Effect of 3D printing technology and print orientation on the trueness of additively manufactured definitive casts with different tooth preparations.

OBJECTIVES: To evaluate the fabrication trueness of additively manufactured maxillary definitive casts with various tooth preparations fabricated with different 3-dimensional (3D) printers and print orientations. METHODS: A maxillary typodont with tooth preparations for a posterior 3-unit fixed partial denture, lateral incisor crown, central incisor and canine veneers, first premolar and second molar inlays, and a first molar crown was digitized with an industrial scanner. This scan file was used to fabricate definitive casts with a digital light processing (DLP) or stereolithography (SLA) 3D printer in different orientations (0-degree, 30-degree, 45-degree, and 90-degree) (n = 7). All casts were digitized with the same scanner, and the deviations within each preparation site were evaluated. Generalized linear model analysis was used for statistical analysis (α = 0.05). RESULTS: The interaction between the 3D printer and the print orientation affected measured deviations within all preparations (P ≤ 0.001) except for the lateral incisor crown and canine veneer (P ≥ 0.094), which were affected only by the main factors (P < 0.001). DLP-90 mostly led to the highest and DLP-0 mostly resulted in the lowest deviations within posterior tooth preparations (P ≤ 0.014). DLP-30 led to the lowest deviations within the first premolar inlay and DLP-45 led to the lowest deviations within the central incisor veneer preparation (P ≤ 0.045). CONCLUSIONS: Posterior preparations of tested casts had the highest trueness with DLP-0 or DLP-30, while central incisor veneer preparations had the highest trueness with DLP-45. DLP-90 led to the lowest trueness for most of the tooth preparations. CLINICAL SIGNIFICANCE: Definitive casts with tooth preparations fabricated with the tested DLP 3D printer and the print orientation adjusted on tooth preparation may enable well-fitting restorations. However, 90-degree print orientation should be avoided with this 3D printer, as it led to the lowest fabrication trueness.

Effect of build orientation on the fracture resistance and marginal quality of 3D-printed anatomic provisional crowns: An in-vitro study.

Introduction: Computer-aided design and computer-aided manufacturing (CAD/CAM) technologies have been increasingly used to fabricate provisional restorations in recent years. This study assessed how build orientation influences the fracture resistance and marginal quality of 3D-printed crowns compared with milled provisional crowns. Methods: The test group included 3D-printed crowns (Freeprint temp Shade A2, Detax, Ettlingen, Germany), which were further subdivided based on print orientation (0°, 45°, and 90°; n = 10 for each subgroup). The control group (n = 10) included milled crowns (Coratemp, White Peaks, Germany) with the same design as those of the test group. The margin quality of each crown was assessed at 60 × magnification using a digital stereomicroscope. A load-to-fracture test was performed by applying a force at a rate of 2 mm/min to assess fracture resistance. One sample from each subgroup was also subjected to scanning electron microscope (SEM) analysis. Results: The milled group exhibited the highest fracture resistance and marginal quality. Within the printed subgroups, the 0° group showed the best mean marginal quality, whereas the 90° group showed the lowest mean marginal quality (p < 0.05). Within the test groups, the 90° group had the highest mean fracture resistance (p < 0.05). In the SEM analysis, the milled group exhibited the most homogenous boundaries, whereas among the 3D-printed subgroups, the samples printed at 0° had the best margin quality. Conclusion: The manufacturing method significantly influences the marginal quality and fracture resistance. Milled crowns demonstrated superior marginal quality and fracture resistance compared to those of 3D printed crowns. Furthermore, the print orientation of 0° led to the best marginal quality, whereas printing at 90° led to the highest fracture resistance.

Surface Roughness of Interior Fine Flow Channels in Selective Laser Melted Ti-6Al-4V Alloy Components.

A challenge remains in achieving adequate surface roughness of SLM fabricated interior channels, which is crucial for fuel delivery in the space industry. This study investigated the surface roughness of interior fine flow channels (1 mm diameter) embedded in SLM fabricated TC4 alloy space components. A machine learning approach identified layer thickness as a significant factor affecting interior channel surface roughness, with an importance score of 1.184, followed by scan speed and laser power with scores of 0.758 and 0.512, respectively. The roughness resulted from thin layer thickness of 20 µm, predominantly formed through powder adherence, while from thicker layer of 50 µm, the roughness was mainly due to the stair step effect. Slow scan speeds increased melt pools solidification time at roof overhangs, causing molten metal to sag under gravity. Higher laser power increased melt pools temperature and led to dross formation at roof overhangs. Smaller hatch spaces increased roughness due to overlapping of melt tracks, while larger hatch spaces reduced surface roughness but led to decreased part density. The surface roughness was recorded at 34 µm for roof areas and 26.15 µm for floor areas. These findings contribute to potential adoption of TC4 alloy components in the space industry.

