Abstract：
OBJECTIVE: The present study evaluated the effects of the root portion design, segment (middle vs. apical), and part (die vs. cast) on the trueness of three-dimensional (3D)-printed removable die-cast complex.
METHODS: The trueness of apical and middle segments of the root portion of 45 3D-printed removable dies and casts with three different root portion designs (n = 15) was assessed using a metrology-grade computer program. The three removable dies and cast designs (root form [RF], conical [CON], and cylindric [CYL]) were created using professional computer-aided manufacturing computer programs (DentalCAD 3.1 Rijeka, and InLab CAD 22.0), and manufactured using stereolithographic 3D printer (Form3; FormLabs, Somerville, MA). Subsequently, the 3D-printed removable dies and casts were scanned by a single operator with an intraoral scanner (PrimeScan; Dentsply Sirona, Charlotte, NC), and their respective standard tessellation language files were aligned and compared to master reference files in a metrology-grade computer program (Geomagic Control X; 3D systems, Rock Hill, NC). The root mean square (RMS) values of the middle and apical segments for each removable die and cast were calculated and analyzed using a mixed model including a repeated measure 3-way analysis of variance (ANOVA) and post-hoc stepdown Bonferroni-corrected pairwise comparisons (α = 0.05).
RESULTS: A statistically significant 3-way interaction between factors was detected, suggesting that the part (removable die or alveolar cast) and their design affected the RMS values of their apical and middle root portion segment. (p = 0.045). The post-hoc analysis identified significant differences between RMS values of the apical segments of the CON and CYL removable dies (p = 0.005). Significant differences were observed between the middle and apical segments of the CON (p < 0.001) and RF removable die designs (p = 0.004). No statistically significant differences were noticed between the RMS of the different alveolar cast designs (p > 0.05). Significant differences were detected between the apical and middle segments of the same alveolar cast design (p < 0.05).
CONCLUSIONS: For the manufacturing trinomial and 3D printing strategy used in the present study, the interaction of the part, design, and segment affected the trueness of removable dies and alveolar casts. The trueness was higher on the middle segment on removable dies and alveolar casts in all designs used, except for CYL removable dies, where the trueness difference between segments was small. Higher trueness values may be achieved with designs with simple apical segment geometries.
METHODS: The trueness of apical and middle segments of the root portion of 45 3D-printed removable dies and casts with three different root portion designs (n = 15) was assessed using a metrology-grade computer program. The three removable dies and cast designs (root form [RF], conical [CON], and cylindric [CYL]) were created using professional computer-aided manufacturing computer programs (DentalCAD 3.1 Rijeka, and InLab CAD 22.0), and manufactured using stereolithographic 3D printer (Form3; FormLabs, Somerville, MA). Subsequently, the 3D-printed removable dies and casts were scanned by a single operator with an intraoral scanner (PrimeScan; Dentsply Sirona, Charlotte, NC), and their respective standard tessellation language files were aligned and compared to master reference files in a metrology-grade computer program (Geomagic Control X; 3D systems, Rock Hill, NC). The root mean square (RMS) values of the middle and apical segments for each removable die and cast were calculated and analyzed using a mixed model including a repeated measure 3-way analysis of variance (ANOVA) and post-hoc stepdown Bonferroni-corrected pairwise comparisons (α = 0.05).
RESULTS: A statistically significant 3-way interaction between factors was detected, suggesting that the part (removable die or alveolar cast) and their design affected the RMS values of their apical and middle root portion segment. (p = 0.045). The post-hoc analysis identified significant differences between RMS values of the apical segments of the CON and CYL removable dies (p = 0.005). Significant differences were observed between the middle and apical segments of the CON (p < 0.001) and RF removable die designs (p = 0.004). No statistically significant differences were noticed between the RMS of the different alveolar cast designs (p > 0.05). Significant differences were detected between the apical and middle segments of the same alveolar cast design (p < 0.05).
CONCLUSIONS: For the manufacturing trinomial and 3D printing strategy used in the present study, the interaction of the part, design, and segment affected the trueness of removable dies and alveolar casts. The trueness was higher on the middle segment on removable dies and alveolar casts in all designs used, except for CYL removable dies, where the trueness difference between segments was small. Higher trueness values may be achieved with designs with simple apical segment geometries.
