影响。

方法

在 Grey V4（Formlabs，马萨诸塞州萨默维尔）树脂中以 3D 方式打印厚度为 500 μm 的数字设计的矫治器，使用立体光刻 3D 打印机以 8 个倾斜角度以 45°间隔打印（每个角度 10 个）。每个矫治器均用光学扫描仪进行扫描，每个扫描的除凹面外的所有部分均被数字去除。每个结果扫描文件与设计主矫治器文件的孤立凹面叠加。使用 Geomagic Control 软件（3D Systems，南卡罗来纳州罗克希尔）量化尺寸偏差，使用 R 统计软件（版本 2018；R Core Team，奥地利维也纳）（P <0.05）分析数据。

结果

打印角度对标准偏差、平均正偏差、绝对平均负偏差和超出范围的点数百分比（公差范围定义为±250 μm）有统计学意义（P <0.05）。对 3D 表面偏差图的定性分析表明，0°和 90°组偏差较小，在前部区域似乎最准确。总体而言，研究的大多数打印角度组都未在临床可接受的公差范围内打印，主要例外是 90°组，名义上在临床可接受的公差范围内打印。