Build angle effect on 3D-printed dental crowns marginal fit using digital light-processing and stereo-lithography technology: an in vitro study.

BACKGROUND: The effect of 3D printing technology and build angle on the marginal fit of printed crowns is unclear. The objective of this research was to use digital light processing (DLP) and stereo-lithography (SLA)-based 3D printing to construct single restorations with varied build angles and to analyze the crowns' marginal fit. METHODS: A prepared resin first molar was scanned utilizing an optical scanner. Three build orientations were used to construct the specimens: 0, 45, and 90º. DLP and SLA technology were used to produce the casting patterns. A digital microscope was used to measure the marginal gaps. The effect of build orientation was statistically analyzed by using Two-way ANOVA followed by pair-wise Tukey test. RESULTS: Two-way ANOVA revealed a significant effect of printer technology and build angle on the marginal discrepancy of 3D printed crowns (p < 0.001). One-way ANOVA revealed that SLA printers (55.6 [± 13.59]) showed significantly better mean [± SD] marginal discrepancy in µm than DLP printers (72 [± 13.67]) (p < 0.001). Regarding build angle, one-way ANOVA revealed significant differences between the different angles. Tukeys post-hoc test revealed that 0° (48.5 [± 9.04]) had the significantly smallest marginal discrepancy followed by 45° (62.5 [± 8.05]) then 90° (80.5 [± 8.99]) (p < 0.001). CONCLUSION: The build orientation affects the marginal discrepancy of single crowns manufactured utilizing DLP and SLA.

Concurrent shape and build orientation optimization for FDM additive manufacturing using the principal stress lines (PSL).

Additive Manufacturing (AM) with the consisting constantly evolving technologies is a particularly popular research area. Based on the shape forming freedom, size, shape, and topology optimization techniques can be validated by AM produced parts. However, in every manufacturing process, AM also has some adverse inherent properties. One and maybe the most significant optimization problem is the mechanical anisotropy caused by the layered structure. In this paper, a simultaneous build orientation and shape optimization method is presented. Both of the approaches are intended to increase the mechanical performance of the produced parts. Shape optimization was accomplished by varying the cross-section of the beam geometries, based on the angle between a PSL section and the characteristic load direction. To test the efficiency and validate the method 2D structures (with relatively small 3rd dimension) and their tensile properties were tested. Based on the results, we can prove that the PSL method works and help to increase the mechanical performance by 19.2% with only 7.8% size increment.

Effects of build orientation and bar addition on accuracy of complete denture base fabricated with digital light projection: An in vitro study.

PURPOSE: We evaluated the effects of build orientation and bar addition between lingual flanges on the accuracy of mandibular denture bases fabricated using a digital light processing (DLP) device. METHODS: Mandibular denture bases with and without a bar at the lingual flanges were virtually designed and assigned to eight build orientations. Six dentures per condition were fabricated using a DLP device with a methacrylate-based photopolymerizable monomer (Dima Print denture base) (n=96). The fabricated denture surfaces were digitized, and intaglio surfaces were obtained. These digitized surfaces were compared via superimposition using graphical software (Artec studio12 profession) to their original designed files, and root mean square estimates were obtained. The trueness of the entire and intaglio data was statistically analyzed non-parametrically. RESULTS: The range of trueness of the entire and intaglio denture bases was 0.15-0.31 mm and 0.11-0.38 mm, respectively. The trueness at 135° and 270° for the entire denture base and that at 270° for the intaglio data without the bar were significantly lower than those for the other build orientations. The trueness at 270° was <0.15 mm irrespective of the conditions. The trueness with the bar of all build orientations, except that of 0° for intaglio data, was significantly smaller than or equal to the trueness without the bar of the corresponding build orientations. CONCLUSIONS: Build orientation and bar addition influenced the accuracy of the complete dentures fabricated using DLP. A build orientation of 270° is recommended for fabricating a mandibular complete denture, irrespective of the bar addition.

