Abstract：
OBJECTIVE: To investigate the influence of material and printing orientation on wear resistance and flexural properties of one low force SLA- and two DLP-printed splint materials and to compare these 3D-printed splints to a subtractively manufactured splint material.
METHODS: Two DLP-printed (V-Print splint, LuxaPrint Ortho Plus) and one low force SLA-printed (Dental LT Clear) material, where specimens were printed in three printing orientations (0°, 45°, 90°), were investigated. In addition, one milled splint material (Zirlux Splint Transparent) was examined. A total of 160 specimens were produced for both test series. The two-body wear test was performed in a chewing simulator (80\'000 cycles at 50 N with 5-55 °C thermocycling). Steatite balls were used as antagonists. The wear pattern was analyzed with a 3D digital microscope in terms of maximum vertical intrusion depth (mm) and total volume loss (mm³). The flexural properties were investigated by three-point bending in accordance with ISO 20795-1: 2013 (denture base polymers). The flexural strength (MPa) and the flexural modulus (MPa) were measured. Two-way ANOVA was performed to investigate the effects of the two independent variables material and printing orientation for the three 3D-printed materials. The comparison of the printing orientations within one material was carried out with one-way ANOVA with post-hoc Tukey tests.
RESULTS: Two-way ANOVA revealed that wear and flexural properties are highly dependent on the 3D-printed material (p < 0.001). Across groups, a significant effect was observed for wear depth (p = 0.031) and wear volume (p = 0.044) with regard to printing orientation but this was not found for flexural strength (p = 0.080) and flexural modulus (p = 0.136). One-way ANOVA showed that both DLP-printed groups showed no significant differences within the printing orientations in terms of wear and flexural properties. Dental LT Clear showed that 90° oriented specimens had higher flexural strength than 0° oriented ones (p < 0.001) and 45° oriented specimens also showed higher values than 0° ones (p = 0.038). No significant differences were observed within the printing orientations for flexural modulus and wear behaviour within this group. T-tests showed that the milled splints exhibited statistically higher wear resistance and flexural properties compared to all three 3D-printed splint materials (p < 0.001) and that highly significant differences were found between the 3D-printed splint materials for both test series.
CONCLUSIONS: Within the limitations of this in vitro study, it can be stated that wear behaviour and flexural properties are highly dependent on the 3D-printed material itself. Currently, milled splints exhibit higher wear resistance and flexural properties compared to 3D-printed splint materials. The printing orientation has a minor influence on the properties investigated. Nevertheless, two-way ANOVA also showed a significant influence of printing orientation in the wear test across groups and one-way ANOVA detected significant effects for SLA material in terms of flexural strength, with printing in 90° showing the highest flexural strength. Therefore, anisotropy was found in SLA material, but it can be limited with the employed printing parameters. Both DLP-printed materials showed no significant difference within the printing orientation.
METHODS: Two DLP-printed (V-Print splint, LuxaPrint Ortho Plus) and one low force SLA-printed (Dental LT Clear) material, where specimens were printed in three printing orientations (0°, 45°, 90°), were investigated. In addition, one milled splint material (Zirlux Splint Transparent) was examined. A total of 160 specimens were produced for both test series. The two-body wear test was performed in a chewing simulator (80\'000 cycles at 50 N with 5-55 °C thermocycling). Steatite balls were used as antagonists. The wear pattern was analyzed with a 3D digital microscope in terms of maximum vertical intrusion depth (mm) and total volume loss (mm³). The flexural properties were investigated by three-point bending in accordance with ISO 20795-1: 2013 (denture base polymers). The flexural strength (MPa) and the flexural modulus (MPa) were measured. Two-way ANOVA was performed to investigate the effects of the two independent variables material and printing orientation for the three 3D-printed materials. The comparison of the printing orientations within one material was carried out with one-way ANOVA with post-hoc Tukey tests.
RESULTS: Two-way ANOVA revealed that wear and flexural properties are highly dependent on the 3D-printed material (p < 0.001). Across groups, a significant effect was observed for wear depth (p = 0.031) and wear volume (p = 0.044) with regard to printing orientation but this was not found for flexural strength (p = 0.080) and flexural modulus (p = 0.136). One-way ANOVA showed that both DLP-printed groups showed no significant differences within the printing orientations in terms of wear and flexural properties. Dental LT Clear showed that 90° oriented specimens had higher flexural strength than 0° oriented ones (p < 0.001) and 45° oriented specimens also showed higher values than 0° ones (p = 0.038). No significant differences were observed within the printing orientations for flexural modulus and wear behaviour within this group. T-tests showed that the milled splints exhibited statistically higher wear resistance and flexural properties compared to all three 3D-printed splint materials (p < 0.001) and that highly significant differences were found between the 3D-printed splint materials for both test series.
CONCLUSIONS: Within the limitations of this in vitro study, it can be stated that wear behaviour and flexural properties are highly dependent on the 3D-printed material itself. Currently, milled splints exhibit higher wear resistance and flexural properties compared to 3D-printed splint materials. The printing orientation has a minor influence on the properties investigated. Nevertheless, two-way ANOVA also showed a significant influence of printing orientation in the wear test across groups and one-way ANOVA detected significant effects for SLA material in terms of flexural strength, with printing in 90° showing the highest flexural strength. Therefore, anisotropy was found in SLA material, but it can be limited with the employed printing parameters. Both DLP-printed materials showed no significant difference within the printing orientation.