摘要：
目的：本研究评估了根部设计的效果，段(中间段与顶端)，和部分(死亡与铸造)关于三维(3D)打印可移动压铸复合体的真实性。
方法：使用计量级计算机程序评估了具有三种不同根部设计（n=15）的45个3D打印可移除模具和铸件的根部顶端和中间段的真实性。三个可拆卸模具和铸造设计(根形[RF]，锥形[CON]，和圆柱[CYL])是使用专业计算机辅助制造计算机程序(DentalCAD3.1Rijeka，和InLabCAD22.0），并使用立体光刻3D打印机制造(Form3；FormLabs，萨默维尔,MA).随后，3D打印的可移动模具和铸件由单个操作员用口内扫描仪扫描(PrimeScan；DentsplySirona，夏洛特,NC),和他们各自的标准镶嵌语言文件对齐，并在计量级计算机程序(GeomagicControlX；3D系统，RockHill,NC）。使用混合模型计算和分析每个可移动模具和铸件的中段和顶端段的均方根（RMS）值，该模型包括重复测量的3向方差分析（ANOVA）和事后降压Bonferroni校正的成对比较（α=0.05）。
结果：检测到因素之间具有统计学意义的3向相互作用，表明该部分（可移动模具或肺泡铸型）及其设计影响了其根尖和中根部分节段的RMS值。（p=0.045）。事后分析确定了CON和CYL可移除模具的顶端段的RMS值之间的显著差异(p=0.005)。在CON(p<0.001)和RF可移除模具设计(p=0.004)的中间段和顶端段之间观察到显著差异。在不同的肺泡铸型设计的RMS之间没有发现统计学上的显着差异（p>0.05）。在相同的肺泡铸型设计的根尖和中段之间检测到显着差异（p<0.05）。
结论：对于本研究中使用的制造三项式和3D打印策略，零件的相互作用，设计,和节段影响可移动模具和肺泡铸型的真实性。在所有使用的设计中，可移动模具和肺泡铸型的中间段的真实性较高，除了CYL可拆卸模具，段之间的真实性差异很小。通过具有简单的顶端段几何形状的设计可以实现更高的真实性值。
方法：使用计量级计算机程序评估了具有三种不同根部设计（n=15）的45个3D打印可移除模具和铸件的根部顶端和中间段的真实性。三个可拆卸模具和铸造设计(根形[RF]，锥形[CON]，和圆柱[CYL])是使用专业计算机辅助制造计算机程序(DentalCAD3.1Rijeka，和InLabCAD22.0），并使用立体光刻3D打印机制造(Form3；FormLabs，萨默维尔,MA).随后，3D打印的可移动模具和铸件由单个操作员用口内扫描仪扫描(PrimeScan；DentsplySirona，夏洛特,NC),和他们各自的标准镶嵌语言文件对齐，并在计量级计算机程序(GeomagicControlX；3D系统，RockHill,NC）。使用混合模型计算和分析每个可移动模具和铸件的中段和顶端段的均方根（RMS）值，该模型包括重复测量的3向方差分析（ANOVA）和事后降压Bonferroni校正的成对比较（α=0.05）。
结果：检测到因素之间具有统计学意义的3向相互作用，表明该部分（可移动模具或肺泡铸型）及其设计影响了其根尖和中根部分节段的RMS值。（p=0.045）。事后分析确定了CON和CYL可移除模具的顶端段的RMS值之间的显著差异(p=0.005)。在CON(p<0.001)和RF可移除模具设计(p=0.004)的中间段和顶端段之间观察到显著差异。在不同的肺泡铸型设计的RMS之间没有发现统计学上的显着差异（p>0.05）。在相同的肺泡铸型设计的根尖和中段之间检测到显着差异（p<0.05）。
结论：对于本研究中使用的制造三项式和3D打印策略，零件的相互作用，设计,和节段影响可移动模具和肺泡铸型的真实性。在所有使用的设计中，可移动模具和肺泡铸型的中间段的真实性较高，除了CYL可拆卸模具，段之间的真实性差异很小。通过具有简单的顶端段几何形状的设计可以实现更高的真实性值。