Tribological Properties of Glass Bead-Filled Polyamide 12 Composite Manufactured by Selective Laser Sintering.

To enhance the properties of polyamide 12 (PA12/Nylon 12) manufactured by the selective laser sintering (SLS) process, micron-sized glass beads are used as a filler, and the resulting composite is known as glass bead-filled PA12 (PA 3200 GF). Despite PA 3200 GF basically being a tribological-grade powder, very little has been reported on the tribological properties of laser-sintered objects based on this powder. As the properties of SLS objects are orientation-dependent, this study is devoted to investigating the friction and wear characteristics of the PA 3200 GF composite sliding against the steel disc in the dry-sliding mode. The test specimens were aligned in the SLS build chamber along five different orientations (X-axis, Y-axis, Z-axis, XY-plane, and YZ-plane). Additionally, the interface temperature and the friction-induced noise were measured. The pin-shaped specimens were examined using a pin-on-disc tribo-tester for 45 min to investigate the steady-state tribological characteristics of the composite material. The results revealed that the orientation of build layers relative to the sliding plane was a ruling parameter that determined the dominant wear pattern and the wear rate. Accordingly, where build layers were parallel or inclined to the sliding plane, abrasive wear predominated, and wear rate became 48% higher than that of specimens with perpendicular build layers, for which adhesive wear predominated. Interestingly, a noticeable synchronous variation of adhesion and friction-induced noise was observed. Taken together, the results from this study can efficiently serve the goals of fabricating SLS-functional parts with customized tribological properties.

Effect of Printing Orientation and Postcuring Time on the Flexural Strength of 3D-Printed Resins.

PURPOSE: To evaluate the effect of printing orientation combined with different postcuring times on the flexural strength of 3D-printed resins. MATERIALS AND METHODS: A total of 480 rectangular specimens with the dimensions of 64×10×3.3 mm were designed and fabricated from two 3D-printed acrylic resins and one heat-polymerized resin (HP). 3D-printed groups were divided into 3 groups according to printing orientations (0-, 45-, 90-degree); each group was subdivided into 4 groups according to postcuring time (30, 60, 90, 120 min.). All specimens were subjected to thermal cycling (10,000 cycles) before testing flexural strength. Fractured surfaces were examined under a scanning electron microscope (SEM). ANOVA and Tukey's post hoc tests were used for data analysis (α = 0.05). RESULTS: The result of this study showed that the highest flexural strength values of 3D-printed resin (NextDent, and ASIGA) were in 0-degree groups. Also, the flexural strength values increased when postcuring time was increased, regardless of the printing orientation; the highest flexural strength was recorded at 120 minutes postcuring time in all orientations. SEM analysis showed a rougher surface with irregular lamellae which represented a ductile fracture confirming that high energy is required for crack propagation and these features markedly increased as postcuring time increased. CONCLUSION: The results showed that the 0-degree orientation groups showed higher flexural strength compared to other groups. Similarly, with increased postcuring time, the flexural strength increased.

A Multi-Part Orientation Planning Schema for Fabrication of Non-Related Components Using Additive Manufacturing.

Additive manufacturing (AM) is a technique that progressively deposits material in layer-by-layer manner (or in additive fashion) for producing a three-dimensional (3D) object, starting from the computer-aided design (CAD) model. This approach allows for the printing of complicated shaped objects and is quickly gaining traction in the aerospace, medical implant, jewelry, footwear, automotive, and fashion industries. AM, which was formerly used for single part customization, is currently being considered for mass customization of parts because of its positive impacts. However, part quality and build time are two main impediments to the deployment of AM for mass production. The optimal part orientation is fundamental for maximizing the part's quality as well as being critical for reducing the fabrication time. This research provides a new method for multi-part AM production that improves quality while reducing overall build time. The automatic setup planning or orientation approach described in this paper employs two objective functions: the quality of the build component and the build time. To tackle the given problem, it introduces a three-step genetic algorithm (GA)-based solution. A feature-based technique is utilized to generate a collection of finite alternative orientations for each component within a specific part group to ensure each part's individual build quality. Then, a GA was utilized to find the best combination of part build orientations at a global optimal level to reduce material consumption and build time. A case study of orienting nine components concurrently inside a given building chamber was provided for illustration. The findings suggest that the developed technique can increase quality, reduce support waste, and shorten overall production time. When components are positioned optimally rather than in random orientations, build time and support volume are reduced by approximately 7% and 16%, respectively.