摘要：
目的：研究材料和打印方向对一种低力SLA-和两种DLP打印的夹板材料的耐磨性和弯曲性能的影响，并将这些3D打印的夹板与减法制造的夹板材料进行比较。
方法：两个DLP打印（V-Print夹板，LuxaPrintOrthoPlus)和一种低力SLA打印(牙科LTClear)材料，其中样本以三种打印方向打印(0°，45°,90°),被调查了。此外,检查一种研磨的夹板材料（Zirlux透明夹板）。两个测试系列总共生产了160个样本。在咀嚼模拟器中进行两体磨损测试（在50N下进行80\'000次循环，并进行5-55°C的热循环）。滑石球被用作拮抗剂。使用3D数字显微镜根据最大垂直侵入深度（mm）和总体积损失（mm9.3）分析了磨损模式。根据ISO20795-1:2013(义齿基托聚合物)通过三点弯曲研究弯曲性能。测量弯曲强度(MPa)和弯曲模量(MPa)。进行双向方差分析以研究两种独立变量材料和打印取向对三种3D打印材料的影响。用单向ANOVA和事后Tukey测试进行一种材料内的印刷取向的比较。
结果：双向方差分析显示，磨损和弯曲性能高度依赖于3D打印材料（p<0.001）。跨群体,磨损深度（p=0.031）和磨损量（p=0.044）对印刷取向有显著影响，但对弯曲强度（p=0.080）和弯曲模量（p=0.136）没有发现。单因素方差分析显示，两个DLP打印组在磨损和弯曲性能方面在打印方向上没有显着差异。牙科LTClear表明，90°取向的试样比0°取向的试样具有更高的弯曲强度（p<0.001），45°取向的试样也比0°取向的试样具有更高的值（p=0.038）。在该组中，在弯曲模量和磨损行为的印刷取向中未观察到显着差异。T测试表明,与所有三种3D打印夹板材料相比,研磨夹板表现出统计学上更高的耐磨性和弯曲性能(p<0.001),并且对于两个测试系列,在3D打印夹板材料之间发现了非常显著的差异。
结论：在本体外研究的局限性内，可以说，磨损行为和弯曲性能高度依赖于3D打印材料本身。目前,与3D打印的夹板材料相比，铣削夹板具有更高的耐磨性和弯曲性能。印刷取向对所研究的性能具有较小的影响。然而，双向方差分析也显示了印刷取向的显著影响在磨损试验中各组和单向方差分析检测到SLA材料在弯曲强度方面的显著影响，90°印刷显示出最高的抗弯强度。因此,在SLA材料中发现了各向异性，但它可以限制与所采用的打印参数。两种DLP打印的材料在打印取向内没有显示出显著差异。
方法：两个DLP打印（V-Print夹板，LuxaPrintOrthoPlus)和一种低力SLA打印(牙科LTClear)材料，其中样本以三种打印方向打印(0°，45°,90°),被调查了。此外,检查一种研磨的夹板材料（Zirlux透明夹板）。两个测试系列总共生产了160个样本。在咀嚼模拟器中进行两体磨损测试（在50N下进行80\'000次循环，并进行5-55°C的热循环）。滑石球被用作拮抗剂。使用3D数字显微镜根据最大垂直侵入深度（mm）和总体积损失（mm9.3）分析了磨损模式。根据ISO20795-1:2013(义齿基托聚合物)通过三点弯曲研究弯曲性能。测量弯曲强度(MPa)和弯曲模量(MPa)。进行双向方差分析以研究两种独立变量材料和打印取向对三种3D打印材料的影响。用单向ANOVA和事后Tukey测试进行一种材料内的印刷取向的比较。
结果：双向方差分析显示，磨损和弯曲性能高度依赖于3D打印材料（p<0.001）。跨群体,磨损深度（p=0.031）和磨损量（p=0.044）对印刷取向有显著影响，但对弯曲强度（p=0.080）和弯曲模量（p=0.136）没有发现。单因素方差分析显示，两个DLP打印组在磨损和弯曲性能方面在打印方向上没有显着差异。牙科LTClear表明，90°取向的试样比0°取向的试样具有更高的弯曲强度（p<0.001），45°取向的试样也比0°取向的试样具有更高的值（p=0.038）。在该组中，在弯曲模量和磨损行为的印刷取向中未观察到显着差异。T测试表明,与所有三种3D打印夹板材料相比,研磨夹板表现出统计学上更高的耐磨性和弯曲性能(p<0.001),并且对于两个测试系列,在3D打印夹板材料之间发现了非常显著的差异。
结论：在本体外研究的局限性内，可以说，磨损行为和弯曲性能高度依赖于3D打印材料本身。目前,与3D打印的夹板材料相比，铣削夹板具有更高的耐磨性和弯曲性能。印刷取向对所研究的性能具有较小的影响。然而，双向方差分析也显示了印刷取向的显著影响在磨损试验中各组和单向方差分析检测到SLA材料在弯曲强度方面的显著影响，90°印刷显示出最高的抗弯强度。因此,在SLA材料中发现了各向异性，但它可以限制与所采用的打印参数。两种DLP打印的材料在打印取向内没有显示出显著差异。