Comparative Evaluation of Surface Roughness and Hardness of 3D Printed Resins.

The effect of printing parameters on the surface characteristics of three-dimensional (3D)-printed denture base resins (DBRs) is neglected. Therefore, this study investigated the effect of printing orientation and post-curing time on the surface roughness and hardness. One conventional heat-polymerized (HP) resin and two 3D-printing resins (NextDent (ND) and ASIGA (AS)) were used to fabricate a total of 250-disc (10 × 2.5 mm) specimens. ND and AS specimens were printed with different orientations (0-, 45-, and 90-degree) and each orientation group was subjected to four post-curing times (30, 60, 90, 120 min). Printed specimens were thermo-cycled (10,000 cycles) followed by the measuring of surface roughness (Profilometer (Ra)) and hardness (a Vickers hardness (VH)). ANOVA and post hoc tests were used for data analysis (α = 0.05) at significant levels. AS and ND showed no significant changes in Ra when compared with HP (p ˃ 0.05), except the 45-degree orientation (AS/90 min and AS/120 min) significantly increased surface roughness (p ˂ 0.001). There was no significant difference in Ra with different orientations and post-curing time for both materials AS and ND (p ˃ 0.05). Compared with HP, 3D-printed DBRs showed low VH values (p ˂ 0.001). For AS, 90-degree orientation showed a significant decrease in VH at 60, 90, and 120 min when compared with 0- and 45-degree orientation (p ˂ 0.001), while ND showed no significant difference in VH with different printing orientations (p ˃ 0.05). The VH of AS and ND improved when increasing post-curing time to 120 min (p ˂ 0.001), and the printing orientations and post-curing time did not affect the Ra of 3D-printed DBRs.

Investigation of the marginal fit of a 3D-printed three-unit resin prosthesis with different build orientations and layer thicknesses.

PURPOSE: The purpose of this study was to analyze the marginal fit of three-unit resin prostheses printed with the stereolithography (SLA) method in two build orientations (45°, 60°) and two layer thicknesses (50 µm, 100 µm). MATERIALS AND METHODS: A master model for a three-unit resin prosthesis was designed with two implant abutments. Forty specimens were printed using an SLA 3D printer. The specimens were printed with two build orientations (45°, 60°), and each orientation was printed with two layer thicknesses (50 µm, 100 µm). The marginal fit was measured as the marginal gap (MG) and absolute marginal discrepancy (AMD), and MG and AMD measurements were performed at 8 points per abutment, for 16 points per specimen. All statistical analyses were performed using SPSS software. Two-way analysis of variance (ANOVA) was separately performed on the MG and AMD values of the build orientations and layer thicknesses. Moreover, one-way ANOVA was performed for each point within each group. RESULTS: The margins of the area adjacent to the pontic showed significantly high values, and the values were smaller when the build orientation was 45° than when it was 60°. However, the margin did not differ significantly according to the layer thicknesses. CONCLUSION: The marginal fit of the three-unit resin prosthesis fabricated by the SLA 3D method was affected by the pontic. Moreover, the marginal fit was affected by the build orientation. The 45° build orientation is recommended.

Optimization of Digital Light Processing Three-Dimensional Printing of the Removable Partial Denture Frameworks; The Role of Build Angle and Support Structure Diameter.

The optimal three-dimensional (3D) printing parameters of removable partial denture (RPD) frameworks should be studied to achieve the best accuracy, printing time, and least materials consumed. This study aimed to find the best build angle and support structures' diameter of the 3D printed (RPD) framework. Sixty (RPD) frameworks (10 in each group) were manufactured by digital light processing (DLP) 3D printing technology at three build angles (110-D, 135-D, and 150-D) and two support structures diameters (thick, L, and thin, S). Six groups were named according to their printing setting as (110-DS, 135-DS, 150-DS, 110-DL, 135-DL, and 150-DL). Frameworks were 3D scanned and compared to the original cast surface using 3D metrology software (Geomagic Control X; 3D Systems, Rock Hill, SC). Both printing time and material consumption were also recorded. Data were tested for the significant difference by one-way analysis of variance (ANOVA) test at (α = 0.05). The correlations between outcome parameters were also calculated. The 110-DL group showed the least accuracy. Significantly, the printing time of the 150-D groups had the lowest time. Material consumption of group 110-DS presented the lowest significantly statistical value. Printing time had a linear correlation with both accuracy and material consumption. Within the study limitations, the 150-degree build angle and thin diameter support structures showed optimal accuracy and time-saving regardless of material consumption.

Study on Geometry, Dimensional Accuracy and Structure of Parts Produced by Multi Jet Fusion.

Multi Jet Fusion (MJF) is one of the newest additive manufacturing technologies for polymer powders, introduced in recent years. This fully industrial technology is gaining big interest as it allows fast, layer-by-layer, printing process, short production cycle, and very high printing resolution. In this paper, twelve thin-walled, spherical PA12 prints were studied in terms of geometry, dimensional accuracy, and fracture surface characteristics. The various characteristic features for MJF prints were observed here for parts produced according to four various print orientations and having different thicknesses, i.e., 1, 2 or 3 mm. The study showed that MJF technology can print such difficult shapes. However, the set of parameters allowing producing parts with highest geometrical and dimensional accuracy causes at the same time some microstructural issues, like great interlayer porosity or high number of non-processed powder particles embedded in the print structure.

Influence of Build Orientation, Geometry and Artificial Saliva Aging on the Mechanical Properties of 3D Printed Poly(ε-caprolactone).

Additive manufacturing of polymers has evolved from rapid prototyping to the production of functional components/parts with applications in distinct areas, ranging from health to aeronautics. The possibility of producing complex customized geometries with less environmental impact is one of the critical factors that leveraged the exponential growth of this processing technology. Among the several processing parameters that influence the properties of the parts, the geometry (shape factor) is amid less reported. Considering the geometric complexity of the mouth, including the uniqueness of each teething, this study can contribute to a better understanding of the performance of polymeric devices used in the oral environment for preventive, restorative, and regenerative therapies. Thus, this work aims to evaluate 3D printed poly(ε-caprolactone) mechanical properties with different build orientations and geometries. Longitudinal and transversal toolpaths produced specimens with parallelepiped and tubular geometry. Moreover, as it is intended to develop devices for dentistry, the influence of artificial saliva on mechanical properties was determined. The research concluded that the best mechanical properties are obtained for parallelepiped geometry with a longitudinal impression and that aging in artificial saliva negatively influences all the mechanical properties evaluated in this study.

The Effect of Build Orientation on the Dimensional Accuracy of 3D-Printed Mandibular Complete Dentures Manufactured with a Multijet 3D Printer.

PURPOSE: To compare the dimensional accuracy of 3D-printed mandibular complete dentures with different build orientations. MATERIAL AND METHODS: A mandibular complete denture was digitized as a virtual reference file. The reference file was 3D-printed at the 0°, 45°, and 90° build orientations with a MultiJet 3D printer (Projet MJP 3600 Dental, 3D systems, Rock Hill, SC). A total of 27 complete dentures were 3D-printed with 9 samples for each orientation. All printed dentures were digitized and separated into teeth, denture extension and intaglio test surfaces. The dimensional accuracy (in root mean square, RMS) was evaluated by comparing whole denture and 3 test surfaces with the reference file. One-way analysis of variance (ANOVA) and a Post-Hoc all pairs Bonferroni test were used to determine statistical differences (α = 0.05). RESULTS: For the dimensional accuracy on whole denture, the 45° build orientation group showed the smallest RMS (0.170 ± 0.043 mm) than those of the 0° build orientation group (0.185 ± 0.060 mm, p < 0.001) and 90° build orientation group (0.183 ± 0.044 mm, p < 0.001). For the dimensional accuracy on the teeth, denture extension and intaglio test surfaces, the 45° build orientation group also show the smallest RMS values (0.140 ± 0.044 mm at teeth surface, 0.176 ± 0.058 mm at denture extension and 0.207 ± 0.006 mm at intaglio surface). The 0°and 90° build orientation groups had similar accuracy at the teeth (0.149 ± 0.056 mm versus 0.154 ± 0.056 mm, p = 0.164) and denture extension surfaces (0.200 ±0.025 mm vs 0.196 ± 0.013 mm, p = 1.000). However, 0° build orientation group (0.228 ± 0.010 mm) has significantly higher RMS values then those of 90° build orientation group (0.218 ± 0.057 mm) in the intaglio surface (p = 0.032). The teeth surfaces were most accurate in each build orientation groups, while the intaglio surfaces were least accurate. CONCLUSIONS: The build orientation affected the dimensional accuracy of 3D-printed mandibular complete dentures, and the 45° build orientation resulted in the most accurate 3D-printed denture from a MultiJet 3D printer.

Research and Optimization of the Three-Dimensional Printing Unloading Process for the Flexible Support Platform.

At present, a three-dimensional (3D) printing model is unloaded from the working platform manually, which hinders the automation of 3D printing. In this article, a new type of 3D printing auxiliary equipment called flexible support platform is designed to achieve automatic unloading. Unloading problems, especially its principle and influencing factors, are investigated in detail. We also study the build orientation optimization to find the optimum solution for unloading. The improved particle swarm optimization algorithm is applied to avoid falling into local optimum. Furthermore, we combine optimization for unloading with our previous work, which is in terms of support structure reduction. The unloading condition has been transformed into the calculation of added support structure owning to the process improvement, so that the optimized model with minimum support structure can be unloaded successfully. In a word, this article fulfills the need of 3D printing unloading research and achieves efficient automatic unloading.

Mechanical Properties of Additively Manufactured Thermoplastic Polyurethane (TPU) Material Affected by Various Processing Parameters.

Thermoplastic polyurethane (TPU) is a polymer material that has high ductility, good biocompatibility and excellent abrasion resistance. These properties open a pathway to manufacturing functional TPU parts for applications in various fields such as aerospace engineering, medical devices and sports equipment. This study aims to investigate the mechanical properties of additively manufactured TPU material affected by three different processing parameters, including build orientation, mix ratio of the new and reused powders and post-processing. A series of material tests are conducted on TPU dumb-bell specimens. It is found that the mix ratio of the new powder is the most critical factor in improving the mechanical properties of the printed TPU parts. Compared to reused powder, new powder has better particle quality and thermal properties. Besides, build orientation is also a very important factor. TPU parts printed in flat and on-edge orientations show better tensile strength and deformability than those printed in upright orientation. In addition, post-processing is found to significantly enhance the deformability of TPU parts.

Mechanical Properties of SLM-Printed Aluminium Alloys: A Review.

Selective laser melting (SLM) is a powder bed fusion type metal additive manufacturing process which is being applied to manufacture highly customised and value-added parts in biomedical, defence, aerospace, and automotive industries. Aluminium alloy is one of the widely used metals in manufacturing parts in SLM in these sectors due to its light weight, high strength, and corrosion resistance properties. Parts used in such applications can be subjected to severe dynamic loadings and high temperature conditions in service. It is important to understand the mechanical response of such products produced by SLM under different loading and operating conditions. This paper presents a comprehensive review of the latest research carried out in understanding the mechanical properties of aluminium alloys processed by SLM under static, dynamic, different build orientations, and heat treatment conditions with the aim of identifying research gaps and future research directions.

The effect of build orientation on both flexural quasi-static and fatigue behaviours of filament deposited PA6 polymer.

The present paper aims to study the effect of manufacturing build orientation on both flexural quasi-static and fatigue behaviours of semi-crystalline polyamide 6 obtained by Fused Filament Fabrication (FFF), by considering the porosity and surface roughness. The glass transition temperature, melting temperature, and crystallinity degree were measured complementary to understand better the process. Fatigue analysis is here fully described in visco-elastic domain of material. The results highlight that the XZ build orientation is better than the XY one and suggest that porosity plays an important role. The obtained results are also compared with conventional techniques given by the literature review.

Effects of build conditions and angle acuteness on edge reproducibility of casting patterns fabricated using digital light projection.

The aim of the present study was to evaluate the effects of build conditions and angle acuteness on edge reproducibility of the casting patterns fabricated using a digital light process. The prism-shaped patterns with various vertex angles were fabricated in three build orientations. The height from the base to the vertex angle point of the fabricated pattern was measured and the incomplete height was calculated as the discrepancy between the original and measured heights. Two-way ANOVA revealed that the vertex angle and build orientation and their interaction were significant (p<0.05). The incomplete height significantly decreased with an increase of the vertex angle. When the vertex angle was 20° and the build-up direction was parallel to the edge of vertex angle and perpendicular to the triangular base, the incomplete height was the smallest. Therefore, build orientation and angle acuteness influenced the edge reproducibility of the casting patterns fabricated using a digital light process.